[mapleridge]

if someone had to pass visual inspections they could gut them, put a straight pipe inside the empty cavity and weld it all together. would be sooooo 007.

[cuco]

UPDATE: I couldn't live with the thought that the exhaust flow in my manifolds wasn't at optimal conditions so I did two jigs out of 2x4s for the manifolds and had the shop weld 2" pipes. Couldn't be happier. With the old setup low end torque was very noticeable but I wasn't satisfied with mid to high end power (Im guessing the turbulent flow was causing it). With this setup mid to high end power are very noticeable. Before I was constantly getting 0 to 60 times of ~6.7 seconds. Now I'm getting consistent ~6.4 seconds from 0 to 60.

[Rival]

much better man.

you transformed those into real headers.

nice work

[essex_lad]

im a bit lost why you didn't just cut the cats out, sell them for $400 and weld a pipe in its place. Also being a highly experienced welder who ever welded them pipes in has done a terrible job, I wont be surprised if they crack or rust till they get pin holes.

[cuco]

Lol

[Eagle1oh7]

Looking forward to seeing the Dyno and I'll probably try this too in time.

[cuco]

Dyno! Very happy!

Mods:
Catless downpipe
Rogue Ikon
Ram Air

Power and torque at crank estimates:
247 bhp
227 ft-lbs

[Tim603]

this is great I would definitely consider doing this. So taking the headers out wasn't too hard?

[cuco]

Originally Posted by Tim603

this is great I would definitely consider doing this. So taking the headers out wasn't too hard?

Not bad at all, first time always sucks but second time you can do under 1 hour.

[Amini77]

Why didn't you cut the cats out and replace them with a pipe instead of gutting them?

[cuco]

Originally Posted by Amini77

Why didn't you cut the cats out and replace them with a pipe instead of gutting them?

I did replace them with pipes, eventually. Look at the pics

[tc535i]

seems like a lot of work for something you can buy for $320 to your door, but maybe that's just because I wish I had nearly that much time to play with my hobbies :/

great job tho!!

[Amini77]

Originally Posted by cuco

I did replace them with pipes, eventually. Look at the pics

Ahh sorry was being lazy and didn't check the next page. I'm doing this soon and came across your thread, very helpful thanks.

[Delusive]

Originally Posted by tc535i

seems like a lot of work for something you can buy for $320 to your door, but maybe that's just because I wish I had nearly that much time to play with my hobbies :/

great job tho!!

Wait, headers for $320? because the cheapest that can be found is around $700 for no name brands and for name brands they go all the way up to $1000-2000.

[tc535i]

Originally Posted by JS-NA.E92

Wait, headers for $320? because the cheapest that can be found is around $700 for no name brands and for name brands they go all the way up to $1000-2000.

Wow, I got linked over and totally thought you were gutting 335 downpipes instead of buying a pair. Lol

[cuco]

Originally Posted by JS-NA.E92

Wait, headers for $320? because the cheapest that can be found is around $700 for no name brands and for name brands they go all the way up to $1000-2000.

I think he meant used OEM manifolds.

[Delusive]

Originally Posted by cuco

I think he meant used OEM manifolds.

He thought you had a 335 and was gutting the catalytic converters after the Primary Cats which are down pipes for 335's, lol.

[2008-335xi-N54-E92]

Originally Posted by cuco

I finally gathered enough courage to gut my primary cats. It was simple; I cut the manifolds to expose the cats, destroyed and removed the cats, and took the manifolds to a shop to get them welded back together. My only mods before doing this were a Rogue Ikon muffler and a homemade ram air with KN filter.

What kept me from doing this before? well, it looks like nobody has done a simple gutting of the primary cats in this forum, and there are lots of haters with enough arguments of why it can't work. Having said that, these were my main concerns upon doing this mod:

1) the hollow cat cavity in the manifolds would create a turbulent flow that would prevent noticeable power gains.

2) gutting the cats would eliminate back pressure and cause a reduction of low end torque.

3) exhaust would sound awful

So, I bolted the gutted manifolds back together earlier today and fired up the engine. The engine sounded deeper but not intrusive or offensive. What I really liked is that there was a noticeable and satisfying burble while in idle. I took the car for a 10 mile drive and these were my first impressions:

1) Improved and noticeable low end torque gains.

2) mid range (3500-5500 rpms) was flat, felt like the engine needed more back pressure.

3) high end power gains were more than noticeable

4) throttle response is instant

5) engine sounds like a vintage bmw straight six with webers (love it!!!!)

6) engine sound inside car is more noticeable but not intrusive.

Overall, the car felt faster, wasn't sure why the mid range felt flatter than the low end power but I found a solution. After I drove the car I went to wash my baby girls, changed their diapers and put them to bed. Immediately after this, I took the car for a second spin. This time I noticed power gains throughout the entire rpm range!!!. I think the reason is because the ECU is adjusting for the no longer existent restriction of the cats.

Conclusion: This is not the most ideal thing to do to the manifolds in terms of flow efficiency but for $50 I have what I feel like a whole new car. I definitely recommend this. All the car needs right now is a tune to adjust the timing/intake/cam and make this mod even better. The check engine light hasn't lit up but the tune will take care of it. Enjoy.

[IMG]http://i197.photobucket.com/albums/a...psc747aeb4.jpg[/IMG]

[IMG]http://i197.photobucket.com/albums/a...ps65aa0bf0.jpg[/IMG]

[IMG]http://i197.photobucket.com/albums/a...psd38c80f7.jpg[/IMG]

Primary Cat down pipe self delete

This is just the primary cat delete I didn't delete my secondary!!!!!


