Hello - and an exhuast question...
Thread Starter
Intermediate
Joined: Jan 2011
Posts: 35
Likes: 3
From: Fort Wayne IN
Hello - and an exhuast question...
Greetings all - long time lurker, first time poster. I have a '78 L-48 auto that I acquired about 2 years ago. She's pretty much all original...so I'm in the process of replacing/rebuilding...well, everything. I plan to stay as close to stock, except where upgrades make sense.
My big project this year is a full rebuild of the front suspension - all poly.
My question is this: one thing that is definitely NOT original is the exhaust. It's true dual straight back to the mufflers - no Y-pipe, no cat. Indiana doesn't have an inspection so I know I'm good for now, anyway. However, would it make sense to rebuild it back to factory? The whole exhaust system is rusty so I'll be replacing it at some point.
What are you guys doing with your exhaust?
My big project this year is a full rebuild of the front suspension - all poly.
My question is this: one thing that is definitely NOT original is the exhaust. It's true dual straight back to the mufflers - no Y-pipe, no cat. Indiana doesn't have an inspection so I know I'm good for now, anyway. However, would it make sense to rebuild it back to factory? The whole exhaust system is rusty so I'll be replacing it at some point.
What are you guys doing with your exhaust?
Melting Slicks
Joined: Mar 2009
Posts: 3,126
Likes: 15
I really like my Volunteer Vette dual system. If you are willing to install the exhaust yourself this is a good option. Several vendors sell them. I believe mine is listed for a '74 but it requires you to have two holes through the trans. crossmember. Also my transmission mounted exhaust hanger had been butchered by the muffler shop, I trusted to do a good job the last time, so it had to be replaced. Good luck with it, mike...
Thread Starter
Intermediate
Joined: Jan 2011
Posts: 35
Likes: 3
From: Fort Wayne IN
Thanks for the reply! I like the sound of the dual and it has been modified for it already, but wonder if there would be any benefit to rebuilding back to factory... I do a lot of research, but there is no substitute for hearing it from people who have "been there and done that".
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
A more free flowing exhaust system is never a bad thing, I can't see any reason to go back to the restrictive stock exhaust system, unless strict originality is your goal, which it doesn't sound like it is. I got a full exhaust system from Corvette Central, header gaskets all the way out to the tailpipes, somewhere around 650 bucks, uses block-hugger headers, (not nearly as efficient as full length headers, but gotta be better than the old cast iron exhaust manifolds) ceramic coated (2 1/2 years, they still look good) 2 1/2 inch aluminized exhaust pipes, Magnaflow mufflers. I'm pretty happy with it so far.
Scott
Scott
Le Mans Master
Joined: Oct 2007
Posts: 7,455
Likes: 977
From: RI, Now Franklin/Nashville TN
The biggest bang for the buck on a 75-82 corvette is ditching the factory Y pipe exhaust system which is VERY restrictive-it is just awful! Headers (full length or shorty's) with 2.5 true duals, and free flowing mufflers will open up the exhaust flow tremendously over the factory system, not to mention it will sound great! The factory L-48 exhaust on your 78 was 2.25 inches at the Y-the L-82's were 2.5 inches-and the head pipes to the engine were 2 inches from each bank of the engine. Factory 2 inch pipes from the engine (4 inches) going into a single 2.5 or 2.25 single pipe is essentially a 2.5/2.25 single exhaust since the single pipe dictates the flow of gases regardless of the pipes before and after the restriction (fluid dynamics). Going from a single 2.5 inch exhaust to duals that are 2.5 pipes individually is a 4 fold increase in flow not double the flow (fluids again). Change it and never look back. Like all of us, if the Al Gore types take over, you can just add dual high flow cats to your existing system, if necessary, down the line. Hope that helps!
Thread Starter
Intermediate
Joined: Jan 2011
Posts: 35
Likes: 3
From: Fort Wayne IN
Awesome - thanks for the replies, all. I always figured high flow exhaust was the way to go...but now and then I'll hear someone say that "the engine was designed for the back pressure" and then I'll start to doubt. Actually, Mid America has a chambered dual system that I've had my eye on for a while. After the suspension and steering rebuild is done, that's probably my next major undertaking.
I'll make sure I get a thread put together so you all can see my (mis)adventures in suspension rebuilding.
I'll make sure I get a thread put together so you all can see my (mis)adventures in suspension rebuilding.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
People who say things like "The engine was designed for the backpressure" are the same people who say things like "The sky is blue because of the reflection off the ocean". Well, how come the sky is still blue in Kansas? It's just a bunch of nonsense.
Scott
Scott
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Racer
Joined: Aug 2007
Posts: 367
Likes: 0
From: Jackson MO
A more free flowing exhaust system is never a bad thing, I can't see any reason to go back to the restrictive stock exhaust system, unless strict originality is your goal, which it doesn't sound like it is. I got a full exhaust system from Corvette Central, header gaskets all the way out to the tailpipes, somewhere around 650 bucks, uses block-hugger headers, (not nearly as efficient as full length headers, but gotta be better than the old cast iron exhaust manifolds) ceramic coated (2 1/2 years, they still look good) 2 1/2 inch aluminized exhaust pipes, Magnaflow mufflers. I'm pretty happy with it so far.
Scott
Scott
Advanced
Joined: Oct 2010
Posts: 98
Likes: 0
From: Edmonton AB
This is great info from the members as I am looking at replacing my original exhaust on my 81' and adding a few more HPs
But does anyone know if the CCC will be effected ? I understand that there are sensors just before the cat....
Thanks in advance !
But does anyone know if the CCC will be effected ? I understand that there are sensors just before the cat....
Thanks in advance !
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
The Corvette Central exhaust system on my 1980 'vette (which I am pretty sure is the identical exhaust system they offer for the 1981 'vette) has a threaded bung on one of the pipes just before where the catalytic converter used to be, another one right after the header collector, looks like 0s sensors could go in there. Is that what you are talking about?
Scott
Advanced
Joined: Oct 2010
Posts: 98
Likes: 0
From: Edmonton AB
The Corvette Central exhaust system on my 1980 'vette (which I am pretty sure is the identical exhaust system they offer for the 1981 'vette) has a threaded bung on one of the pipes just before where the catalytic converter used to be, another one right after the header collector, looks like 0s sensors could go in there. Is that what you are talking about?
Scott
Scott
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Call Corvette Central and ask 'em about it, they might be able to help ya.
Scott
Racer
Joined: Nov 2009
Posts: 489
Likes: 1
From: Suffolk Virginia
ditch the original system. If the value of the car ever goes up to the point that non-original equipment hurts the value you can put it back on.
I installed 2.5" stainless chambered system last year and I love it.
Makes it sound like a big boy car.
Nice looking car Kahle!
I installed 2.5" stainless chambered system last year and I love it.
Makes it sound like a big boy car
.Nice looking car Kahle!
