LCR Man
Guest
when car manufacturers in general quote a BHP in the book e.g. LCR 225, Is that at the fly wheel or at the wheels.
Cheers !
Cheers !
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manufacturer BHP figures
- Thread starter LCR Man
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LCR Man
Guest
cheers, i always get confused as when you look at rolling road day figures, somehow seem to vary massivly !!!!
Yes it is. I wish that they gave the figures at the wheel too. It would be easier to compare car with car. Transmission losses vary so much.
LCR Man
Guest
ah OK, so i assume all car makers quote BHP from the flywheel as i have also seem M3 Evo's that are only (i say only) 270bhp rather than the qouted 320bhp from BMW!!
The VW group declares power at the flywheel.
FWD losses are around 15% (it can vary a little though).
FWD losses are around 15% (it can vary a little though).
LCR Man
Guest
i assume that the figures at the flywheel is an industry standard accross all car builders cos they'd all have to stick to some kind of script !!!!
CHILLED76
Guest
Car manufactures all quote bhp/torque at the flywheel, as the figures are more impressive (higher at the flywheel than at the wheels).
Generally front wheel drive cars have between 12-17% transmission loss, rear wheel drive cars somewhere between 13-19% and 4wd usually around the 20% loss mark.
When cars are rolling roaded the computer actually adds a % increase on to the output figures so that the graph's show an estimated power/torque at the flywheel (kind of an educated guess using the power/torque measured at the wheels).
On some rolling roads you can change the % increase figure which is why you can get massive differences for the same vehicle between different rolling roads.
When doing a before and after tune up print out the rolling road tuning company have to stick to the same % increase for each graph as otherwise they are breaching trade laws (basically would be conning you).
Because of these % increases and differences between rolling roads you can basically say unless two cars are tested on the same rolling road they are not directly comparible for performance using rolling road print outs.
The rolling road is a good before and after measure for performance tuning as when you are showing the difference in power/torque from before and after a remap as the numbers at the side are irrelivent (if the curve is fatter and higher the car will be quicker) as the total energy output from the engine is derived from the area under the curves.
Anyway to answer your original question again manufacturers all quote bhp/torque at the flywheel as do everyone else i.e (tuning companies) unless stated otherwise, but beware rolling road at the flywheel figures can often be taken with a pinch of salt!!
Generally front wheel drive cars have between 12-17% transmission loss, rear wheel drive cars somewhere between 13-19% and 4wd usually around the 20% loss mark.
When cars are rolling roaded the computer actually adds a % increase on to the output figures so that the graph's show an estimated power/torque at the flywheel (kind of an educated guess using the power/torque measured at the wheels).
On some rolling roads you can change the % increase figure which is why you can get massive differences for the same vehicle between different rolling roads.
When doing a before and after tune up print out the rolling road tuning company have to stick to the same % increase for each graph as otherwise they are breaching trade laws (basically would be conning you).
Because of these % increases and differences between rolling roads you can basically say unless two cars are tested on the same rolling road they are not directly comparible for performance using rolling road print outs.
The rolling road is a good before and after measure for performance tuning as when you are showing the difference in power/torque from before and after a remap as the numbers at the side are irrelivent (if the curve is fatter and higher the car will be quicker) as the total energy output from the engine is derived from the area under the curves.
Anyway to answer your original question again manufacturers all quote bhp/torque at the flywheel as do everyone else i.e (tuning companies) unless stated otherwise, but beware rolling road at the flywheel figures can often be taken with a pinch of salt!!
As an addition to this, most manufacturers (including SEAT) don't actually quote the power in bhp, they do it in PS.
The Leon is 225 PS.
1 PS = 0.986320165 hp
So it's actually only 221.9 bhp.
(Like you're actually going to notice the difference!)
The Leon is 225 PS.
1 PS = 0.986320165 hp
So it's actually only 221.9 bhp.
(Like you're actually going to notice the difference!)
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