Being new to this. I am looking at changing from the standard exhaust on my 97 UK turbo wagon. I keep hearing about a de-cat system as the Scoob has 2 cats. What is involved in this and with the one remaining cat will it get through the MOT. I am just impressed at how much extra power I can get from just a de-cat and filter. Thanks

 

2 cats, one in the downpipe and one in the centre section. Decatting involves replacing these sections of the exhaust with aftermarket items which dont incorporate a cat. The std downpipe is particularly restrictive hence the popularity of replacing it.

Car should pass MOT with just the downpipe cat in place, and in some cases will pass with just the centre cat in place.

Alternative is to choose an aftermarket exhaust with a sports cat, which has the high flow characteristics of a decatted pipe, while still remaining emissions friendly. Only downside of this option is cost.

For prices and more info try Hayward and Scott or Power Engineering.

 

A fair bit of the extra power comes from the fact you are leaning out the mixture. This is why you get such good results from these simple mods.