True Dual Exhaust
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Joined: Jan 2003
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From: Battle Creek MI
True Dual Exhaust
I have read alot in the forum about cat back systems, but has anyone put a true dual system on their C4, excluding racing purposes? If so, are you happy with the results? Lastly, what are the benefits of dual vs upgrading y pipe and cat back?
Thanks :rolleyes:
Thanks :rolleyes:
Racer
Joined: Jul 2002
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From: Paris AR, USA
Re: True Dual Exhaust (sporanox1)
You may already know this, but MidAmerica has a true dual setup for L98 cars. It's off-road only (heh-heh) as it eliminates the converters. I'm considering this exhaust for my car. I have heard that it is loud and that resonance is substantial, regardless of muffler used. Nevertheless it's a less expensive way to go, and the dual 2.25" pipes should out-flow most of the cat-back systems.
Jason
Jason
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From: New Albany IN
St. Jude Donor '03-'04-'06-'08-'09
Re: True Dual Exhaust (sporanox1)
I am by no means an exhaust expert, but I would think that if you "opened up" your exhaust and let it flow too freely, i.e. less exhaust pressure, you would be losing some bottom end. This is kinda the consensus I have been getting. Anyone please correct me if i am wrong :)
Melting Slicks
Joined: Sep 2000
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From: PITTSBURGH PA
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Re: True Dual Exhaust (Bruthish)
i think on a stock car you might i said might lose some bottem end but on all my own stuff which none of it was close to stock i never lost anything just gained power every where my setup now consists of long tube headers dumping in to a pair of 3 inch pipes then they go into a 3 inch by 6 inch oval for about 18 inches which helps quiet done some what then back out to dual 3 inch pipes then dump in to 3 inch flowmasters and all the pipe is mandrell bent the hp tq loss is zero :cheers:
Le Mans Master
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From: DrunkDefender
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St. Jude Donor '07-'10
Re: True Dual Exhaust (sporanox1)
Heres my opinion. You wont lose any low end at all, even if youre stock or slightly modded. Heres what I did. On my bone stock 1990 6 speed L98 I dynoed 216 rwhp and 316 rwtrq. I put on a set of flowmasters and removed the main cat. At this point the car was undrivable because of the resonance and it only picked up 5 rwhp. I then went to a local shop and had them put on true duals using 2.5" pipes and put on muffler elims at the same time. It was loud, too loud still so I had them make an H-pipe and put it in as far forward as possible. This made a HUGE difference. It quieted the car down alot. At idle it was very very quiet till you mashed the loud pedal then it really sang. I also gained hp and trq at every rpm when I went to true duals with muffler elims and H-pipe. I used to have a dyno graph scanned in somewhere that showed before and after. If I can dig it up I'll post it. If youre stock then expect to see a solid 20 hp gain from going the true duals, H-pipe, muffler elims route.
Racer
Joined: Nov 2002
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From: Stillwater OK, Fun City USA
Re: True Dual Exhaust (needanother1)
I have this very exhaust on my '86, I am running '91-'96 LT1 GM mufflers, I also added an H-pipe behind the transmission. It sounds really, really good. Not too loud, sounds tough. It is my daily driver, interstate @ 70 MPH for 50 miles. I do not notice any resonance, of course I had flowmasters before, talk about mind numbing. The flowmaster exhaust would literally make me sick after about 1 hour in the pilot seat. :U
Le Mans Master
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From: DrunkDefender
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St. Jude Donor '07-'10
Re: True Dual Exhaust (red90sixspeed)
OK I found one. Here is a before and after dyno on my 90. For the first dyno I had pretty much stock with the exceptions of throttle body bypass, airfoil, K&N and cut lid. Its hard to see but I had 216 rwhp and 316 rwtrq. I then went with true duals, no cats, muffler elims and thats what you see in the other dyno. It put down 226.7 rwhp and 331.2 rwtrq
What it doesnt show is the H-pipe. When i put it on I picked up another 5 hp and a bit more torque. Not to mention how it made the car drivable again.
What it doesnt show is the H-pipe. When i put it on I picked up another 5 hp and a bit more torque. Not to mention how it made the car drivable again.
