Engine HP..need smart Gearhead!!!
Thread Starter
Racer
Joined: Feb 2016
Posts: 373
Likes: 37
From: West Palm Beach Florida
Engine HP..need smart Gearhead!!!
OK......example LT1...460 HP?.....is that 460 hp in the enclosed engine room Dyno with no add on to put drag on motor like AC,Alt,Power steering transmission etc....or is that 460 hp to the rear wheels (rwhp)..if it is rwhp then you need to add approx 15% ( for standard Trans) to the rwhp to get hp to crank.....which would make the LT1 (460 rwhp + 15%=529 hp to crank (motor).....Talk to me...what is on motor when dynoed at 460?
Thanks
Thanks
Thread Starter
Racer
Joined: Feb 2016
Posts: 373
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From: West Palm Beach Florida
I agree 100%...that comes out to about 400 rwhp on stock LT1......Its amazing how many people have gotten base line dynos and their numbers are nowhere close to that.....Which means after their mods the hp is not close either....I know Mustang dynos are better for tuning and read about 10% less than a Dynojet which should be close....If you take the time to search a bunch of dynos it becomes funny..
Pro
Joined: Mar 1999
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From: Bowling Green, Kentucky
Dave 502
The SAE rating is 460 hp at the flywheel. It includes all accessory loads. IN 1972 Socoety of Automotibve Engineers (SAE) changed the standard hp rating to include all engine loads. The rear wheel power will be reduced by an amount for the traansmission and differential and other drive train losses (inefficiencies).
I agree the RWHP will be 12 to 15% less than the 460 at the flywheel.
The SAE rating is 460 hp at the flywheel. It includes all accessory loads. IN 1972 Socoety of Automotibve Engineers (SAE) changed the standard hp rating to include all engine loads. The rear wheel power will be reduced by an amount for the traansmission and differential and other drive train losses (inefficiencies).
I agree the RWHP will be 12 to 15% less than the 460 at the flywheel.
Last edited by GarryZR1; Aug 26, 2017 at 05:11 PM.
Thread Starter
Racer
Joined: Feb 2016
Posts: 373
Likes: 37
From: West Palm Beach Florida
Dave 502
The SAE rating is 460 hp at the flywheel. It includes all accessory loads. IN 1972 Socoety of Automotibve Engineers (SAE) changed the standard hp rating to include all engine loads. The rear wheel power will be reduced by an amount for the traansmission and differential and other drive train losses (inefficiencies).
I agree the RWHP will be 12 to 15% less than the 460 at the flywheel.
The SAE rating is 460 hp at the flywheel. It includes all accessory loads. IN 1972 Socoety of Automotibve Engineers (SAE) changed the standard hp rating to include all engine loads. The rear wheel power will be reduced by an amount for the traansmission and differential and other drive train losses (inefficiencies).
I agree the RWHP will be 12 to 15% less than the 460 at the flywheel.
Thanks for the info....Does that mean that the top Dog in 1970 the 450 hp 454 Chevelle was really only 392 hp with 13% loss?...Just kidding ...The point is that all these shops that have dynos hacked up to show you that you have a lot more Hp and torque than you do should Quit that
Thread Starter
Racer
Joined: Feb 2016
Posts: 373
Likes: 37
From: West Palm Beach Florida
I answered my own question from a article from Hagerty...
“Rear wheel horsepower was at least 30 percent lower than the reported gross figure, in some cases even more,” Campisano said.
Some Super Chevy readers must have been stunned to see that an LS6 Chevelle SS, with 450-hp rating, put down 288 rear wheel hp in the dyno test. That would have put a net hp rating at around 350 hp for that legendary big block.
Great article about 1972 hp change
https://www.hagerty.com/articles-vid.../13/horsepower
“Rear wheel horsepower was at least 30 percent lower than the reported gross figure, in some cases even more,” Campisano said.
Some Super Chevy readers must have been stunned to see that an LS6 Chevelle SS, with 450-hp rating, put down 288 rear wheel hp in the dyno test. That would have put a net hp rating at around 350 hp for that legendary big block.
Great article about 1972 hp change
https://www.hagerty.com/articles-vid.../13/horsepower
Last edited by Dave502; Aug 26, 2017 at 08:03 PM.
Race Director
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I answered my own question from a article from Hagerty...
“Rear wheel horsepower was at least 30 percent lower than the reported gross figure, in some cases even more,” Campisano said.
Some Super Chevy readers must have been stunned to see that an LS6 Chevelle SS, with 450-hp rating, put down 288 rear wheel hp in the dyno test. That would have put a net hp rating at around 350 hp for that legendary big block.
“Rear wheel horsepower was at least 30 percent lower than the reported gross figure, in some cases even more,” Campisano said.
Some Super Chevy readers must have been stunned to see that an LS6 Chevelle SS, with 450-hp rating, put down 288 rear wheel hp in the dyno test. That would have put a net hp rating at around 350 hp for that legendary big block.
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Race Director
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From: Texas Hill Country
what this means is that engine advancements, drivetrain efficiency, and automotive technology in general has come even farther than we give it credit for.
Tech Contributor
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From: Charlotte, NC (formerly Endicott, NY)
Thanks for the info....Does that mean that the top Dog in 1970 the 450 hp 454 Chevelle was really only 392 hp with 13% loss?...Just kidding ...The point is that all these shops that have dynos hacked up to show you that you have a lot more Hp and torque than you do should Quit that
With newer engines accessories have gotten more efficient and stock exhaust manifolds have also gotten more efficient so Net HP ratings are much closer to Gross HP if they actually measured gross HP anymore.
Bill
Safety Car
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From: Kilmarnock Va
OK......example LT1...460 HP?.....is that 460 hp in the enclosed engine room Dyno with no add on to put drag on motor like AC,Alt,Power steering transmission etc....or is that 460 hp to the rear wheels (rwhp)..if it is rwhp then you need to add approx 15% ( for standard Trans) to the rwhp to get hp to crank.....which would make the LT1 (460 rwhp + 15%=529 hp to crank (motor).....Talk to me...what is on motor when dynoed at 460?
Thanks
Thanks
I'm Batman..
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From: Lehigh Acres FL
Tech Contributor
Safety Car
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Safety Car
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more than the Z06.
Last edited by thrilled; Sep 4, 2017 at 04:21 PM.
Team Owner
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St. Jude Donor '05
This!!
True compression, cam specs etc. Still done today by many mfrs.....dont get hung up on dyno #s car will still run the same.
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St. Jude Donor '13
In the past, some of GM's performance specifications seemed to have been written by the Advertising Department rather than by Engineering.
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Bill