Exhausting L-98 question(I know,I know)
Thread Starter
Le Mans Master
Joined: Feb 1999
Posts: 6,470
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From: levittown pa. usa Even a bad day with my `Vette, is better than a good day at work
St. Jude Donor '10
Exhausting L-98 question(I know,I know)
--- There has been a lot of posts that state that you should put headers on your car. The fact is, I`ve been in my local Corvette junk---err, recycling yard looking at the wrecked, burned out etc. Vettes of different gens, & of all the ones that I saw (about 200 or so cars) only three ( 3 ) had headers. My question is; if I don`t want the cost/aggrivation factor of putting headers on my `87 coupe, A4, 2:59, Magnaflow cat back. What kind of performance kick will I get if I replace the pre-cat front "Y" pipe with a non-cat one, & replace the main stock cat, with a high flow type, like a random tech modelthanks
Ken
Cruising
Joined: May 2005
Posts: 13
Likes: 0
From: Chicago IL
I'm glad you asked the question. I'm basically in the same boat, have an 89 and about to put a set of Borla Stingers on this weekend. Wasn't sure if I should order the high flow cat and the front pipe without the pre cats. Headers are on the list, but that won't be until next year when the engine comes out, install should be easy at that point.
Team Owner
Joined: Sep 2001
Posts: 62,171
Likes: 1,735
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
somewhere between 5-10hp
If you pulled the exhaust manifolds off, you'd see why the headers do us so well, the ports are miniscule.
If you pulled the exhaust manifolds off, you'd see why the headers do us so well, the ports are miniscule.
Team Owner
Joined: Sep 2002
Posts: 22,209
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From: OBAMA IS HITLER
you saw only 3 of 200 with exhaust headers probably because the previous owners thought it was more important to buy accessories, trinkets and other silly paraphanalia for their vette rather than doing something real and worthwhile to increase performance 
Melting Slicks
Joined: May 2004
Posts: 2,524
Likes: 10
From: Lufkin Texas
St. Jude Donor '05-'06
I initially replaced the pre cats with straight sections of pipe and gutted the cat. It got a bit louder but I honestly couldn't feel a difference.
After a scolding from bogus for gutting the cat
and little to no gains I made the decision to do it right and ordered a set of Hooker 2149's and a free flow cat. BAM!, theres the difference I was looking for! 
A 15-18+ RWHP bump that could be felt for sure. 
After a scolding from bogus for gutting the cat
and little to no gains I made the decision to do it right and ordered a set of Hooker 2149's and a free flow cat. BAM!, theres the difference I was looking for! A 15-18+ RWHP bump that could be felt for sure.
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Both Vic'89 and I had the same exhaust systems on our cars, i.e. 2 1/2" mandrel bent front Y, hi-flow cat & cat-back and we both gained around 15-20chp (based on time slip trap speed) over bone stock exhaust. BTW, that time slip data was normalized for variations in weather. So, yes this setup is worth some nice gains.
Vic later installed a set of 1 3/4" coated FL headers and picked up another 15-20chp. And, yes this is the prefered setup for best power gains. Only true duals would give better results, due to main single cat flow restrictions.
If you are planning on FL headers next year, just do the cat-back now; do the main cat and headers together to simplify your life.
Vic later installed a set of 1 3/4" coated FL headers and picked up another 15-20chp. And, yes this is the prefered setup for best power gains. Only true duals would give better results, due to main single cat flow restrictions.
If you are planning on FL headers next year, just do the cat-back now; do the main cat and headers together to simplify your life.
Drifting
Joined: Mar 2005
Posts: 1,923
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From: GA
Headers are good for a nice little HP increase on their own...but what they really do is pave the way for getting more power out of the mods to come, ie; better heads, better flowing intake, larger cam, forced induction.....If you take more air into the engine you have got to have a way for it to get out easily.
Le Mans Master
Joined: Jan 2003
Posts: 5,858
Likes: 7
From: Santa Maria CA
Originally Posted by kenv
.
My question is; if I don`t want the cost/aggrivation factor of putting headers on my `87 coupe, A4, 2:59, Magnaflow cat back. What kind of performance kick will I get if I replace the pre-cat front "Y" pipe with a non-cat one, & replace the main stock cat, with a high flow type, like a random tech model
My question is; if I don`t want the cost/aggrivation factor of putting headers on my `87 coupe, A4, 2:59, Magnaflow cat back. What kind of performance kick will I get if I replace the pre-cat front "Y" pipe with a non-cat one, & replace the main stock cat, with a high flow type, like a random tech model
I opened up an issue of Corvette Trader magazine and called just about every Corvette speacialty shop that had an ad in there. I asked them their opinion of going with FL Headers and how difficult it would be to install them in a C4. Just about every one of them told me they either don't or rather not install FL headers in C4's. They told me it was a real "knightmare" to install them, that ground clearance on speed bumps would be an issue, having to jack up one side of the motor, burn plug wires, heat issues, leaks, ect.
Took on the task of intalling my Hooker 2151's myself anyway, and it was not nearly a PITA as they made it sound like. Ground clearance is not an issue over my stock y-pipe. It's about the same. No problems with speed bumps, heat, installation, fit or anything. I have way better access to my spark plugs now. And a set of dead soft aluminum collector gaskets seal pretty good too.
My point is that Installing FL headers is not all that bad given you have the tools do to it. As far as cost, well that is an issue that is different from person to person.
Last edited by 86PACER; Jun 8, 2005 at 02:43 AM.
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Safety Car
Joined: Aug 1999
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From: Fort Lauderdale FL
Originally Posted by Drinker77
I'm basically in the same boat, have an 89 and about to put a set of Borla Stingers on this weekend.
Cruising
Joined: May 2005
Posts: 13
Likes: 0
From: Chicago IL
Well thanks for all the info. Had originally planned to wait for the engine to come out and do all the work at the same time, heads, cam, mini ram, internals, and headers. But if the install is not all that bad, well then I may have to start shopping around for some. I'm sure they'll help to really bring out the sound of the stingers.