Hilltop 18th April 2015
Deleted account 211025001
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Just add another 20bhp to the back wheel figure if your bike's shaft driven or 5bhp if it's chain driven
Andres
Just add another 20bhp to the back wheel figure if your bike's shaft driven or 5bhp if it's chain driven
Andres
I seem to remember the figures of 18% loss for shaft drive and 11% loss for chain drive!
......but then again I'm old and knackered and might be talking complete bollocks
125 bhp + 10% at hilltop = 137.5 - 18% = 112.75 Not too far off. Geoff reckons 20 bhp loss that makes it 117.5 ......spot on
I don't believe him 'sorry' for 2 reasons Geoff guarantees BMW cannot see the mapping he flashes and 2 my bike was inspected by BMW head tech and I was asked if my bike was mapped due to the headers and NO was my answer, and trust me it was there get out of jail card so if they found such thing they would have pulled the plug because they wanted rid of me
I think they may guess as Blackal suggests and by taking a look at the bike, fully Akro and purrs like a cat when they ride it ! Rather than the iffy fuelling stock bike . So tell em nowt and act stupid .
Or maybe they would just look on here?
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I seem to remember the figures of 18% loss for shaft drive
On that basis then, my single cam Hexhead is outputting 133bhp at the crank.....
It's quite easy to work out.
Everything is easy if you're just guessing.
There's no guessing when you have a calculator
But that's only as accurate as the numbers you're putting in, so if they're guesses you're fecked. So come on tell me how you can be accurate knowing how much a R1200GS loses in power due to the delivery system. Is it really 18% or is it 15% or 20%. Is this the same for all shaft drive bikes? How did you measure it and using what equipment?
BMW state that the bike has 125bhp, so if the Dyno says that it's actually producing 90bhp at the rear wheel before the remap, then 115bhp at the rear wheel after the remap, then add the same percentage difference to the 115bhp, and that will give you a more accurate bhp at the crank figure.
Easy.
Not sure if a bike dyno works the same way but a car dyno takes a power run with the engine powering the rollers then the rollers drive the engine and there fore know hat power is needed to overcome the transmission losses.
Add that to the measured output at the wheels and get a pretty accurate crank output figure.
Add that to the measured output at the wheels and get a pretty accurate crank output figure.
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