oh yeah............true duals will have a ton of resonance inside, way more than any catback.............but personally it really doesnt bother me.....as long as no interior pieces make that loose rattling sound
im going to point the turndowns outwards so hopefully it will cut down on resonance.

as for gains, from a cat back to true duals.........here is a dyno graph i found............most people just spit out their personal opinions, but here is actual proof..........true duals with an x-pipe gains power over 3" ypipe/catback combo.

not a whole lot peak, but look at the area under the curve....BIG difference!
look at where your rpms drop to on a shift, and look how much more power the true duals have at that point.


dyno graph

 

Go to their website, they have a lot of sound clips.

 

keep in mind, all the cars on their website are LS1's with aftermarket cams.

much different exhaust sound then an LT1

 

Yes, you (got_hp) pointed out another one of the reasons I am finding it hard to make a straight decision on the true duals vs GMMG..the power gains of duals are unmatched by any catback, especially the fact that the power is increased over the entire curve(s)...I was aware of this and it makes the decision so difficult, but the problem I have it that if I get duals I have to get the headers at the same time. Not an appealing option for a college student, but then again neither is $700-850 for a cat-back. *sigh* decisions...

Bersaglieri

PS thanks for the response Indy, and did you ever get any clips of rev action?

 

I will try and get a nice rev clip put together for you guys shortly

 

yeah......that can be expensive.........but if you do the labor on the headers, it can be done around the same price


used longtubes = $350ish
gaskets = $40 (header, collectors)
stage8 locking bolts = $30

thats about $450 with shipping.........plus $300 for a true dual setup.........so $750ish total
so if you do your own labor.......you can have headers and true duals for the price of a catback!

 

I'm probably going to get bashed for saying this, but just put the duals on with your factory manifolds for now. They could be very easily adapted to fit headers when the time comes, definately no more than $50. Yes it's a somewhat unnecessary additional $50 at the time of the headers install, but it'll do everything for your car now that just getting a catback would. It's not hard at all for this to be done, I ran AS&M midlengths with true duals. There's nothing special about running duals with manifolds/shorties aside from the fact that no one generally does it.

 

I think what needs to be done is I need to find someone local with true duals on their f-body and ride/drive it and see how the interior resonance is...then decide whether or not I want that kind of sound in my daily driver. Then maybe just spit $300 on a Magnaflow for now then switch when I have an alternate vehicle. I'm just not sure Ill be able to stand the drone of duals, my friend had them on his truck and they even exited out, and it was cool for a while but then just annoying...

Thanks for all the help...really appiricate it...

Bersaglieri

 

I would like true duals on my car, espically since I seen a post with a guy whole had them come out the back and not turn downs. Hey if you're the guy that did that....I need some detailed pics please =) thanks

 

Hey, I too would really, really appreciate it if ya could put together a nice clip of your LT1 with some idling and some revving while fully-warmed up like you're last video(except without the cold start).

I'll be getting rid of my LS1 soon so I think I'm just gonna re-install the GMMG on the LT1 I'll get to replace it...

BTW, this is on an LS1, but mine picked up exactly 26rwhp & 26rwtq with ONLY a Direct-Flo lid and the GMMG cat-back. I would have liked to dynoed it with just the addition of the GMMG only, but as you can see, it obviously flows well on my simple bolt-on car making 325rwhp.

 

Well as far as fitting the LS1 version on the LT1...I have found a used system for sale that I am planning on buying but it is for an LS1 (99), so I called GMMG today and asked them if i can "make" it fit...the representitive (which was so very polite and helpful) explained that all of the people who were capable of answering my question had already left for the day, she took me number and assured me that someone would call me back ASAP. What great service. How do you plan on making the LS1 version fit? and what year is the LT1 you are getting ? (2002LS1z28) What is different about the two? Hangers or the Intermediate pipe or both? hmmm, I can only wonder...hope it can be fitted without to much trouble for both of our sakes...Good Luck.

Bersaglieri

 

I'll be getting a single cat LT1 like what you already have.

Yeah, the hangers(and location of them?) are different I believe as well as the fact that we'll need an "S" pipe to be made up as you're also right about the I-pipe fitting differently. Shouldn't cost much to have that done and any good exhaust shop can easily do this and make it fit properly because I've seen this done before with other LS1-style cat-backs on single cat LT1's...

Good luck yourself,

Mike

 

I called GMMG they have superior service, they said they could send me a kit with parts and intructions to move the hangers and make the piping work...GREAT PEOPLE OVER AT GMMG!!

Bersaglieri