Best 3" setup for a GLHS?

[Marcus86GLHS]

good news is the emissions testing laws here in CT have changed, so my '86 glhs is now exempt from all testing, so, its time to get rid of the cat. and while i am at it, go from 2.5" system (current) to a full 3" system.....i currently run a 2.5" swingvalve as well.

Whos makes the best all SS 3" system for my car, and, does it require a seperate "test-pipe" to fill in for the missing cat (i'd prefer it not to need a seperate pipe)? I see the ones from FWD Perf. do need a seperate test-pipe is that correct?

Should I change the swingvalve to 3"? who supplies those?

Muffler recommendations?

thanx folks for the feedback.

[iTurbo]

I have 3" exhaust on my Omni. I had a TII turbocharger rebuilt by Turbos Unleashed and at that time had the swingvalve upgraded to the 3" unit. I also purchased the matching 3" downpipe. The downpipe from TU is very nice and fits perfect. It comes with a custom SS donut flange and 3" donut. From there it connects to a 3" FWDP catback exhaust. Since I live in Wyoming, I don't use a catylitic converter. I also bought FWDP's 'test pipe'. The muffler is a 3" Dynomax Ultraflo round. After that, a short, straight section of 3" pipe is used to extend the exhaust to the rear of the car, using the stock exhaust pipe cutout, under the bumper. Everything is aluminized, but also available in stainless steel.

I'm very happy with it. It's a little loud, especially with the 2.5L in the car. My Shadow also has an identical 2.5L T1 and identical exhaust system, except it has an oval muffler, and a Mitsu turbocharger. The two cars sound exactly alike, except for the Omni is a just a little louder. I have a digital camera and can take some pictures of it soon. I just wish my computer had a USB port...

[Marcus86GLHS]

thanx for the info.....so your system consists of (5) parts?: the downpipe, the test pipe, the main pipe, the muffler (behind the rear axle) and lastly the tailpipe. do i have it right?

doesnt anyone make a setup that goes direct from downpipe to the muffler, giving one less piece (the test pipe)?

yes i'd like to see any pix if it isnt too much hassle....

i dont mind loud as i use the car only for occasional cruise nites.

[iTurbo]

After the swingvalve, it's: downpipe, test pipe, cat-back pipe, over-axle pipe, muffler, tailpipe.

[Marcus86GLHS]

wow thats a lot of welding!

any pix?

btw, can you use 2.5" swingvalve w/ a 3" system? i always wondered what gains are to be had w/ the larger swingvalve.

[iTurbo]

Quote:

Originally posted by Marcus86GLHS wow thats a lot of welding! any pix? btw, can you use 2.5" swingvalve w/ a 3" system? i always wondered what gains are to be had w/ the larger swingvalve.

Yes. I have 3" exhaust on my Shadow, but it still uses the factory '89 Mitsu 2.5" turbo exhaust outlet. When I bought the exhaust system for that car, it came from JRBExhaust. That kit is a little different than the FWDP cat-back system. It comes complete from downpipe to rear bumper (just pipe). The JRB Exhaust system didn't come with a donut or flange, so I had the exhaust shop weld the 3" downpipe to the stock 2.5" downpipe. I had them weld the 3" as close as possible to the turbo, so the factory downpipe extends for about 6", which is when the 3" starts. For this reason alone, I decided to get the TU 3" swingvalve and downpipe for my Omni.

I can get pics, but it will be Friday at the earliest.

[Marcus86GLHS]

good info.

i sent a message to chris at TU asking about availability for 3" swing valves, i suppose the extra $175 will be a wise investment since i am tearing into the system anyways might as well replace the valve.

when you take your pix, can you take one showing how low the system dangles down below the floorboards? that is a concern of mine, i dont want the pipes to be real visible, or worry about bottoming out/scraping in certain situations. you ever have a problem like that?