Some of you wanted to see pictures of the finished project. Here's my '87 IROC-Z With true Dual 3" mandrel bent exhaust with H pipe, dual Hooker Aerochambers, and 3.5" stainless slant cut tips.

This was my first exhaust job, and I've only been welding for about 2 months so I'm VERY happy. Made a HUGE seat of the pants difference from the 2 7/8 single exhaust I had.


http://home.comcast.net/~twilightoptics/exhaustfullside.jpg

http://home.comcast.net/~twilightoptics/exhaustclearance.jpg

http://home.comcast.net/~twilightoptics/exhaustcornerbumper.jpg

http://home.comcast.net/~twilightoptics/exhaustreardown.jpg

http://home.comcast.net/~twilightoptics/headersback.jpg

http://home.comcast.net/~twilightoptics/Hpipe.jpg

http://home.comcast.net/~twilightoptics/exhaustrearup.jpg

What do you guys think? I ran 13.0@107 before exhaust/throttlebody. I hope to hit 12.7ish on street tires still and maybe that magical 11.XX pass with some stickies!

Nice work! I've still got to get on mine, got a box of aluminized 3" 90's and 180's waiting patiently, for the El Camino. I've done numerous 2 1/2" dual systems for myself and friends, and a couple dual 2 1/4" into single 3" for my trucks, too. Keep it up, you'll never go back to storebought. graemlins/thumbsup.gif

Great work! My little brother has a '82 Camaro with a 383. Man those things a cramped under there. I'm amazed it fit. He has a single 3" system. Most impressive! graemlins/thumbsup.gif

What, no sound clip? Been wanting to hear what a dual Hooker Aerochamber exhaust sounds like on a small block chevy.

Looks sweet. Was it a single 2 7/8 system before?

Awesome job and nice looking car ;) (I have a '91 RS). I've seen other pictures of it from John and through Cascade. Are you using a stock oilpan with that exhaust? How close is it to your oil pan?

I posted a link of this on my webboard for the guys to check out. It's really impressive.

where do you guys get the piping to do this?

Thanks for the compliments guys!

Stock oil pan, no closer than the non mandrel bent 3" pipe there before. Maybe this will help. It seemed to have plenty of room. Hangs down a HAIR lower than the tube bent one, but I wasn't going to complain. I did have to "massage" the underbody for the straight pieces that run along the driveshaft.

http://home.comcast.net/~twilightoptics/pipeundersmall.jpg

Slowpoke, no sound clip yet, have to find a way to get one. It's a very different sound from the single flowmaster I had before. It was a single 2 7/8..... the Y pipe was 3" tube bent, into 3" cutout, into the factory Intermediate 2 7/8" pipe that was... a bit crushed where it went over the axle. Then a crossflow flowmaster. It sounded pretty darn healthy before with the flowmaster, now it's deeper and well not so flowmastery. It IS louder and sounds more beefy! hehe

Originally posted by pro785racr:
where do you guys get the piping to do this? I second that question.

I bought 2 lengths of 4ft pipe from Summit, and 8 Mandrel U bends 4 or 4.5" dia(Can't remember which it is they offer) Use the U bends and cut the angled piece off it that you need!

Hangers/Tips I got from Baxter Auto

Flanges to the headers I used standard 3" 3bolt header flanges(Had to weld flanges onto my shorty headers) Local exhaust shop has some that are twice as thick! $12 a pop though but I've had enough leaks in the past on my old pickup with the regular ones that I opted for these.

I forgot, what size motor/did you do it so that it needs a dual 3" exhaust instead of a single 3" or dual 2 1/2"? Is your sig everything that you've done to it? Or is there more?

I'm in the process of getting my '91 Z28 up and running again (FINALLY!!!!). According to my buddy, the guy who I bought it from, it was running low to mid 13s. All that was done to it was ported and polished heads, runners where ported, not sure if the plenum was ported but I'd imagine that it would be since the runners are ported, 4.11s out back, and the cats were gutted, I believe that's about it. What did you to yours to get it to run 13 flat, and now expect 12s/11s? Sorry for the Q's, I'm just really curious.

Had an epiphany! Laptop I use for tuning the commander + microphone = sound clip

The first one is from about 3ft back from the exhaust. The 2nd one is about 10ft back. They are about 1.4mb (I don't know how to scale them)

Idling in park/gear/park/rev

Exhaustnear (http://home.comcast.net/~twilightoptics/exhaustnear.wav)
Exhaustfar (http://home.comcast.net/~twilightoptics/exhaustfar.wav)

I only got to hear the 1st one, and boy did that take FOREVER!!!! (d*mn dial up!!!) but man was it worth it!!! a very big graemlins/thumbsup.gif

I get my mandrel bends from J.C. Whitney, 16 gauge aluminized, and straight 14 gauge aluminized tubing lengths from the local Napa. Saves on shipping oversized stuff, and JCW is a little cheaper on their bends than Summit or Jegs. The 3" stuff is kinda pricey, though. I think the stuff I bought for the El Camino came in close to $200. Friend I was building an exhaust for at the time paid the shipping, along with his 2 1/2" stuff.

Glad to hear it fits fine. I have to build myself a 3" y-pipe with cutout this spring. Good choice on the Aerochambers as well graemlins/thumbsup.gif . I run a single 3" aerochamber catback behind my 406. Love the sound at idle, very close to yours but 50 cubes deeper sounding :D

Nice job..bet it sounds awesome graemlins/thumbsup.gif

thumbs up. everyone's got to like that sound. very healthy.

Everything that's in the sig is what I've got.

From what I've read, word of mouth is dual 3" was a HAIR to big for me, and the exhaust companies (Hooker, Flowmaster, Dynomax, etc) Say that I'm just at where dual 3" would be benifical. I figure if I ever put a play shot of n20 or put a supercharger on or even more cubes, I'm good to go. It made a HUGE difference over the single 3" cutout, so I'm happy with that!

Should be somewhere around 430-450HP at the crank. I'll find out on the 26th what I've got on the ground.

Thanks guys!