Just some info that I want to pass along for those thinking of installing a true dual exhaust on their thirdgen Z. GO FOR IT! You will be completely satisfied with this kind of exhaust. My exhaust consists of: hooker headers,2.5 pipes,The Flowsmasters and real nice looking tips. I wish I could get set up to take pictures and post them. The first guys I took my Z to told me it could not be done. I ingored him and went on to the next guy. This guy did all the work for a total fo 230.00$$(tips included).I noticed a power increase at midrange . My car now sounds like the torque monster that is . A catback can be quite an improvement with the right parts but a true dual exhuast is the best. End of report.

------------------
Big 454 72 Chevy Nova
383 86 Camaro Z28
10.5:1compression 186 casting Heads,234dur.488lift exh&int,Edelbrock performer intake, Holley750 vac.sec 400 crank,flat top pistons,edelbrock valve springs and lifters,tranny shift kit,2500 stall converter. Will install 3.73's later on and might go with a more aggresive cam.As of 4/01 added Hooker Headers,2.5inchpipes with 40 s. Flowmasters.Ignition upgrade include: MSD Coil and MSD module.

 

Get pictures or make sound files!!

 

I'll second that - installing dual exhaust was my best power mod since yanking out the 305.

 

Hey Big Block, I'm desperately trying to get a dual exhaust system installed, but nobody around here will do it.They all say that a dual system will not fit under a 92 RS.I also want to go with-out cats, but nobody will do that either. Some say you have to remove your tags or trailer your car in for them to even think about it ( race cars only). Has anyone heard anything like this, or is it just in my area( South Florida)?

 

Yes.. need pics.. must.. make.. true..dual..exhaust..

------------------
Third Gen Project
1989 305 tbi Camaro RS Red/Red
Ram Air II Hood
Centerline Champ 500 Rims
Edelbrock Open Element
MacEwen White Faced Guages

"Stock?! Theres nothing "stock" about a stock car."

 

LILRED383 here in Texas we are supposed to have one of the hardest emission inspections in the nation(California being the hardest)but I still got around it. Keep looking if they don't want to take the cat off entirely maybe they are willing to gut it. You can actually make a true dual exhuast emissions legal if you have the cats to go on each pipe can't you? ? Not sure on that one but I will ask about it.

------------------
Big 454 72 Chevy Nova
383 86 Camaro Z28
10.5:1compression 186 casting Heads,234dur.488lift exh&int,Edelbrock performer intake, Holley750 vac.sec 400 crank,flat top pistons,edelbrock valve springs and lifters,tranny shift kit,2500 stall converter. Will install 3.73's later on and might go with a more aggresive cam.As of 4/01 added Hooker Headers,2.5inchpipes with 40 s. Flowmasters.Ignition upgrade include: MSD Coil and MSD module.

 

Actually, I don't think you're allowed mess with the cat at all, unless replacing it with an approved one. So, I don't think putting a cat on each pipe would be legal.

------------------
'88 IROC TPI 355, '69 truck 4-bolt, fully balanced, 9.75:1 compression, fully ported '70 truck heads(for now), Harland Sharp 1.6 Roller Rockers, Comp Cams CS 252AH-12, ported '86 TPI converted to speed density, Crane AFPR, Flowmaster 3in. exhaust, Edelbrock TES headers, all emissions equipment is still intact, plan on burning my own chips, many more mods and parts on the way as time and money permits =(
Best E.T. with TBI 305: 16.11 @ 82mph
Haven't been to track with new motor
If you have any questions on converting from TBI to TPI email me at jdkchevy70@yahoo.com
In memory of Dale Earnhardt, I'll miss cheering for that black #3 on raceday!!!

 

It's perfectly legal. As long as each pipe has a CAT or both pipes lead into a cat, you will pass the inspection and be legal. I could be wrong but it's only illegal to do anything to the cat if the car has less than 50,000 miles on it and the cat us not damaged. But then how are they going to know?

------------------
'91 Z-28 5.7, SLP 1 3/4 headers, 4 inch Mufflex/Flowmaster cat back, gutted cats, Edelbrock intake, 8.5mm Jacob wires, MSD Blaster coil, S&W subframe setup, Jacob Pro Street Ignition, complete Kenwood system.

 

Big454blockchevy, Welcome to the dark side!
I was getting worried that you might not go this route. I guess theres a few of us here that know the truth "duals will increse every aspect of performance ". Just to clarify how's the low end performance? better, I asume. Well that shoots the backs pressure BS in the A**. Also watch your gas mileage if you can keep your pedal from sticking to the floor, it should also increase dramaticly.
Well congrats!!!!!
SSC

 

Thanks SUPERSPORTCHEVY . Low end performance did improve all the way up to top end. What got me really excited is mid range power on my Z improved big time. For all u non- believers out there, you're low end power will improve.

------------------
Big 454 72 Chevy Nova
383 86 Camaro Z28
10.5:1compression 186 casting Heads,234dur.488lift exh&int,Edelbrock performer intake, Holley750 vac.sec 400 crank,flat top pistons,edelbrock valve springs and lifters,tranny shift kit,2500 stall converter. Will install 3.73's later on and might go with a more aggresive cam.As of 4/01 added Hooker Headers,2.5inchpipes with 40 s. Flowmasters.Ignition upgrade include: MSD Coil and MSD module.

