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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > 335i E90 LCI – Experiences and review of various modifications (long!)



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      11-15-2009, 07:50 PM   #1
Alpina_B3_Lux
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2009 335i  [4.39]
335i E90 LCI – Experiences and review of various modifications (long!)

- Disclaimer -
Reading of this review is made entirely at your own risk and I may in no way be held liable for any depletion of monetary resources that ensues following the reading of this article, nor of any matrimonial disputes arising out of said depletion!


Some of you may have read the review I have written for my ride some time ago (see this link), in which I also promised an additional review about all modifications that have been done to the car. In the meantime, I have driven the 335i since almost 8 months and about 20.000 km, and most of that time with a number of modifications which I would like to describe here along with my experiences of these. I hope that this may help some of you that are on the fence for one or the other mod in your decision making process, and may also answer some of the questions that may arise in the context of these mods.

Please note that this is a very long review - if only sections of it are of interest to one or the other particular reader, please skip ahead!


1. Starting Position

As already mentioned in my previous review, one of the reasons for me to choose the 335i over other options was that it disposes of an engine that is quite easy to tune. I intended since the very beginning to optimise the power output of this engine and to be at least in the same league as an Alpina B3 Biturbo (i.e. 360hp / 500 Nm) in the end. However, as such increased performance and the removal of the speed limiter meant that I would be able to drive at much higher speeds more often (remember, I frequently drive in Germany where there are substantial stretches of Autobahn without speed limit), a number of modifications were done right after I bought the car and which I have already described in my above mentioned review. However, as you probably do not want to read my previous entire review again (it IS quite long), I have decided to reiterate them here, along with a more systematic approach that will be take for each of the modifications: I think that it would be nice to know (i) why I did the modification, (ii) how it was done (if necessary), (iii) which improvement I could experience and (iv) which problems or disadvantages I encountered.


2. Rims and tires

A) Summer wheels

Why?
My car initially came equipped with the OEM 17 inch light weight wheels (model no. 285 that is used since the LCI) which look fine but for me were (i) too small in my opinion and (ii) equipped with runflat tires. The ride was not very smooth, rather bumpy and stiff (even less comfortable than in my previous Alpina B3 E46) and the noise level coming from the wheels was a bit higher than I expected. I therefore decided to replace the stock wheels with ALPINA Classic rims in 19 inches on Michelin Pilot Sport II tires (235mm front, 265mm rear). For that the rear fenders had to be slightly modified which was done at ALPINA in Buchloe directly and in a very professional manner. My intention was to achieve (i) a better travel comfort due to the absence of the runflat tires, (ii) higher stability at greater speed due to the fact that the Michelin tires are specced for up to 300 km/h and (iii) better traction / braking due to the increased width of the tires.

Improvements?
The above mentioned goals were all achieved: In spite of the bigger diameter of the wheels and consequently less rubber that can cushion bumps, the ride got noticeably more comfortable. Stability at very high speeds was no problem either, at 250 km/h I felt much more at ease, for example, than I had with my previous Alpina B3. I also did not experience any loss of stability that has sometimes been mentioned from users switching from runflat tires to non-runflat tires. The traction also is amazing, at least under dry road conditions where it was hard to break traction in the first and second gear without any engine modification. I am also quite satisfied with the looks of the wheels, but that is a subjective matter. Still, here’s a photo of the car with these wheels, as well as a photo of the stock rims so that you can at least compare the two to some extent:




Problems / disadvantages?
Well, the first disadvantage is obviously the price – the Alpina wheels are very expensive (catalog price with tires is 4100 EUR), as are the tires. Some weeks ago I had a flat tire due to a metal pin that became embedded in my left rear tire, and as both tires had to be replaced that alone came with a price tag of 700 EUR. BTW, do NOT expect BMW to be of any assistance (by way of their “BMW Assist” function) in such case, as they are of the opinion that if you’re no more running the stock tires you’re out of their hands.
Secondly, the rims are a bitch to keep clean – the 20 spokes that they feature certainly look nice, but to keep them all looking spotless is quite a task!
Thirdly, due to the increased width the car is somewhat more prone to aquaplaning, so that one has to be a bit careful when it rains real hard.


B) Winter wheels

Why?
Well, the car is my daily driver, and as it does get rather cold where I live in winter and there occasionally falls snow, it was mandatory for me to get winter wheels. Initially I had intended to use the 17 inch stock rims as my winter wheels (which is why they were already equipped with runflat winter tires), but as I was immediately quite disappointed with the runflat tires I decided to consider alternatives. As said above, I found 17 inch wheels looked a bit forlorn in the big wheel wells of the 3 series, so that I resolved to put them out of their misery and get 19 inch wheels instead also for the winter. The problem was that there do not exist any 19 inch winter tires that are officially approved for the 335i, and Alpina only had 18 inch wheels for the 3 series. By chance, however, another member of this forum had exactly what I needed and had to get rid of them: BMW Performance 269 rims with Vredestein Wintrac Xtreme winter tires (non-runflat) in 19 inch and 235 mm all around, along with spacers for the rear. With this, I wanted to (i) get rid of the runflat tires, (ii) obtain tires that are specced for 270 km/h (the Vredestein are to my knowledge the only ones on the market) and (iii) improve the looks as I would hate to drive a car half of the year that does not exactly look like I want it to (ok I’m a bit maniacal about that, but we’re in a car forum after all, aren’t we?).

Improvements?
I have only had the winter tires on my car since about 5 weeks, so it’s a bit early for a definite summary, but they certainly are more comfortable than the 17 inch runflat tires. Also, I did not notice a substantial difference in stability to the summer tires during high speeds – and they look really cool. Here are two photos so that you can see what I’m so enthusastic about (IMO they are particularly well suited for cars with dark exterior colors):




Problems / disadvantages?
Again, the price of the BMW Performance rims along with the big tires is somewhat prohibitive. I managed to get a good price as I bought them used, but I probably would not have had the cash to buy them new as they are almost as expensive as the Alpina summer wheels.
The second disadvantage is that due to the fact that the rear tires are 30 mm narrower each than the summer tires, you do feel a difference in traction immediately, once you go WOT in first or second gear, even under dry road conditions. It’s therefore more difficult to get the power on the road, and the rear end tends to slip out more easily than with the summer tires. If I had to do it again, I would probably get the same width on my winter tires as for the summer, but with the rear rims that I have now that is not possible.
The last disadvantage is that you cannot mount snow chains with 19 inch wheels, that’s only possible up to 18 inch wheels. But as I do not really intend to use my car for driving to ski resorts, I don’t really mind that.


3. Aerodynamic optimisation – ALPINA aerodynamics package

Why?
The faster you go, the more aerodynamic forces affect your car. Basically, until around 100 km/h that’s not so important as there are other resistances that are more noticeable. But if you approach or surpass 200 km/h, the downpressure applied to your car decreases as does the contact to the road, thus inviting instability if sudden manoeuvers are necessary or the road condition worsens. That’s by the way one of the major tricks of Ferrari’s 599 as it has a completely optimised undercarriage, which results in an almost unbelievable stability even at speeds exceeding 300 km/h. Now, obviously we can’t go that far with the 335i, but ALPINA has at least brought out an aerodynamics package consisting of front and rear spoilers that helps keeping the car “sucked” to the road at higher speeds. It has been developed in their wind tunnel and optimised for the B3 Biturbo which is more or less identical to the 335i and has an official top speed of 285 km/h. As it would be possible for me to drive at such speeds in Germany, I wanted to keep that experience as safe as possible (certainly a tad schizophrenic, but you get the idea).

How?
I had everything painted and installed at ALPINA in Buchloe directly, also because a local BMW dealer gave me an insulting price quote – the install would have been more expensive than the price of the whole package, including installation, at ALPINA (which was around 1200 EUR). It was, as could be expected, done perfectly, everything fits just as if the car had been born like this. The rear spoiler is in fact glued onto the boot (which is why you have to wait one day for the glue to dry properly before driving again), while the front spoiler is attached with screws.
Both spoilers can (and should) be registered with the TÜV if your car is registered in Germany, which is no problem at all as ALPINA provides you with the necessary certificate for that procedure. By the way, that certificate says that the front spoiler is only approved for up to 290 km/h…I believe that may not be enough!
If you consider acquiring this package, go to your local ALPINA dealer or contact ALPINA directly, they are always very helpful (go to this link and contact the guys listed under “Export”).

