[Roman]

I'm saying that measuring flywheel horsepower is nonsense, and have been giving valid reasons as to why I think this is the case.

I've yet to read a satisfactory explanation as to how measuring flywheel HP is possible to do with any degree of accuracy, or how it's at all relevant to your cars performance (which is the point of going to the dyno, is it not?)

This is a discussion board afterall, for sharing knowledge. If measuring flywheel horsepower is a fallacy in some ways, isnt that something that you'd like to know?

It's mostly bandied about because people who dont know much about cars cant understand why their car is making (for example) 200hp (at the wheels) instead of the 250 (at the engine) that it's supposed to (and does!) make. But adding on a random % to appease the unwashed masses shouldnt sit well with anyone interested in having relevant, and comparable results. (which is the point of this post, to ascertain which modifications give benefits, etc)

As a good example, check out the post just put in by nikki1887.

In the first run, it says 161hp ATW, and 197hp @ engine.

In the second run, it says 163hp ATW, and 196hp @ engine.

How is it that despite the fact that he's making MORE power at the wheels in the second run, it shows him making less if you only went by the 'at the engine' figures?

If (like some dynos do) they only showed the 'at the engine' figures, he'd probably think "Aaah rats, I just lost 1hp, I'll change back to what I had in the first run" When in reality, he'd hav gained approx 3hp from doing whatever he did. If that doesnt tell you that 'at the engine' is a load of useless nonsense, then there's no convincing you.