bHP vs. RWHP
Thread Starter
Instructor
Joined: Jul 2002
Posts: 120
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From: You guess it
bHP vs. RWHP
How much horsepower, approximately, is lost in the transmission and rear end? I'm wondering what the horsepower is at the flywheel is if a car pulls, say 330 rwhp on a dyno.
[Modified by Bill Burkert, 2:41 AM 10/14/2002]
[Modified by Bill Burkert, 2:41 AM 10/14/2002]
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Re: bHP vs. RWHP (Bill Burkert)
usually 15-16% for a manual
17-18% for an automatic
So if we were talking about a ZF6, you would be putting out just under 400hp at the flywheel if you had 330rwhp. Cars are rated at flywheel HP.
[Modified by vader86, 9:44 PM 10/13/2002]
17-18% for an automatic
So if we were talking about a ZF6, you would be putting out just under 400hp at the flywheel if you had 330rwhp. Cars are rated at flywheel HP.
[Modified by vader86, 9:44 PM 10/13/2002]
Racer
Joined: Nov 2000
Posts: 253
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From: battle creek mi
Re: bHP vs. RWHP (Bill Burkert)
this is another debateable subject...i have a mustang chassis dyno and my partner has a land & sea engine dyno. i just finished testing a car 2 weeks ago..the engine was ran on his dyno then,without me knowing the output he brought the car to me,i told him the rwhp and calculated the flywheel hp..i said the car made 575hp..the engine dyno said 605. the numbers i use are based on the driveline in the car,the tire size,the transmission..heck i even look to see if the driveshaft has been lubed! the #'s i use are based only on the car that i see...not just a simple percentage....can you guess which car on my website has the highest output? leave out the super gas mustang!
Burning Brakes
Joined: Jun 2001
Posts: 838
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From: Out by the bridge again, TampaBay
Re: bHP vs. RWHP (65Z01)
Gears, and loose converters on automatics can increase that to as high as 20%. For a stock car 14-15% for a manual and 17-18% for an auto is a good rule of thumb. :yesnod:
Racer
Joined: Nov 2000
Posts: 253
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From: battle creek mi
Re: bHP vs. RWHP (BiZ)
ooops..didnt mean to hijack the thread :crazy: all of the newer cars ive run on the dyno are very efficient...the trailblazer that i ran made 218rwhp,thru the 4wd!!! i believe the percentages found above would apply to the c5
Team Owner
Joined: Sep 2001
Posts: 62,160
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
Re: bHP vs. RWHP (1985z51)
Yes different type/brands of dyno will give different numbers for some reason.
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Racer
Joined: Nov 2000
Posts: 253
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From: battle creek mi
Re: bHP vs. RWHP (vader86)
different dynos test engines different ways..engine dynos control the rate of acceleration and measure output at different rpms ,chassis dynos are loaded and then the car has to accelerate the load...and the output is measured at various times(not predetermined rpms)....hopefully i havent confused anyone. :)
