de-cat advice

[911mark911]

hi I have already done the gundo hack mod to my 996 exhaust but it still is too quiet I am looking at making the x style decat pipes (pic below)just not sure about the lamda sensors and light etc
Q1 when I use a x type pipe do I have to move the lamda sensors to the opposite side (original cross over side) ?
Q2 do the o2 spacers work to stop the engine light coming on?
thanks

[Gibbo205]

Don't do it.

I did these to my 997 C2S, the result was:-
30BHP / 40lb/ft lost below 4400rpm compared to stock cats and design.
However over 5500rpm there were gains of nearly 35BHP and 30lb/ft between 5500-6500rpm with a peak power output of 391BHP, car also had BMC filters, X51 manifolds, softronic map etc.

The noise was awful as well, sounded rubbish and crazy loud!

I went with stock design crossover pipes with 200 cel cats, this resulted in no losses in power or torque anywhere in the rev range and over 3500rpm power and torque was up, car now makes peak power of 378BHP and also has GT3 throttle body / plenum to fit.

In short get some crossover (stock design) pipes with 200 cel cats. X-pipe design is not good for our cars and in my opinion sounds carp.

[911mark911]

hi thanks for the advice I think I will opt for the 200 cell cats

[Gibbo205]

911mark911 said:

hi thanks for the advice I think I will opt for the 200 cell cats

Good idea and avoid xpipe designs.