Improvements?
I do not have any way of comparing various aerodynamics kits, obviously, but I do trust in the R&D skills of the ALPINA engineers and also read a test in a German car magazine that put the B3 Biturbo in a wind tunnel and noticed an increase in downpressure and less aerodynamic resistance than with the stock 335i. In addition, driving at very high speeds does not feel uncomfortable and I do believe it’s a combination of the tires and the spoilers that at least contributes to that.
Another advantage: The looks. OK, that’s subjective again and I know some people that don’t like spoilers at all, anywhere on their car. But I find the ALPINA ones quite discreet (see photos below) and think they give the car a more sporty look.
ALPINA front spoiler:

ALPINA rear spoiler:


Problems / disadvantages?
None so far. As my car is not lowered for the time being, I do not have any problems with the front spoiler making unwanted contact with a curb.


4. Speedometer extension

Why?
The OEM speedo for the 335i goes up to 280 km/h, and any sane person might argue that this should be enough and if you considered driving beyond that point you may be diagnosed with suicidal tendencies (trust me, I’m very familiar with these comments). However, after an engine tuning and removal of the speed limiter I definitely WILL be able to drive faster than 280 km/h on the speedo (which in any case always exceeds the real speed to some extent). I already heard of forum members that made the experience of reaching the limit of the speedo and watching their revs increase without knowing how fast they actually were driving. I just knew that I would hate to be in a situation like that. You may call me a slightly deranged individual, but I was fairly certain that seeing the needle of the speedo going into no-man’s-land would annoy me.

How?
The company with the best reputation on the market for aftermarket speedometers is (to my knowledge) WSM in Darmstadt / Germany. They fabricate aftermarket speedos for quite a number of other tuning firms like Schnitzer or Gemballa. You can in fact choose out of a number of options, such as a scale of up to 320/330/340/360 or even more, white or red needles and particular emblems or designs on your speedo scale. They also have a model for mph speedos (up to 220 mph) as they also sell these to the UK for example.
Price is 599 EUR for a simple version up to 320/330/340, 818 EUR if you want red needles (which I chose). Installation time was around 3 hours, which also includes the reprogramming of the speedo and of the cruise control unit.

Improvements?
I found it perfect – the looks were just like OEM, with the improvement of the larger scale and the red needles, which give it a more sporty look in my opinion (I find the white needles rather boring I must admit). I chose the scale of up to 330 km/h as I assumed that would be enough. Until now I have tested it up to around 305 km/h, and it works fine without any hitch. Here’s a photo:


Problems / disadvantages?
Well, the price of more than 800 EUR is not negligible for a simple speedo, but I find the professional make and OEM looks of it well worth the price. The scale is a bit unsual at first, as the steps are 30 km/h instead of 20 km/h, but I got used to that rather quickly.


5. Flash tuning

Why?
I believe I do not really need to explain why I wanted to have more power under the hood – and the removal of the speed limiter was a must-have as I have always hated it when others wanted to tell me what I could or could not do. As stated above, a simple tweaking with some parameters of a forced induction engine can yield a substantial increase in horsepower and torque, and that even more so on a biturbo engine. I also wanted a car that was substantially faster than my last ALPINA B3 E46, and in stock form the 335i was not much faster (although with a better power delivery due to the higher torque).

The next question is then: why flash tuning and not a piggyback? Well, first of all it should be said that piggybacks are not very common in Europe, contrary to the US, and did not have any particular experience or knowledge of the Juicebox or Vishnu’s PROcede. That said, I also believed that the DME of the current BMW cars is so far advanced and takes so many parameters into account that I believed it to be safer to have directly reprogrammed some of the parameters only, in order to ensure that any in-built safety catches remain intact and do not receive simulated parameters from an external chip. I also did not really see (for me personally) the necessity for user programming and map-switching that is offered by the two above mentioned solutions, I just wanted a once-in-then-forget solution. Now, I do not want to start a discussion on flashes-against-piggybacks here, and I’m also certain that both the JB and the PROcede are excellent products; they just do not fit my needs, and I’d like to leave it at that.

Now, which flash to choose? I heard very good user feedbacks on the tune from Noelle Motors as well as Evotech, which are in fact one and the same, due to a group buy done on this in 2008. The flash exists in two stages, 360 and 400 hp (crank) / 520 and 550 Nm torque (crank), the stage 2 flash coming with modified downpipes. However, they are rather expensive – catalogue price for both is around 2600 EUR.

Therefore I did some research on less expensive flashes (in particular in this forum here!) and came across the norwegian company ESSTuning that offered a similar flash in three stages (355/380/400 hp) for only 750 USD. ESS are very well known in Europe for their supercharger kits (they just finished developing one for the current M3, by the way) and have a good reputation in general, being also endorsed by one of the vendors here on the forum (ar design). The main disadvantage of that option was that I had to send my DME all the way to Norway, which meant some downtime for my car during this period. However, in the end I decided to go with ESS as they reacted very promptly and courteously on various e-mails that I sent them with lots of questions on their tune. In view of the fact that I already had an intercooler installed at the time (more on that later on), I chose their stage 3 flash that was specifically designed for cars with improved intercoolers and was supposed to yield 400hp (crank).

How?
As I’m a mechanical noob myself, I had the DME removed at a garage near where I lived (they didn’t mind that I left my car with them for some days) and sent it to Norway. I got it back from ESS 12 days later, which was longer than I had expected but was caused by the slowness of the postal service, in particular as Norway is not part of the EU. The turnaround at ESS was very quick, and they updated me at once with the status of the shipment.

Problems / disadvantages?
First test drive - big disappointment: When pressing down the throttle a little to see how the car now accelerates, it went into a limp mode right away with oscillating revs between 1000 and 2000 rpm and no response at all to throttle commands, and a whole lot of warnings on the dash. Stopping the car, switching it off and then on again made the warnings disappear and the car roll normally again, but every time I went WOT or even 3/4 WOT the car went into the same limp mode. Which was quite dangerous at times, as it happened on highway ramps or on motorways without any distress lane! Several e-mail exhanges and phone calls with ESS later as well as research done in this forum revealed that the problem apparently stems from a certain version of the BMW software sold in Europe and Canada and which ESS was unable to properly modify (which was unknown to them at the time they received my DME). You can imagine I was quite annoyed, to put it lightly, to not have been able to drive my car for 10 days and then get back an inoperable DME! As it was not clear whether ESS would be able to rectify these problems and I was not really interested in sending them my DME again, I told them I wanted a refund and went to BMW to flash my car back to stock. ESS paid both the refund and the cost for the reflash to stock without any arguing.

Improvements?
I do not want to conceal that the above mentioned problem only appeared in gear 1-4, and not in 5 or 6. I was therefore able to at least get an impression of the added power at high speeds, which was quite awe-inspiring as the car felt completely transformed and accelerated impressively from 180 km/h onwards, as if there was no tomorrow. This way I however also discovered that the speed limiter had not been removed, as no acceleration beyond 270 km/h on the speedo was possible, although there clearly was enough power to go faster.


6. Flash tuning - second try

Why?
Well, I must admit that at the time I was really fed up with sending in my DME and having no guarantee that the next tuner would be able to overcome the problem I experienced. I therefore decided to go the safe, but more expensive route with the Evotech flash - the installation would be in Germany not far from where I lived, so that I could drive the car there and have any glitches worked out right away, instead of having my DME go sightseeing around the globe. I chose their stage 3 flash that was also said to yield 400hp (crank) and was adapted for aftermarket downpipes (which I already had installed at the time).

