Drivetrain losses are subjective at best... I have seen wildly varying figures on the dyno on fwd and haldex awd cars in the past... also depends on things like how warm the drive train is, grip of the tyres etc... it varies from run to run too as things warm up... you see higher WHP but less coastdown loss as things warm up... doesn't effect the final output of course as its relative
This dyno plot of JoJo's S3 from a recent dyno day at Bill's highlights the issue...
56.7hp (26.47%) loss on the first run, 50.8hp (23.26%) on the second...
Here is a run on mine...
64.3hp difference which equates too 20.76% loss
<tuffty/>
Thanks.
So...more like 20-23% then based on your sample of two. Mine is likely to be the higher end as it looks similar in spec to jojo's but again it's all subjective.
What's interesting is that, despite greater power, your drivetrain loss is actually less as a percentage of your power. My assumption would have been the other way around and incorrect as a result.
I'm keen to measure speed across a variety of distances from standing start and test it on the track with the iphone mounting and require a drivetrain loss measurement for more accurate reading. I'm on a rolling road thursday, so will measure it then before popping to castle combe then.
Thanks.
So...more like 20-23% then based on your sample of two. Mine is likely to be the higher end as it looks similar in spec to jojo's but again it's all subjective.
What's interesting is that, despite greater power, your drivetrain loss is actually less as a percentage of your power. My assumption would have been the other way around and incorrect as a result.
I'm keen to measure speed across a variety of distances from standing start and test it on the track with the iphone mounting and require a drivetrain loss measurement for more accurate reading. I'm on a rolling road thursday, so will measure it then before popping to castle combe then.
whilst on the subject i thought i'd also point out that although fwd cars put more power down on a dyno when compared to awd cars, what everyone fails to think of is the fact that the rear wheels on a fwd will create drag / resistance, which a dyno will not show.....
therefor the advantage of a fwd on a dyno over a awd on a dyno means nothing in the real world
whilst on the subject i thought i'd also point out that although fwd cars put more power down on a dyno when compared to awd cars, what everyone fails to think of is the fact that the rear wheels on a fwd will create drag / resistance, which a dyno will not show.....
therefor the advantage of a fwd on a dyno over a awd on a dyno means nothing in the real world
... so if comparing power to weight, your shafted. lighter, same power car will be the one accelerating away.