rkbycrof

Hi all,

I'm the proud owner of a new afterburner vortex back box and de-resonated centre section. I'm well chuffed with the vocal change and now planning my next move.

I'm thinking about removing the centre section cat and fitting a Green Panel Filter. I understand that the car should stand a chance of passing its MOT with the original downpipe cat left in place, but by removing the centre section cat will I disturb any sensors that should be installed in that section? The last thing I want is for any engine warning lights to be coming on and I don't really want to be messing around with any software fixes or remaps at this stage.

Your thoughts would be very much appreciated.

Cheers,
Rich

SSCJAY

If you were changing the pipe for the second cat you need to make sure it will have a bung for the lambda sensor.

Personally I would recommend keeping the second Cat and changing the down pipe to a decat twin dump down pipe, removing the first Cat will give you more gains in terms of Power, and providing you get the exhaust nice and hot the second cat should do enough to get you through the MOT.

rkbycrof

Thanks for replying!

I assume that ensuring that you have a bung means that the lambda sensor will no longer be used? Is this in anyway dangerous for the car? The last thing I want to do is cause is any needless damage for small gains! Probably lame questions but I'm new to this modding lark

I was thinking about removing the centre cat now and looking to upgrade to a high flow sport downpipe cat at a later date, and then at that point have a remap, it would mean running with a decat centre section for several months though! plastic only stretches so far!

mwilliams

Hi mate,

I too am new to this modding lark. But advice I've got from the forum says you're on the right track. Best way to go is de-cat the centre and go for a sports-cat downpipe. This should see maximum gains and still be well under on the emissions. In fact my 51' WRX has a third cat in the uppipe to the turbo too (not sure if that applies to an 03' blob, possibly not) which the guys seem to think I can also remove and still be safe come MOT time. Also it seems doing the above along with a panel filter won't cause any damage, although you won't get the full performance benefits from it all untill remapped.

Scoobyworld do a sports-cat downpipe for 299 inc vat which looks a quality bit of kit and offers only fractionally less gains than a full decat.

rkbycrof

Hi mate,

I've seen the Scoobyworld sport-cat downpipe and I thought that would be the one I would probably go for, it does look quality and I've purchased my back box from the same site, great service! I'm just worried about sensors that may or may not be placed at various places along the exhaust and what affect changing the centre cat for a straight through pipe, and the downpipe for the sport-cat will have on them. Are there any sensors on the downpipe cat section or the centre cat section?

I've seen on these forums that you can get mechanical or software fixes for these sensors but these only seem to make them redundant and remove the warning light, its this part that worries me because surely they're there for a reason in the first place!

scooby,dlm.

if you remove that cat,you stand a chance of the senor light coming up on the dash!!would need a remap

SSCJAY

No!! Bung is the boss to screw the Lambda sensor into, the Lambda must be used or you will have serious problems, In terms of gains decat downpipe will give you 15 - 20 bhp, decat centre will give you 5-10 bhp.

rkbycrof

I see now, many thanks, so I guess I just have to check that the decat pipe I buy has the correct hole to fit the lambda sensor then I'm away!