I'm trying to figure out what exhaust setup that I want. If I didn't have a Formula, it would be pretty easy choice for me with the true dual setup and just put dumps on, but having a Formula, I like the tailpipe style, and in my opinion, it just wouldn't look right without the tailpipes there:

http://paradox.shacknet.nu/dave88lx/formula/back.jpg

I've got a 383 going togother, should be putting down around 400 to the wheels. I'm going to use Jet Hot's Long Tubes. I also want to use the DMH Electronic Cut-Out. I don't think I've really seen anyone run true duals all the way to the back, so I was thinking this:

Each header collector is 3". Run both 3" collectors in to a step UP adapter to 4". Run both 4" into a Y, or merge them both into a 4" electronic cut-out, and then run 4" all the way back for the rest of the exhaust. Either run regular custom pipe and make sure it goes in the right places out the back, or do an aftermarket catback, and just have an exhuast shop connect the collectors ro the cutout to the aftermarket catback like described.

The reason for the step UP would be for the least amount of backpressure through the dump?

I'm really lost as to what to do, but I want to figure out what to do, with this proposed GP coming up and all. I don't think I'll really be able to run true duals, so I won't be needing the dual dump kit, but I'll need to know what size single cut-out to get...

 

My friend did on his 98 Z28. He has true dual Flowmasters 40's series. He had to bang up the floorboard to fit them though. His clearance was a pretty big issue though. But he did extend it to 3" tips out the back. I didn't like the sound, and he eventually got tired of it and chopped the tips off and left it open after the mufflers. Sounded much better.

 

Thanks man...ttt

 

a local guy has it done on an LS1 SS
they are using those small bullit mufflers, so they fit in fine
it sounds awesome
-keith-

 

I have true duals out the back. You can see pics on my web site. A local exhaust shop did mine. Awesome setup.
http://members.fbody.com/furely/

 

How much did that set up cost you furely?

 

You would probably be better off just running normal cat back of your choice and having dual cut outs like the DMHs or regular Flo techs on the y pipe. It would be close to the same performance and you can keep your tail pipes. It comes out to be a little more expensive though than true duals but you gotta do what ya gotta do.

Good Luck,
-JohN

 

Im confused about the question. You asked about true duals out the back, but what you are asking is not true duals. True duals would not involve a "Y" at all, the only merging there is in true duals is an X or H pipe for equalization and to deaden the sound a little bit.

So what you are actually asking about is just a normal catback system which you can buy in 4" from Mufflex that will hook right up to their, or any other Y pipe with no fabrication required.

 

Correct, I was asking how difficult true duals would be to do, but it seems a bit much of a PITA, that's why I mentioned just going the Y-Pipe route instead...

I guess my main question was if you're running a single exhaust, would you just have it fabbed up with one cutout? Or would you still run a cut-out for each side, then have it Y-up togother....

Be cheaper to "Y" it then dump it...

 

I have done it on my 98 T/A and if I were to do it again I would not. There are to many fitment issues. The link below contains pictures, etc.

http://ericcer.tripod.com/TA/true_dual.htm

 

I think if I remember correctly my set-up cost $225 to have it done.

 

checl out www.lanesperformance.com

 

I had a custom system installed per my specs.
The flp y-pipe was chopsawed and opened up. Their restriction is a joke. The muffler shop reminded me that my setup was basically illegal, and proceeded with the work.

From there a single 3.0" pipe was installed over the axle to a flowmaster 2-into-1 pipe. I wanted a 3.5" pipe, but the muffler guy could not get it. The other option was 2-2.5" pipes. This option was scraped because lack of room under the car. Dual exhaust under the car is impractical, not necessary, and a PITA.

From the flowmaster pipe emerges 2-2.5" pipes, each leading to a small 4"diameter x 2.5 out magnaflow ss polished straight thru muffler. It's all mandrel bent 14 gauge exhaust pipe.

This sounds awesome, very deep. And supports a lot of power.
The cats quiet it down a lot. I haven't run it yet without the cats.