I wrote a while back after having Flo-Pro Twisters installed with an H-pipe under-axle true dual system. Sorry I was never able to get pictures or sound clips. After having it for a couple months, I noticed some rubbing issues around the rear-end. Also, when I put the car on a lift, the axle laid on the exhaust. Not so good! So I went today and had the tips and pipe under the axle removed and turndowns put in behind the Twisters. Sounds a little louder, and I got a slightly deeper tone from the echo off the ground. But there is no more rubbing. I still recommend the Twisters to anyone wanting a slightly different LS1 sound. Very deep and in your face at WOT, but quiet as hell at idle. Have yet to hear an LS1 that sounds like mine. Just wanted to let anyone considering under axle know that there is potential for rubbing and sagging tips after lifting the car. Also, quick question. When I had the true duals put on, the cross piece under the tranny was removed. Is that something I needed, or no big deal? Thanks a lot.

 

eek, i want that same setup without the twisters... does this happen to about everyone that does under axle true duels?

how about the H pipe...do you notice a difference in sound between them and the x's? thanks for the heads up.

 

If you go with an under the axle exhaust. You either always need to use a drive on lift. Lifting the car by the jack points will only cause the problems that you've mentioned.

A solution to this problem. Have the under the axle exhaust setup so that it can be removed at or after the mufflers so that the car can be lifted without issues.

There are a few pics of a red TA that had flanges right before the rearend so that the exhaust could be removed.

 

just leave it dumped and put some dummy tips in. thats what im working on now. just get long (18-22 inch) tail pipes so you can't see the ends of them unless you look under the car.

 

Of course under the axle duals have that "problem" as you call it. You just have to be more careful and understand how your car and axle work. Under axle duals are fine as long as you drive on a lift, jack from the axle, or disconnect the back part when lifting. As for the rubbing, your exhaust guy didnt know what he was doing if he put it that close to the axle at rest.

 

Thats what I'm going to do.

 

the tunnel brace, no biggie, almost everyone with true duals takes it off.

 

How much pressure do the rear springs supply when at rest? Maybe a few hundred? How much pressure do you think the springs would have unloaded an inch and resting on the exhaust? Maybe a hundred or so? Hundred and a half? I dont really know, but I bet its not too much. Maybe if you put exhaust hangers both in front and behind the rear axle, the exhaust can support the pressure of the rear springs without deflecting? Just food for thought - I cant say that it will actually work.

-T

 

You also have to be careful with the suspension travel when going under the axle. If you hit a pothole or something the axle will drop and hit the pipes.

 

as i was saying, just like a bitchy chick, dump it and leave it...life is always wonderful afterwards!

 

i would..but its my daily driver..plus im doing it more for looks, cuz i think that seeing the duels dumped from behind looks unclean...for lack of a better word.

 

my car is a daily driver. i set myself up with some bullets, sounds too good dumped to put tail pipes on. plus its been ap ain in the *** just to get the x pipe to fit right (bad shop experience). I did pu t a set of long tips in the rear to clean up the look. that would work especially well for a trans am cause of the rear valance. you couldn't see the ends of the tips. mine i used 22 inch tips. so they go far back enough that the only way to see where they end is if you look up really close.

it is pretty damn loud though, i shoulda gone with some differen tmufflers but hell the ground clearance is great without even having to do any floor board modification.

 

you might have just sold me, i will try to get an h fabbed up with sweet thunder muffs...cant wait, im ordering the pacesetters when there are more in stock.

 

**** are places out of stock of the pacesetters again?!?!?

lemme know how the H pipe sounds with sweet thunders, i have heard that this kind of set up is actually louder than if using bullets!

 

As far as the axle hanging on the exhaust, I knew it was a possibility, but I really didn't like it after I saw it. I could live with it, but I don't like half-assed at all. So I changed it to my liking and it really does sound a lot better dumped. I can live without tips. It makes people ask questions and lets me show off the car. As for the rubbing, I didn't see how it could on acceleration. There was a ton of space between the mufflers and the bottom of the car. But after ditching the under-axle setup, no more noises, so it fixed it. My muffler guy did a really good job though. Just the car being silly I guess.