Originally Posted by EscortWRC

It is very common for people to be disappointed with their results on the dyno. Everyone thinks they have more power than they actually do.

The thing with dynos is that as long as they are repeatable, you're fine. Absolute numbers are mostly irrelevant (except for bragging rights)

If you go to a dyno and you make tuning changes, as long as it is repeatable, you can see if it was a positive (hopefully) or negative change.

There is no specific 'formula' to determine the drivetrain losses. The only thing you can really say with any certainty is that AWD/4WD drivelines tend to have more losses than a 2WD one. Other than that, its pretty much a crap shoot to come up with actual figures for losses, since they vary widely.