porscheplus

Has Anyone Any Experience Of Removing The Catalyst Bricks Or By Passing The Cat.
A Lot Of The 911 Nuts Do It Here Using A Bypass Pipe On The Cars From 89 On.
Does This Improve Performance Or Fuel Economy.
Regards David Mather

bamberger_1

I would severely doubt if there would any positive improvement if you take out one of the important components of the motor management. The engine controlling has been designed to optimize fuel consumption, performance and loading to the engine, so any intervention removing just one part would not change any thing to the better. Besides that: Don't you have any legislation in the UK prohibiting the removal of the catalytic converters?

newton22

Don't do that. You can remove the resonators instead. Keep cats intact or at least replace it with an aftermarket one.

porscheplus

hi newton22,
what are the resonators
regards david mather

newton22

The "boxes" (for lack of a better term) ahead of the cats (near the headers). The sole function of those is to reduce noise. Removing them and welding on straight pipes won't do the car any harm. You will get little, if any, of a performance/mpg increase by removing them though. If it's performance you are looking for, try a full-on aftermarket exhaust set up, coupled to aftermarket headers (which I don't know of any for the w220).

Thrillhouse

those things after the exhaust manifolds are catalysts, not resonators, the resonator is near the middle of the exhaust before the muffler, if you remove the cats your asking for a world of hurt and check engine lights, if you wanted to do it tho your best bet would be to get or build yourself an o2 simulator, either way its gunna be too much hassle

newton22

Where are you getting that? I'm quite positive resonators come after the headers. Can anyone confirm?

bamberger_1

If I'm not fully mistaken, both are right Newton and Thrillhouse. Here in Germany the dealer said those BOXES are kind of a "pre cat", uncontrolled but definitely part of the exaust cleaning system. It is not like in the early days of the cat, late '70s oder '80s, where the cat only was a componente within the muffler system, and had nothing to do with any motor management. This is also the reason the newer engines won't work properly if you just take them out or bypass them, even simulation of signals would not let your engine perform any better.

Thrillhouse

I am getting that cuz I have replaced many of them under warranty for catalyst coming apart and we had 4 german engineers at my shop for a week tearing them apart and trying to figure out why their catalysts suck so bad, but yes they are basically pre cats, still a catalyst tho.........