TheRapture

You'll all have to forgive me, but i'm just learning all about the exhaust systems, so i have a couple more questions for you... I have a '97 GS-R Integra

1. Is it true that the Cat cuts down about 80% of the "loudness" of the exhast, and the other 20% is the muffler?

2. I do NOT have emmisions laws where i live... so if i put a test pipe on, in place of the Cat, would the exhaust be almost as loud as a straight pipe?

3. And along with a test pipe... what muffler sounds the loudest with the lowest tone?

speedyg

hope this helps!

1) yeah that's about right. It might be 70% Cat and 30% muffler.

2) It'll probably be louder with just the straight pipe in. Why don't you try taking out the muffler but leave the Cat in or switch them, to see which one sounds louder.

3)Well you should try a universal muffler with a wide tip, like an SPP or HKS. The bigger the opening, the deeper the sound.

jgrotkier

If you don't care about emissions and you obviously want loud, why don't you just get a straight pipe the whole way back.

95acurals

I put a hi-flow cat on my 95 ls and I really couldn't tell much of a difference in sound. I did seem to lose a little power though. I guess I lost a little backpressure or something. Be careful if you are just going to go straight pipe all the way back because my might end up losing power. But since the gs-r has more horsepower you might be ok. and if you want loud get the apexi n1. that is loud.

Paul

you want ZERO backpressure, it's a common misconception.

jgrotkier

:eh:

sinfestboy

:eh: to you.

its true, having back pressure has no positive effects at all.

but unfortunatly it isnt a common misconception, its a honda misconception

TheRapture

jeez, which is it? i keep getting the BACK PRESSURE IS GOOD... BACK PRESSURE IS BAD, from everyone!!!!!!!

which is ittttttttttttt????????
ahhhhhhhhhhhhhhhhh!!!!!!!!!!!!

sinfestboy

IT IS BAD

go to a forum that is based purely on performance and aske there... here are a couple

streetracing.org
freshalloy.com
rx7club.com (It may be based on rotaries, but ig you go to the general automotive section, its stuff besides rotaries)

thx247

I think it depends on the engine really, you need SOME back pressure in any NA car because when the fast moving exhaust gases are expelled from the piston and into the exhaust manifold, they create a low pressure area behind the fast moving gas which ideally should suck in fresh air/fuel through the intake port. This is why NA engines have valve overlap, to promote more sucking action in the piston chamber (when the intake and exhaust valve are both open at the same time)

How much back pressure and how little I don't know for honda engines. I would guess that you want just enough to suck in air, but not enough pressure to pull air in through the exhaust port.