How?
A Saturday morning not much later I therefore drove to Ludwigsburg, which is a medium-sized town in the southern part of Germany in order to have my car flashed at Evotech on site. I had participated in an ongoing group buy for that flash in a German car forum, so that I was able to get it at a somewhat more reasonable price of 1600 EUR. The flashing procedure itself took around 2 hours, and the contact to the chief programmer Kai Neumann was really nice, one could talk shop and he answered my questions patiently and - as far as I can judge that as a layman - quite competently. They also have a very modern MaHa dyno on which they do their research and which is to my knowledge the most accurate dyno on the market. They made a dyno run before the flash (which showed almost exactly the 306 hp (crank) that BMW claims for the 335i, and another one right after the flash. The latter yielded 389 hp and 560 Nm torque; another run done on the same dyno several weeks later (when the DME had adapted and my exhaust system was broken in) revealed an increase to 399 hp, which is a delta of almost 100 hp (crank - with ar design catted dps and Bastuck exhaust plus intercooler, see below). Here's the diagram for the second dyno run:

Improvements?
Right after that dyno run I did a test drive together with Kai Neumann that already revealed a considerable increase in power. On the drive back (around 400 km) I dared to push the car more and more, which was at the beginning an almost scary experience as I had the impression to drive a completely different car! Acceleration without almost any lag and indifferently of the gear chosen, the car just kept on pulling like there was no tomorrow. I noticed that in the first two gears I had severe problems to get the power on the ground, and the DSC kept on flashing like a christmas tree, even on a straight and dry road, if I accelerated using high rpms. I was also amazed at the pull under high speeds - if I floored it at, say, 210 km/h in 6th gear you could observe the speedo needle rise without any hesitation and A LOT more quickly than before the flash. It's almost as if there was no aerodynamic resistance any more. Under the following link I have tried to record some acceleration runs from 100 to 200 km/h (speedo, no GPS speeds) in order to give a more realistic impression on the power that the tune can actually put on the road:


The car is MUCH more fun to drive now, you have so much more power at your disposal at the least push of the throttle. Even now, almost 8 months after the flash, I still observe myself grinning like a maniac any time I go WOT in second or third gear, or overtaking other cars on the Autobahn using the incredible torque that the car puts out now. The speed limiter has also been removed, and I've been able to accelerate until slightly above 300 km/h on an unlimited portion of a German Autobahn before running out of straight road. There was still a bit of a margin left, so I would assume I could attain around 310 km/h on the speedo (around 295 km/h real speed). But that's more of a theoretical figure, on public roads you can almost never make use of the top speed anyway - and the acceleration is much more fun!

Problems / disadvantages?
Well, the first disadvantage is that you've got now so much power that you find yourself using it a lot, because it's so much fun. Why do I say disadvantage? Because it leads to an increased wear of the rubber on the tires, fuel consumption goes up as well, naturally, and as all other cars are now rather obstacles than traffic participants you have to use your brakes more often. Fuel consumption depends a lot on your driving style - I achieved a minimum of 8,4 l on 100 km/h (around 28 mpg), a maximum of 15 l (around 16 mpg) and an average of 12,5 (around 19 mpg) by driving not aggressively but still quite dynamically.

There's also a slight turbo lag if you accelerate from only minimally open throttle to WOT in low revs, which is obviously due to the increase in boost which has almost doubled. If you're however already rolling over 2000 rpm or throttle is already wide open, I can't notice any turbo lag at all and the car surges forward without any hesitation.

Power delivery is less linear than under stock conditions, you feel the maximum torque at around 2800 rpm quite clearly, even though acceleration is already excellent from revs below this. I also noticed a slightly "wavy" power delivery which can be observed on the dyno sheet and can also be felt at hard runs - there are two power spikes in the rev band that make the power delivery slightly irregular, not as smooth as with the stock car. That is one of the reasons why I'll be trying out the GIAC flash as soon as its stage 2 comes out, as I believe it may be smoother than my current Evotech flash.

Another problem is traction - as long as the road is dry and straight or you're driving at speeds in excess of 100 km/h it's more or less alright, but as soon as you want to accelerate out of turns or on a wet road, the DSC starts its light show and the electronic differential (what a misnomer!) cuts off your power on a regular basis, which leads to a sort of "hickup" effect when you drive the car hard. A real torsen differential is needed here - which I'll have installed next spring, most probably. What good is power if you can't use it properly?


7. Intercooler

Why?
Even before I bought the car, I already had the intention to provide it with a more performing intercooler. The function of any intercooler is to reduce the intake temperatures of the air the turbos are sucking in; cooler air means denser air equals more oxygen for the engine to mix with fuel, thus enabling it to achieve the same power with less effort (i.e. boost). The problem with the stock intercooler is that it's basically undersized, in particular if you're running a tune that spins the turbos higher and automatically produces more heat. As a consequence, you get "heatsoak" rather quickly, i.e. the engine's motor management cuts down power due to the thermal stress after some spirited runs, in particular in the upper rpms. That can be avoided or at least improved by fixing a bigger and more efficient intercooler as a replacement of the stock unit.
At the time I did my research, there was substantially less choice than today and I basically had to choose between the Helix, RPi and the Code3 Performance intercoolers. One of the moderators here (Eugen) had the Code3 on his car, and as I also read a number of additional positive feedbacks and numbers (see under this link) I decided to go with this model by way of a group buy organized on this forum. Here's a photo of the Code3 Performance intercooler:


How?
HP Autowerks shipped the intercooler to me without any incident, and it looked (to my layman's eye) very well made and solid, and after seeing the stock intercooler also a good size bigger than the latter. As stated before I'm not really technically inclined, so I entrusted the install of the intercooler to my garage, Daum Motorsport. From what I was told the install was rather straightforward, but the plastic shroud around the intercooler had to be cut back somewhat in order to accommodate the Code3's increased bulk. That was not visible however, except if one starts to crawl under the car and looking for it very closely. Install time was around 3 hours, all in all.

Improvements?
Unfortunately I can't provide any before/after comparisons on a dyno, also because the car was flashed after the install of the intercooler. However, on the dyno runs I did after flashing the car, the intake air temperatures (IAT) were not high and even quite low compared to another car with stock intercooler that was dynoed at the same time. I would therefore assume that the intercooler is doing its job. Here's a photo after the install (even if I will the first to admit it's not that illustrative - I'll try to get a better one once I'll have the car on the ramp again):


Problems / disadvantages?
The Code3 Performance is one of the more expensive intercoolers, retailing for around 1300 USD. It's well made though and performs equally well (as far as I can say), so I would say it's worth its price.
Another disadvantage is that you have to trim the plastic shroud. But although a number of vendors claim that their product does not require trimming, the majority of people said differently, from what I've read. And as it's not visible from the outside, I don't mind that in any case.


8. Diverter Valves

Why?
The OEM valves that the N54 engine comes with are not really made to sustain the increased boost a tuned car is running for a long time, as they're simple rubber diaphragm valves that can rip under increased boost pressure. Therefore the company Forge Motorsport has designed significantly improved diverter valves that increase reliability over the OEM valves, due to the fact that they're entirely made of aluminium and have been made so as to be fully tunable for both boost holding capacity and response, by way of interchangeable springs and shims. Furthermore, hoses are included in the kit that are a custom made multi-layer fabric reinforced flexible silicone hose, designed to allow compatibility with the stock airbox and charge piping setup without any permanent modification being required. As for me personally the reliability of the tuned engine was very important, I decided to have these installed even before modifying the engine.

How?
I bought these from North American Motorsport as they had the valves available in black color, which as the advantage of being more stealth than the "normal" aluminum color. Again they were installed at my garage without any problem. Here is one picture of how they look like when installed (the photo is from the NA Motorsports web site, not from my own car):


Improvements?
Unlike others I can't really pretend to feel any significant difference to how the car responds after the install was done. But I would assume they're doing their job!

Problems / disadvantages?
None so far; I also think that the price of around 270 USD is not too much, as they're visibly very well made. However, if you want to install a modified charge pipe (such as the one from STETT), the OEM replacement valves do not fit any more and an adapter is needed (usually provided along with the charge pipe).
Since I bought the DVs, Forge has apparently redesigned them slightly for better fitment, but from what I've heard there's no difference as to their functionality.


