Ok, I've purchased a P1 back box for my MY98 Turbo, just been thinking about de cat pipe for the centra cat, just looking on JW Racing web site and its say "Centre Decat £55 or £115 with Resonator". I know a down pipe would give better power increase but I cant afford one at mo

Question Time

1. What is a Resonator?
2. What benefit will I get?
3. How much power does it release?
4. Does it sound better?
5. Any down sides of having a centre de cat?

I'm sorry if these questions have been asked before

Thanks

Dan

Thanks

Dan

 

A resonator takes the edge off the noise a little - I'm thinking of ditching mines to make it louder

The centre cat and back box give a little extra power and noise but isn't massively noticeable. If your going to keep the standard downpipe I'd get a straight through (non-resonated) decat centre for a little extra noise and performance.

 

It's all marginal compared to changing the BB (noise) and DP (power), but 'helps' both.
Removing the centre cat releases a tad more power, makes no real difference to MOT/emissions, and makes a slightly 'harder' sound than with the cat. The hardness also makes it marginally louder.
The resonator is a 'box' on the pipe that reduces the noise level slightly.

 

If you have replaced the centre Cat, then replaced the down pipe with a decat one, is it then sufficient to fit a centre cat for the MOT?


I assume a UK MY99 has 2 cats?

 

Sometimes yes, sometimes no. It would most probably fail the low-idle test, but may be OK on a fast idle. Results vary but a serious blast immediately before the MOT helps!