2.5" TD's H-pipe into GMMG
 

I should be finishing up my over the axle true duals this week. I went with the 2.5” stainless flowmaster mandrel bent universal kit, Founders PHB relocation, magnaflow metallic substrate 3” cats, H-pipe, 3” to 2.5” reducers, and am tying into my GMMG catback.

I will post pics and a sound clip but I remember seeing someone else that did something similar. The problem is I can’t find the thread. Anyone have it and/or a sound clip?

Just finished this up. I must say, it sounds absolutely nasty! The car just sounds mean. All rasp is gone but still has that GMMG sound. It's a tad loud for my taste but still ok. It's on my procharged 402 car so I'm sure on a 347 it wouldn't be as loud.

I'll try to take a sound clip soon and post it.

Sounds unique. Look forward to hearing it

I assume you went the 2.5" route over the 3" route due to clearance?

Ground clearance yes, but also a number of other reasons. I think dual 3" is pointless, I doubt it gets you anymore power, much easier to route dual 2.5's over the axle, 3" would be louder, and also 3" is pointless dumping into a muffler system with 2.25" inlets.

All that said, I just got a great deal on a catted kooks TD system. Taht will go on my blue TA though. It would be great if Kooks would offer a 2.5". It would be quieter, not melt gas tanks, and not hit against everything underneath the car.

Anyway, I'll post pics and a sound clip asap.

got the part # for the xpipe?

I used the Hpipe from the kit.

Pics below of it tack welded together. Most came out crappy because of low light I guess.

do'h I meant to ask the H pipe kit but I found it.

Pictures look great.

Respectfully disagree based on personal experience. My car responds very well to anything freeing the exhaust flow. Even with 3" duals on a ls1 with barely touched 799 heads and a mid size cam the car was gaining around .1 and 1mph in the 1/4 running open cutouts rather than through the 3" exhaust.


If the muffler inlets are truly 2.25" that will likely pose a restriction as well. My car had 2.25" duals from the old engine setup and piece by piece it transitioned to 3" and each time part of it opened up the car went a little faster. Some guys do contest that since the exhaust gasses near the rear of the car are cooler the smaller pipe back there is less detrimental though.

But if you aren't after every little bit it's not worth worrying about. Setups also vary so in some cases I can agree with you there might be no gains

My bullet inlets/outlets are 3". Full 3" true duals here, and I know it's worth power over 2.5" duals.

Awesome exhaust setup! Catted true duals owners unite haha.

Sound clips?!

In for a sound clip. Doing Basani td myself soon.waiting for it to be delivered

Not looking for a 2.5 vs 3" argument. Just didn't think it made sense here or at all for my car.

Thanks for the compliments. I was putting some finishing touches on it last night. I will have a sound clip over the weekend. I actually wish it sounded a little smoother than it does. I might have to add some resonators.

Awesome. I actually wanted the bassani kit but couldn't see hacking up a brand new system to fit my headers. This was cheaper and I always wanted to hear what it would sound like. The bassani system sounds excellent. I wish they offered it catted for headers.

Great concept and it looks like a very clean install. Time will tell if it will give you a sound you like. When I tried an ORY into my GMMG on my stock 346, I found it intolerably loud. Had to go with cats, powerstick, and resonator tips to tone it down.

In for some sound clips.

Sorry for the long delay on the sound clips. the car is down right now for some other work. I just don't have time to get it back together and get a good sound clip. Once I get time to get it back together and running, the first thing I'll do is get a sound clip.

best sound ive heard yet
 

Damn this thing is bad ass. Kooks 1- 7/8 headers and basani true dual
https://youtu.be/CXBvFq9rnw0

Try this link