85_tpi_350

Why is it that any Mustang owner can go out and buy a straight-up illegal exhaust system, mail-order, ready to bolt on, have it delivered to their door, and roll around with an ideal exhaust system with no trouble whatsoever while the Camaro brethren have to put up with these choked-up single systems that flow marginally well enough to get the job done? It ain't fair. I have an '85 Z28 with a TPI 350 in it (not sure how it got there, it's an MAF system that looks just like the 305 version, but the longblock is definitely a 350, I overhauled it myself) with a Flowmaster after-cat system. It sounds cool, I guess, and it flows OK (I can't really tell a difference from the factory muffler), but it just not the same as the real deal. Aftermarket companies have made leaps and bounds in performance technology, including the x-pipe, a very cool trick which actually creates a vacuum at the x, increasing flow dramatically and really waking up the horses.

Is there ANYONE that makes a true dual exhaust system for a 3rd-gen Camaro? I've looked all over, with no luck yet. I'm about to order some tubing from Summit and start cobbling...

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Horsepower is like cheese, you can add it to ANYTHING and it's a little more enjoyable.

-Posey

aklim

They don't make one becuase it is too much work for too little gain. I do believe a 3 in SLP is more than enought for what you are running and then some. That is if you use headers and a free flowing cat.

You'd end up having to either crimp the hell out of your pipe or sacrifice a lot of ground clearance.

85_tpi_350

See, that's just it, I'm not stopping with the stock TPI 350, I'm going to a twin turbo setup eventually (I've got a friend who knows his stuff, otherwise I'd be squeezing the bejesus out of it), and I'd like to be able to take advantage of a true dual exhaust system as well as a crossover pipe. That and SLP's parts, albeit great quality parts, tend to be ridiculously expensive. I have a Flowmaster crossflow muffler on the car now, in addition to what I'm pretty sure is a "rebuilt" cat (if you catch my drift), and it does OK on the stock motor, but I would truly prefer to have a way more free-flowing system if I'm to churn out 650 HP or so. That's the great thing about KY, no state inspection! I know guys who have cobbled together a dual setup that hangs down real low, and it works okay, provided you have air shocks in the rear and don't have to pull into any upward-sloping parking lots. I'd like to put together a system that crosses over and runs the pipes side-by-side along the factory path, with possibly an H or X pipe somewhere in there, most likely where the cat would normally be, into a set of straight-through mufflers, most likely glasspacks, then goes over the rear axle and straight out from the factory location with turn-downs. That or use a pair of 40-series Flowmasters behind the rear axle, like a Caprice or Crown Vic, again with turndowns. Naturally no one makes an "off-road" system such as this for a Camaro, but you can get droves of them for any Mustang, and it just chaps me real good.

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Horsepower is like cheese, you can add it to ANYTHING and it's a little more enjoyable.

-Posey

DukeofBird

just out of curiosity what size duals where u thinking of running? and part of the reason for the no dual exhaust kits is that there is a lack of space for two pipes where the stock single runs

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1984 project bird 2.5/ 5spd, soon to be 400+cu in smallblock/th350

85_tpi_350

For a high-horsepower application such as what I'm considering, I'd need at least a 2.5-3" dual system. I realize that'd make a grand total of 6" across that I'd need to run in that factory path, I'm not sure how feasible it is, it may just be easier to make the system straight back and let 'em hang, although I seriously dislike this idea; I've always been taught that anything worth doing is worth doing right. In fact I'd have to add subframe connectors to the car to run this much power, so I'd probably be S.O.L. for using the stock path anyway. I thought about that elliptical tubing that Dr. Gas uses on his systems, but I don't know what all is involved in its use. Anything I do is obviously gonna be custom-made, most likely by me.

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Horsepower is like cheese, you can add it to ANYTHING and it's a little more enjoyable.

-Posey

IrocSS85

well the easy way out is to use dual exh. that ends before the rearend. now I have dynomax bullets though. which are much louder and hopefully decrease backpressure even more. but Im going to test the old cheapo muff.s against the bullets at the track. also, i have never still hit the exh. on anything. but im at stock ride height. you can see pics of my setup at

http://photos.yahoo.com/bc/irocss86/...xhaust&.view=t

but my friend at work has a new exh. sys. that is 2.5" and all the way out the back. has 2 pipes that go into one muffler that has two exits. so you get the dual pipes, but only one muff. it has a dynomax muff. thats made for a grand national. it sounds ok but is too quiet for my tastes. his system is just like mine, exc. where the turndowns are, there are tail pipes that go ovr the axles. the drivers side goes right in betweent he panhard bar and brace above it. seems like it will hit the panhard rod if you go over a big enough bump. we'll see though. Im taking my camera to work tomorrow to get some pics.
chris

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1986 Iroc Z
355, cleaned up trick flow twisted wedge G1 heads, 750 holley, 700r4, 10:1 compr., forged flat tops, solidcam .501I .510E, 4gen rear w/3:73 posi, girdle, and disc's, Edel. torker II, shift kit, 2500 stal, hedmann LT. headers, 4 gen seats, man. strg., lt1 starter, alum. w/p, msd 6al, coil, dist., mallory wires.
12.86 @109mph so far(still need fine tuning)

