I have an '86 Z-28 an i want to install true dual exhast with two cats and two mufflers. My only concern is the exhaust being too low to the ground...any suggestions?

 

this idea has been gone over a lot, many will tell you that a single pipe is all you need, i personally see true duals as the coolest mod you can do. and people wonder why mustangs sound so much better than 3rdgens, mustangs have dual exhaust, we do not. here is a link
http://home.nycap.rr.com/gbeard1/mod.../exhaust1.html
this is for dual exhaust with glass packs and cats, i have been studying the pics and it looks plausible.

 

mustangs sound better because they have a better sounding engine.

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-Tas
'89 Formula WS-6

305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options

 

The past couple weeks it's been discussed to death over at camaroz28.com. Apparantly it's the firing order, or so they say...

 

Tas is right: Mustangs sound different because of their different firing order, among other things.
Edit: forget the firing order argument--renumber the cylinders on either an FI 5.0 (or 351W) or an LS1 so that they use the same numbering system and the LS1, 5.0, and 351W all use the same firing order. A 5.0 sounds different (and much better, IMO) than an LS1.

This is my true dual setup:

SLP shorty headers

1 Car-Sound cat on each side, under the front floorboard, as far forward as possible so that they just clear the frame. Fab pipes to connect the headers to the appropriate cats. Each cat will be about at whatever level puts it's inlet right under the frame. The cats will be partially tucked up in the space under the floor pan. I am having each cat's inlet flared to slip over the pipe going into it if I can; I'll have the pipe going into it flared to slip over the cat inlet other wise.

I am using Moroso Spiral Flow mufflers (4" diameter, about 12" long body), one mounted right after each cat. I am going to cut, have the inlet flared, or a combination so that I can get the muffler as close to the cat as possible. If I have enough space for this, it will be very tight. Alternatively, I'll just weld the cat right onto the muffler. This would be nice because it would free up some space up front, possibly allowing me to get the cat away from the frame and put a bend in there, which would let me tuck the cat up higher for better-than-stock ground clearance. The goal is to fit the cat and muffler in (on each side) before the floor starts to slope downward. This would give as much clearance as stock.

After the mufflers, I have pipes going straight back to in front of the axle. I will either use turn downs or straight exits. I don't want to go out the sides, in front of the rear tires because that would interfere with my SFCs that I will be putting on--Steve Spohn says leave a good 3" between the rocker panel and the exhaust (he has a 4" dual setup on his car!). Anyway, I'll probably experiment with different tips to see what sounds best and quiestest from inside the car--the morosos are race mufflers.
Cheap turn downs or tips: cut off the stock tail pipes and paint them. Mine are 2 1/2" so it works out perfectly.

I'm going to be using 2 1/2" everything after the headers. All pipes (not very much pipe, though) will be sections of Hooker mandrel U-bends from summit. I'll cut the sections I need and weld it all up. I'm painting pipes, mufflers, exit pipes/turn downs or tips (cats are stainless) with VHT header paint. I doubt I'll be able to put an X-pipe in like I want, but I'll probably be able to run an H. Cheap X: weld two U-bends together and work on the inside to make it all smooth. Anyway, I'll weld everything together (got a mig the other day so I don't have to use the old stick welder--would've been very messy, hard to do).

I'm putting 2000 deg F heatshielding probably under the floorpans, but maybe on top of them, inside the car. Either way, I'm putting extra insulation under the carpets. I'm heatshielding the fuel lines (may not need to do any of this, but...)

Oh yeah, I need to get some small pipe to hook the AIR up to the cats.

If you want to use different mufflers, Borla makes 12" long XR-1 sportsman race mufflers(not the glass-pack-looking ones, all stainless, but $125 each). I like the morosos because of the general good reputation of the company, CarNDrvr uses them in his true dual setup (mufflers under floor pans, no cats) on his 500+hp camaro, and they are about $60 each from Jeg's--Summit doesn't have them. They come bare, not painted, like in the picture.

I can't wait until I put this system on. I hope it's not too loud. There is this one new Celica that parks on the side of the street by the parking lot I park in at college. An old guy on a Harley set off its alarm the other day with his exhaust and he wasn't even revving it or anything. I plan on setting off this car's alarm at least once a week on purpose plus any other time I go past it Just one of the stupid things I have planned. Although I will be happy if I have to rev to do it because I don't want something so loud I can't take it on the highway. I can take a lot, though, and I rarely drive for more than 45 minutes at a time...

This is my setup (as of a week or two from now). Right now the car has no exhaust (sounded so good for those 15 seconds I had it going!) and I just sanded and painted the headers (they have never been used, but are a couple years old). I hope that paint (DEI silicone 1500 deg F black exhaust paint--VHT mentioned above hadn't arrived yet and I wanted to do something--should be very comparable stuff, though) doesn't burn off. Oh well, over Christmas break I'll be polishing my whole tpi setup, so stuff will have to come off anyway.

Hope this helped.

Edit: these plans have changed as per some of my newer posts.

 

pretty long, huh. even so, I'm surprised no one has said anything about it.

 

too much to read when you get it on the web let me know. I'll add it to my page.

------------------
-Tas
'89 Formula WS-6

305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options

 

thankyou for your info cort351w, the only addition i plan to make is running the pipes up and over out the rear as opposed to infront of the rear wheels...my only concern is if it will be emissions friendly???