I have been planning on going with a true dual exhaust for a while, but I just installed some G2 springs, and I don't know how it is going to work. What would be the power difference by going from a 3" dual to a 3" y-pipe to a GMMG exhaust? Anybody have before and after track times or conclusive dyno results? Opinions are welcome too. Thanks in advance.

 

I don't know what your HP mods are or how well the GMMG exhaust flows, but a 3" y-pipe with a quality catback will flow very well. A 3" y won't even be needed until you start pushing well over 400 RWHP. I'm running an SLP dual/dual catback, and I love it. It's quiet, and it flows REALLY well. I've track-tested it three times vs. my cutout, and not once have I lost any ET or gained any MPH by running w/ the cutout open. One board member made 429 RWHP through the dual/dual catback with a heads/cam setup.

 

not sure which board it was but someone did a dyno of the gmmg versus the cutout and the gmmg only lost 3hp over the cutout so id say the gmmg flows quite well.

 

True Duel is going to change your sound but its not really going to better your performance... My y pipe is 3 inches also but i am also pushing 400+ hp. Ground clearance might be a problem with the G2 springs... My y pipe sits a bit lower then the body and i haven't scraped yet but its low. Having that Duel installed is going to be even lower so they can fit the piping. Good luck with it but I don't think you will make more power... Hope this helps... <img border="0" alt="[Burnout]" title="" src="graemlins/burnout.gif" />

 

I've normally seen only 3-4RWHP gains with cutout vs. good catback systems. I think the true dual setup won't see signifigant gains until you're dealing with a big cube motor or a highly modded stock motor 450hp+``

Shane

 

i am gonna bring this back from the dead... 10 years later lol! procharged 403 cu ls2 with approx 19 psi and 100% alky.. shooting for high 7 low 800 rwhp.. i have victor series 1 3/4-1 7/8 stepped headers w 3.5 flanges.. unsure if i wanna reduce it and go dual 3 inch or 3.5 all the way out.. i like the dual idea since its different but a. dont know if the power gains are worth it and b. i have to run dual bullets so i dont know what its going to sound like.. i am a fan of stock driveability till you wake the beast up.

 

This probably should be in a new thread.

 

If you run a y pipe on that motor expect loses of 20/20 minimum

 

Hands down, duals are the best flowing, best sounding exhaust. Period. You will gain everywhere, albeit low gains or high depending on application, you will gain.

 

what mufflers/bullet do u guys think sounds the best.. i dont like the raspy sound

 

If you go with duals, you wont have to worry about rasp. I have yet to hear a TD that has rasp (I had a loudmouth, talk about rasp). This isnt even a questions, TD hands down in all areas. Will it increase your performance? Well, the higher the exhaust requirement, the better the increase but that isnt until you get high into the HP range which you are. Are they worth it? Well its up to you.

 

I just got back from trying to get a quote on a custom true dual setup and the guy was insistent that duals were not the way to go on my WS.6. He told me that he owned an SS for years with different systems and he claimed that by far the best system for flow is the borla-type system. He told me that when he did duals on his car and customers cars that they actually lost power. This sucks. I like the sound of duals with dynomax bullets way better. I wish that somebody had a thread with before and after dynos.

 

that guy sounds like a tard no offense. if duals are so bad why dont vette's 5th gens, gto's, mustangs and even nascar cars run y-pipes?? Simply because duals are better, a dual 2.5 system will flow as much as a 3.5-4" catback system. Dual routinely will add 10rwhp or so over a catback across the board... bottom line is theyre worth it and sound the best

 

Your on the best tech advice site...Don't listen to "he" and "that guy". I've gone through 2 catbacks before switching to duals. It wasn't enough to feel a difference in performance, but I'm sure a wot on a dyno would show gains running duals.
With that said....the quality of sound and the "feeling" of my car roar alittle louder/deeper makes it feel like I've picked up 25+hp. I would never run a y pipe again. Not even a hint of rasp...nothing but pure muscle.
The lowest part of my system is the header collector..and I'm run under the axle, so I sacrificed no clearence issues. I have a few pics if you care.

 

I'm interested in pics lol

 

Yeah, post em up!

 

http://share.shutterfly.com/action/w...ZNGTJu0bM2bV3Y heres a couple.
I cannot find my pic folder of the duals directly under the lift. Pissing me off!! but whatever.

 

A system like this will flow as good or better than duals. Think about duals merging into one chamber at the x then out to two 3" pipes. Well this merges into one very very well flowing merge out to a 4" pipe thats not long enough to matter that its a single 4" vs dual 3". I have built several of these for people and you will not be able to tell me which is which by sound when compared to the dual 3" after the merge version.

 

I've ran both systems on my Trans Am. TDs (X and H) as well as custom Y with GMMG. Both dynoed jsut about the same. I ended up going back to Y and GMMG cannot beat that sound.

 

So you did not feel any loss of acceleration? Yeah I agree about the sound for sure. I love the sound of duals far better than any of the Y-pipe catbacks but that exhaust guy turned me off when he talked about a loss of acceleration.