 

Anyone got a schematic on how they ran the true dual exhaust? I want to use the full length headers and a crossover pipe, not sure if im gonna use a x pipe or h pipe. and borla mufflers. how do you run the exhaust over the rear axle on both sides? i want exhaust tips on both sides of the rear, not two on one side as ive seen before.


thanx

dan

 

here's some food for thought ---> http://members.tripod.com/GRK_Taz/lowduals.html

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

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Soon to be installed:
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
EFI & Intake Options
AOL IM: superGRtaz

 

Tas it never crossed my mind to do it that way but it is a great idea. I might still consider doing it with that muffler (which mag was this from?)

------------------
Big 454 72 Chevy Nova
383 86 Camaro Z28
10.5:1compression 186 casting Heads,234dur.488lift exh&int,Edelbrock performer intake, Holley750 vac.sec 400 crank,flat top pistons,edelbrock valve springs and lifters,tranny shift kit,2500 stall converter. Will install 3.73's later on and might go with a more aggresive cam.As of 4/01 added Hooker Headers,2.5inchpipes with 40 s. Flowmasters.Ignition upgrade include: MSD Coil and MSD module.

[This message has been edited by Big454blockchevy (edited April 19, 2001).]

 

sorry I don't remember what mag. it was probably CHP or Hot Rod.

 

It was in the September 2000 issue of Super Chevy. Pretty good setup, i'm thinkin of doing a setup kinda like this for my '89 Camaro with dual borla XR1 race mufflers.

 

[QUOTE]Originally posted by buddha6974:
[B]Anyone got a schematic on how they ran the true dual exhaust? I want to use the full length headers and a crossover pipe, not sure if im gonna use a x pipe or h pipe. and borla mufflers. how do you run the exhaust over the rear axle on both sides? i want exhaust tips on both sides of the rear, not two on one side as ive seen before.

http://darcom.home.texas.net/ he has the setup with 2 exiting on one side but it can be done with, 1 and 1.

The x or h pipe wont work on our cars. You dont want an x pipe if you run dual's defeat the pourpose of "dual" an H pipe could be done but if you needed to take the transmition out good luck!

 

I'm almost positive that you can't use a panhard rear suspension setup with true dual exhaust. The only way would be to go to a aftermarket rear ladder bar setup. At least that's what I figured.

------------------
, Jon (350 TBI! it's trenuous and efficacious while getting 23mpg highway with off the shelf eprom)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)AIM: JPrevost

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

 

And.......how much ground clearance did you lose?

 

Thanx Guys

i think ill still go with the h pipe as it will be stainless and if i have to pull the trans it will come right out. that muffler is cool, i gotta look into that. i will try to figure out a schematic sometime tomarrow

dan

------------------
i got an 84 camaro, shes got a 89 mustang. which do i have to work on more?

 

I forgot to add that ground clearance is not really an issue as i can make custom floorpans if i need to. (i work at a F*rd dealer by day and run a custom shop at night)
i just want to figure out how i wanna route the exhaust before i do floorpans.

------------------
i got an 84 camaro, shes got a 89 mustang. which do i have to work on more?

 

I am thinking of addding some suspension mods next. I will post whatever problems I encounter with the dual exhaust.

------------------
Big 454 72 Chevy Nova
383 86 Camaro Z28
10.5:1compression 186 casting Heads,234dur.488lift exh&int,Edelbrock performer intake, Holley750 vac.sec 400 crank,flat top pistons,edelbrock valve springs and lifters,tranny shift kit,2500 stall converter. Will install 3.73's later on and might go with a more aggresive cam.As of 4/01 added Hooker Headers,2.5inchpipes with 40 s. Flowmasters.Ignition upgrade include: MSD Coil and MSD module.

 

I made real dual exaust page. Check my signature.

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

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Soon to be installed:
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

 

The transverse mufflers were stock on some older f-bodys, but most people ripped them out and put in glasspacks. The true duals shouldn't be a problem for third gens, just takes a little planning. As far as a crossover goes, they are used for a reason or no one would use them.

 

the cross over pipe is to stop the lil popping sound when u rev your motor up then let off

 

Are u going to make any sound files or videos??

 

Are you serious that it only cost you $260? Most cat-backs cost that much and don't have the exhaust note that a true dual system would. What kind of muffler shop did you go to to have them make that?

Thanks,
Jon

------------------
82 Trans Am
Original 134,000 mile LG4
Holley 600 cfm carb, Weiand Stealth Intake manifold, no smog equipment, Hooker headers are in a box next to the car, and the cat back is on the way... now all I need is that elusive Y-pipe....

 

Anybody has true duals on a late model firebird thirdgen (maybe 91 or 92 ). I know i only have an LO3 but I like the idea of true duals, lol. Thanks

 

The labor cost alone were 230.00$$ the headers were 140.00, and The FLOWMASTERS were 110.00 total for both. Which brings the total to : 480.00.

