Dual Exhaust/ Compression and HP loss??

[1992eclipseGS]

Good Evening,
I'm pretty much building a show car out of my RS.. Due to the fact that I have the Bomber rear bumper, it would look better with the Dual exhaust..I want to have the exhaust build before I paint it.. I have a 4-1 aftermarket header, And i'm probably going to use the factory Cat (unless I can find a aftermarket. After the cat i'm going to y pipe the exhaust.. I wanted to do 2.5 inch pipe, but i'm worried about lossing the little power that I have. Now I don't know much about Compression and what not, but I know to much of an exhaust is bad for a N/T. So would I be lossing compression or hp if I go with a 2 1/4 or perhaps 2 inch?? Also, what kind of sound do you suppose I would get with this set up?

[l_eclipse_l]

Dual exhaust on a N/T is just silly.

[JoeShmoe]

New bumper man, lol. JK

[SilvrEclipse]

I would just run 2.5" to the y-pipe then like 2" to each muffler. As long as you keep the cat you will be fine. Bigger exhaust wont make you lose compression. It will mess with your exhaust gas velosity and that is what slows down your car.

[1992eclipseGS]

Originally Posted by l_eclipse_l

Dual exhaust on a N/T is just silly.

For future reference, If your not going to be of any help, don't bother posting your un-related comment in my threads.. thanks. And like I said, its not for power gain purposes. I have the Bomber rear bumper which is built for a dual exhaust. So it will actually look nice on my car.

Originally Posted by SilvrEclipse

I would just run 2.5" to the y-pipe then like 2" to each muffler. As long as you keep the cat you will be fine. Bigger exhaust wont make you lose compression. It will mess with your exhaust gas velosity and that is what slows down your car.

Damn, do you know how much of a slow down I'm looking at?? As you know the 420A isn't that powerful to began with. This is mostly a show car, but I still would like to obtain the little bit of extra HP (and i do mean little) that I have gained from my basic mods. If you seriously think its beneficial to have only one exhaust, I can just by a different bumper OR do one exhaust with the bomber bumper which will look a little silly in my opinion. I just think the bumper looks really nice on my car.

[david-b]

The exhaust has no impact on the compression of the engine.

I agree with Silver on the size. You said this is going to be a show car right? So show, no go? If so, 2 1/4" to the y-pipe, then 2" back would be better. 2 1/2 may be too big for a car with no mods done. Either way you'll be fine though.

On a side note, make sure your mufflers are actually hanging properly. That's the thing that pisses me off the most is when people spend money to have duals, and then they're all cock-eyed and falling off. Lame.

[david-b]

Originally Posted by 1992eclipseGS

For future reference, If your not going to be of any help, don't bother posting your un-related comment in my threads.. thanks. And like I said, its not for power gain purposes. I have the Bomber rear bumper which is built for a dual exhaust. So it will actually look nice on my car.

That wasn't an un-related comment. It's true. You get no gains from it, you actually lose power. It was being stated. If you want to keep the rear end and still have the gains, be a ricer and hang a second muffler in that spot. Seen that before. But that's the only way to have duals and not lose.

[1992eclipseGS]

Originally Posted by david-b

The exhaust has no impact on the compression of the engine.

I agree with Silver on the size. You said this is going to be a show car right? So show, no go? If so, 2 1/4" to the y-pipe, then 2" back would be better. 2 1/2 may be too big for a car with no mods done. Either way you'll be fine though.

On a side note, make sure your mufflers are actually hanging properly. That's the thing that pisses me off the most is when people spend money to have duals, and then they're all cock-eyed and falling off. Lame.

The only Mods I have is the 4-1 header and a CAI. But yea its just a car that'll turn a few heads. But I don't want to be moving in slow motion either. I just wanna get a heads up on how much power i'm looking to lose here and when am I'm going to suffer the most (low RPMS or high RPMS??). And if i'm going pay my hard earned $$$ to have this done, I'm gonna make sure it looks decent.

[SilvrEclipse]

I believe I have a 420a also, and yes it is very slow. But what you dont understand is that as long as you keep your cat, your catback wont have a whole lot of effect on your car. The cat will give it enough restriction to keep from hurting the cars performance. Unless you go with some rediculous 3" pipe. 2.5" y-ed to 2" should be fine.

Your only going to loose bottom end to. Top end will increase.

[1992eclipseGS]

Originally Posted by david-b

That wasn't an un-related comment. It's true. You get no gains from it, you actually lose power. It was being stated. If you want to keep the rear end and still have the gains, be a ricer and hang a second muffler in that spot. Seen that before. But that's the only way to have duals and not lose.

LOL no thanks, my days of "ricing" have been gone for more than 4 years now. Along with the 1996 Plymouth Neon that I rice the hell out of.

[1992eclipseGS]

Originally Posted by SilvrEclipse

I believe I have a 420a also, and yes it is very slow. But what you dont understand is that as long as you keep your cat, your catback wont have a whole lot of effect on your car. The cat will give it enough restriction to keep from hurting the cars performance. Unless you go with some rediculous 3" pipe. 2.5" y-ed to 2" should be fine.

Your only going to loose bottom end to. Top end will increase.

so basically I'm be a turtle from neutral to first and second to third??

[david-b]

Originally Posted by 1992eclipseGS

so basically I'm be a turtle from neutral to first and second to third??

I don't understand this. Silver said lose lower end... in the powerband. Usually around 1500 - 3000 rpm or so you will lose, but maybe 5500 - 8000 you'll gain. Not gears... rpms.

[1992eclipseGS]

Originally Posted by david-b

I don't understand this. Silver said lose lower end... in the powerband. Usually around 1500 - 3000 rpm or so you will lose, but maybe 5500 - 8000 you'll gain. Not gears... rpms.

I don't drive my car past 5500 RPMS.. I might go up to 5000 if i'm not paying attention. Normally I shift arund 4000 maybe 4500. So like when i'm in less than 3000rpms, you'll hear my engine reving but I won't be moving?I'll be moving slow like that? Please bare with me, I don't know much about engine and power aspects.

[david-b]

Then you'll never feel any gained power. You'll have it drag a little more while driving though.

[1992eclipseGS]

Originally Posted by david-b

Then you'll never feel any gained power. You'll have it drag a little more while driving though.

Damn!!! Drag?? I can't deal with that, not in my eclipse.. My 4cyl dodge dakota drags like crazy. I can have the peddle all the way down to the ground and it still won't move any faster. I can't deal with that in my eclipse. no sir. Hmm.. I'ma have to think of what i'm going to do now.

Edit: So Could I just keep it at high RPMS than? My engine gets rather loud after 4500 RPMS (which is why I tend to shift by then). How safe is it to drive at 5500 to 6500?