right guys i have a 2005 sti with a 3"exhaust and k&n panel filter and the car runs great,i have just bought a 2nd decat pipe and still keeping the stock catted down pipe,would i need a remap if i fit the 2nd decat pipe as im sure it gives a couple of extra psi of boost when fitted.

cheers.

 

Hi mate. I fitted a 2nd decat pipe to my 2006 WRX around six months before I finally had a remap, without any issues at all. It did make the exhaust a lot louder though! As far as I know, you only need a remap if you decat the downpipe.

 

which cat are you removing? the 3rd one in the mid pipe after the one in the DP? curious as im looking into decats/sports cats at the minute as so far have a 3 inch catback and panel filter on my 06 WRX.

 

thanks guys,i had a 2004 sti a while ago and fitted the 2nd decat on that and im sure i was told by scoobyclinic that it would be ok.

yes its the small one after the down pipe,prodrive remove them as part of there ppp.

 

ive had everything from the cat in the downpipe back replaced with no new map on a 2005 wrx, as long as the lambda sensor is put back in

 

so basically a turboback system with no cats then? people say you cant but tbh i have been taking it with a pinch of salt. i plan on working my way up from the beginning of my catback to the turbo outlet while checking readings with a wideband to see just what if any change to the AFR there is without any mapping. i reckoned it would run ok just not be ideal and possibly overboost a little without cats behind the turbo to bottleneck it.

 

no it will still have the cat in the stock downpipe.