% Of HP Loss With Options?
03-12-2003, 03:43 PM
#1
Le Mans Master
Thread Starter
% Of HP Loss With Options?
What is the approx % of horsepower loss at the rear wheels with things like PWR steering, fan , alternator, and automatic?
Thanks
Eddie
Thanks
Eddie
03-12-2003, 04:04 PM
#2
Team Owner
Re: % Of HP Loss With Options? (Silvr77)
What is the approx % of horsepower loss at the rear wheels with things like PWR steering, fan , alternator, and automatic?
Thanks
Eddie
Thanks
Eddie
On a older car - it's probably 25 - 30%...
03-12-2003, 05:01 PM
#3
Safety Car
Re: % Of HP Loss With Options? (Silvr77)
The loss doesn't need ot be measured at the rear wheels it could be measured at the flywheel. If you choose to measure at the rear wheels you are incorporating drivetrain loss too. So measuring it at the flywheel on an engine dyno would be a more accurate way to find out how much power your power steering, AC, alternator, water pump & clutch fan are really robbing you of.
Personally, I'm running one belt that wraps around my alternator, waterpump and crankshaft. I am also getting rid of my clutch fan and going to dual electric fans (should be worth 5 horsepower or so). I would tend to think that power steering could rob you of 5 horspower or so. I believe I remember Jim (427hotrod) telling me that he used to disconnect the power steering belt on his Camaro whenever he went drag racing. He said he raced it with the belt and without the belt and noticed it robbed him of a little bit of power (I don't want to quote any numbers because I can't remember off hand).
Personally, I'm running one belt that wraps around my alternator, waterpump and crankshaft. I am also getting rid of my clutch fan and going to dual electric fans (should be worth 5 horsepower or so). I would tend to think that power steering could rob you of 5 horspower or so. I believe I remember Jim (427hotrod) telling me that he used to disconnect the power steering belt on his Camaro whenever he went drag racing. He said he raced it with the belt and without the belt and noticed it robbed him of a little bit of power (I don't want to quote any numbers because I can't remember off hand).
03-12-2003, 06:36 PM
#6
Team Owner
Re: % Of HP Loss With Options? (THawkbh)
Why would power steering reduce your hp rating?
[Modified by Corey 68, 8:55 PM 3/12/2003]
03-12-2003, 09:53 PM
#7
Pro
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Re: % Of HP Loss With Options? (GrandSportC3)
What is the approx % of horsepower loss at the rear wheels with things like PWR steering, fan , alternator, and automatic?
Thanks
Eddie
On a modern car with AT it's approx. 15 - 20%
On a older car - it's probably 25 - 30%...
Thanks
Eddie
On a modern car with AT it's approx. 15 - 20%
On a older car - it's probably 25 - 30%...
03-13-2003, 08:53 AM
#8
Melting Slicks
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Re: % Of HP Loss With Options? (Silvr77)
minus another 15% for the TWO blondes Ed, THOSE ARE NOT standard GM OPTIONS !
Then again, they might be an aftermarket performance option resulting in +105% , since they produce more testosterone in the driver ! :lolg:
Then again, they might be an aftermarket performance option resulting in +105% , since they produce more testosterone in the driver ! :lolg:
03-13-2003, 09:42 AM
#9
Le Mans Master
Thread Starter
Re: % Of HP Loss With Options? (ylose)
minus another 15% for the TWO blondes Ed...... they produce more testosterone in the drive
:eek: :D :eek: :D :eek: :D :eek: :D
03-13-2003, 10:49 AM
#10
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Re: % Of HP Loss With Options? (Silvr77)
AT will be your biggest loss. The Power steering as another said is ~5HP from Gross... Alt 3or 4 HP, exhasut restriction maybe 10-15 HP, etc.. AT is calculated loss from NET to RW. 4-5 % above that of a manual which is around ~18% for my 69. Gross is measured with open headers and NO accessories on a chassis dyno.
So start with Gross HP, say 400. Subtract all accessories. Say this is 40 HP loss (depends completely on your accessories though). Now you have NET at 360HP. Now Subtract 18 % more to go from NET to RW for a manual and 22% for AT. So for AT RWHP would be 280.8 HP. this should be pretty close...
So start with Gross HP, say 400. Subtract all accessories. Say this is 40 HP loss (depends completely on your accessories though). Now you have NET at 360HP. Now Subtract 18 % more to go from NET to RW for a manual and 22% for AT. So for AT RWHP would be 280.8 HP. this should be pretty close...