hey guys,

I suspect my standard cat is rooted and am wondering what the lowest "cpsi" rated cat I can go without overboost problems? I have found a couple of well priced 300cpsi metal cats, but am worried these may still be a little to free flowing? does anyone know what "cpsi" the standard ones are?

And one last thing, what size do I need for the standard exhaust in inches, 2", 2.5", 3"......?

Edited February 5, 201115 yr by r32dan

Think standard exhaust is 3' to cat and twin 2.5' cat back

Think standard exhaust is 3' to cat and twin 2.5' cat back

factory cats are usually 400 cpsi but I dont think 300 will make it overboost, probably best to ask one of the forum sponsors who tune these cars

does anyone know at what power level the stock BF cat is holding back more power?

With just injectors and tune most BFs pull 270 odd, J.Ds and I's with 5" cats are just over 300rwkw. So theres gains there straight away.

My cats collapsed so got them "high flowed" and gained about 1 psi boost and a reasonably restrictive 3" exhaust though..