Fintile

I was just reading a few older exhaust threads and got to thinking. Has anyone tried to upgrade their V6 exhaust by using the stock GT exhaust? I'm thinking the H/X pipe most likely wouldn't work but could the over axel pipes? I'm mostly thinking out loud on this one. Seeing as most cat-back exhaust systems for the V6 are 2.5" and from what I've read the factory GT exhaust is also 2.5", might serve as a less expensive way to upgrade the exhaust that is if its not too complicated to have fabricated.

SilverSkoundrel

i would think on those newer models the v6 & GT had the same exhaust since the v6 is now dual setup stock. on my 05 it was stock y pipe exhaust and i had it upgraded to pypes dual with an X pipe and GT mufflers and i love it the way it is now. rolled muffler deletes for awhile and now im back to my GT mufflers.

steven46746

The mid pipe is 2.5 and over Axle back is 2.25 I think.

Fintile

On the GT? Does that mean the V6 has a smaller over axel pipe as well?

steven46746

Yes GT, not sure about v6.

JCStang

If it is better sound you are going for, I doubt that is the way to go since most GT owners have indicated the stock set-up is way too quiet.

Fintile

No I got a great sound with just my Magnaflow Street axel backs. I'm going for better flow. Was looking into the street series cat-back but then i realized I'd just be paying for their over axel pipes. So I thought I could remedy that by using GT over axel pipes. They would be roughly the same size as aftermarket for the V6. Figured it might be worth looking into.

Fintile

Found it! I visited a guy who was selling his stock exhaust H pipe back to muffler. We got to sizing up his stock exhaust and ya know with minor modification it can be made to fit the v6. Problem is its bigger than any of the aftermarket exhausts for the V6, 2.75" at the OA pipes, they also use what looks like the same ball joint with the mufflers. Didn't take it apart to fit. Now I haven't done any exhaust modifications to any car larger than a 2.7 before but from what I've experienced is there is a huge drop in trq when the exhaust is too big ( all sound and barely any movement). Would an extra .25" affect the 3.7 that way?

2012GT

I promise you're wasting your time putting GT exhaust on a V6. It won't sound any more aggressive. A stock GT exhaust sounds like a Taurus.

Fintile

Not looking for sound. Looking for a less expensive performance improvement. If I can keep my sound the way it is great. If it eats louder no worries.

2012GT

You will get absolutely Zero performance from this. Cai &Tune the car from a reputable company for gains. Gears and aluminum driveshaft also wake up the V6s.

Fintile

I already got all that and looking to see why else I can do. I've seen dynos with X pipes and exhaust paird ip with cai an tunes and they've shown some decent gains.

2012GT

Get a cat back system and get your tune revised. Or X pipe w axleback & do the same (tune update for the mods). You will be good for about 10 rwhp doing this.

Fintile

That's just leads me to go back to this again lol. The GT exhaust is just as big if not bigger than any of the car-back systems /x pipes out there. And even if the flow isn't good it's still better than what's factory. I could always get a tune for it afterward. There's gotta be another way that doesn't involve spending 1k for just 10 hp.

Christopher Van Hoose

I have factory exhaust on my pony, It sounds lovely and do not like the constant deepness from after market exhausts. I would love to replace the complete factory exhaust to get ride of the extra weight that the factory pipes bring. every pound makes a difference. In my opinion, the exhaust drones out the lovely sound that comes from the front end

Fintile

There's a guy I meet out here that did just that. Took off his factory cats, H pipe, and over axels. Had stock GT H pipe custom fitted with GT over axels and Roush axel backs for $150. Says he got a good 12-15 hp in the top end after a dyno. Now it might be because he removed his cats but some of the cat backs for our car state they will give the same gains so I figure for that kind of money it's worth a shot.

GreenCars

On the older V6's pre 2011 with the 4.0 adding duals + GT exhaust was worth it. with the newer 3.7 Duals factory adding the GT mufflers IMO would be moot. The best you are going to do if you want different or loader would be axle-backs from a third party.

Fintile

I have my V6 Magnaflow street mufflers I'm connecting it all to with a 2.5" inlet. Not using GT mufflers. Just H pipe and OA pipes.

Fintile

wow, funny how this thread just dropped an no one answered the question. lol

OK! So to revise my question. Would changing the over axel pipes on a 2011+ V6 3.7 give any noticeable performance gains?

spqr

For the original, I haven't heard of it being done. The only issue I can think of is that the pipes probably won't be the correct length as the exhaust manifolds don't line up.

No, I don't think changing the over axle pipes alone will net any gain. They shouldn't be a bottleneck on the system, particularly if other things haven't been upgraded.