------------------
Big 454 72 Chevy Nova
383 86 Camaro Z28
10.5:1compression 186 casting Heads,234dur.488lift exh&int,Edelbrock performer intake, Holley750 vac.sec 400 crank,flat top pistons,edelbrock valve springs and lifters,tranny shift kit,2500 stall converter. Will install 3.73's later on and might go with a more aggresive cam.As of 4/01 added Hooker Headers,2.5inchpipes with 40 s. Flowmasters.Ignition upgrade include: MSD Coil and MSD module.

 

Iv'e designed my custom exaust for my third gen. its a true duel, going from headers into 2 40-series flowmasters. i own 3 cars, one has a flowmaster catback (hollowed cat) one has true duel that go all the way to the end into 2 40-series with tips, and one goes from headers, to 2 40-series, to DUMPS right under the passenger and driver chairs. (thats the loudest one!!)
i will make some crappy skematics in photoshop to show you how I did it all.
may take me some time tho, i will make a new post called "true duel skematics" and post it when im done.

 

with cars as low and wide as ours, that's a good way to DIE from carbon monoxide. When I got my car it had pipes that didn't go to the bumper of the car and I was choking on that crap I can't imagine yours.

 

BigBlock,
What kind of shop did you get that done at? Was it a regular muffler shop or a hipo shop?


------------------
82 Trans Am
Original 134,000 mile LG4
Holley 600 cfm carb, Weiand Stealth Intake manifold, no smog equipment, Hooker headers are in a box next to the car, and the cat back is on the way... now all I need is that elusive Y-pipe....

 

I got true duals on my 88 IROC. My headers are Hooker 1 5/8 shorties. The total cost, labor and parts, for getting duals was $180 at a muffler shop. The guy did a great job. He ran the two 2.5" pipes straight back and over the rear axle and put a mini turbo muffler on each pipe. No clearance problems. I still need to get some tips though.

[This message has been edited by speedlvr (edited April 22, 2001).]

 

82Resto it was a regular muffler shop. This place was not one of the big name muffler shops but that is kind of what you need to look for cuz they are more willing to do the dirty work. Big name shops tend to shy away from gutting or removing cats.

------------------
Big 454 72 Chevy Nova
383 86 Camaro Z28
10.5:1compression 186 casting Heads,234dur.488lift exh&int,Edelbrock performer intake, Holley750 vac.sec 400 crank,flat top pistons,edelbrock valve springs and lifters,tranny shift kit,2500 stall converter. Will install 3.73's later on and might go with a more aggresive cam.As of 4/01 added Hooker Headers,2.5inchpipes with 40 s. Flowmasters.Ignition upgrade include: MSD Coil and MSD module.

 

Thanks a lot, bigblock. I do believe I will be swinging by the muffler shop with my headers in the trunk some time in the next few weeks. I've got to get duals installed before cruising season starts in a few weeks.

Sweet.

------------------
82 Trans Am
Original 134,000 mile LG4
Holley 600 cfm carb, Weiand Stealth Intake manifold, no smog equipment, Hooker headers are in a box next to the car, and the cat back is on the way... now all I need is that elusive Y-pipe....

 

hehe it doesnt smell all THAT bad. i live in florida so my windows are ALWAYS down ( i have no A/C in my monster ) and so far my passenger windows has cracked and my driver side has been replaced with plexy glass. thats how thumpy my exaust is. i will have to replace it all soon, its so loud. but you dont smell it too bad, not much worse than running straight headers to dumps in the rear, which is what i HAD before i actually added mufflers.

 

I updated my dual exaust page again. I have 9 links on there. If I missed one please let me know. If you have pics I can make a page for you to put up.

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

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Soon to be installed:
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

 

I plan on doing it soon to my Iroc, a similar setup to below, except I can live with out stainless and polished steel.

I have to pass CA smog so I intend to have a cat on each pipe up there somewhere. I also probably wont have tailpipes, just turn downs after the mufflers.








Damn geocities, if you cant see 'em go here:
http://www.geocities.com/norine.geo/Exhaust.html

[This message has been edited by Timmys88Z (edited April 25, 2001).]

 

I don't think CA lets you move where the stock cat(s) should be. I heard you can't even go to the stock dual cats if yours came with a single cat.

 

You really should extend the exhaust to the factory locations. Even at crusing speeds there are low pressure areas under the car that can force the fumes into the car, you would think this would only be a problem at idle, but it can get in the car at highway speeds! So be safe and dump it PAST the rear bumpber the way it comes from the factory.

 

true, I believe from what I;ve read it will increase performance by allowing the two banks of cylinders to opperate smoother by taking the exhaust load off eachother. but the book I read also warned that if the crossover wasnt done right it would hurt performance, so it might be better to not have one at all if you are unsure.

 

Hey all check out my post on true duals and catbacks I Made those skematics I promised to make!!!!
https://www.thirdgen.org/messgboard/...ML/001638.html

 

Hey Big454, what kind of Hooker headers are you running? I am gonna go true duals on mine with cutouts behind headers. Not sure about mufflers yet.

------------------
89 RS 350 TBI auto