True Dual ?
True Dual ? I am getting ready to purchase mufflers, cats, etc for a dual set-up. I want to go out the back with it, but I am torn on piping size. I have had an idea stuck in my head of what I want to go with and was just looking for some feedback on what you guys think it might sound like or could point me in the right direction. I was looking to go with LT's into some fresh high flow cats, to 3' piping, into spiral flows and then necking down into 2.5" piping under the axle.
I want something that has a good low rumble to it but is still quite smooth sounding at most RPM's.
I want something that has a good low rumble to it but is still quite smooth sounding at most RPM's.
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
I would buy the panhard relocation bracket and make room to go over the rear axle if I wanted all the way out the back...I am sure you will end up with a ton of clearance issues if you try to go under it...Why not just run 2 1/2 duals under the car and dump at the axle like everyone else..Just wondering.
I would buy the panhard relocation bracket and make room to go over the rear axle if I wanted all the way out the back...I am sure you will end up with a ton of clearance issues if you try to go under it...Why not just run 2 1/2 duals under the car and dump at the axle like everyone else..Just wondering.
The majority of dumped duals are 3''.
TECH Resident
Joined: Jul 2007
Posts: 818
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From: Iowa
heres some pics and info if you havent seen it already https://ls1tech.com/forums/generation-iii-external-engine/531756-true-duals-questions-answered-here-post-your-information-pics-too.html
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What blows about having it dumped at the axle is all the dirt that it blows up. I dont drive down dirt roads but some parking lots are bad. Choice of muffler come own to sound. I took off my bullets for 1 cambers. No X or H pipe. Im for topend and those are to help low end Tq. And the noise in the interior, unless you have the pipes extend to the axle and turned a little more than a 45 degree. Not at the tires, but kinda towards them. A 2 1/2 system will be enough and give you more ground clearance, and over the axle. It will support up to 450-500 hp, contrary to what most on here believe.
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What blows about having it dumped at the axle is all the dirt that it blows up. I dont drive down dirt roads but some parking lots are bad. Choice of muffler come own to sound. I took off my bullets for 1 cambers. No X or H pipe. Im for topend and those are to help low end Tq. And the noise in the interior, unless you have the pipes extend to the axle and turned a little more than a 45 degree. Not at the tires, but kinda towards them. A 2 1/2 system will be enough and give you more ground clearance, and over the axle. It will support up to 450-500 hp, contrary to what most on here believe.
2.5 is more than enough for the average car with duals. People like to get stuck on the 3in figure for some reason, it is great for catbacks but overkill and cost more on duals. 
Teching In
Joined: Oct 2006
Posts: 44
Likes: 0
From: Maryland
TECH Addict
Joined: Nov 2005
Posts: 2,379
Likes: 2
Run the panhard relocation kit. People think its a waste of money to run duals out the back, but if you are going to do duals, might as well make it look good. We spend god knows how much more on other stuff, what's a few extra $ on that little extra bit.
I run true duals out the back, 2 x 2.5 inch. SS all the way to polished SS Z28 tips.
I wouldn't have my car look any other way than be proud that it's a Z28.
As for flow, I went from 306HP to 349HP at the wheels from doing longtubes + 2.5 inch true duals. I think up to 450 HP at the wheels, 2.5 inch true duals will be fine. After that goal, think bigger.
I run true duals out the back, 2 x 2.5 inch. SS all the way to polished SS Z28 tips.
I wouldn't have my car look any other way than be proud that it's a Z28.
As for flow, I went from 306HP to 349HP at the wheels from doing longtubes + 2.5 inch true duals. I think up to 450 HP at the wheels, 2.5 inch true duals will be fine. After that goal, think bigger.
The cheap way to get the exhaust "out the back". lol
I know a lot of guys that do this with the CME exhaust on camaros.
Just leave the CME tips and dump it at the axle.
I would buy the panhard relocation bracket and make room to go over the rear axle if I wanted all the way out the back...I am sure you will end up with a ton of clearance issues if you try to go under it...Why not just run 2 1/2 duals under the car and dump at the axle like everyone else..Just wondering.
Wanted to use the TA cut-outs and under the axle for cost and less bends. Have read and heard of good success with under the axle, too.
I was also thinking that, with 2.5 after the mufflers, the gasses should have sufficiently cooled to not require as much piping. Didn't know if it would sound any different from 3" all the way vs. 3"-2.5"
I was also thinking that, with 2.5 after the mufflers, the gasses should have sufficiently cooled to not require as much piping. Didn't know if it would sound any different from 3" all the way vs. 3"-2.5"
Whoops...what he said. Just read SOM's post.
My future mods aren't really anything more than h/c. Probably pp ls6 heads and 224 cam.
I know 2.5" will support more than I'll need for a long while, but I am mainly going for sound, unless it's going to drastically affect my low end, i.e. non-lead footed mpg.
My future mods aren't really anything more than h/c. Probably pp ls6 heads and 224 cam.
I know 2.5" will support more than I'll need for a long while, but I am mainly going for sound, unless it's going to drastically affect my low end, i.e. non-lead footed mpg.
Teching In
Joined: Oct 2008
Posts: 40
Likes: 0
From: The 717
I have 3" all the way out back and under the axle (they are low because I did not want to have to chain the axle), magnaflows under the bumper.
-The front half of my exhaust was done a year ago and was a TERRIBLE JOB and the shop refused to change it/refund me my money, so it's a work in progress lol. I just had to get it out the back and emissions legal.
Hope this helps!
-The front half of my exhaust was done a year ago and was a TERRIBLE JOB and the shop refused to change it/refund me my money, so it's a work in progress lol. I just had to get it out the back and emissions legal.
Hope this helps!
Teching In
Joined: Oct 2008
Posts: 40
Likes: 0
From: The 717
Run the panhard relocation kit. People think its a waste of money to run duals out the back, but if you are going to do duals, might as well make it look good. We spend god knows how much more on other stuff, what's a few extra $ on that little extra bit.
I run true duals out the back, 2 x 2.5 inch. SS all the way to polished SS Z28 tips.
I wouldn't have my car look any other way than be proud that it's a Z28.
As for flow, I went from 306HP to 349HP at the wheels from doing longtubes + 2.5 inch true duals. I think up to 450 HP at the wheels, 2.5 inch true duals will be fine. After that goal, think bigger.
I run true duals out the back, 2 x 2.5 inch. SS all the way to polished SS Z28 tips.
I wouldn't have my car look any other way than be proud that it's a Z28.
As for flow, I went from 306HP to 349HP at the wheels from doing longtubes + 2.5 inch true duals. I think up to 450 HP at the wheels, 2.5 inch true duals will be fine. After that goal, think bigger.
11 Second Club
Joined: Dec 2007
Posts: 868
Likes: 0
From: Charleston, SC
I got my duals finished up today. i got better ground clearance than i did with my lt's, o/r Y and lm2 setup. mine looks identical to the red t/a above except i dumped before the axle. although most people say that dynomax bullets are LOUD, i went with them anyway and to my suprise they werent that loud. in the car you really cant hear em unless your idling, hardly any drone and no rasp whatsoever! the best part is that i only paid 300 for em.