[lukasbmw]

I originally was not planning on upgrading the intake system on my car because I feel that in most cases, upgraded intakes are not worth the cost, hassle, and potential problems. I was also really worried about heat since the N54 engine generates so much heat.

Yet after reading up on some threads here I found:

• The BMS intake showed noticeable dyno gains in a number of different tests by both vendors and members.
• BMS did a test showing that while a dual cone intakes do initially suck in warmer air, because they are less restrictive, the turbos don’t have to work as hard and thus the turbos generate less heat making the entire thing a wash.
• When increasing the boost with software, allowing the engine to breathe easier is important.

Additionally, something no one seems to have mentioned in the threads I read was that all the air that comes in (hot, warm, cold, whatever) must pass through the plumbing and turbos. Regardless of whatever the initial intake temperature is at the filters, it is going to significantly heat up as it passes through the turbos. Cold air is going to turn hot. Warm air is going to turn hot. If you boil 80o water and you boil 120o water, you are going to get the same result. This is why an intercooler is so important. (Already got one of those).

I briefly considered the Mr.5/Dinan style mod, but I honestly thought the idea was really stupid. After taking apart the airbox and installing the DCI intake, I retract this statement. I now think that the Mr.5/Dinan CAI style intake is a great idea, but the dyno graphs I’ve seen only show tiny gains over a dual cone intake system. Therefore I think the DCI wins due to ease of install and low cost.

Install wasn’t too difficult. Detaching the hose at the front of the airbox was easy. Not sure why everyone makes such a big deal over this. The hardest part was disconnecting the rear of the airbox from the rear intake tube. I DID NOT remove the firewall cover. I was able to do this with just a ratchet and extension. If you are going to try this install with the firewall in place, then I’d really say that a set of extensions are a must. An elbow joint would make install even easier, but I did not have one on me. I’d also recommend a flashlight so you can see what you are doing. Without my high powered flashlight, I couldn’t have pulled this off.

I’m attaching a picture of the stock airbox (now cleaned) so you can see the 3 tabs where the wires attach to. Disconnecting them would have been eaiser if I had a better idea of how they were mounted:





The biggest surprise of the install was how restrictive the factory intake system is. I’ve installed intakes on E30’s, E36’s, E39’s and E46’s, and all of the stock air boxes are pretty well put together. I think the design of the stock e92 box where air must flow up through the filter and then through an even smaller opening that then splits off between the two pipes is ridiculous. Speaking of ridiculous, the tubing that wraps around the engine sucks. It’s cheap and I think it has a poor design. I’m surprised there are not more issues with the intake tubing cracking given the heat that the N54 puts out.

The second biggest surprise of the install was how dirty the stock intake pipes were. The amount of debris in the “clean” side of the intake box and the intake pipes shocked me. My worry about the aftermarket filters not doing a good job of filtering went out the window. Quite honestly, they can’t be much worse then the stock filter (if at all).

The photo below doesn't do it justice, but there was quite a bit of sand in the "clean side" of the intake:



The BMS DCI comes with two filers, two hose clamps, and two pieces of pipe. I was impressed with the quality of the filters but I thought the quality of the pipes were horrible. The edges were rough. It looks like BMS just cuts up a generic pipe, tries to sand down the edges, and then powder coats the pieces. That would be fine if they had a bit more quality control over the pipes. If I still had access to my sander or grinder, I would have smoothed them out.

I had the stock airbox removed in 10-15 minutes. I then spent about an hour trying to position the cone filters correctly. From the pictures I’ve seen online, there is really no “set way” and everyone seems to have their filters in a slightly different position. The tuners show pictures of the filters ALMOST touching where everyone else have the filters barley resting on each other.









I was a bit annoyed that I couldn’t get quite the clearance I wanted on the filters and thus mine are resting on eachother. I’m 100% sure that the installed the pipes correctly in the filter. I’m 90% right I installed the pipes correctly in the stock intake tubes. I might have been able to shove them in a bit more, but I’m not sure it would have given the difference necessary to keep the intakes from touching.