Race Director
Joined: Mar 2002
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Re: True Dual Exhaust (sporanox1)
i have headers, dual pipes, no cats, and summit turbo mufflers, it sounds mean although a little loud, it is too loud in the car, i may have to put some more sound deadening material in the rear. :yesnod: :cheers:
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Safety Car
Joined: Dec 2002
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From: Charleston SC
Re: True Dual Exhaust (sporanox1)
I have to agree the H pipe is the key my car was way to loud before I had the H pipe put in I have true duel exhaust running to a set of C5 mufflers and love the way it sounds
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Joined: Jan 2003
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From: Battle Creek MI
Re: True Dual Exhaust (red90sixspeed)
I thought about the elims, did the muffler shop make them or did you order them? I want it louder, but do not want to lose my hearing in the next six months since my vette is a convertable. Also, how did you get the muffler shop to take the cat off?
Thanks :rolleyes:
Thanks :rolleyes:
Le Mans Master
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From: DrunkDefender
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St. Jude Donor '07-'10
Re: True Dual Exhaust (sporanox1)
I thought about the elims, did the muffler shop make them or did you order them? I want it louder, but do not want to lose my hearing in the next six months since my vette is a convertable. Also, how did you get the muffler shop to take the cat off?
Thanks :rolleyes:
Thanks :rolleyes:
As for the elims, it'll be loud and in my experience it can vary from one car to another based on who does the work and exactly what pipe they use, where the place it, bends etc etc. Around here there is a speed shop that has some pretty good muffler elims, dual tips, chrome with baffles in them for about $25 each.
Racer
Joined: Sep 2000
Posts: 337
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Re: True Dual Exhaust (red90sixspeed)
This is what my system looks like. Dual 3” pipes. Two Catco converters, no more!
It sounds awesome!!! But it is loud, a bit too loud, so I am going to put on some mufflers this winter so I don’t have to use Peltor ear protections this summer :)
[Modified by Cratzy, 5:56 AM 1/19/2003]
[Modified by Cratzy, 6:03 AM 1/19/2003]
It sounds awesome!!! But it is loud, a bit too loud, so I am going to put on some mufflers this winter so I don’t have to use Peltor ear protections this summer :)
[Modified by Cratzy, 5:56 AM 1/19/2003]
[Modified by Cratzy, 6:03 AM 1/19/2003]
Melting Slicks
Joined: Feb 2002
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From: The Black Hole LA
Re: True Dual Exhaust (sporanox1)
I've got 2.5 true duals from the precats back with a set of turbo mufflers. The only reason I left the precats is the muffler shop wouldn't take them out for liability reasons or something + one of these days I'll go to headers and that will take care of them anyway. I can say that they are loud but I have had this setup since I've had the car (5+years daily driver) and I'm not deaf yet, I just turn the radio up a little more.
I have heard that the sound deadening materials make a big difference. I am looking into this at the moment.
I have heard that the sound deadening materials make a big difference. I am looking into this at the moment.
Intermediate
Joined: May 2002
Posts: 32
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Re: True Dual Exhaust (sporanox1)
QUOTE]I have read alot in the forum about cat back systems, but has anyone put a true dual system on their C4, excluding racing purposes? If so, are you happy with the results? Lastly, what are the benefits of dual vs upgrading y pipe and cat back?
[/QUOTE]
Benefits of true duals vs the very best "cat back" are much-reduced backpressure and much lighter weight.
A worked with the C4-C5 exhaust engineer, Zoltan Varga, and he told me that the C4 L98 exhaust system 'cost' you about 30 - 35 HP as compared to a straight pipe, and that low-restriction mufflers in a true dual system should be good for a 20 - 25 HP gain.
In working on the C5 exhaust development, I found this to be true, and we designed the C5 system to have about a third lower backpressure - in spite of the hugely increased exhaust flow with the new engine!
And we did this with smaller diameter system piping than the C4 has.[
[/QUOTE]
Benefits of true duals vs the very best "cat back" are much-reduced backpressure and much lighter weight.
A worked with the C4-C5 exhaust engineer, Zoltan Varga, and he told me that the C4 L98 exhaust system 'cost' you about 30 - 35 HP as compared to a straight pipe, and that low-restriction mufflers in a true dual system should be good for a 20 - 25 HP gain.
