Quick question

[wonkey85]

Ive got a cat back exhaust on my51 bug. Question is I've got the chance to either replace both cats with a down pipe. Or do I just replace the rear cat? Is it illegal if I do both? And do I have to map it once done? Many thanks Wonkey

[jura11]

Not sure,but if you have just DP which replace only DP section,on your bug you have two(2) cats one in DP and one in Up pipe,you can run without the remap on WRX with removed 1 cat and you will still pass MOT.

About legality or illegality i wouldn't care so much,everybody doing this...
If you are replace cat in Up pipe/both cats(DP plus Up pipe) i would recommend Remap straight away.

Jura

[wonkey85]

I was thinking of removing both. But leaving the one in the up pipe. Wasn't sure if it was ok with out map and the mot

[jura11]

Originally Posted by wonkey85

I was thinking of removing both. But leaving the one in the up pipe. Wasn't sure if it was ok with out map and the mot

I've run few months without the remap on mine WRX decatted exhaust,only OE Up pipe has been fitted,but everything worked like normal,just sometimes i've hit overboost when outside has been too cold or colder.

Jura

[wonkey85]

Cheers mate. I'll I only remove the one for now untill I get a map

[Steve_PPP]

I disagree, the cat in the downpipe is the big one you need to pass an MOT. Removing it requires a remap to be safe. No way will you pass an MOT with just the uppipe cat.

There are 3 cats on a bugeye wrx - uppipe, downpipe and centre (and there's also a resonator in the long straight section which meets the backbox).

The uppipe cat doesn't do much, plus its a sod to change - either headers off or turbo off, depending on which way you want to do it. If your car has the PPP, it will already have had the centre cat removed.

[C. J.]

Originally Posted by Steve_PPP

I disagree, the cat in the downpipe is the big one you need to pass an MOT. Removing it requires a remap to be safe. No way will you pass an MOT with just the uppipe cat.

There are 3 cats on a bugeye wrx - uppipe, downpipe and centre (and there's also a resonator in the long straight section which meets the backbox).

The uppipe cat doesn't do much, plus its a sod to change - either headers off or turbo off, depending on which way you want to do it. If your car has the PPP, it will already have had the centre cat removed.

Would say the same , keep the down pipe one if you want to comply but would needing a remapp / check of AFR's

[jura11]

I know from mine when on mine center pipe has been decatted,maybe has been JDM,but has been decatted.
Yes if he remove DP and center pipe i would check AFR for sure...
About the passing MOT mine pass just with OE up pipe which i know from last time.

As i said i've run few months without the remap on decatted exhaust and i've been advised run off the boost

Jura

[C. J.]

Originally Posted by jura11

I know from mine when on mine center pipe has been decatted,maybe has been JDM,but has been decatted.
Yes if he remove DP and center pipe i would check AFR for sure...
About the passing MOT mine pass just with OE up pipe which i know from last time.

As i said i've run few months without the remap on decatted exhaust and i've been advised run off the boost

Jura

but some pass with no catts !

[wonkey85]

Originally Posted by C. J.

but some pass with no catts !

Suppose it's who you know down the mot station

[Mortster]

Ive removed all mine apart from the DP, sails through MOTs.