fastfu

iTrader: (1)

ive heard that i can remove one of the cats and still get through the mot, is it either one of the 2 ?

Ben WRX Bug-Eye

Pretty sure its removing the downpipe cat that will result in an MOT failure. Can get away with removing the centre cat without MOT problems.

Ben WRX Bug-Eye

ought to add... removing the centre cat will give only a fraction of the gains to be had from a de-catted down pipe. Also bear in mind that some on here recommend an ECU remap if you are tempted to do a full de-cat, as fueling needs to be re-matched, else you may risk engine damage.

CyprusScooby

Oh, oh! I've got a full de-cat! You've got me worried now!

jjones

classic should go through with just centre cat.

Ben WRX Bug-Eye

The reason is because with the massively reduced back pressure the turbo is spooling much more freely. Basically i've heard you can end up with the engine being unable to provide adaquate fuel to match the air.

I think you can also have problems with it overboosting, which is where the fuel is simply cut off past the point of maximum allowable boost to protect the engine. Apparently it is like hitting a brick wall.

Saying that, you could fit a boost guage to just monitor whats happening and drive it accordingly. Also seen plenty of people post up saying they have done 10's of thousands of miles on full de-cats and nothing else done, without the car missing a beat, so hope I haven't made you overly paranoid.