hi

does anyone know if its wise or worth it to fit a decat pipe taking one or two cats out

was told about a a problem of over boost ?

would it have to have a re map or would it be safe to fit with no adverse affects

would there be any sound or bhp gain


i have a 2005 wrx with 3inch cat back with an air filter in the void at the front wheel for the cold air and a forge dv



thanks

 

the de cat down pipe takes out the two front cats (the 3rd is located just after the flange in the centre section)...

i highly recommend it, you'll notice an instant ~20bhp power increase as the exhaust gases will become fast-flow as opposed to the ristriction of the cats. I'd also recommend getting a straight thru centre section to remove the 3rd cat.

the noise/volume of the exhaust will increase alot too!

i dont think you'll need a remap for that mod on your yr car, the newage do pretty well at compensating that change. early classics not so much and do tend to fuel all wrong after as the lambda sensors get all confused and tell the ECU theres a problem coz they still think the cats are there and not working properly.

altho if you can afford it, a remap will make it run much better after and will also ensure you're getting optimum power out of the mod.

 

dont take this for gospel but I changed my exhaust in stages before getting it mapped, my car started life as an my05 wrx ppp, so the first thing I did was add a decat uppipe and a sports cat downpipe, this made the turbo spool up a little earlier and gave a slight noticeable increase in sound and power. then I eneded up doing the rest of the exhaust, turbo etc and went for a remap.

So from my experience yes it will be ok, but you will need / should get a remap to get the full benefit etc

 

thanks for the info