Stock dual exhaust to a single. [Archive] - GrandAmGT.com Forum

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abusedgt97
09-12-2004, 11:41 AM
I have a 97 gt with the factory duals. I was looking under the car the other day and noticed the right side pipe connects to the left with a two bolt flange. I was wondering if I took the right pipe off and capped the flange if I would see a significant difference. I was wanting to run a single flow master out the left hand side. I was wondering if the angle and extra space from the right pipe flange would make the flow worse.

My main question is, would I be better to stick with the stock dual setup because if I cap off the right hand pipe would I have degraded performance.

Thanks.

Gold99HO
09-12-2004, 11:47 AM
just get a hole new custom exhaust with bigger piping.. with 2 following mufflers and 2 1/4 piping

UNCTYPE-S
09-12-2004, 11:47 AM
not sure about an answer on the "flow", but if it came like that stock, i wouldnt worry. but dont ya think having 2 exhaust tip cutouts but only one exhaust stip is gonna look retarded.

juanvan
09-12-2004, 11:47 AM
you would constrict the flow of air, so yes there would be some mild performance lose

abusedgt97
09-12-2004, 12:07 PM
juanvan - thanks, thats what I was thinking.

I am going to be pulling the engine to rebuild it, I might just run a single 2 1/2" pipe from the cat to the back. What diameter is the stock exhaust?


UNCTYPE-S - I could really care less about aesthetics.

juanvan
09-12-2004, 06:46 PM
i think the stock on the 99+ are 2"
On that year would be around the same 1 3/4" but not more 2"

abusedgt97
09-12-2004, 08:57 PM
juanvan - thanks, I will get out the tape tomarrow and check.

Roush GT
09-13-2004, 05:09 AM
why would you even wanna do this is beyond me ...not to mention its gonna look retarded

juanvan
09-13-2004, 06:44 AM
hey man to each his own

One mans junk is another mans treasure

I would not want to do it eather but...

abusedgt97
09-13-2004, 09:47 AM
I am rebuilding the engine and trans, I want a single larger pipe for better flow, the factory dual is fake, hardly anythings flows through the y split out to the right. Its just for looks. If I ever ran a dual I would run a true dual but I am going to stick with a single larger diameter. I do not care what other people think of the looks of my car.

atc3434
09-13-2004, 06:41 PM
i think the stock on the 99+ are 2"
On that year would be around the same 1 3/4" but not more 2"

Its 2 1/4" on 99+, and I'm pretty sure on 94 - 98 as well. GM usually used 2 1/4" with any v6 motor.

nomojo
09-13-2004, 07:35 PM
you would constrict the flow of air, so yes there would be some mild performance lose

I'm not an expert, but its only one pipe coming off the manifold at the engine, and only splits into 2 off the muffler. Since you've already constricted the airflow from the engine by having only 1 pipe off the exhaust, you're pressure is being divided into 2 streams after the muffer.. All things being equal, the air pressure after the muffler should be divided 50% 50% per side of the exhaust side of the muffler pipes (its usually favoured to one side though).

My point is, one pipe split to 2 pipes should be the same flow as 1 pipe to 1 pipe. I dont see how closing off one of the exhaust outlets after the muffler on a fake-dual-exhaust would decrease performance. IMO, the "quasi-dual-exhaust" is all about looks, not performance. Only real dual exhaust is for performance.

Another way to look at it: if you have a full jug of water, and pour that jug into two smaller, equally sized jugs, you still end up with the same amount of water in 2 small jugs as 1 large jug, and the faucet that filled the jug didnt get any bigger. If you have an internet connection that can supply 10k per second, and you put 2x 5k per second downloads off of it, its still 10k per second.

I could be wrong, but I kinda doubt it :)

Just my 2 C.