In working on the C5 exhaust development, I found this to be true, and we designed the C5 system to have about a third lower backpressure - in spite of the hugely increased exhaust flow with the new engine!
And we did this with smaller diameter system piping than the C4 has.[
Intermediate
Joined: May 2002
Posts: 32
Likes: 0
Re: True Dual Exhaust (Bruthish)
I am by no means an exhaust expert, but I would think that if you "opened up" your exhaust and let it flow too freely, i.e. less exhaust pressure, you would be losing some bottom end. This is kinda the consensus I have been getting. Anyone please correct me if i am wrong.
Burning Brakes
Joined: Jan 2002
Posts: 1,228
Likes: 1
From: Dallas Texas
Re: True Dual Exhaust (Cratzy)
Cratzy-
Nice exhaust. Looks like you proved all those people wrong that say you cannot run dual cats with an automatic. Well, they are not in the stock locations, but if it cleans the exhaust enough to pass emissions, who cares!
Do you have emissions where you live? We have a sniffer test here in Seattle, but no visual, so I will probably do something like what you have done when I finally get my headers.
Good job-
Mike
Nice exhaust. Looks like you proved all those people wrong that say you cannot run dual cats with an automatic. Well, they are not in the stock locations, but if it cleans the exhaust enough to pass emissions, who cares!
Do you have emissions where you live? We have a sniffer test here in Seattle, but no visual, so I will probably do something like what you have done when I finally get my headers.
Good job-
Mike
Thread Starter
Advanced
Joined: Jan 2003
Posts: 64
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From: Battle Creek MI
Re: True Dual Exhaust (Cratzy)
Are those CATCO converters universal and what is the length? I am looking at the summit page and I see there are many options. Lastly, what was the aproximate cost of the exhaust upgrade.
Thanks :rolleyes:
Thanks :rolleyes:
Melting Slicks
Joined: Feb 2002
Posts: 2,699
Likes: 2
From: The Black Hole LA
Re: True Dual Exhaust (sporanox1)
I don't know about the convertors but I just had mine redone about a year ago. From the pre-cat back new pipes and one new muffler(other was still in good shape) it cost me about $150-$175, can't remember exactly how much the muffler was.
[Modified by hz900, 10:46 AM 1/23/2003]
[Modified by hz900, 10:46 AM 1/23/2003]
Racer
Joined: Sep 2000
Posts: 337
Likes: 0
Re: True Dual Exhaust (sporanox1)
Cratzy-
Nice exhaust. Looks like you proved all those people wrong that say you cannot run dual cats with an automatic. Well, they are not in the stock locations, but if it cleans the exhaust enough to pass emissions, who cares!
Do you have emissions where you live? We have a sniffer test here in Seattle, but no visual, so I will probably do something like what you have done when I finally get my headers.
Good job-
Mike
Nice exhaust. Looks like you proved all those people wrong that say you cannot run dual cats with an automatic. Well, they are not in the stock locations, but if it cleans the exhaust enough to pass emissions, who cares!
Do you have emissions where you live? We have a sniffer test here in Seattle, but no visual, so I will probably do something like what you have done when I finally get my headers.
Good job-
Mike
It is tight under there but it fit! I think that it helped that I didn’t know that people say it is impossible to run dual cats with an automatic. :)
Yes we do have emissions where I live, not like in California but pretty tough. I passed them though, but I had to make sure that the engine and the exhaust were really warm before I could pass. I think it is because the converters are non-air. The only complain I got from the emission was the sound, they claimed it was too loud!! Can it be too loud? :D
I can tell you that my “Tupperware Terror” sounds awesome, like a Nascar when I go wot.
Are those CATCO converters universal and what is the length? I am looking at the summit page and I see there are many options. Lastly, what was the aproximate cost of the exhaust upgrade.
Thanks :rolleyes:
Thanks :rolleyes:
The cost is difficult to estimate since I live in Sweden and you don’t. I think labour is cheaper in the USA. But I got a friend at the workshop that did the bending of the pipes. For the bending and the material I had to pay 1400 sek (=$150, converters not included, they cost me another $300). Then another friend did the welding, $80 (he thought it was fun and didn’t want to get paid, and I can’t force him can I?). :D
I think I got a nice exhaust system pretty cheap. But I will invest in a pair of Flowtech muffler this year.
BR