9. Downpipes

Why?
Initially I had only planned to get a flash for the engine and not to do any additional modifications to it that result in an increased power output. Noelle/Evotech officially offered their stage 3 setup for a prohibitive price tag of almost 8000 EUR, which included fitting the OEM downpipes with metal race cats from HJS (which are rather expensive) and an upgraded oil cooler. After doing some research, however, it appeared that the increase in power almost exclusively resulted from the modification of the downpipes, as the stock catalysts are made out of ceramic and are rather restrictive, meaning making it harder for air to pass through them and therefore increasing backpressure and thus the workload for the turbos. Furthermore, it seemed that the main function of these primary catalysts (there are further secondary ones just before the mufflers at the end of the exhaust system) consisted in filtering the exhausts during a cold start, and that once the engine warmed up the filtering of the secondary catalysts was largely sufficient to pass emission testing.
I also learned that there were some tuning companies in the US offering downpipes with high flow metal cats comparable to the HJS ones that Noelle/Evotech are offering, but at a considerably more reasonable price. Another alternative of which I subsequently learned was to remove the primary cats altogether, either by simply cleaning out the ceramic cats from the OEM downpipes or by fixing catless aftermarket downpipes, some of which have a larger diameter than the stock downpipes and therefore further reducing backpressure. The problem with this however would have been that it was unlikely I could pass emission testing with such a setup; furthermore I know of at least one person whose secondary cats burned out due to the higher exhaust temperatures going through the catless downpipes. That could have been avoided by replacing the secondary cats with high flow metal cats as well, but which was too costly for me at that time. I therefore decided to get catted downpipes and combine them with the Evotech stage 3 flash, which was sold at the same price as the stage 2 flash.
So, which catted downpipes to choose? At the time there was the choice between RissRacing, UR and ar design. After some research it seemed to me that the downpipes from ar design had the most positive user feedback and no fitment issues, which was quite important due to the extremely restricted space in the engine bay where the downpipes are located. Furthermore, they came with 200 cells race cats from Magnaflow, which as far as I could discern have a good reputation.

How?
I bought the downpipes through a group buy organized in the present forum, and got them at quite a fair price from N54Tuning. Payment and shipping was no problem, and I had them installed at my garage alongside the Bastuck quad exhaust (see below). Here's what they look like before the install (photo is taken from ar design's website):

From what my garage told me they fit without any problem, although it's not so easy to install them as there is very little wriggle room. During the several hundred kilometers I had to drive to get my car flashed, no CEL came on and it might be that the Magnaflow cats are enough not to trigger the CEL - but I believe the trip I made is too short to allow for a definite answer in this. The Evotech flash deactivated the O2 sensors, so that I won't have to worry about CEL even should I switch to a catless setup in the future.

Improvements?
Again, I'm no dyno fetishist and did not have the time to document extensively the power output before and after the install. However, I did notice an increased throttle responsiveness of the engine, and the final dyno run that I did with the downpipes led exactly to the figure advertised by Evotech with their high quality cats. I would therefore figure that the power has indeed increased as claimed by ar design. Furthermore, you can hear the turbos spool up more distinctly, at least if you're driving with the window rolled down. Nice sound!
It also should not be forgotten that by reducing backpressure the downpipes should contribute to the reliability of the engine and the turbos - at least theoretically, meaning if you don't counteract that by driving like a madman due to the increased power…which IS very tempting!

Problems / disadvantages?
The downpipes from ar design are not the cheapest on the market, but then they don't want to be, and quality is not cheap to have - in my opinion they're well worth the money.
They're not easy to install (due to them being bigger than the OEM downpipes), but the fitment is spot on, so that's no major issue.
It could be that you don't pass emission testing any more (I haven't had the time to evaluate that), but in any case you change your car's emissions which might be reprehensible in some jurisdictions.
One thing I noticed is that, in particular in summer and when driving the car hard, but also under more or less normal conditions there is a considerable heat developing in the driver's footwell area (and no, that's not due to the attribute of any female copilot…!), and if you touch the plastic just besides the driver's right shin it's actually rather hot. When asking HP Autowerks about that they told me that this could be a result of the metal cats heating up as they're intended to do, the missing isolation (apparently the OEM cats have two walls instead of just one like the ar design ones) and higher exhaust temperatures due to the tuning. This effect may be lessened by using catless downpipes with ceramic coating that functions like a heat shield. I'll try that shortly and will let you know whether it works.


10. Bastuck exhaust

Why?
If there’s something I was a bit disappointed in, it was the sound of the 335i in its stock form. Even though I’m no fan of ricey sounding exhaust systems for people with an attention deficite syndrome (“if the whole block doesn't know I've started my car I don't exist”) where you need a hearing aid after 200 km, the 335i just sounded too tame, especially compared to my previous Alpina. If you have a car with more than 300 hp I think the sound can be a bit more on the sportive side, and so I started looking for some alternatives. The first I took into consideration was the BMW Performance exhaust, but I finally preferred a quad system for optical reasons (not everyone's taste, I know, but well it's my car). In Germany there are mainly two companies who do a quad exhaust system, Eisenmann and Bastuck. There are, of course, a number of other tuners that you can buy them from, but most of them are just rebranded versions of these two.
Why I didn't go with a full exhaust system like the Autobahn Exotics or CP-E? No chance to have that TÜV approved either, so unfortunately that was out of the question.
So, after a comparison between the Eisenmann in its "sport" version (the "race" version is just too loud, and cannot be TÜV approved either, so the first cop who doesn't like your mug can give you trouble) and the Bastuck, my vote went to the latter as it was less expensive than the Eisenmann but sounded just as good. Even better, I would be tempted to say as I noticed a slight drone with the Eisenmann at around 3000 rpm which is basically cruising speed on the Autobahn.

How?
Unfortunately Bastuck have no diffusors available for their quad system for the sedan (only for the E92/93), but again I had my first-rate garage Daum Motorsport at hand who cut out the stock diffusor very precisely. To me it looks really good - ok, a diffusor would have been nicer still, but you can't have everything. Looking at the photos below you may notice that the tips of the exhaust stick out a bit (that is because Bastuck uses the same system for both the E90 and E92), but I like it that way. The install was otherwise very straightforward and without any problems; the exhaust is also delivered with a certificate for having it TÜV approved and entered into your official papers, which is very easy to do. Here are some photos from the result:





Improvements?
So, how's the sound? First of all, it took several hundred kilometers to achieve the final sound - when I got my car back right after the install it still sounded rather tame, and I have to admit to a slight disappointment. But after around 1000-1500 km it sounded just like I wanted it to have – sharper, more throaty and beyond 4000 rpm outright angry without any droning; I'm very satisfied with it, and even on long distances it never gets annoying. During this summer I caught myself regularly switching off my car stereo, rolling down the window and just driving while listening to the exhaust sound. Yeah, it's that intoxicating!
But you probably want to hear it for yourself. Well, actually microphones never do these things real justice, but I tried to shoot at least a short vid of a cold start in the morning, a procedure that always puts a smile on my face (even if I take my car to go to work):


Problems / disadvantages?
The quad system stands out more than any stock-like dual system, obviously. So if you're the type who's into the stealth look, quads are not for you. That said, it's not too conspicuous even as a quad system, in my opinion - the first time I saw a photo of the Racing Dynamics tailpipes I knew what the definition of conspicuous would look like.
The sound also attracts more attention than the stock system, of course. But it's a very confident, throaty sound and not in the league of some cheap Golf GTI stove pipe.
If you have a sedan, you have the disadvantage of not having a proper diffusor - if you live the US, you may just take an aftermarkets diffusor (I believe there is one or two on the market), but in Germany that's not possible; however, if you have a competent garage that can cut out the stock diffusor like mine did, it still looks good enough (at least to me).
Price is always a factor, but the Bastuck comes in at around 1000 EUR which is not too expensive for what you get - and it's well crafted.