Cheers

Afterthought: Although, the muffler will introduce further flow restriction, so having two exhausts from the muffler might reduce any introduction of restriction. However, the flow of an aftermarket muffler should be better anyways. I highly doubt you'd find any measurable difference.

juanvan
09-14-2004, 09:20 AM
I'm not an expert, but its only one pipe coming off the manifold at the engine, and only splits into 2 off the muffler. Since you've already constricted the airflow from the engine by having only 1 pipe off the exhaust, you're pressure is being divided into 2 streams after the muffer.. All things being equal, the air pressure after the muffler should be divided 50% 50% per side of the exhaust side of the muffler pipes (its usually favoured to one side though).

My point is, one pipe split to 2 pipes should be the same flow as 1 pipe to 1 pipe. I dont see how closing off one of the exhaust outlets after the muffler on a fake-dual-exhaust would decrease performance. IMO, the "quasi-dual-exhaust" is all about looks, not performance. Only real dual exhaust is for performance.

Another way to look at it: if you have a full jug of water, and pour that jug into two smaller, equally sized jugs, you still end up with the same amount of water in 2 small jugs as 1 large jug, and the faucet that filled the jug didnt get any bigger. If you have an internet connection that can supply 10k per second, and you put 2x 5k per second downloads off of it, its still 10k per second.

I could be wrong, but I kinda doubt it :)

Just my 2 C.

Cheers

Afterthought: Although, the muffler will introduce further flow restriction, so having two exhausts from the muffler might reduce any introduction of restriction. However, the flow of an aftermarket muffler should be better anyways. I highly doubt you'd find any measurable difference.


since its going 1 to 2 there is more "free" space after the split even though its "fake" more free space is more free space the end it realy does not make a big diffrence but a slight diffrence will be there

10 psi threw 1 pipe into 2 pipes of the same size will not give you 5 psi in one and 5 psi in the other ~ it will switch it up maybe 8 and 2 or something but its not restriced to being the straight 10 psi max in the single pipe all
about the free space :ec:

Air is not like current it will not take the path of least resistence...

Azrael
09-14-2004, 05:25 PM
GM usually used 2 1/4" with any v6 motor.
There's ~ 0.5" difference between my 2.25" pipe and the outlet of my stock cat (soon to be fixed). So saying 1.75" on pre 99 V6 GA exhausts wouldn't be too far off.

GTguy
09-15-2004, 01:44 AM
I see you all are missing the main point here look at it this way - exhaust systems restrict air from leaving the combustion chanber, no matter which way its goin. if the exaust pipes are bigger or there is more space it will leave it faster making more hp. Look at the quad pipes for the GA's all 4 also leave 1 big muffler that also restricts air flowing outwards... but the hp increases because the muffler is opened up . The more u can open up the airflow the better ur engine will perform. Just like if u got a whole anywhere in ur exhaust system from the headers to ur tail pipes the hp would increase also.

atc3434
09-15-2004, 07:09 AM
I see you all are missing the main point here look at it this way - exhaust systems restrict air from leaving the combustion chanber, no matter which way its goin. if the exaust pipes are bigger or there is more space it will leave it faster making more hp. Look at the quad pipes for the GA's all 4 also leave 1 big muffler that also restricts air flowing outwards... but the hp increases because the muffler is opened up . The more u can open up the airflow the better ur engine will perform. Just like if u got a whole anywhere in ur exhaust system from the headers to ur tail pipes the hp would increase also.

Dude, getting the most performance from an exhaust system involves a lot more than just having big pipes and holes in your muffler. ;) What is critical to the exhaust system is the velocity you can create in the system, how fast you can move it out, which will help create a scavenging effect, which in turn will actually help pull the exhaust out of the combustion chambers. Have a hole in your exhaust system might even hurt performance, because of a turbulence in the exhaust. You gotta figure, any exhaust going out that hole has gotta trun 90 degrees to get out it, so thats not exactly unrestrictive.

Also, with the 1 into 2 mufflers, there really isn't much better flow than a straight through design. Again, you've gotta make a major direction change to get the exhaust out the side it comes in, it has to 180, which isn't very conducive to good flow. Your concepts are right, getting the exhaust out makes power, but the methods include more than just opening up the exhaust system where-ever is convenient.