PERFORMANCE Exhaust (Resonance be damned)

[Lahodny]

I have read all of the threads on what SOUND everyone likes, but which cat-back exhaust system provides the best PERFORMANCE? My muffler eliminators gave be a definite SOTP DECREASE in performance. So whose system will help my '95 LT1 coupe go quicker off the line? Thanks!

--Larry LaHodny

 

[Vettefan87]

Wow, that is weird that you say you lost power. I have not heard anybody saying that taking the mufflers off reduced power. I just could not take spending some of the money that some cat back systems are so I just run the stock exhaust, and I like the sound I have. http://www.corvetteactioncenter.com/forums/showthread.php?t=66889 Even though I have big ugly canister mufflers on there now I will probably be getting chambered muffler elims pretty soon.

 

[Lahodny]

I have read many posts which have indicated a loss of HP when going to eliminators. An engineer type tried to explain it to me (something about a balance of backpressure), but I didn't quite get it. Bottom line: I sure could tell the difference (for the worse).

--Larry

 

[Vettefan87]

Well my car had plenty of back pressure since it had three cats, not sure about your LT cars. You sure it just didn't move the power up in the RPM band? Seat of the pants is not always the best indicator, just a thought.

 

[Edmond]

I think it just moved the HP up the RPM band.

Most of the exhaust systems out there roughly produce the same results. There is a small difference, probably in the 3-5 HP range but you won't feel that difference in the seat of the pants.

 

[Moonunit 451]

But Edmond, are you saying that there is NOTHING to the backpressure argument?

Larry, what else have you done to the car? Muffs are a small part of the equasion in the quest for more

 

[Lahodny]

MoonUnit,

The muffler eliminators were prior to 3.73 gears and better tires, but after Hypertech tuning, 60 degree thermostat, K&N filter, airfoil, throttlebody byhpass, and cut airfilter lid. But maybe the 58mm throttlebody I bought could balance things out!

--Larry

 

[Vettefan87]

Yeah I did notice an improvement when I put those canister mufflers on the car rather then just open exhaust, that is why I am a little hesitant to get chambered muffler eliminators, I am not sure if they will provide me with enough back pressure.

 

[Edmond]

But maybe the 58mm throttlebody I bought could balance things out!

--Larry

That's too big of a TB. You need more cubic inches to need even the 52mm TB, nonetheless a 58mm TB.

Moon,

Can't say about the back pressure.

 

[Vettefan87]

Way way to big unless you have done serious mods. I think that will make your car run worse then it is now IMO.

 

[shawn tallent]

The other guy was right unless you build the crap out of the motor it will run worse with no back pressure.Try B & B exhaust or corsa both are about the same price & make about the same power , I just ordered my B & B 3 in. system today , sweet system , 26 hosrepower at the rear wheels. GOOD LUCK

 

[Moonunit 451]

I'm an L98 guy, wish I was more familiar with the later models. I know there was a breathing (intake) problem with the L98 that I don't think was as much of an issue with the LT1's.

Are you having bad 60" fts.? I still think more info on what you perceive the problem to be would be helpful. The 58 is not gonna help as far as I know.

BTW don't believe ANY advertised HP gains

 

[Vettefan87]

I am with Moon. The L98 was fitted with the 305, which the vette was supposed to have, but at the last minute they decided to give it a 350, but they didn't redo the intakes. THANKS GM. I don't see any way to get 26 RWHP with just a catback. You need to get long tube headers for gains like that, or gut the cats IMO.

 

[Edmond]

26 to the rear wheels is a lot, that's more than 30 at the flywheel. On a stock motor, I don't know if that's realistic. If we factor in that he's talking about an LT1, which has a better stock flowing exhaust than the L98's...

 

[shawn tallent]

Hey guys I agree I couldn't believe it either when the guys at B & B told me 26 rwhp but it's true,Go to there web site gives a dino chart for a bone stone stock LT1 & of corse this is a average (maximum ) one guys vette may make 26 & the next guys may only make 20 we all know every engine is different.They say the 2.5 system makes 9 rwhp & the 3.0 system makes 25 -26 rwhp.Nothing flows like a 3.0 inch exhaust most of us are used to 2.5 inch , this is my first 3.0 inch system.I will update when I have it dynoed ( maybe I'm wrong & B & B is strecthing the truth )

 

[shawn tallent]

Hey fellows B & B web site is ( bbtriflo.com ) enjoy

 

[grapeknutz]

I did not use a cat back kit on my 92 vette, what I did was make my own set up using a Dyno Max super turbos and a Dr Gas X crossover. I have noticed that it did take some low end out and add it to the mid range, but the good news is NO resonance at low speeds.

 

[Vettefan87]

On a stock motor I don't think there would be much difference between a 2.5 inch exhaust and a 3 inch exhaust. Does the LT1 really breath that much better?

 

[Edmond]

On a stock motor I don't think there would be much difference between a 2.5 inch exhaust and a 3 inch exhaust. Does the LT1 really breath that much better?

I think it does. They have almost a dual exhaust where as we're using y-pipes.