Catalytic converter question

[slowCRXinPitt]

I was considering getting a hi-flow converter for my 91 crx w/ d15b vtec. (Its a true converter, not a hollowed out pipe) situation is, that it has a 2.5" opening which is what my cat-back and header are. My friend says to stick with my stock converter because i need back-pressure. Is this true? or is he

[FrodoGT]

hes a moron.

[slowCRXinPitt]

I thought so.... sad thing is he's a "mechanic". I think I'll stick to my automotive forum gurus from now on

[J-Mech]

You absolutely do not want back pressure. Unless you have a ford diesel. they have sensors on the exhaust to measure it. Which is stupid. Let the damn thing breath!!!!!!!!

[slowCRXinPitt]

Awesome, great to know!

[kris]

Originally Posted by J-Mech

You absolutely do not want back pressure. Unless you have a ford diesel. they have sensors on the exhaust to measure it. Which is stupid. Let the damn thing breath!!!!!!!!

Care to rephrase that statement?

[CRXperiment]

Originally Posted by J-Mech

You absolutely do not want back pressure. Unless you have a ford diesel. they have sensors on the exhaust to measure it. Which is stupid. Let the damn thing breath!!!!!!!!

Ummm, theres something you need to understand about exhaust gas velocity. Contrary to popular belief, throwing on a 3" muffler system will actually decrease exhaust gas velocity and the exhaust gas isn't pushed out as fast as a stock system. Its like the analogy of a garden hose and you putting your finger over the end. What you need to understand is that you need to compromise between exhaust velocity and backpressure, too much or too little of either is bad. NA hondas need backpressure, a little bit of it is a good thing.

[FrodoGT]

But hes not going to a 3" exhaust..now is he? 2.5 will do fine.