HP ratings RW vs. Flywheel
07-11-2007, 01:59 PM
#1
HP ratings RW vs. Flywheel Not sure where to post this one but here goes.
My car is about 350 rwhp. My work truck is about 200 rwhp. Car ads on tv ect. will say a car has 260hp. Are most of these readings on the motor or are they rear wheel.
For instance there is a newer mustang that is supposed to be a 500hp car. Is that at the Flywheel motor or rear wheels?
Can any one clarify?
My car is about 350 rwhp. My work truck is about 200 rwhp. Car ads on tv ect. will say a car has 260hp. Are most of these readings on the motor or are they rear wheel.
For instance there is a newer mustang that is supposed to be a 500hp car. Is that at the Flywheel motor or rear wheels?
Can any one clarify?
07-11-2007, 02:06 PM
#3
Yeah, pretty much all advertised manufacturer horsepower ratings are at the flywheel. The ls1 is rare in the respect that the dyno #'s for rwhp are pretty close to the advertised hp by GM. Most cars don't dyno anywhere close to the advertised hp at the wheels.
07-11-2007, 02:29 PM
#4
Originally Posted by Starion
Yeah, pretty much all advertised manufacturer horsepower ratings are at the flywheel. The ls1 is rare in the respect that the dyno #'s for rwhp are pretty close to the advertised hp by GM. Most cars don't dyno anywhere close to the advertised hp at the wheels.
A standard LS1 rated at say 345 makes around 300 or so to the ground. The math certainly works but the RWHP is not that close to its rated power, nor should it be.
Tony
07-11-2007, 02:53 PM
#7
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Originally Posted by 1FSTLS1
So could there be a general rule of thumb that RWHP is about 50 less than advertsed???
If a car comes in both auto and manual, then the auto will eat more power than the manual does.
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07-11-2007, 06:11 PM
#9
Originally Posted by Tony Mamo @ AFR
Its not that close....A Z06 Vette at an advertised 405 makes like 350-355 RWHP (which very much backs the Generals claim).
A standard LS1 rated at say 345 makes around 300 or so to the ground. The math certainly works but the RWHP is not that close to its rated power, nor should it be.
Tony
A standard LS1 rated at say 345 makes around 300 or so to the ground. The math certainly works but the RWHP is not that close to its rated power, nor should it be.
Tony
An Fbody is rated at 305 by GM and it dyno's damn close to it rwhp. Maybe a corvette is rated at 345, but not fbody's. I guess i should have said "fbody" instead of ls1. That's what I meant.....sorry if I mis-spoke.
07-11-2007, 06:14 PM
#10
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Originally Posted by Starion
An Fbody is rated at 305 by GM and it dyno's damn close to it rwhp. Maybe a corvette is rated at 345, but not fbody's. I guess i should have said "fbody" instead of ls1. That's what I meant.....sorry if I mis-spoke.
07-11-2007, 06:28 PM
#11
Depending what rear youhave, there's more loss as well. A 12 bolt is going to lose a little more over a 10 bolt due to the larger rotating mass. A 9 inch will lose more due to the rotating weight and pinion angle.
As mentioend above a T56 vs a 4l60 will also make difference.
Different exhaust set up all add up too vs open headers on an engine dyno.
As mentioend above a T56 vs a 4l60 will also make difference.
Different exhaust set up all add up too vs open headers on an engine dyno.
07-12-2007, 07:05 PM
#12
Originally Posted by Starion
An Fbody is rated at 305 by GM and it dyno's damn close to it rwhp. Maybe a corvette is rated at 345, but not fbody's. I guess i should have said "fbody" instead of ls1. That's what I meant.....sorry if I mis-spoke.
