convert BHP @ wheels into BHP @ flyheel
14 February 2007, 07:07 PM
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convert BHP @ wheels into BHP @ flyheel
Took mine on the rolling road today just for the sake of checking things over.
BHP at the wheels was 364.
How do you work out the BHP at the flywheel?
TIA
BHP at the wheels was 364.
How do you work out the BHP at the flywheel?
TIA
14 February 2007, 07:15 PM
#2
at wheels is normally about 75% of flywheel figure
Or use the search engine...LOL https://www.scoobynet.com/general-te...atw+horsepower
Or use the search engine...LOL https://www.scoobynet.com/general-te...atw+horsepower
Last edited by Scott.T; 14 February 2007 at 07:17 PM.
14 February 2007, 09:27 PM
#4
There is no hard and fast rule for converting as it all depends on the transmission losses in the particular vehicle, which in a 4WD are quite high. Most rolling roads will measure the losses on the run-down and therefore provide the flywheel figure.
JohnD
14 February 2007, 11:45 PM
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Yes, 364 was at the wheels and yes it's AWD.
So, if the 364 BHP is right does this mean it's nearly 500bhp?
Would like someone who knows the know to step forward
So, if the 364 BHP is right does this mean it's nearly 500bhp?
Would like someone who knows the know to step forward
14 February 2007, 11:54 PM
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The flywheel figure will vary depending on several things, including what type of rolling road it is.
Roughly speaking, I would expect the flywheel to be anywhere between 440-480bhp.
Who ever did the runs for you, should have given you a print out of the graph, and been able to do a flywheel version. Ask them for it.
Mark.
Roughly speaking, I would expect the flywheel to be anywhere between 440-480bhp.
Who ever did the runs for you, should have given you a print out of the graph, and been able to do a flywheel version. Ask them for it.
Mark.
15 February 2007, 12:28 AM
#7
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Or more to the point, 500bhp (or whatever it is) at the flywheel is a pretty much worthless measurement seeing as it is the power at your WHEELS that defines your car's accelerative performance. I'd always be much happier with a figure at the wheels than at the flywheel.
E.g. Scoob A has been told they have 500 bhp at the flywheel, calculated from a 350bhp at the wheels measurement. Scooby B has been told they have 400bhp at the wheels and a much more cautious calculation of 450bhp at the flywheel.
YOU know which one's faster and hence genuinely more powerful, if you're into that kind of thing.
E.g. Scoob A has been told they have 500 bhp at the flywheel, calculated from a 350bhp at the wheels measurement. Scooby B has been told they have 400bhp at the wheels and a much more cautious calculation of 450bhp at the flywheel.
YOU know which one's faster and hence genuinely more powerful, if you're into that kind of thing.
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15 February 2007, 12:35 AM
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Or more to the point, 500bhp (or whatever it is) at the flywheel is a pretty much worthless measurement seeing as it is the power at your WHEELS that defines your car's accelerative performance. I'd always be much happier with a figure at the wheels than at the flywheel.
E.g. Scoob A has been told they have 500 bhp at the flywheel, calculated from a 350bhp at the wheels measurement. Scooby B has been told they have 400bhp at the wheels and a much more cautious calculation of 450bhp at the flywheel.
YOU know which one's faster and hence genuinely more powerful, if you're into that kind of thing.
E.g. Scoob A has been told they have 500 bhp at the flywheel, calculated from a 350bhp at the wheels measurement. Scooby B has been told they have 400bhp at the wheels and a much more cautious calculation of 450bhp at the flywheel.
YOU know which one's faster and hence genuinely more powerful, if you're into that kind of thing.
Different rolling roads will produce different figures and create their own losses due to how the tyres are loaded. A Maha rolling road will typically see 100hp losses on a 350hp car, but a Dastek will see probably 60hp losses. The same car will likely produce similar flywheel figures, but with different recorded wheel figures.
If you're measuring hp at the hubs, then that's generally the best case, and the losses will probably be less than any roller type dyno. Although it may produce the highest "wheel" figure, it doesn't make the car any faster than running it on a rolling road type dyno.
Paul
15 February 2007, 01:03 AM
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No you don't.
Different rolling roads will produce different figures and create their own losses due to how the tyres are loaded. A Maha rolling road will typically see 100hp losses on a 350hp car, but a Dastek will see probably 60hp losses. The same car will likely produce similar flywheel figures, but with different recorded wheel figures.
If you're measuring hp at the hubs, then that's generally the best case, and the losses will probably be less than any roller type dyno. Although it may produce the highest "wheel" figure, it doesn't make the car any faster than running it on a rolling road type dyno.
Paul
Different rolling roads will produce different figures and create their own losses due to how the tyres are loaded. A Maha rolling road will typically see 100hp losses on a 350hp car, but a Dastek will see probably 60hp losses. The same car will likely produce similar flywheel figures, but with different recorded wheel figures.
If you're measuring hp at the hubs, then that's generally the best case, and the losses will probably be less than any roller type dyno. Although it may produce the highest "wheel" figure, it doesn't make the car any faster than running it on a rolling road type dyno.
Paul
ah and there cannot be BHP at the wheels.... thats WHP!
BHP is at the Break, or crank, or flywheel .
15 February 2007, 10:19 AM
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