My biggest concern is that one of the stock intake tubes touches the alternator. Then again, I noticed this tube was touching the alternator when the stock airbox was on, so maybe it’s not a huge issue. I just would prefer at least an inch of clearance. Anyone else have this problem?





Test Drive:

At low speeds, you can definitely hear more intake noise. I’m happy about this as I could barley hear the turbo’s spool before. Now the “whooshing” of intake noise and turbo spool is a bit more pronounced. However, at high speeds, the windnoise cancels out any added intake/spool noise. : (

I can’t say I really noticed a huge power difference, but I definitely think that the reports of the intake reducing turbo lag are accurate. The car starts to pull harder now at lower RPM’s.


Conclusion:

My unprofessional opinion is that BMW really could have designed a better intake system. I think cost and lack of room in the engine space probably forced them to put together such a restrictive system.

I think that the best intake would be an active auto works E39 M5 style intake where the footlights are replaced with air ducts and each air duct feeds an air filter box which then connects to the stock plumbing. Unfortunately, due to limited space, this really is not an option.

I guess you could say that the Mr.5/Dinan/Helix style intake are as close as you can get to this, but as mentioned before, the dyno gains seem minimal over the DCI.

I think the next best intake option would be to relocate the filters to the turbo side of the engine so the filters are closer to the turbo’s and find a way to box them off from the engine and expose them to a rush of external air. However, again, due to space, this would be almost impossible.

I’d also like to replace the stock intake tubes with something better built to handle extreme heat. I know there are a few 4 figure carbon fiber options out there, but for the price, I’d say it is probably not worth it.

So, for $99, I’d say that the BMS intake really is the best “bang for your buck”. You’ll probably get a bit more power (especially if you have a tune), and as long as you have a good aftermarket intercooler, I doubt intake temps will increase.

[135Pats]

Ive seen multiple cars with the inlet tube touching the alternator, and mine has had the same fitment since i installed them almost a year ago. No issues.

[Maxspeed]

Nice write up.
I Definitely agree that the stock airbox is restrictive, and that for the price, you really can't beat the BMS intake.

[idyfohu]

Nice detailed write-up! I have mine sitting in a box waiting to be installed.

[lukasbmw]

Originally Posted by 135Pats

Ive seen multiple cars with the inlet tube touching the alternator, and mine has had the same fitment since i installed them almost a year ago. No issues.

Good to know. Hell, I'm pretty sure the tube was touching with the stock airbox.

I'm just a bit paranoid as I used to work at a BMW dealership back in the day and I remember a customer coming in who's E36 has caught fire because the alternator had been touching a plastic heatshield for an aftermarket intake. The alternator had gotten so hot that the plastic heatshield had started to melt and actually caught fire.

Then again this was during a week where is was 117o in AZ.

Originally Posted by idyfohu

Nice detailed write-up! I have mine sitting in a box waiting to be installed.

It's easy. Use the BMS instructions. The only additional tools I'd recommend are a flashlight and ratchet extensions so you don't have to remove the cowl/firewall cover thing.

The front hose pops off easily if you look at it for a few seconds and take the time to figure out how it detaches.

The 3 clips on the airbox that hold on the wires are a pain, but use the photo I posted above as a reference. It will help you know where/how to apply pressure when pulling them off.

The BMS instructions also say to install the front filter first. I think it might be easier to install the rear filter first.

[zefsinz]

That was a great DIY, very helpful and clear!

Thanks man!

[335twins]

I'm in Arizona as well and i want to change the stock airbox but was worried about the super hot summers here..i guess it doesn't make a huge difference though.. about to pull a trigger for one of those bad boys, but white filters...

[Jeff@TopGearSolutions]

At the end of the day the intercooler will reduce intake air temps before they get to the motor, but it is an ideal solution to give the turbo's cooler air when you can.

[luv135i]

Mine touches the alt but my filters are no where near touching but mine is a 135 though