Exhaust performance

[blackshine007]

ok so im putting an exhaust on my 240sx coupe with DE and i just got a great deal on a #1 drag thats 2.5 in and 4.5 out and the barrel is huge as hell but my bigest worry is what effects it will have on my HP and performance ??

I know alot off ppl talk about back pressure and etc.

Is the rest of your exhast the same size? If not, you're just wasting your time and money. Most of the time, when you tend to go with a bigger sized exhaust, you gain HP and sacrifice TQ in the process due to the fact that you're reducing the restriction. That's why most hondas make more hp than tq. Their heads flow real good and the exhaust is opened up to the right size (most of the time). Being that your KA is only a single cam and you plan on doing nothing to that particular engine, a 2.5 inch exhaust is gonna be over kill. Most people is gonna disagree with me. But for what it's worth, I have a 2.5L and I run a 2.5 inch exhaust all the way to the muffler, which is reduced to 2 1/4 ID (inside diameter) so I have good midrange and still have decent top end. I think you'll be just fine with a 2 1/4 inch exhaust and muffler. Like I said, anything else will be overkill. You may gain maybe 2 to 5 hp, but you loose midrange tq.

[SE-Rious1]

Is the rest of your exhast the same size? If not, you're just wasting your time and money. Most of the time, when you tend to go with a bigger sized exhaust, you gain HP and sacrifice TQ in the process due to the fact that you're reducing the restriction. That's why most hondas make more hp than tq. Their heads flow real good and the exhaust is opened up to the right size (most of the time). Being that your KA is only a single cam and you plan on doing nothing to that particular engine, a 2.5 inch exhaust is gonna be over kill. Most people is gonna disagree with me. But for what it's worth, I have a 2.5L and I run a 2.5 inch exhaust all the way to the muffler, which is reduced to 2 1/4 ID (inside diameter) so I have good midrange and still have decent top end. I think you'll be just fine with a 2 1/4 inch exhaust and muffler. Like I said, anything else will be overkill. You may gain maybe 2 to 5 hp, but you loose midrange tq.

well my 240 is a twincam DE not SOHC if that helps any lol

[blackshine007]

well my 240 is a twincam DE not SOHC if that helps any lol

Not really. It's gonna have the same effect regardless

[SE-Rious1]

Not really. It's gonna have the same effect regardless

well damn hmm