11. Oil cooler

Why?
Evotech (and also DMS to my knowledge) offer an upgraded oil cooler with their most powerful stage three flashes, and ALPINA (that are using the N54 with forged Mahle pistons and a flash, basically) also offer that as an option. To my mind this makes a lot of sense, as any biturbo engine runs already quite hot in stock form (due to their high rpms turbos do create a lot of heat) and that is valid even more so if the boost is increased, the turbos spin even faster and more fuel is ignited to create additional power. A permanent thermal strain shortens the life span of the engine and its components and can furthermore lead to a "limp mode", where the engine management decided it has worked enough and any more would damage it, and therefore reduces power significantly. Most of the 335i (in fact, all in Europe have one but not all in the US) come equipped with an oil cooler that is located in the passenger wheel well. It has however a rather small core that soon reaches its limits: After the flashing of my car I could practically watch the oil temperature gauge rising when I drove consistently faster than 200 km/h, and that in spite of the fact that a lot of cooling was effected due to the airflow at such high speeds. If going 250 km/h or faster, oil temperatures easily rose until 130 degrees Celsius, and on the track it even went beyond that.
A research in this forum resulted in two options that were available: One could either replace the stock oil cooler by a bigger and therefore more efficient one; this solution was offered by VK Motorwerks. The alternative consisted in mounting an additional oil cooler that was (after a redesign took place) located in front of the radiator; that solution was done by ar design - more info under this link. Although I knew some very satisfied customers with the VK Motowerks solution, I opted for the alternative as I believed that the bigger cooling surface promised even better cooling, and I would not have to remove my stock oil cooler - and the price was almost identical.

How?
No sooner said than done - I ordered the ar design oil cooler with another group buy and had it installed very quickly as I had a trip to the famous Nürburgring in Germany scheduled where I wanted to test it. The install was a bit tricky, as you really have to squeeze the oil cooler in front of the radiator and there is very little space to fit it into. But it did fit, and as far as I can see all components were of a very high quality. Here's a photo where you can get an idea of where it is placed:


Improvements?
So, first of all I did some normal driving on limited motorways and could already discern that under normal driving conditions the oil temperature stays consistently slightly below 110 degrees Celsius (230 F). Some trips on unlimited German Autobahn with speeds in excess of 230 km/h did not yield oil temperatures in excess of 120 C (248 F).
But - the real test came on my above mentioned trip to the 'Ring - it was mid-August, really hot (around 30 degrees celsius), the tarmac was quite a lot hotter than that and I did 10 laps (20 km each) on the 'Ring, pushing the car real hard. Even after two consecutive laps, the temperature hardly rose above 120 C (248 F), whereas other participants did have some problems with the heat. So yes, there definitely is a considerable improvement over having only the stock oil cooler, and I can only highly recommend this if reliability and consistent power is important for you.
Here are two photos of me in action - it was a great meet with some friends from the UK forum here:






Problems / disadvantages?
The oil cooler is, of course, quite visible - so if you go to the dealer, you can't hide it and its removal is quite complicated. However, as it's only an added value for your engine's life expectation, I would be surprised if any dealer would make an issue of that.
The install is not that easy, I wouldn't recommend this as a DIY - but then I'm not gifted with anything mechanical, so don't overvalue what I say.
Now, would I say an additional water cooling is needed if you're running a tune on your car? BMW puts an additional radiator and a bigger fan into its performance package which only slightly increases the engine's output. Personally, I don't think it's imperative as after the upgrade the oil cooling system is quite efficient. Then again, an additional cooling can't do any harm either - so if it's possible to source the additional radiator from the BMW performance package separately (apparently that will be an option shortly, at least inofficially), I would probably do it. VK Motorwerks announced some months ago they would be developing a bigger radiator out of aluminium (see this thread), but it seems they have abandoned this project since.


12. Brake upgrade

Why?
If you increase the power of your engine, I believe it's always sensible to give some thought to a possible increase in stopping power as well. Now, the stock braking system the 335i is equipped with is not bad at all - the brake discs are big (348 mm), and the pads are good for spirited street driving. However, some of my German colleagues from another forum complained about insufficient braking power from very high speeds (>250 km/h) with the stock system, something I personally have not yet experienced. I did experience some fading after two laps on the track, though, as well as on at least one occasion a lag in braking response under wet conditions and a veering of the car to one direction that was probably caused by uneven braking power due to the water film on the brake discs.
I therefore decided to upgrade the brakes within short - and there are two basic options to do this: Either you go for a so-called "big brake kit" (BBK), meaning a complete new brake set from Brembo, AP Racing or StopTech for example with bigger discs, more heat-resistant pads, multi-piston calipers and steel flex lines; or you can just upgrade the stock system with other discs, more efficient pads and steel flex lines. The first solution will of course yield optimal results in stopping power but is also rather expensive, while the second one can come quite close to the same result as long as you don't track your car very regularly. As my funds were somewhat depleted (see other mods above…) and after having talked about this with my very knowledgeable friend E92fan, I decided on the second option for the time being.

How?
I therefore obtained (i) steel flex lines for improved pedal feel (from Goodridge for around 140 EUR), (ii) brake pads from Cool Carbon that I had read excellent feedback from in the forum here (thanks to Mr. 5), (iii) high boiling brake fluid (ATE Blue Racing) and (iv) slotted and dimpled discs from EBC that are called "Turbo Groove" and go for around 500 EUR (front and back). In order to slightly improve the looks, I also had my calipers painted in black. The install of the discs and pads was of course quite easy, but apparently the fixing of the steel flex lines needed a little improvisation pursuant to my garage (that may be particular to sedans, as other users with E92 have not had the same problem).
Here's a photo of the end result - sorry the weather was not great, therefore it's a bit dark:


Improvements?
Well, first of all there was no improvement but rather a worsening of the braking power - much more pedal travel was necessary, no bite at all. Was something wrong? No, not at all - finally it's the friction between the disc and the pad that determines the braking power of a car, and if both components are new they first have to be bedded in (see here). That procedure means a number of brakes from increasing speeds - I did 10 stops from 120 km/h to around 40, and that four times in a row. After that, the feel improved significantly but was not yet perfect; now after around 1500 additional kilometers it's as it should be - crisp bite (but a little less than with the stock system), very linear and consistent braking power and no fade at all under any conditions.
Update
I have now had the occasion to test it on the track extensively - on the famous "Nordschleife" of the Nürburgring, to be more precise. The pads surprised me positively: No fade at all even after two consecutive laps (40 km) of really hard driving, and very linear braking power which is particularly important on the track as otherwise it is really difficult to gauge when and how you need to brake at a given point. Also, I noticed that the brakes now bite harder after having warmed up, i.e. after having braked hard twice; I would assume that this is due to the brake pads reaching their optimal working temperature only when being warm.

There is, of course, some brake dust coming off the pads - but I would venture to say that it's considerably less than with the OEM brake pads.

Both the steel flex lines and the discs can also be TÜV approved, if some of our European friends read this review. The steel flex lines come with an ABE, meaning no further documentation is necessary; however, the discs were more difficult to approve as since about 2008 the TÜV in Germany has become stricter and does not allow any "comparative expertises" ("Vergleichsgutachten") any more. That means you need to provide them with detailed drawings of the rotors as well as a written statement of the manufacturer that they have quality control procedures in place. This cost me some time (writing back and forth with EBC) and also money, as the procedure with the TÜV cost in the end around 400 EUR. For anyone willing to do this, here are also the drawings of the rotors which I had to make available to the TÜV:

Front brake discs


Rear brake discs



Problems / disadvantages?
Now, the bedding in procedure is somewhat annoying, and I would strongly recommend (i) not to take any passenger during that procedure (except if you have a very big barf bag stashed in your car) and (ii) to do that late in the evening on some lonely roads. I think the cars passing me or driving behind me for some time must have thought me quite nuts - I could almost hear them thinking "who's this crazy guy that accelerates like the devil's on his tail and than brakes as if Penélope Cruz materialised on the road before him???"

