No garages around me work with 3" custom exhaust and I want to connect my Huron Speed AC Turbo kit back to a 3" GMMG catback on my DD 02 Trans Am. Single pipe no cats.

It appears I just really need one custom pipe connecting to the Huron Speed exit that has a few slight bends to get under the driver's seat, from there I can just do 90 degrees towards passenger side and another 90 degrees pointed back with a long pipe to reach the catback. Can use stock pipes with expander and cut/make those last two.

I have a harbor freight welder, and have frankensteined a few welds in the past, but that's the extent of my welding skill. Highly doubt I could make the custom pipe myself.

I really don't want to do a flexpipe sorta thing, very ghetto.

I could reduce the 3" down to 2.5" possibly and see if some garage can do 2.5" custom I guess and skip the GMMG, not sure if they even do that or if that'd be problematic for my setup. Planning on keeping it around the 500hp it has now.

I understand there used to be a pre-made pipe you could buy for this but it's no longer available...?

Anyone have suggestions I'd like to hear. I've literally done this whole build myself, not a single other person has turned a single bolt on this car, and I have it built this far just to be stopped by a problem like this.

 

If you were able to make the pipe yourself, tack it together and take it to a shop and have them finish weld it up for you.

 

I guess I was just hoping to hear that there's an aftermarket one I could buy, instead of learning how to be an exhaust fabricator (on top of car tuner and mechanic LOL).

Yes, that sounds like a good plan, thought of that myself, I'll just tack weld some pipes to hold the shape and get the actual seams done by a real welder if I can't find a better plan.

I am going to talk to the shop ahead of time and ask them if there's any limitations, like how big can gaps can be, and how small the slivers can be, stuff like that.

I think I am going to give it a shot with one of those amazon 3" eight-piece custom exhaust kits that has all the various pre-bent piping, I'll just chop it up with my cutter wheel tool and try to tack 'er up and we'll see what we get. Should be interesting.

 

For future searchers, I was able to make a pretty good exhaust using one of the 3" universal kits on amazon/ebay for like $100. You'll need at least two 45's and two 90's and some straight pipe. From the Huron Speed exit which is already bent down somwhat, I used a 45* pre-bent pipe angled down-and-outwards which attached to a second 45* pipe angled level parallel and straight back. Had to trim the two pipes to get the right fit but it put the exhaust right into the depression where the drivers stock exhaust indent would go, under the driver's seat. From there I used a 90* to point straight across towards passenger side under the driveshaft and another 90* to point straight backwards where I used a straight 3" to meet up with the typical 3" catback. It lined up really well. I used a pipe expander rented from advance auto to make it all slip fit (even though most of it already had the slip fit ends, I think I had to do one pipe). I understand that the two 90's are sub-optimum but I was still able to eek out an 11.48 at 123 with 11psi so it must not be too bad LOL.

 

Needs an electric cutout, my last car had a full 3" exhaust with a big Magnaflow muffler and adding a cutout made a massive difference.
The spot under the driver floor board is a perfect spot as well, it tucks up in there nicely, is far enough away from the turbo to provide long trouble free life for the cutout and there's a grommet in the floor so running wiring is cake.

 

Good thought, good point, but I'm at an odd place with this car that most people won't understand. I actually keep forgetting this myself.. the "go fast" bug really holds strong ha ha

At this point no other mods really make sense. *If* I did want any more power at all, I'd just throw a stronger spring or boost controller for the WG LOL... I'm only at 10psi (sometimes 11psi) so lots of room to grow power there.

I am in a mode of "the most reliable power" for a daily driver car, meaning I am hovering right around the point where I still think the stock 4l60e and rear will "likely" survive a while. I figure i'm at around 530HP based on my trap speed of 123mph

I know this is basically opposite of what everyone else on this board is doing :-)