I currently running LPP lontubes, ORY, and a GMMG catback. I have toyed with the idea of selling the GMMG and ORY and getting the LPP true duals that just came out. Before I make a decision, I just want to know, realistically, how much power would I pick up with TD's?

The only pro I can see is picking up some ponies.

The cons are I would lose a little ground clearance, my DS loop would no longer work and I would have to figure something else out on that, and I don't know if they would drone at all at highway speeds.

For anyone who has true duals, do they drone at all while driving around? These will be dumped at the axle.

 

Yes it will drone, and no you won't see noticeable gains.

 

Problem solved. LOL thanks man

 

I've seen local guys pick up anywhere from 10-12rwh by ditching their catbacks and going TD's...so to say there won't be a noticeable gain, I disagree.

 

GMMG is essentially straight through, though (right?). This is why I made my statement.

 

It might be I'm not for certain. Regardless it's a catback and it will be more restrictive and hold out on HP over TD's. With TD's though you do give up ground cleance, it will be louder etc etc. Me, I would stick with the GMMG. If you sell it, send it my way

 

what else is done to the car? if its a bolt on car i would say your not going to pick up anything. if its Heads/Cam i think you will.

 

Agree ^

 

If you do sell it, how much would you want for your GMMG?

I'd say there should be a slight gain.. Depends on your setup and budget. Does every last HP out of your setup matter to you?

 

The REAL problem with a F body catback is the crossflow muffler. Take that off, put a straight single in out muffler on with a single outlet on the drivers side and you would be amazed the power even a stock catback can support.

I would venture to say a LSx catback with a muffler like above would support 450rwhp.

A buddy has a 2001 SS with heads,cam etc with a SLP center mount exhaust (CME) with a 2 1/4! y pipe It gained nothing uncapped. Makes 450rwhp.

 

I don't think you'd see much gains going from GMMG to TD's...

GMMG isn't as loud and doesn't drone as bad as TD's and you have essentially the exact same performance. GMMG is probably THE catback for LS1's.

 

Im thinking about switching back to a cat back, with cut outs untill I start to spray the car.
A. I really love the sound a H/C package makes with a cut out at idle.(Awesome crisp crackle)
B. Im sure you loose low end HP/TQ with 3" TDs unless your car is a monster 450-500hp
C. I cant get any DSL to fit
D. TDs drone alot
E. TDs are loud as hell and cops dont like that.
F. I see lots of cars that dont make any gains by switching from a good CB w/cutouts
G. My car has dynoed less ever since I switched to TDs(with that said I also made a bunch of other changes so I cant really say it was the TDs)
H. Ground clearance
I. With a CB and cut out you can be loud or quite at the flick of a switch
J. Its illegal

Now dont get me wrong!!! I love my TDs and they look and sound bad ***, and for a track only car its great but its annoying on the street. For that reason Ill prob switch back sooner or later.

 

^ that sums it up pretty nice.

 

That's because the Y-pipe is his restriction!

 

Well put! I got a good deal on a jethot ORY with 2 3" cutouts on it... Not sure what I'm going to do with that setup but I'm running it through my loud mouth. I personally like loud, but to each is their own.. I can get over raspyness too

 

The main reason I went with TD's is for weight. But I also have mine dumped at the axle.

 

i have a ypipe with a bullet dumped at the rear axle for weight, weighs A LOT less than my old Trueduals set up

 

Yea I had that for a while. I don't think the true duals are that much heavier. It is an X instead of a Y and then another bullet muffler.

 

Ummm, he uncapped it on the dyno at the collector and it made the same rwhp as it did going through the 2 1/4 Y pipe, May have been a 2 1/2 pipe. Either way it made no improvements uncapped.

 

This would be THE way to go, put a Magnaflow round muffler on, ding the floorboard a little and turn it out. Less weight.

I have considered this, but I am too old for that crap!