13. Optimization of the exhaust system: Catless downpipes, secondary race cats

Why?
As already mentioned previously, I initially intended to only use upgraded downpipes from ar design with high-flow cats (300 cells from Magnaflow). However, as time went by and I started reading more and more positive reviews about the GIAC stage 2 flash, I decided to give this flash a try, as I thought it to be a considerable improvement over my current Evotech flash. Now, the GIAC stage 2 flash is intended to be used with a more or less free-flowing exhaust system, as it runs with much higher maximum boost (up to around 18 psi) than the stage 1 (which is more or less identical in this respect to the Evotech flash, i.e. 14 psi). Such increase in boost of course means the turbos need to do more work to create that boost, and if there was much backpressure they need to work even harder to overcome it. In order therefore to minimize backpressure and danger to damage the turbos, it is advised to remove more or less all catalysts out of the exhaust system. For me that meant replacing the catted downpipes through catless ones, and also removing or replacing the secondary catalysts which are located right before the mufflers.

Of course, I could also have left the stock catalysts in place - but a friend of mine (E92Fan) had done this and as a result toasted his stock catalysts after some time, as they could not withstand the high exhaust temperatures resulting from the catless downpipes (and the tune, of course).

So, why not remove the secondary catalysts altogether? Well, I had heard some reports about smelly exhaust fumes that result from this measure, and I also feared that - in combination with my Bastuck exhaust and catless downpipes - the noise level resulting from this would be too much to bear on a daily basis. As a consequence, I chose to replace the stock secondary catalysts with high flow metal catalysts that minimize back pressure but still filter the exhaust gases to some extent and muffle the exhaust noise somewhat.

How?
As far as the downpipes were concerned, my choice was fairly easy: I had had excellent experiences with the ar design catted downpipes, both from a customer service standpoint and from a fitment and quality perspective. I therefore chose to also order and install their catless downpipes. This time, however, I also went for the option of a ceramic coating; as mentioned above, I had experienced some heat radiating into the driver cabin which may have resulted from the downpipes - and even if not, it is obvious that the turbos create lots of heat in a very limited space that should transfer as little as possible to other engine components.

Here's a picture of the downpipes before the install (sorry, I don't have pictures after the install yet):


For the replacement of the secondary catalysts, the choice was slightly more difficult. I knew the company HJS Motorsport which has an excellent reputation and produce first class catalysts for lots of motorsport vehicles; many car manufacturer and reputed tuning companies use their products. They have two products that could fit our cars:
• Universal, 200 cell metal catalysts (article number 90 95 0040) that cost 370 EUR (+ VAT) - as you'll need two of those, it sets you back around 880 EUR if you live in Germany. They have the advantage that you could have them TÜV approved if you so desire, as they comply with current emissions regulations.
• Motosport race catalysts with 100 cells and platinum covering (article number 90 95 0058 - WRC 1112/10 PE) which cost 560 EUR (+VAT), making it around 1500 EUR for both including VAT. With these, you will not be able to pass emission regulations and therefore they cannot be TÜV approved. However, I would imagine that if you have catted downpipes in addition to those (not catless ones as I have), you should still be able to pass emission testing.
As I knew that I would install catless downpipes anyway, emissions testing was not really a factor for me. The price tag of the 100 cells caused some hesitation, though, but in the end I went with those in order to maximize performance and because I knew that Tony had successfully installed them in his car already.

Here's a schematic drawing of the secondary catalysts with some data in it:


The install went smoothly, as expected with ar design downpipes the fitment was excellent. The stock secondary catalysts needed to be cut out and the new ones had to be welded in place. They are very unobtrusive and look almost identical to the stock ones, so that unless you look very closely and know exactly what you're looking for, you cannot detect the change. I kept the stock cats in case I should need them to pass emissions testing, or should I sell the car (which is unlikely to happen in the foreseeable future).

Improvements?
After having the catless downpipes along with the secondary motorsport race cats installed, I immediately felt that the car pulled harder, revved more readily up beyond 5000 rpms and felt more responsive. There was an additional edge to it that I hadn't felt before. Unfortunately I can't provide you with exact numbers, as I didn't dyno the car again right after the install. From my very subjective butt-dyno I would say it added around 10-15hp to the car, but that's just a guess. The driving pleasure has certainly increased!

Another very significant change was the sound. The car now sounded much more aggressively, in particular during a cold start-up or when revving it beyond 3000 rpms. When I first drove with it to the underground parking lot of my company, I just revved it up (very slightly!), and the alarm of one of the cars went off. Wow! Really awesome. My garage also told me that from the outside it sounded really great, the best sound they had heard so far of a turbo car. I can second this opinion - when I drive in a tunnel with the windows rolled down it is outright addictive. I'm now looking forward to summer to do that more often! However, the noise is NOT intrusive in the cabin - if I roll the windows up, it's slightly louder than before but not annoyingly so, no perceptible drone and long stretches of driving can still be done quite comfortably.

Problems / disadvantages?
None - aside from the price tag obviously, if you take both the downpipes, the secondary cats and the install together. Fortunately, I managed to sell the catted downpipes to a member from a forum in Germany (for his 135i), and he's quite happy with them.


14. Short shift kit + double shear selector rod + modified clutch delay valve

Why?
It had been some time since I had the idea of acquiring a short shift kit. I found that the stock shifting experience, if better than in my previous E46, still was not optimal. I was looking for a shortened throw, slight reduction of notchiness and in-gear slop. What's more, the OEM clutch delay valve annoyed me as it was almost impossible to engage the clutch properly when shifting through the gears quickly.

How?

I therefore did some research on what was available, and first stumbled across the short shift kit from the BMW Performance line. It had the advantage of being OEM material and generally favorable reviews of users who had this kit installed. However, I wondered if there was not something more sophisticated on the market - and it was not long before I learned about the short shift kit from UUC Motorwerks. While reading on their short shift kits and double shear selector rods (DSSR), it became clear to me that they had invested quite a lot of research into their products and had considerably improved the stock shift lever and linkage. Their new short shift kit is called "Evo 3" and boasts 35% reduction in shift travel (100mm from 3rd gear to 4th gear total travel) if stock height is retained (the height of the shifter is adjustable, another plus), and down to over 40% when height is adjusted to the short end of the adjustment range. Also, 100% CNC-machined 303 stainless steel and 6061-T6 aircraft-grade aluminum is used in construction, and not mostly plastic like the OEM parts, while the design still absorbs vibration via the rubber inner section.

Now, what is the DSSR mentioned above? I came across this particular piece when reading on UUC's website. You can find all the details under this link on the UUC Motorwerks homepage, but the main issue is that one significant wear area that has never been addressed is the wear and ovalization of the linkage connection points at the transmission and the shifter's lower pivot. In the original BMW design, the connection at both ends has a large injection-molded plastic bushing, which wears over time and results in additional slop and loss of precision. To permanently fix this, a change in the fundamental design of the pivot is required, changing the assembly to a double shear system that redistributes the torsional forces from the pin/bushing interface to the complete face area on both sides of the selector joint.

Even though I'm by no means a technical expert, the explanation sounded reasonable to me and I thought it to be a good idea to have the DSSR installed at the same time as the short shift kit, in particular as UUC had a package deal going on at the time I ordered both items. Currently, they're available for the 135i, 335i and E9x M3 at a price of 355 USD for the SSK and 129 USD for the DSSR. I find that price to be quite reasonable, as it's still less than I would have paid for the BMW Performance SSK and seemed to be superior in quality to it.

Now, what about the clutch delay valve (CDV)? It is there to minimize stress to the drivetrain by increasing the engagement time of the clutch, i.e. pretty much prevents you from popping the clutch. In fact, it's mainly there to keep warranty costs down for BMW - and if you know how to drive a stick and how to properly engage the clutch, it should be removed as quickly as possible. This results in a more natural clutch feel and enables you to shift through gears more quickly and efficiently, as the engagement of the clutch can be timed correctly.

