Can i confirm that the dyno function provides estimated wheel BHP and not estimated engine BHP as it doesn't compensate for drivetrain losses.

In order to estimate engine BHP what drivetrain loss figure is reasonable. I know there is no hard and fast rule for this and up to now i've been using 16% . I've heard of loss figures being used as high as 22%-25% but this sounds very high to me.

Any thoughts??

Obviously not

Not to sound dismissive but who cares. The difference between starting power and ending power is all that matters.

Fair comment