L98 Basic Mods?
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
I dont think removing the frisbee gives 10 crank horsepower. A 160 thermo and fan swtich more ten??
Indeed there are nearly always tradeoffs in doing performance mods.
If you read the "frisbee" rightup on my site you will see that Gordon Killebrew mentioned the possibility of vibrartion during A/C compressor cycling after removal of the disc. Upon removing it from my '88 I indeed saw a repeatable 1mph gain in trap speed; that amounts to 10chp.
Other mods that I mentioned have netted me the gains listed, though I do not guarantee identical results, you should see similar gains.
BTW, check out my mods, dyno results and trap speed vs launch weight and you will see that my mods have indeed brought close to a 60chp increase in power. That gain was, in large part, due to those "simple" mods mentioned above.
When does weight reduction make horsepower?
Also, remember that you will likely not even "feel" a 10-15chp increase in power. In fact, if track conditions vary and you do not normalize trap speed for weather, you might not even see the results there.
Last edited by 65Z01; Dec 9, 2006 at 09:43 AM.
Safety Car
Joined: Jun 2000
Posts: 4,870
Likes: 25
From: Long Island, NY
The original poster of the question asked about "Basic mods" for an L98.
All the things that 65Z01 mentioned do indeed make you car "quicker". This in turn is like adding HP.
Lots of guys on this forum have done all the simple & minor bolton mods, they all have gone about 1/2 second quicker in the 1/4 mile.
I have performed extensive track and dyno testing. Running the car at 160 degs compared to 220 degs at the track does make a big difference. About .15 seconds in my case.
My bolton setup dynoed about 271 RWHP, stock was about 210 RWHP. So there was a measured 61 RWHP gain with my mods.
And exhaust was about 25 RWHP of the total.
Vic
All the things that 65Z01 mentioned do indeed make you car "quicker". This in turn is like adding HP.
Lots of guys on this forum have done all the simple & minor bolton mods, they all have gone about 1/2 second quicker in the 1/4 mile.
I have performed extensive track and dyno testing. Running the car at 160 degs compared to 220 degs at the track does make a big difference. About .15 seconds in my case.
My bolton setup dynoed about 271 RWHP, stock was about 210 RWHP. So there was a measured 61 RWHP gain with my mods.
And exhaust was about 25 RWHP of the total.
Vic
Pro
Joined: Nov 2006
Posts: 729
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From: Concord North Carolina
O. Sorry. I thought you meant it was really adding "motor" horsepower. I understand now. Sorry about that. Well I did basic mods like mentioned. When I did them yes it felt different but I am sure alot of it was mind wise. My car feels faster when I wax it.
Which is about once a year. I see your site now. Impressive. I will read thru it. Thanks.
Burning Brakes
Joined: Aug 2005
Posts: 1,172
Likes: 9
From: '88 TPI L98/HotCam Powell, Ohio
Hi guys and nice posts above. I just wanted to add my experience with adding Headers and exhaust. I gained roughly 25 peak rwhp like others have stated but hp gained throughout the Dyno chart showed as much as 45 rwhp and 50 rwtq compared to stock. Pretty big improvement and a good starting point IMHO for other mods. The stock system needs to go.
Pro
Joined: Nov 2006
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From: Concord North Carolina
Originally Posted by mrc24x
Hi guys and nice posts above. I just wanted to add my experience with adding Headers and exhaust. I gained roughly 25 peak rwhp like others have stated but hp gained throughout the Dyno chart showed as much as 45 rwhp and 50 rwtq compared to stock. Pretty big improvement and a good starting point IMHO for other mods. The stock system needs to go.
Hey can you give me a horsepower gueistmate on my future exaust mods. Stock L-98 exaust converted to true dual, no cats, no mufflers, logn tube headers...??? Say 40 chp?
Burning Brakes
Joined: Aug 2005
Posts: 1,172
Likes: 9
From: '88 TPI L98/HotCam Powell, Ohio
This link has my dyno chart and there is another pretty stock l98 dyno chart (cuisinartvette) posted before mine. Like I said before a gain of 25 peak HP doesn't tell the story. To answer your question...Yes,based on my experience you should gain 40-50 rwhp/tq at 5000rpm vs stock at 5000rpm.
http://forums.corvetteforum.com/show....php?t=1548235
http://forums.corvetteforum.com/show....php?t=1548235
Last edited by mrc24x; Dec 9, 2006 at 11:58 AM.
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Originally Posted by vader86
thats not what he's trying to tell you
65Z01 goes by track ETs, where 0.1 = roughly 10hp at our power levels.
Removing weight effected his ET, which he's showing you is equivalent to adding power.
The number that really matters for any car is power/weight ratio.
65Z01 goes by track ETs, where 0.1 = roughly 10hp at our power levels.
Removing weight effected his ET, which he's showing you is equivalent to adding power.
The number that really matters for any car is power/weight ratio.
Pro
Joined: Nov 2006
Posts: 729
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From: Concord North Carolina
Originally Posted by lefoy84
I replied to what 65Z01 said about gaining 5 chp by removing the spare and jack. It may give a performance increase but does not add hp.
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Exactly; guess I should have been a little clearer on that one, sorry.
There is an equation to calculate 1/4 mile trap speed that involves the ratio of chp to weight, so reducing weight has the effect on performance of increasing power. That acceleration effect is that a weight reduction of 100lbs is about equivalent to increasing power by 10chp, for our Vettes anyway.
There is an equation to calculate 1/4 mile trap speed that involves the ratio of chp to weight, so reducing weight has the effect on performance of increasing power. That acceleration effect is that a weight reduction of 100lbs is about equivalent to increasing power by 10chp, for our Vettes anyway.
You have a bad attitude problem ya no. Anyway back on topic.
Team Owner
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From: Athens AL
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Originally Posted by lefoy84
I replied to what 65Z01 said about gaining 5 chp by removing the spare and jack. It may give a performance increase but does not add hp.
When you've answered this question 10,000 times like he and I both have, you become hopeful that most members can read and comprehend, clearly that is not the case.
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Originally Posted by vader86
read my website (click my name)
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Originally Posted by vader86
Perhaps we should stop assuming people around here have common sense and understand what is being written.
When you've answered this question 10,000 times like he and I both have, you become hopeful that most members can read and comprehend, clearly that is not the case.
When you've answered this question 10,000 times like he and I both have, you become hopeful that most members can read and comprehend, clearly that is not the case.
