LT4 Specific STOCK Exhaust Question
Thread Starter
Race Director
Joined: Mar 1999
Posts: 12,597
Likes: 237
From: Bartlett Illinois
LT4 Specific STOCK Exhaust Question
Looking at the exhaust from the exhaust Manifolds to the Tips.. which pieces are most restrictive? Where did you see any flow iimprovement from?
Thanks
Thanks
Melting Slicks
Joined: Aug 2001
Posts: 2,047
Likes: 0
Re: LT4 Specific STOCK Exhaust Question (-=Jeff=-)
the cataclysmic converters are the most restrictive. A cut off wheel, an air chisel, vacuum and a welder are all you need to clean'em out, and weld the holes back up. Manifolds are next. Headers are better. The stock mufflers are pretty good, maybe somebody'll post before and after results from a dyno test of stock vs. aftermarket mufflers only.
Race Director
Joined: Mar 1999
Posts: 16,950
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From: Stafford, Virginia Kittah, Kittah, Kittah...
Re: LT4 Specific STOCK Exhaust Question (-=Jeff=-)
Looking at the exhaust itself, the most restrictive part are the mufflers themselves... On my LT1, I replaced the mufflers with higher flowing units and that made the biggest performance diff... Since the muffler replacements, I am consistenly .3 faster at the strip...
I've got a stock LT4 system in the garage going on my car soon because my Dynomax mufflers turned out to be junk, rusting out after 3 years at the hangers... I live in Southern CA, where there is no snow/salting so 3 years is totally unacceptable... So far Dynomax isn't responding to my emails, so I can't recommend them right now... Muffler choices are hard on later C4s because of resonance issues, especially with the A4 trans... The LT4 system looks to be exactly like the LT1 system that year with the exception of an H pipe at the rear, behind the resonator...
I've got a stock LT4 system in the garage going on my car soon because my Dynomax mufflers turned out to be junk, rusting out after 3 years at the hangers... I live in Southern CA, where there is no snow/salting so 3 years is totally unacceptable... So far Dynomax isn't responding to my emails, so I can't recommend them right now... Muffler choices are hard on later C4s because of resonance issues, especially with the A4 trans... The LT4 system looks to be exactly like the LT1 system that year with the exception of an H pipe at the rear, behind the resonator...
Race Director
Joined: Mar 1999
Posts: 16,950
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From: Stafford, Virginia Kittah, Kittah, Kittah...
Re: LT4 Specific STOCK Exhaust Question (RichS)
My 95 stock exhaust had the same crossover as my LT4 exhaust. The only restriction in the systems are the mufflers.
Anyone else have the crossover on the LT1 stock system???
Jim
Burning Brakes
Joined: Nov 2000
Posts: 1,117
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From: DFW TX
Re: LT4 Specific STOCK Exhaust Question (-=Jeff=-)
Yea, I was wondering if the LT4 'muffflers' are any different than the LT1.
Are they any less restrictive. I have a new set of LT4 mufflers I got from
a forum member but haven't put them on yet. I am planning on making
them clamp on so I can change back and forth with my eliminators.
Are they any less restrictive. I have a new set of LT4 mufflers I got from
a forum member but haven't put them on yet. I am planning on making
them clamp on so I can change back and forth with my eliminators.
Race Director
Joined: May 2001
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Re: LT4 Specific STOCK Exhaust Question (wake)
Anyone else have the crossover on the LT1 stock system???
Melting Slicks
Joined: Oct 2000
Posts: 2,726
Likes: 24
From: Freehold, NJ
Re: LT4 Specific STOCK Exhaust Question (-=Jeff=-)
I don't think the LT4 exhaust is restrictive AT ALL. We are running the full stock exhaust on my Dad's CE. The only exception is that he changed to Borla mufflers for the looks and sound. Didn't notice any real improvement in ET or MPH when we put on the Borla's.
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Thread Starter
Race Director
Joined: Mar 1999
Posts: 12,597
Likes: 237
From: Bartlett Illinois
Re: LT4 Specific STOCK Exhaust Question (Eric Fischer)
I don't think the LT4 exhaust is restrictive AT ALL. We are running the full stock exhaust on my Dad's CE. The only exception is that he changed to Borla mufflers for the looks and sound. Didn't notice any real improvement in ET or MPH when we put on the Borla's.
Drifting
Joined: Apr 2000
Posts: 1,390
Likes: 36
From: INDIANA
Re: LT4 Specific STOCK Exhaust Question (Vette92)
Jeff, I am using the Borla mufflers, good tone and no resonance, I did them early in the modification process, but I did notice an improvement, but my car is a convertible and the verts have more restrictive mufflers because of noise issues. Gutting the cats on the car last summer with all the mods did nothing for top speed or accell, so cannot say they are restrictive. I do not know whats in the resonator, but I'm leary of removing it because of comments here on resonance issues. If you go with the Borlas, cut the exhaust pipe longer than you think you need, because they do not come with instructions and its difficult to align them if you get the pipe too short. :)
Melting Slicks
Joined: Jun 2000
Posts: 3,215
Likes: 6
From: Tampa Florida
Re: LT4 Specific STOCK Exhaust Question (Eric Fischer)
Well on my test from stock to Corsa, I gained 17 HP at rear wheels. No hidden changes, no icing the intake, just ran the tests (3 actually each time to ensure reliable numbers).
Graph is on my webpage under Engine stuff I believe.
That is pretty significant-17 HP...
:)
Graph is on my webpage under Engine stuff I believe.
That is pretty significant-17 HP...
:)
Team Owner
Joined: Nov 1999
Posts: 32,782
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From: Former NCM Drag Racing coordinator, National director Corvette Challenge Spring Hill, Tennessee: Whiting, New Jersey
Cruise-In VI Veteran
Cruise-In VII Veteran
Re: LT4 Specific STOCK Exhaust Question (wake)
Muffler choices are hard on later C4s because of resonance issues, especially with the A4 trans...
Since I put the long tubes on, it almost to loud and has to much resonance for ME :yesnod:
[Modified by mackeyred96, 7:08 PM 12/17/2001]