I ordered the SSK directly from UUC, together with the DSSR and got a good package deal including shipping to Europe. Everything arrived rather quickly and nicely packaged. Here's a photo of it all when I got it:



I do not have any photos of the installation procedure, unfortunately. I had it done again at my favorite installation shop Daum Motorsport who told me that the SSK was easy to install, but that the DSSR necessitated some more work and was more complicated. If you would like to know more about the installation procedure, please see Former_Boosted_IS' excellent review and DIY.

The CDV was also quite easy to install. I went with a modified CDV that looks just like the stock one (you can also just take it out entirely), as I wanted the modification to be as stealth as possible. I got it from (the now defunct) Riss Racing, but you can also order it here on the ar design homepage. Here's what it looks like:




Improvements?
When I got the car back from the garage and took it out for a drive for the first time, the difference was remarkable. The shifts were noticeably shorter and much more precise, you almost had the impression of having another gearbox, and the UUC DSSR improved the lateral slop. Although the lever is not completely locked in place, the improvement is really considerable. The UUC short shifter height suited me perfectly just how it came from the factory, and it centered just right on my car for neutral.

When driving it for the first time with the SSK and DSSR, I have to say that this is one of the best modifications I have made so far, because you feel it every single time you drive your car. It has a bit the same effect on me as the active steering, which is also something that has immensely improved my driving pleasure on a daily basis. - Some weeks later I had a rental car for some days (as other modifications were done to my car), and when I got back into my car again it was really surprising - you really don't realize how bad and long the shifts on a "normal" car are until you get an SSK. I really feel it connects me better to the car and it's much more fun to change gears quickly and precisely. Also, there is no gear noise whatsoever in the cabin from the shifter at all.

The absence of the CDV is also noticeable, even though it's not an as drastic change as some have reported it to be. I can time my clutch engagement more precisely now, and do not have the feeling that the car does not really do what I want it to do - I feel more in control of the clutch.

Problems / disadvantages?
I noticed a slightly more notchy feel when engaging gears every once in a while, but it is very minimal and happens in particular when the car is still cold (which happened a lot during the past winter months). The effort it takes to change gears is very, very slightly increased, but it's something you get used to very quickly and it doesn't bother me at all.

Due to the modified CDV it is of course now easier to damage the clutch. But as I've driven manual transmissions all my life and do not intend to drag race my car anyway, that is not an issue that worries me.

All in all the SSK, DSSR and CDV are modifications that I can recommend without reserve and which I believe will increase anyone's driving pleasure considerably.


15. STETT charge pipe & cold air intake

Why?
Concerning the charge pipe, there have been some reports of stock charge pipes blowing off due to the increased boost pressure of a tuned N54 engine; I wanted to avoid something similar happening if I choose to considerably increase the boost my turbos are running at. For comparison, the stock turbos run at around 8 psi maximum boost, my Evotech flash had a maximum boost of 14 psi and my future GIAC stage 2 flash would have about 18 psi - and this is even without taking into account additional airflow due to upgraded turbos which is also something I intend to tackle in the near future. So, avoiding boost leaks by upgrading the charge pipe seemed a good idea to me! - Secondly, I had heard that a certain charge pipe already features bungs for methanol injection, i.e. openings where a methanol nozzle could be placed without having to drill any additional holes. As I also had the intention of installing a methanol/water injection system (from Snow Performance) in the near future, this was a nice bonus from upgrading the charge pipe.

As far as the cold air intake is concerned, anybody active on this forum has seen the countless threads on intakes. For forced induction cars a good air supply is vital, as a turbo car is in fact just a huge air pump and more air means (in simplified terms) the possibility for more power. Also, the colder the air is the better it is, as colder air means denser air and thus more power at the same boost level and less stress on the turbos. Now, I had already decided not to go with a dual cone intake as I found them much too obtrusive in the engine bay; I also had some doubts that sucking in air from the (usually quite hot) engine bay was structurally speaking a good idea. Now, I know that this is an endless debate and emotions tend to run high in relation thereto, but these were just my subjective preferences. Also, my decision was strengthened when I read Former_Boosted_IS' thread comparing DCI and CAI, the result of which was that a cold air intake provides better cooling than a dual cone intake. Another reason for me in my particular configuration to go with a different intake was also due to the placement of my additional oil cooler: It is situated in front of the radiator and directly below the stock intake pipes behind the grille, partially blocking one of them and potentially radiating heat to the air that is sucked in through them. I did not find that ideal and suspected that this setup could lead to higher intake air temperatures (IAT) or even insufficient air flow for the turbos.

How?
Although there are several charge pipes on the market for the N54, the choice for STETT Performance was comparatively easy as it seemed to be made of high quality materials and had gathered a number of positive reviews from customers. It is made from 100% 304 stainless steel plus a custom designed throttle body connector that forms a tight seal, and it is therefore highly unlikely that it will come of or produce any boost leaks, when properly installed. Furthermore, it featured the two meth bungs I mentioned earlier, which will come handy once I get my meth kit installed. The STETT charge pipe can also be used with a number of aftermarket diverter or blow off valves, which was also important to me as I had the Forge diverter valves (see my previous review). One should note, however, that due to the fact that Forge has changed the design of their DVs somewhat, I was in need of an adapter for my DVs which STETT also provided. What's more, the adapter was initially in silver, but I absolutely wanted it in black to blend in with my black DVs - and STETT anodized these without any extra charge. Thanks for this! Here's a photo of the charge pipe prior to installation (in silver, though, mine is black), as well of the clamps connecting it to the throttle body:





As to the cold air intake, there is not that much choice available actually. Dinan has just released their CAI which looks nice but is extremely expensive (plus I'm not sure it's compatible with my charge pipe and diverter valves), and Mr. 5 has designed his own CAI. As I had already taken the decision to acquire the STETT charge pipe, it was fairly self-evident to have a look at their CAI as well. Moreover, at the time I was contemplating this, there was a group buy going on which combined both items, and made the decision even easier. Several positive reviews in this forum and a look at the build quality of the CAI on their website also convinced me that it was a good choice. Here's what it looks like prior to installation:



This time, the installation of the charge pipe was done by Birds in the UK (on the same occasion when my M3 components and the Quaife differential were installed), whereas the installation of the CAI was done by Daum Motorsport. Actually, Birds claimed that the CAI would not fit or that in order to make it fit the whole xenon light assembly on the left side of the car would have to be removed and probably modified. Luckily, that was not correct and although it was a VERY tight fit (mainly due to the big air filter), it did fit indeed. Here are some photos of what the engine bay now looks like with the cold air intake (on top) and the charge pipe (mostly hidden, but you can see the chunky black hoses leading away from the diverter valves):

Installation picture 1 (view from in front of the engine bay):


Installation picture 2 (view standing on the left side of the car):


Improvements?
As far as the charge pipe is concerned, there is not much to say - it looks nice and solid and does its job. I will probably be able to say a bit more once my meth kit is installed and the meth bungs operational as well.

The CAI looks nice too, and it also sounds amazing. You can't really hear the stock intake, but if you push down the throttle now, you can easily hear the CAI sucking in air. It's not an annoying noise, and once you're driving fast it's drowned out by other noises anyway, but between let's say 0 and 80 km/h it is noticeable. I like it very much, it gives the car a nice sporty performance sound. I also have the impression that the car pulls better now, in particular in high rpms. I haven't been able to verify this on the dyno, though - and in any case I think the CAI will be most useful in summer when temperatures are rising, to provide low intake air temperatures. I would somewhat doubt that it really provides an additional 20hp as STETT claims on its website - but an improvement is (at least for me) definitely perceptible.

Problems / disadvantages?
The fitment of both items in the tight engine bay of our cars isn't obvious, as with other aftermarket items. Another disadvantage is also that it is quite obvious that these are not stock items - so you may want to consider taking it out for any maintenance at the dealership (which is a hassle as it's not that easy to take out).

