bigheadnyc

anyone decatted their exhaust? does the check engine light come on? Anyone know how to bypass or prevent it from coming on? and also when in manual gear, shifting up , do you let off gas? like on the bmw smg transmissions?

C63newdude

You can get o2 sensor foulers(or is written something similar). Eventually running no cats will cause a CEL unless is tweaked with a tune.

_AMG_

You will get CEL if you remove the primaries, to turn it off you will need to tune the car.
If your removing 2ndary cats then you don't have to worry about CEL.

As far as shifting goes, No you don't need to let off the gas when shifting up.

JM

it shifts even better without letting off throttle

AMG-010

How much louder is it when you remove the secondary cats?

bigheadnyc

thanks guys!!

_AMG_

Depends, If you replace it with straight pipes it will be much louder.
Replacing with an X pipe wont be that much louder then stock but it'll sound smoother.

emericr

LOL, even with X pipe, it is much louder than stock and very close to a car with headers.
I have mine decatted with X pipe. I love it but it's not for everyone.

bigheadnyc

where is the secondary cats? i want to decat it but i don't want the engine light to come on.

bigheadnyc

Where is the secondary cat?

BO Knows

see pics

_AMG_

Behind the primary cats.

_AMG_

Did you remove all 4 cats or just secondaries?

I have had both straight pipe and X pipe setups (both with resonator delete)
Straight pipes are WAY louder, and much closer to LTH's imo.

bigheadnyc

Sweet man! thanks!!!! to recap, remove ONLY secondary cat = no CEL ? and if i remove ONLY secondary cat, would there be a sound difference between the first cats?

BO Knows

I removed my secondary cat, no CEL, and was louder. If you remove the first cat (called Primary Cats) you will have CEL, then you need a tune to remove CEL.

_AMG_

For those interested in what X pipe + resonator delete (straight pipes) sounds like.

http://www.youtube.com/watch?v=Ws3lFoqD2mo