Do i have enough Back Pressure?

[WoR]

Ive heard some talk about quad4's needing a good amount of back pressure to run right. I think most FI engines do? All i have for an exauhst is the manifold, downpipe, and a 2.5' glass pack. Would that make enough bp?

[azeniskid]

you need another muffler.

[bbechtel16]

Whever told you Quad4s need a good amount of back pressure is smoking crack. In fact, the backpressure argument in general is mostly a bunch of crap. Your Quad will run great with that setup, though it may be unbarably loud.

[WoR]

Its actually not that loud at all, its a very long glass pack so its not too bad (but the sound i get isnt all that great). But i like my cars about as loud as i can get them without a ticket. My '88 ga that i used to have had a straight pipe front too back and it sounded awesome, But i got a warning and a ticket before i got rid of the car. It was fun to go thew tunnels with that car, sounded like you were in an indy car.

[bbechtel16]

LOL, nice. Tunnels are fun, they make even stock setups seem loud under throttle.

[Brad97GS]

There was a short period of time with my old '89 GA Q4 when I had no muffler because of an exhaust problem. I drove it around for a few days until I got the muffler I was waiting for. When I accelerated, it literally sounded like some big old propeller plane! Needless to say, I used the gas as little as possible in town to avoid tickets...and didn't even use it much on the highway because I didn't want to blow out my ear drums! :) I did find out at one point though, that the sound improved in the higher revs - not so loud.

It was the quietest sound I ever heard when I put the muffler on that car and started it... :D

As for the backpressure issue, I'd have to agree that it doesn't lose power with less backpressure. But it could push the power curve up the rpm range a little, so your peak power is at a higher rpm than before. Since the Q4 likes to rev, this probably isn't too big a deal. I say just go by how you like it, or if you have the time and money, run a before/after dyno and see what happens.

[bbechtel16]

Yeah the only thing you really have to watch is not making the piping too big, not because of back pressure but something about the axhaust and the pipe staying hot to drawl the exhaust out into the atmosphere...I have an article somewhere that I'll post the link to eventually.

[WHOOPhondaASS]

Once i took the pipe off my car behind the cat, so that I could change the gasket there, and I didn't get done in time, and had to put it back in the garage, oh my god that was loud as hell! Terrible sound!

[WoR]

lol, that would be loud but have you ever heard a quad 4 with just the manifold and down pipe? i had mine like that for one day and it took it out on some gravel roads and had some fun. It was louder than anything ive ever heard just idling, but when i let her loose it was just f'ing crazy. Then i just put a straight pipe alll the way back, quieted it down a little but it was still the loudest thing around with 4 doors. Sounded pretty dam good too for just straight. GO QUAD 4!!!

[WHOOPhondaASS]

I made CAI and I made the stock pipe a bit louder and better flowing by opening it up and making biger holes in the two pipes then put it back together. Its nice to hear the deep sound from the front and back.