[EastCoast335i]

How do the gains of the BMW Performance Exhaust compare to all the other after market exhausts?


Anyone know where I can pick one up for a good price other then Tischer?

Thanks

[Forcefed3]

You don't really get exhaust for gains they are all really the same around 8-11 hp

[EastCoast335i]

Originally Posted by gbreeE90

You don't really get exhaust for gains they are all really the same around 8-11 hp

I know the gains are minimal, but I assumed that since most aftermarket exhaust are catless they would yield slightly higher gains.
Am I correct in assuming the BMW Perf exhaust is catted?

[Ilma]

Originally Posted by EastCoast335i

I know the gains are minimal, but I assumed that since most aftermarket exhaust are catless they would yield slightly higher gains.
Am I correct in assuming the BMW Perf exhaust is catted?

Yes....it attaches downstream from the cats.

BMW is not going to issue a performance part that would not comply with emission stantdards.

It's getting rid of your cats that nets more significant gains.

[Forcefed3]

Not positive but I'm pretty sure it's carted.

Originally Posted by EastCoast335i

I know the gains are minimal, but I assumed [/B]that since most aftermarket exhaust are catless they would yield slightly higher gains.
Am I correct in assuming the BMW Perf exhaust is catted?

[Bagelfast]

Bmw performance exhaust is connected to the factory cats. Bmw peformance exhaust and cutting the Cats out for straight pipes would be about 100 bucks at a local muffler shop. It would sound louder, but free up some hp aswell.

[Dackz]

Originally Posted by 1LUMI335

Bmw performance exhaust is connected to the factory cats. Bmw peformance exhaust and cutting the Cats out for straight pipes would be about 100 bucks at a local muffler shop. It would sound louder, but free up some hp aswell.

Yup. it will be 2-3 HP max from just the PE. It does to me, seem that it pulls more 'freely' when doing 70+ though just keeping it in 6th.

[BayMoWe335]

Originally Posted by Ilma

Yes....it attaches downstream from the cats.

BMW is not going to issue a performance part that would not comply with emission stantdards.

It's getting rid of your cats that nets more significant gains.

Would straight pipes make you fail emission testing and possible cause engine codes?

[EastCoast335i]

Originally Posted by BayMoWe335

Would straight pipes make you fail emission testing and possible cause engine codes?

No it shouldn't... as long as you still have your primary cats (on DP's) intact.
Our cars have two sets of cats.

[BayMoWe335]

Originally Posted by EastCoast335i

No it shouldn't... as long as you still have your primary cats (on DP's) intact.
Our cars have two sets of cats.

Then what is the purpose of the secondary cats?

[EastCoast335i]

Originally Posted by BayMoWe335

Then what is the purpose of the secondary cats?

No purpose other then to "exceed" emission standards...
At least as far as I know... Maybe in CA where emissions are more stringent you need both cats.