1995 z28,SS Hood, Iroc style spoiler, tints and black outs, 700r4,2400 act. stall speed,B&M hammer shifter, 17" budnick trilogy III wheels, 275/40 ZR17, 160 stat, man. cooling fan sw., homemaid CAI,1LE elbow, hypertech airfoil, t.b.bypass,!cat, flowmaster, !maf screen, relocated batt., 1LE front l.c.a.s', poly trans and torq.arm bushings, MSD 6AL, custom program, p&p maf, accel coil, and under drive pulley

mods that i have, just not on car yet:
msd wires, edelbrock mid. headers, edelbrock rpm catback

85_tpi_350

Props on the exhaust, you've got it tucked up a hell of a lot tighter than I figured was possible. Who did yours? They do excellent work. I have a similar system on my El Camino, which, you can understand, is why I show so much enthusiasm for the H pipe. My friend's exhaust hangs down like mad; it's clearly visible under the car and scrapes if you're not REALLY careful.

I'd like to see the pics from your friend's car, I'm getting inspired.

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Horsepower is like cheese, you can add it to ANYTHING and it's a little more enjoyable.

-Posey

jayman350

wow irocss85 you have done almost exactly what I want to do for my exhaust.

I am planning on hooker super comp long tubes w/ a very similar h-pipe setup, hell i may bring in the pics to the exhaust shop and tell them to match yours. I want to use the dynomax turbo mufflers and have them come out the back of the car.

btw, how loud is that inside w/ the turndowns there?

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Jay
black 85 Z28 - waiting on a new paint job, then she'll be real purty
blue 85 Z28- not running right now, but that should be fixed soon (I hope)
87 Chevy S10 Blazer- 2.8 liters of pure fury

Jay's Website
yahoo im: wildcat856
AIM: Jayman85Z
Homer no function beer well without
check out GMPerformance.org

85_tpi_350

Hey, bro, how "cool" is your muffler shop? Not every shop will do a system like that. There are a few scattered here and there that will do work like that, and they don't advertise, believe me.

Here's one way around:
Take the license plate of your car, tow it up to the shop on a trailer, saying it's a race car. Some muffler shops buy this, or at least give you an A for effort and do it anyway. Many don't; they realize they can screw you for another $200 or so by forcing you to put a "legal" system on your car.

85_tpi_350

sorry I meant to say take the license plate OFF your car!

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Horsepower is like cheese, you can add it to ANYTHING and it's a little more enjoyable.

-Posey

IrocSS85

well, I actually bought it used and had to adapt it to the hedmann headers I have. they were on a car w/supercomps. just so you know, the supercomps hang down about 1-1.5" lower then the hedmanns. thats another reason why I dont scrape when you hear about some people doin that all the time. the only crimp in the whole system is at the trans crossmember on both sides. it prolly wasnt necessary but did save about 1" ground clearance.

as for the sound, w/the old cheap super turbo's on there it was very quiet at cruise speeds. ofcourse youd hear it when you get on it, but other then that it was real quiet. even w/the turndowns on. w/the new muff.s (bullets) it is loud pretty much all the time, but I dont have the turndowns on it yet, so that may quiet it down a bit. if the bullets dont give me more then a tenth at the track, the cheap muff.s are qoing back on. if I get the pics, I'll keep ya posted.
chris

jayman350

do you know what model for the heddmans you have are? I thought that the only long tubes available for the 3rd gens were the hookers (obviously I'm wrong) One more question, are those 1 5/8 or 1 3/4 headers?

jd13

You have to find someone willing to do the work. Dynomax makes a dual exhaust system for our cars, but it sucks.

I am getting what you want done today and tomorrow. 2.5" duals down the factory path, over the axle, and into 2 40 series flowmasters. Nothing is impossible, you just gotta find the right guy to work with.

Honestly, I don't know how this system would hold up with your twin turbos you plan on running. For that you may want to go to a 4" single.

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1990 IROC-Z 5.7l
1/8: 8.9 at 77 mph with a 1.99 60'
- 3" exhaust no cats, slp headers, underdrive pulleys, 160 stat

85_tpi_350

I've seen the sewer-pipe single systems to which you refer in Car Craft when they did a spread on EFI class drag racing. Apparently they work pretty well, but I'm not sure if you can even run the factory path with subframe connectors at all, I don't know if you've seen the H-pipe setup that IrocSS85 posted on here, but it's a real good setup from what I can gather, I think to run it over the back axle you'd have to make the left pipe cross over to the right side behind the trans and put your H or X in that area and then route it over the back axle for everything to work together. One thing I really like about the dual setup with a balance tube is the dynamic increase in midrange power. You just don't get that with a single system, no matter how big it is. I suppose an upside to not having a ready made setup from the aftermarket is having the freedom to make it totally original in design. Again, I'm wondering how difficult it would be to run the elliptical tubing like the Dr. Gas systems use. I would think that would improve the ground clearance situation dramatically. I suppose what I really need to do is put the car up on stands and get under it and do some heavy studying. Keep the suggestions coming, guys, this is definitely a good thing. We can overcome the lack of aftermarket as compared to the Ford guys yet.

IrocSS85

they are 1 5/8 primary tubing into 3" collectors. summit sells them for around $90 uncoated. I think $180 or so coated. not sure. mine are uncoated. dont let the smaller collectors fool you. they will be fine for under 500 horsepower. esp. if you drive it on the street more then race it. you may be giving up maybe 5 horsepower at the top end, but you gain alot of lower -mid range w/the smaller tubing.
chris