New Custom Exhaust Installed - Review

Originally Posted by cssnms

Eliminating the cat will more than likely cause problems for the urea injection system. There is a n02 sensor just after the car. Removing the cat will likey increase the n02 output which would then trigger the def to inject more urea and or possibly throw codes. i thought about this long and hard and it wasn't a risk i was willing to take at least until someone can demonstrate they can reprogram the ecu/def. the dpf can be deleted and the ecu reflashed to accomodate for this. there is a company in europe offering this service for u.s. cars and i believe there is a u.s. company on the west coast now offering this service. not sure if one can delete/remove the dpf without addressing the def system though.

I know on some other cars to get past such issues people put in "dummy" sensors. Basically they feed back to the ECU what the ECU wants to normally see. Probably something we'd never see for our cars since imagine would entail a bit of R&D

Why would u want to do this anyways?

Sent from my MB525 using Bimmer App

If you are asking why for removing the cat then my guess is in hopes of unrestricting the exhaust flow and in turn making more power. I'd think the DPF though is the biggest restriction. Another reason might be in hopes of having a more aggressive sounding exhaust.

ecotune seems to have removed the dpf.. check this vid out.

The only problem I see is that I feel terrible about "knowingly" polluting the air by removing it...At least the DPF makes the exhaust somewhat cleaner...

Other tuners can tune to remove the dpf, like Evolve. But removing the dpf is only one piece of the puzzle, the other is the def system.

Do you think the DEF physically needs to be removed or is just bypassing it via programming more than sufficient? I am just guessing it physically is not an obstruction or much of one to the exhaust flow.

Originally Posted by Snipe656

Do you think the DEF physically needs to be removed or is just bypassing it via programming more than sufficient? I am just guessing it physically is not an obstruction or much of one to the exhaust flow.

I suspect just some coding/tuning to delete/disable it. I don't see the harm in leaving the tanks and injectors in place as I don't think it poses a restriction. But one would want to drain the tanks and clean everything since I suspect the urea reminance will crystalize over time.

that was a sweet video!!!

That sounds wicked! I want that diesel turbo spool sound now! I'm surprised that there isn't that much smoke compared to diesel trucks. Thew new gen diesel engines seem to be smoking a whole lot less than the older ones.

I finally heard the video DAMN that was a SWEEET sound of turbo spool, I want one LOL

Originally Posted by Axel61

I finally heard the video DAMN that was a SWEEET sound of turbo spool, I want one LOL

Take your car to Renntech and get the DPF/Cat bypassed and I bet you will have the sound of the turbo spooling.

@Snipe trust me I would but DAMN it I live in Puerto Rico

Originally Posted by Axel61

@Snipe trust me I would but DAMN it I live in Puerto Rico

Come on now, man up and get that thing shipped to them so we can see what it takes.

Ok Ill man up but the tabs on YOU!!!

Just let me know what the bill is after they are all done. I got some buddies that still work on shipping vessels, maybe we can sneak the car into a cargo hold for some free shipping ....

@snipe to difficult for me , **** you live in the states you MAN up amigo. Touche my friend, or better yet let Flyingman go for both of us he lives in MIAMI, WTF. Flyingman your up next to bat, we got your back amigo!!

I would but I just spent all of my car fund on a new toy for my garage. So unfortunately Flyingman needs to step up to the plate on this one.

yes indeed batter up!! Flyingman you are the man!!!!

car sounds really good!
the way i see it is that if you ditch the emissions systems and get a considerable amount better hp/tq and mpg's. the overall effect is not very bad. at 50mpg's the emissions from a cleanly tuned 335d would be nothing compared to many of the older diesels still on the road. and you don't have to buy a gas guzzling v8 to go fast

Just my thoughts on the matter

They do some very nice work. The welds are very neat and clean. Very nice.

I agree on the tips. I'd actually prefer to keep the stock tips and stay stealth. But, as you say, tips are quick and easy to change at any time as your tastes might change.

PS - Yes cats muffle a lot of sound. I did a custom exhaust on a Corvette many years ago. And it wasn't until I found a guy to fabricate some flanged straight pipes that I could bolt in as (temporary ) replacements for the cats that the sound of the whole system really came to life.

Simmer down guys, I'm just a middle aged commuter minding his own business here in South Florida. Driving at 120mph in his turbo "D", Baby!

Love to hear the turbo spool, reminds me of my grand national.

Originally Posted by ljgmdad

PS - Yes cats muffle a lot of sound. I did a custom exhaust on a Corvette many years ago. And it wasn't until I found a guy to fabricate some flanged straight pipes that I could bolt in as (temporary ) replacements for the cats that the sound of the whole system really came to life.

They do muffle a lot of sound but any car with a cat and no DPF can have a pretty nice sounding exhaust. All the vehicles with the DPF though it really seems that the DPF absorbs a lot of the sound and makes changes downstream not near as significant.

Originally Posted by Talstar

Love to hear the turbo spool, reminds me of my grand national.

Reminds me a good bit of my trucks turbo.

I know in the truck world, a DPF back exhaust is basically considered a waste of money. Not a whole lot of sound gains for your dollar. Gotta get rid of that filter if you want it to scream

So after all this, did the OP actually get any measurable gains or not?