The main issue I had was however with something else: The inside of the CAI was dirty and rusted, and big flakes were coming off. Had my installation shop not noticed this, the flakes would certainly have damaged the engine as they would have been fed directly into the turbos. A recipe for disaster! Even though I don't think it happens often, STETT should improve their quality control in this respect. Also, I wasn't quite happy with the fact that neither installation instructions nor a shipping list were provided when I received the package, but these are only minor criticism.

In summary, both the charge pipe and the CAI are solid quality products and are a definite improvement over the stock items, in particular if you intend to go with a meth kit or have the ar design oil cooler installed.

16. Plans

Yes, it's far from over yet - I'll be back, as some governor in your country used to say when he still had a real job.

UPDATE:

The following modifications have been done, reviews have been published further down in this thread:

• installation of Quaife limited slip differential
• installation of M3 suspension parts: front control arm kit = wishbones+tension rods; rear subframe bushings; rear guide rod kit; rear upper link kit; M3 anti-roll bars; see the website of HP Autowerks); photo before the install:

• ar design oil catch can:


• BMW Performance glossy black grille

• BMW Performance side skirts

Other modifications that are already installed but that I have not yet have time to write a review about are the following:

• GIAC stage 2+ flash

• Sport suspension Bilstein B16 Ride Control (April)

Methanol injection kit (stage 3) from Snow Performance (TBD)

• AR design aluminium high performance radiator

• Dinan camber plates

Other ideas of mine that - cash flow permitting - will be realised at the beginning of 2011:

• Turbo-Upgrade (stage 2) from Turbo Dynamics; for more information about this particular upgrade see this thread in the UK forum

• forged lower compression pistons + titanium conrods

So, I hope you've enjoyed reading what I wrote here - if so, I'd be delighted to learn so. Any mistakes and linguistic inaccuracies are entirely mine and result of an imperfect grasp of the various subtleties of the English language which is not my mother tongue.

Alpina_B3_Lux
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      11-15-2009, 07:56 PM   #2
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Holy Crap man!
Superb article.
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      11-15-2009, 08:00 PM   #3
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Nice extensive review! Thanks
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      11-15-2009, 08:07 PM   #4
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Great write up. Only thing I would change is I am not a fan of those 19" wheels, your winter 18" bmw performance rims look much better.
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      11-15-2009, 08:23 PM   #5
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Nice article !!!
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      11-15-2009, 08:27 PM   #6
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WOW

By far the best read on this forum...well done do you work for a magazine. You should. Only I wish you got the Helix instead of the code 3..lol
Tks
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      11-15-2009, 08:31 PM   #7
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Awesome write up!

Makes me want to spend money.
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      11-15-2009, 08:34 PM   #8
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Good read - and very appropriate disclaimer at the beginning! And no worries - your English is as good as any on this forum, including yours truly
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      11-15-2009, 08:49 PM   #9
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Amazing write up, really enjoyed reading it! Looking forward to seeing more in the future.

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      11-15-2009, 08:52 PM   #10
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Great write up! I read 3/4ths of it...very interesting.
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      11-15-2009, 08:55 PM   #11
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Enjoyed the read and amazing list of mods and appreciate the meticulous write up!

thanks!
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      11-15-2009, 09:04 PM   #12
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Excellent write up!

Definitely an on going project...
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      11-15-2009, 10:23 PM   #13
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thanks for the info - So is it like you want it now or can we look forward to more FYIs?
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      11-16-2009, 02:08 AM   #14
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As a future 335 owner - I really appreciate your write-up! THANKS!
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      11-16-2009, 02:17 AM   #15
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great writeup/review!!
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      11-16-2009, 03:50 AM   #16
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Great writeup!! Looking forward to reviews of your next mods!
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      11-16-2009, 04:50 AM   #17
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Quote:
Originally Posted by Mr. 5 View Post
Holy Crap man!
Superb article.
Thanks for your kind words! Your own mods have been an inspiration on a number of occasions as well...
Quote:
Originally Posted by new2the3 View Post
Great write up. Only thing I would change is I am not a fan of those 19" wheels, your winter 18" bmw performance rims look much better.
I know that the ALPINA rims are not for everyone - but I like them. BTW, the winter rims are 19" not 18".
Quote:
Originally Posted by cn555ic View Post
Nice extensive review! Thanks
You're welcome!
Quote:
Originally Posted by FLA 335 View Post
Nice article !!!
Thank you!
Quote:
Originally Posted by Graystone View Post
By far the best read on this forum...well done do you work for a magazine. You should. Only I wish you got the Helix instead of the code 3..lol
Tks
Thanks a lot for your compliments! And in my next modding life I'll try out the Helix...
Quote:
Originally Posted by shoes View Post
Awesome write up!

Makes me want to spend money.
I see the disclaimer seems to have been a good idea...
Quote:
Originally Posted by alextremo View Post
Good read - and very appropriate disclaimer at the beginning! And no worries - your English is as good as any on this forum, including yours truly
That's very nice of you to say - I tried to do my best!
Quote:
Originally Posted by jopa489 View Post
Amazing write up, really enjoyed reading it! Looking forward to seeing more in the future.

Your wish is my command...and if you want to accelerate things I can always let you know my PayPal account...
Quote:
Originally Posted by MuchMoore View Post
Great write up! I read 3/4ths of it...very interesting.
Thanks - I know it's not obvious to go through it all...
Quote:
Originally Posted by Julius@WSTO View Post
Enjoyed the read and amazing list of mods and appreciate the meticulous write up!

thanks!
You're welcome! I thought that if I do a write-up, it should be a detailed one as I like to read those best myself.
Quote:
Originally Posted by XPO186 View Post
Excellent write up!

Definitely an on going project...
Oh yeah, very much so. And this forum gives me more ideas on an almost too regular basis...
Quote:
Originally Posted by 335e92tx View Post
thanks for the info - So is it like you want it now or can we look forward to more FYIs?
It seems to me you didn't have the courage to read it through until the very end...not that I blame you!
Quote:
Originally Posted by s.myrr View Post
As a future 335 owner - I really appreciate your write-up! THANKS!
You're welcome - that's what these write-ups are for!
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Originally Posted by Craig@SupremePower View Post
great writeup/review!!
Thanks!
Quote:
Originally Posted by Autobahn335i View Post
Great writeup!! Looking forward to reviews of your next mods!
I see the Luxembourg fraction is strong here!

Alpina_B3_Lux
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      11-16-2009, 05:56 AM   #18
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Great writeup and great car.

And now to the next steps Meth injection + GIAC 2+
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      11-16-2009, 10:15 AM   #19
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Quote:
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It seems to me you didn't have the courage to read it through until the very end...not that I blame you!

Point taken - I see your plans section.
It wasn't a courage issue - more time than anything else.
My mistake.
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      11-16-2009, 10:38 AM   #20
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Great write up. Good info for a new owner.
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      11-16-2009, 11:00 AM   #21
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Very, very nice writeup!!!!!!!
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      11-16-2009, 11:51 AM   #22
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great review

Once again B3 Lux, a very thoughtfull review & sharing your experiences in such detail. I like your new rims, i bought the same BMW performance rims last month, which cost a shitload of money, but great looking on a black car.

Sorry to hear about the initial tuning hassles...glad it was sorted. I should have just given you a JB3 as a present while you were in the Cape...

I don't understand the dynograph but like those kilowat figures...nice indeed.

Everything you have done to the car from the rear wing to the speedometre extension is just perfect...!
I recall one of your conversations when you said something like..."the subtlest modification to a car is not what someone else think about it but how it makes YOU feel..." Some profound words there but i get the point...i have been doing some subtle styling as well....

Those track shots of your car are simply amazing

So B3 Lux...if you count all the euros together and of course the Rands down here we have probably spend M3 money on our babies hey...? You lucky you still single; i still have a wife to report & account to... (Inhouse Government)

Upgraded turbos are on my list and might have it before Xmas so i can write a beautiful review like yours as well.

Well done my friend. I will definitely see you in the new year. I will be in Austria during April 2010 (will meet up with you)...then i have to rush back because South Africa is host to (FIFA) football world cup 2010...
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