gains from 3" exhaust on F22/H22

[jdm92_accorn]

recently i've been thinking about having a 2nd exhaust setup made with just a 3" in/out 6" round muffler from vibrant and a 3" inlet canister with 3" mandrel bent tubing by mandrelexhaustsystems.com. my question is would this see a gain or not. if it will gain anything over 3-5whp it'd be worth it to me. im one of the few that have a complete understanding that n/a dollar per hp is high and im still ok with it.

[19dabeast85]

What is your current setup? I have a f22 with full bolt-ons and bisi header and have 2.5" exhaust. 2.5" should easily support up to 200whp. I wouldn't consider stepping up to 3" unless I was making AT LEAST 200whp.

[TheNextEpisode]

3" does seem like a plausible route. There are more articles on this that you can google, but here's a start.

http://www.honda-tech.com/showthread.php?t=2197695

[PirateMcFred]

Well, what's more important another 3whp or another 5lbs?

2.5" 16ga 304ss tube = 1.69lb per ft.
3.0" 16ga 304ss tube = 2.04lb per ft.

[jdm92_accorn]

3whp will over rule the 5lbs. besides if you read that thread, http://www.honda-tech.com/showthread.php?t=2197695. later im planning on spraying so i think it'll be worth it.

[visualpoet]

3whp will over rule the 5lbs. besides if you read that thread, http://www.honda-tech.com/showthread.php?t=2197695. later im planning on spraying so i think it'll be worth it.

Hp can't over rule torque. Horsepower is how quickly you can apply torque over a given distance; without torque you can't have horsepower. Carroll Shelby said it best: "Horsepower sells cars, but torque wins races."

It would definitely be worth going to a 3" from stock, but if you've already dropped the money on a full 2.25" or 2.5" exhaust, I don't see that the dollar/hp ratio makes it worth switching pipe. 4-5 hp and almost 4 lbs of torque? It's a tenth of a second under ideal conditions. You won't notice it anywhere but on the dyno. You'd be just as well off pulling your spare, jack and some other crap out of the trunk and lightening the car a little instead. 40-50 lbs of weight reduction would give you the same boost in acceleration for free.

[PirateMcFred]

read that thread, http://www.honda-tech.com/showthread.php?t=2197695. later im planning on spraying so i think it'll be worth it.

Did you fix your dented header B-pipe? That would help you more than a huge, loud ø3" exhaust.

Another test you can do is fix the header, tune for A/F on the dyno then pull the headerback exhaust and see exactly how much of a restriction the ø2.5" exhaust is. In my testing a 200whp 156wtq JDM H22 didn't get hardly any more power open header vs. full 60mm Greddy exhaust with gutted Prelude cat.

Overall design of the system should be a consideration. A little testing could save you a few hundred dollars on "upgrades."

Also for your consideration. My K24 hybrid makes 260whp 210wtq through a full ø2.5" exhaust. Do you think that the 180whp you have now is suffering that much from a restrictive exhaust? How much nitrous are you going to spray? 150 shot?

-P

[cb7_with_snail]

The gains from a 2.5 to 3" would never be noticed unless u had a fully built massive turbo track car. Stick with ur 2.5

[gloryaccordy]

The gains from a 2.5 to 3" would never be noticed unless u had a fully built massive turbo track car. Stick with ur 2.5

People see gains on stock H22s with 3" exhausts over 2.5" exhausts

For dude's build I think it's worth it

[jdm92_accorn]

http://www.k20a.org/forum/showthread.php?t=46317 another 2.5 to 3" story.
and yes i fixed the b-pipe. also i finally got my catch canister on, im sure that'll make a huge difference considering it doesnt have oil contaminating the burn now. i also changed the o2 sensor and the plugs. there has been alot of changes since the last dyno. i still need to adjust the valves. they should be at .009" intake and .011" exhaust and the exhaust is at .026" and the intake is probably just as far off. the cam is finally wore in so.....anyways back to the subject at hand, i know open header it makes quite a bit of difference so i just figured 3" exhaust would prove worth it. i actually found a good deal on 3" tubing. 120 for just the tubing. and i already have two mufflers. and it will add 8lbs. by the way it is full interior excluding the trunk. trunk is now gutted.

[cb7_with_snail]

I'm not trin to discourage u from it but remember. The noise will be un bearable the hp and tq gain will rise but not enough to feel much and u going to spend the money u could save or spend on a cam or cams

[jdm92_accorn]

the cam is as far as i want to go. i like where my power is at. as far as loudness that can be dealt with by using mufflers.

[gloryaccordy]

I'm not trin to discourage u from it but remember. The noise will be un bearable the hp and tq gain will rise but not enough to feel much and u going to spend the money u could save or spend on a cam or cams

If he has a resonator + decent (not straight thru) muffler it will be fine. I had 2.5" piping on my first CB, no cat, just a resonator and stock style 2.5 I-O muffler... everyone said "ITLL BE TOO LOUD! YOULL LOSE TORQUE!" It was fcking perfect... damn near as quiet as torque, good response all the way up to redline. I don't think 3" is too much, people throw them on H's all the time w/o complain.

[98vtec]

i had a 3" dump and i thought it sounded really good....but then again my setup wasnt cheap.

[jdm92_accorn]

i have 2.5" with two mufflers and its barely louder than a new si civic with stock exhaust at cruising speed and quieter than one at idle. i think it will be very tolerable. besides did anyone look at the gains on that stock jdm h22 and that k20 with bolt-ons. i really dont see it losing power.