So I've got my GT take off mufflers and bumper cover arriving from Casco tomorrow, and decide to call the largest custom exhaust place in my area for a rough quote.

I talk to the guy explain that I have a new Mustang V6 and I already have the GT mufflers and I just need them to fabricate a reverse "Y" and tie in the second muffler. The guy goes on to quote adding dual mufflers they'd supply and running seperated duals (no connection) He comes up with $375.

I explain again I already have the mufflers and want a reverse "Y" as "true" duals are not going to sound good on a V6 and might harm performance. He goes "oh" and requotes the job without the shop mufflers at $350

Somehow methinks I'll go elsewhere

 

true duals won't sound as good???

also, how would they hurt performance?

 

Well its based at horror stories toward some who have gotten true duals and lost power because of loss of backpressure. Those people also didn't do it right by not having a crossover pipe, so a well done true dual setup is untested as far as I know. Dyno tells all.

 

loss of backpressure will harm performance.

 

To me it sounds like the Exhaust guy didn't want to do the work so he quoted you an artificially high price.

 

Hmmm, I wonder if I get the JBA true duals if I will have lack of back pressure??

 

There was a thread while back that talked about this. It introduced the Magnaflow exhaust systems for the V-6. One of the guys from Magnaflow answered some questions. What I took away, true duals on stock 4.0L is took much. It seems you need to keep the velocity of the exhaust gases up and an oversized pipe will kill this. He said you would make some top end power with true dual/x-pipe but you would lose more power down low. You got more power under the curve with a y-pipe. I went to their website and looked around. Some interesting points, according to Magnaflow's frequently asked questions, most people are better off with a single exhaust except for extreme engines. The ideal size for a 4.0L engine with 200 HP was a single 2.5" pipe. If you run duals, 2" to 2 1/4" was the ideal size. I noticed the Lincoln Aviator runs a single 2.5" pipe with a 300HP V-8. I would still get dual for appearance but wouldn't expect a lot of performance gains.

 

Just to clarify by "true" duals in the Muffler guy's context he meant each cat feeding one muffler, with no "X" "H" or "Double Y" connecting the two sides at all. People who have tried this with a six have been disappointed with the resulting sound.

I don't think he was trying to duck getting the work, I just got the feeling that $300+ is the price range that makes him happy and he was going to shoot for that whatever the labor involved

 

I'm one of the V6 owners that wanted to go the x-pipe route but the exhaust guy said he'd tie into the y-pipe. What he did was cut the y-pipe out and it's now running true duals. It stinks big time. Sounds horrible - almost ricey. Lost HP & TQ. We went to another shop last night and I'm going the x-pipe route. Ordered the Bassanni x-pipe and can't wait for it to get here....

 

Ive been running true duals for almost 7 months now.. doesnt sound ricey at all. There is a HP loss down low, but the car really loves to pull through the higher RPMS. I have 2 small resonators in to help with the backpressure loss. And yes, you're all right.. these cars DEPEND on backpressure for performance. The JBA "true duals" arent really true duals as far as I can tell, they look to have an H-pipe right behind the cats. Personally, I havent decided what Im going to do yet as far as a midpipe. Ill probably have an Hpipe added in because its my cheapest route to go, and no one has really gone that route yet with the v6.

 

Frank: Is the Bassani X-pipe a direct bolt up on the V6? I'll be very curious to hear your results. If it works well, that seems like a fine way to go.

 

I had also heard the horror stories about true duals and instructed my muffler shop to install a reverse Y for my GT mufflers. They didn't do it because they were concerned about the proximity to the driveshaft. They ran the left pipe up and torched through the headpipe and welded it in there leaving the stock Y intact as a crossover. Initially it sounded strange because the right muffler was already broken in and the left wasn't. But over time the sound has balanced out and it sounds really good now. If there is any loss of power, I can't tell. Seems pretty darned quick for a 6 in fact. I romped on it yesterday to make a light and scratched the tires on the downshift (auto) Cool!

 

Since I can't find the info on the JBA site, are their H pipe duals 2 1/2"? I guess I'm gonna wait untill I can get some that are 2" even.

I have heard about having too much volume that makes it unefficient. Cooler gases are harder to push than hot gases, so that is the reason why with duals at 2.5 each would get you more on top but less down low. I suppose duals at 2" would keep piping at a level where gases will remain hot and easy to be pushed and still be better than a single 2.5 Y pipe.

 

I would assume that JBA would have known about the backpressure issue when they made the true duals for the V6. Hopefully these issues will be addressed soon.

 

I guess asking them directly will be better, lets see how fast they reply.

 

The JBA's are not true duals, they come off of a y-pipe. I'm guessing for the same reasons previous discussed.

 

JBA has released what looks like an H-Pipe, as their True Duals. The y is a part of their Evol set-up. Of course, I could be wrong....

 

Paul - yes the Bassani is a direct bolt-on to the cats. I picked mine up from 50resto.com

As far as the JBA setups, Doc0075579 is correct in his post...

 

I went to the JBA website and did not see a H-pipe for the V-6. Is it listed some place else? The "dual exhaust" system shown at the site has a reverse y-pipe that connects to the stock y-pipe.

 

1trickpony - here's a link that shows that 2 different JBA systems

http://v6mustangstuff.com/05V6Exhaust.htm

The "2005 Mustang V6 JBA Evol Dual Exhaust" for $559.00 is the setup that uses the reverse Y pipe.

The "2005 Mustang V6 JBA True Duals" for $629.00 looks like it's making it's own H pipe connection.

Hope that helps...