Which Decat ?
 

Hi, Im still struggling on where to go next on power mods. I'm not planning on remapping the car at the moment, but I still want to squeeze as much power as I can out of the engine, safely.

So far my list of mods are : Green Panel Filter, Prodrive Backbox, De resonated rear pipe, and I have a Prodrive Intercooler Y Pipe to fit at some point. I know alot of people replace parts of the exhaust with catalytic converters in them to up the BHP, but which one is the safest one to do and help with the emissions issues Im no doubt going to come across.

My first throughts were to just replace the centre pipe with a decat one, similar to the one supplied with the WRX PPP. However I've seen alot of people leave this in place and replace the downpipe with a decat pipe.

As I've said above, I dont want to remap, but I also want the mods to be safe and fairly MOT Friendly.

Thanks for your help folks.

The centre decat is the one to replace next if you haven't done so yet and won't require the remap. If you do the d/p then a remap is a must.

Is changing the centre decat going to screw with my emissions enough to fail its MOT ? Also, some of the advertisements I've seen for these replacement pipes say for track day use, not for road use, why is this ? is it just the vendors covering there own backs.

A point was made in another thread I was reading about the Up Pipe Cat in the WRX, is it a definate requirement to de cat this pipe prior to a remap.

Scoobyworld recommend doing this as part of there ECUTek mapping procedure as after a remap it could get hot and damage the turbo ?

Any thought on this ?

I've ordered a centre decat pipe to replace this for the time being to give me a couple of BHP more, with a plan to remap next year, would I need to remove the up pipe ?

I had a centre decat first, even on standard map never had a cel and it passed mot fine, since then have decatted the up pipe and fitted an sti ppp downpipe, this again flew through the mot no probs, I added a ppp wrx map and had no overboost and checked for knock and also none present, maybe I was lucky, but I wouldn't decat the downpipe as ppp downpipes are available used at a reasonable cost and no swapping for MOT. just unsure where to go now.

Thanks for the response, I'll just stick to my original plan then at the moment and add the decat centre pipe, as I have the other PPP components on my car now. Prodrive Back box and Prodrive Intercooler Y Pipe, once I have the centre decat on I should be fine to remap next year sometime :thumb: