LT4 Exhaust
Thread Starter
Racer
Joined: Sep 2005
Posts: 417
Likes: 0
LT4 Exhaust
I just found out that the stock LT4 exhaust is 2.75". I bought and have had Corsa Exhaust 2.5". Im thinking I restricted it a little out of the manifolds especially if im going to end up putting long tube headers. Should I sell the Corsa and get a 3" system...maybe B&B?!?
Race Director
Joined: Dec 2002
Posts: 13,348
Likes: 233
From: SCMR Rat Pack'r Charter Member..Great Bend KS
If I were in the market for a cat-back, it would be the 3" B&B.
The stock system is 99% 3" diameter....it necks down to 2.5" just before the mufflers. Having a full 3" system will only help...there are no downsides.
Larry
code5coupe
The stock system is 99% 3" diameter....it necks down to 2.5" just before the mufflers. Having a full 3" system will only help...there are no downsides.
Larry
code5coupe
Melting Slicks
Joined: May 2002
Posts: 2,670
Likes: 4
From: Severna Park MD
Originally Posted by Achilleus07
I just found out that the stock LT4 exhaust is 2.75". I bought and have had Corsa Exhaust 2.5". Im thinking I restricted it a little out of the manifolds especially if im going to end up putting long tube headers. Should I sell the Corsa and get a 3" system...maybe B&B?!?
Good aftermarket catbacks are the same section width all the way back, and the bends are smooth with mandrel bends. They also replace the front section that is flattened on the stock exhaust.
The front section makes a great difference on a heads/cam car, but probably doesn't matter as much on a stock engine.
I went with 3" pipe all the way on my custom exhaust. I get plenty of argument from some on here who swear that 3" is way too large for a 350 cu in engine. All I can say is I got a lot more power in the mid range. No one needs 3" all the way, just as no one NEEDS all the power their engine can make.
Last edited by FELNGR8; May 15, 2006 at 12:24 PM.
Thread Starter
Racer
Joined: Sep 2005
Posts: 417
Likes: 0
Originally Posted by FELNGR8
Take that 2 3/4" with a grain of salt. Better yet, get your car on a lift and take a close look. Yes, the LT1/4 stock exhaust starts at 2 3/4" pipe at the back of the cats, but then the bend toward the center tunnel has the pipe flattened creating a restriction. Then the resonator is 2 1/2". Look closely at the stock muffler, especially the point where the output bends to the rectangular tip. Right at the muffler connection that's a mighty narrow section of pipe, another cork in your exhaust.
Good aftermarket catbacks are the same section width all the way back, and the bends are smooth with mandrel bends. They also replace the front section that is flattened on the stock exhaust.
The front section makes a great difference on a heads/cam car, but probably doesn't matter as much on a stock engine.
I went with 3" pipe all the way on my custom exhaust. I get plenty of argument from some on here who swear that 3" is way too large for a 350 cu in engine. All I can say is I got a lot more power in the mid range. No one needs 3" all the way, just as no one NEEDS all the power their engine can make.
Good aftermarket catbacks are the same section width all the way back, and the bends are smooth with mandrel bends. They also replace the front section that is flattened on the stock exhaust.
The front section makes a great difference on a heads/cam car, but probably doesn't matter as much on a stock engine.
I went with 3" pipe all the way on my custom exhaust. I get plenty of argument from some on here who swear that 3" is way too large for a 350 cu in engine. All I can say is I got a lot more power in the mid range. No one needs 3" all the way, just as no one NEEDS all the power their engine can make.
Burning Brakes
Joined: Jul 2005
Posts: 758
Likes: 6
From: Gainesville, FL
FELNGR8 confirms what I said a few hours ago on your other post (I just wasn't sure if LT4s had the same exhaust - in which case your stock exhaust goes down to 2.25" at the muffler as I previosuly mentioned...) so unless you don't like the sound there is little reason to get rid of the Corsa (performance wise on a stock motor)... though B&B does look and sound great too...
Melting Slicks
Joined: Jan 2000
Posts: 3,418
Likes: 1
From: NW Chicago Suburbs
Stock LT1/4 exhaust system is 2.75" OD, 2.5" ID except where it necks down to almost 2.25" OD at the resonator and mufflers. Corsa is 2.75" OD, 2.5" ID all the way. It's good for at least 450HP, and no resonation.
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
Likes: 71
From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Although slightly smaller, the Corsa will outflow the stock system due to better overall design. Don't worry about it.
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Safety Car
Joined: Jun 2004
Posts: 4,197
Likes: 0
From: lafayette co
Originally Posted by rocco16
If I were in the market for a cat-back, it would be the 3" B&B.
The stock system is 99% 3" diameter....it necks down to 2.5" just before the mufflers. Having a full 3" system will only help...there are no downsides.
Larry
code5coupe
The stock system is 99% 3" diameter....it necks down to 2.5" just before the mufflers. Having a full 3" system will only help...there are no downsides.
Larry
code5coupe
I love my B&Bs!!!