I just replace both my turbo on my 2008 335xi N54 and decided to delete the primary cats myself before re-installing the stock down pipes back on.

Look guys replacing your stock turbos isn't so bad like what other people say. I have an XI and did not have to lower or remove my subframe at all. I didn't even remove my tires or any steering pinions or wheel control. Every thing that was hooked up to my front passenger side tire remain from start to finish.

Now the only thing I did differently from every one is I cut off the rear flat metal in the back of the subframe that is right underneath the two front catylic converter pipe so I can pull them off without removing the subframe. I decide to save time and since I have a welder I simply spot weld it back. I only cut out about 9" worth of flat piece of metal that is there for nothing any ways.

Instead of buying aftermarket down pipes that is useless and unnecessary I decided to gut all the Cats components and keep the stock look but without the signs of cats missing since I live in California.

The entire process took me about 7 mins to gut both primary cats with the following tools and I'm not exaggerating one bit.

1) cordless drill with 1/2" slots minimum to hold my long standard wood drill bit (see photos). My drill bit is 12 inches long because I happen to own this one but a shorter one like 10 inches or a standard 6!inch wood drill spade bit from Home Depot or harbor freight will work as long as you have some kind of adapter to extend it.
2) a hammer.
3) and extra pipe to shove in after drilling.

NOTE: There is NO NEED to cut and weld any of these stock down pipe catylic converter to remove the honey comb at all!!!!! It so simple. Now if you happen to own a short drill bit and have to extend it to another drill bit sleeve and duct tape it together it will also work, and don't worry if the drill bit get stuck and come apart into the muffler because the honey come is like foam and it will break easily to remove the bit.

What will also work if you don't have a drill bit long enough a standard car jack crow bar with a sharp end to remove your tire lug nut will work as well but it might take longer then 7 min to do both.


1st. I drill through the end of the stock cat that I can see the honey comb and done it this way with each stock cats.

2nd. Drill many different holes through breaking the honey comb and turn each pipe over to dump out the broken internal pieces.

3rd. I then use the hammer to bang each outer side of the round part of where I drill knocking the inside loose and breaking the side glue.

4th. And that's it repeat with the other cat and re-install the O2 sensors.

Whole process took me exactly 3 min with one cat and 4 min on the other. How and why??? Well because the first one will take 4 min longer then the 2nd one....why? Because once you get the hang of doing the first one the second one is easier and don't be afraid to bang hard on the outside part of the catt because you won't hurt it or break it. I bang the chit of mine and put a few scratches and dents but it's a stock down pipe it's fugly and hideous as is.


Lastly I don't understand how people can reply to other posting about check engine light coming on or no power gain and so on so on if they haven't done it themselves.

After I install it back and start the car here's the end result.

1) the sound of the muffler is awesome like a tuned car with after market muffler but using my stock down pipe.

2) non of my check engine light for O2 sensor came on (at least not yet going on a week now)

3) I definitely feel more torque and more response from the turbo soon as I floor the pedal it definitely boost faster then before.

4) regrading any more horse power I'd have to say yes I gain more power from it. How many???? I don't know maybe 1 horse power more maybe 15 or 30 but I doesn't matter to me because if I gain 1 HP that's more then what I had before and the 2nd reason why I didn't care if I gain more then 1 or 30 horse power is the sound is GOOOOOOOOD, and the response from the turbo is INSTANT!!!!

5) I remove my stock air filter and order a cheapie $25 cones air filters from eBay and I define hear the turbo hiss from that and I love it.

Any ways this is what my end results are and so I can't speak for others since I did mine and this is what I got maybe some people do get the check engine lights but again all cars are not the same some cars DME might be set differently with other options turned on when mine isn't....it's like one buys a f150 and it last that person 20 years when the next guy buys the same kind of f150 and it breaks down 6 months later. It's the bad batch of cat that person happens to buy!!!

Sooooo any post or comment that says none of what I did can't be good or done or will make your car go into limp mode is FULL of Ccchhhhiiit since they haven't done it they shouldn't discourage people with what they ThOUGHT!!!!


So guys if you want to save money from ridiculous stainless steel down pipe that looks shiny and fancy by crawling under the car to appreciate it then this is the way to go. I mean what better way to guarantee your bolt pattern will fit perfectly or if or O2 sensor are going to fit back in right then to use your stock parts that was engineered by the BMW factory themselves.


As far as how long it took for me to replace my own turbos well that took me 12 hours from start to finish since I have to crawl under neath my car like 200 times for smoke break and cursing break from busting my fingers and hands. In the end it was all worth it.

And I didn't buy new turbos or rebuild my old one I simply bought two used complete turbo off eBay for $275 for both, I checked the blades for play or rattling before installing it. The turbo I bought off eBay were from a car that gotten into a wreck and I don't care if it breaks down in a week or month because now I know how to replace my turbo the way I did before and knowing it wasn't so bad or too hard I'd do it again if I had to next week but thats just me since I'm the owner of the car and need to be the one working on it any ways!!!


I will guarantee every one that my BMW 335xi will be breaking down real soon....again....and I will be fixing more crap on it like every car out there. What I'm saying is buying new parts or used parts is all the same it's when things break if the person know how to fix it makes a difference. If some one told me it's a high risk Im taking for installing used turbos instead of new one my question back would be "What about my engine? Shouldn't I replace the engine with new since you recommend me to buy brand new turbo instead of used?"

[Aode06]

Mdd e85 e50 full bolt on, gutted the front cats and the car loves it! No issues at all, except cel for rear o2 but oh well