ok so after i cleaned all conectors and swapped my ptu I found that I had alot more power but am now getting my cat over heat light coming on. so i've now decided to de-cat the beast and got intouch with the local garage that says they will do it but dont know how many cats the z has nor do they know anywhere I can get replacement pipes from. so firstly is there 1 or 2 cats (Iv looked and I think i can see 2) on the zed, and secondly do any of the leicester boys know of a local place where i can get replacement pipes from??? :D

How can you get backpressure back throught the turbos when the exhaust is flying through them at a high pressure.

 

OK, create a restriction after the tubs & you have back pressure before that point. that is what back pressure is!

 

back pressure is NOT good for performance, however it is what helps keep the oil in the turbo!

 

mark - there is no definitive answer, its gonna largely depend on the wear on your turbos. many people decat & have no smoke. theres also a lot of people that have started to smoke within days of decatting!

Usually, the turbos will fail after de-catting if the breather system isn't up to scratch ;) If you're decatting its a good time to replace all the breather hoses to try and reduce crankcase pressure....

 

How does that sound? From a non subscribed member too :D I must remember not to help myself :D:D:D

Paul C, is it not the fact that the cats "REMOVE" the smoke that makes it seem like the turbos die after the cats are removed????? A friend had a tuned Carlton 24v GSi that smoked, but only after the cats came out.

CATS dont remove smoke, they convert specific emissions to harmless gasses!

Well yes, but the fact is that on many occasions removing the cats allows the smoke to be seen, I dont know how but it does seem to work that way. As I said my mate had a 24GSi, basically it smoked on the overrun all of the time, but each year come MOT time he put the cats back in, and hey presto no smoke, and then when they were out again, smoke.????