Exhuast systems
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Intermediate
Joined: Jan 2010
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Exhuast systems
First, I'm a new member and I would like to say thanks for the great resource. I've been reading the archives with regard to L98 and LT1 corvette stock exhaust systems. From what I've read it appears the LT1 system is much more efficient than the L98 system. Is this accurate? If so, what is the choke in the L98 system? I've heard cats but not sure. Also, I've read several times that modifying the stock system isn't necessary until the HP numbers are north of 350. Does this apply to L98 and LT1? I'm considering the purchase of a 91 L98 auto and I would like to drive it longer distances. So, in my case, a quiet stock exhaust would be nice if it isn't too much of a hinderance. Any mods I perform probably wouldn't push the HP much past 1HP/cube.
Instructor
Joined: Aug 2006
Posts: 220
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From: Hagerstown MD
alot of people are goin to tell you to search the forums before posting exhaust topics. they have been covered many times. the LT1 system flows better than a L98.The LT1 is a true dual system. The L98 had a bottleneck with the single massive cat. i had a 85 (L98) and i replaced everything. Long tubes, High Flow cat, and a B&B cat back. it was a huge diffrence. On my 96 i went with a shorties, stock cats, and a Magnaflow 3' cat back system. Honestly I noticed more on my 85 then i did on my 96.
Burning Brakes
Joined: May 2004
Posts: 1,230
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From: Athens Ohio
I adapted a LT4 system to my 86. You will need to buy all new hangers. You will need to fabricate the connection coming from the manifolds. When I first installed it I left the precats on. I later removed them.
It is quite an improvement over the L98 system. I also like that it is fairly quiet.
It is quite an improvement over the L98 system. I also like that it is fairly quiet.
Le Mans Master
Joined: Jun 2009
Posts: 5,060
Likes: 1
From: Tabernacle NJ
St. Jude Donor '10-'11-'12-'13
http://www.hottexhaust.com/detail.asp?product_id=16837 go to make offer section and lowball them like 450 bucks and they will counter offer around 550 bucks .A good system,search their website for any year etc
Pro
Joined: Oct 2008
Posts: 704
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From: Jyväskylä, FINLAND
I will also have it at the dyno later on to have the chip optimized for my present combination. I do have the numbers with the stock L98 mufflers, so it will be interesting to see, if there is a difference with the LT-1 mufflers.
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Instructor
Joined: Aug 2006
Posts: 220
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From: Hagerstown MD
Ks5, that is the system i have on my 96. my honest input on it. I got it from Performance pedler for around $550. If i had to do it again. I wouldn't. the mufflers hang down to much and are not the best fitting system i have seen. Maybe i just didn't install it right but the B&B system i had on my 85 was a snap
Last edited by ittybittyfds; Jan 9, 2010 at 12:24 PM.
Thread Starter
Intermediate
Joined: Jan 2010
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Yorcci, interested in seeing the dyno numbers. Would you have the numbers for the complete stock L98 (heads to tailpipes) vs the LT1 setup? I wasn't able to find any archived examples of actual dyno numbers when making this change. Certainly a good number of legitimate anecdotal responses but I'd like to see some actual numbers. Are the stock LT1 manifolds that different than the stock L98 manifolds?
Last edited by 71blackbird; Jan 9, 2010 at 01:47 PM.
Thread Starter
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ittybitty, thanks for the pics. Nice to see the system on a car. I tend to like the stock appearing systems. The exhaust tips are nice but too similar in appearance to the "fart" cans on tuner cars! Again, just my opinion (which doesn't really matter). Is the system fairly quiet? I think utlimately my goal on this car would be stock appearing as possible. I've always liked the stealth approach. I once had a 71 pontiac ventura (nova) stock appearing with the exception of the 30 over 455 under the hood. This was in the days when C4s were new. Lets just say a couple of C4 owners were surprised!
Last edited by 71blackbird; Jan 9, 2010 at 01:56 PM.
Instructor
Joined: Aug 2006
Posts: 220
Likes: 12
From: Hagerstown MD
you may want to look at the Corvette Central Exhaust Site
http://www.corvettecentralexhaust.com/
they have some better flowing systems that will keep the stock tip look.
answer to your question.. Yea its Quiet. almost 2 quiet for me. I like that Load growling sound.
http://www.corvettecentralexhaust.com/
they have some better flowing systems that will keep the stock tip look.
answer to your question.. Yea its Quiet. almost 2 quiet for me. I like that Load growling sound.
Pro
Joined: Oct 2008
Posts: 704
Likes: 264
From: Jyväskylä, FINLAND
I'll take the car to the dyno shop sometime in the end of January.
Thread Starter
Intermediate
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Yorcci, thanks of the info. Very informative. And, when you consider that you are still running the stock heads and cam (with 1.6 rockers) your HP numbers are great. I figure around 350 at the crank when you consider 15-20% drive train loss! That's about where I would like to be!
Pro
Joined: Oct 2008
Posts: 704
Likes: 264
From: Jyväskylä, FINLAND
I will have LT-1 mufflers installed in my '91 (probably) next weekend. I'll let you know, how it sounds like compared with the present factory mufflers it has. For now, it's quiet (true duals, LT headers, no cat(s))
I will also have it at the dyno later on to have the chip optimized for my present combination. I do have the numbers with the stock L98 mufflers, so it will be interesting to see, if there is a difference with the LT-1 mufflers.
I will also have it at the dyno later on to have the chip optimized for my present combination. I do have the numbers with the stock L98 mufflers, so it will be interesting to see, if there is a difference with the LT-1 mufflers.
Here is a video clip of the car with the newly installed LT-1 mufflers:
http://penthouse.homelinux.net/fs10/...mentimilla.wmv
and this one is otherwise all the same, except with the car's original mufflers a little time ago:
http://kuvaton.com/finnshark/video-m...laputkilla.wmv
Pro
Joined: Oct 2008
Posts: 704
Likes: 264
From: Jyväskylä, FINLAND
Yorcci, thanks of the info. Very informative. And, when you consider that you are still running the stock heads and cam (with 1.6 rockers) your HP numbers are great. I figure around 350 at the crank when you consider 15-20% drive train loss! That's about where I would like to be!
But still, I'll take the car to the same dyno in a few weeks (maybe a fortnight or so) and the only change for now is the mufflers. I might change the injectors also to the Bosch III, if I get those in time.