Dyno Results: Flywheel to Roller premiums

[damdy-cash]

Hi Guys, got my 2L Duratec last week mapped and found out the guy added "only" a loss of 20HP, or 8% to get the flywheel HP. Plot attached. Even if this is anyway not a percentage function, but a dedicated loss on a given speed on the rollers (or street) depending on mainly the gearbox and diff used and other paramaters, quite often people calculate 15%-20% for it, what would mean double the losses in my case and very high HP of 278 on the flywheel. Even if that would be a very nice number, the spec of the engine doesn't provide this.

I ask the dyno guy and he told me the 20HP loss is measured not a guess only. The gearbox is a T9 SPC semi helycoil, diff a ZF LSD, so nothing very special. The others stuff in our cars should have around the same losses, do they?

What you guys think about this? Cheers Volker

[Vixpy1]

Dynojet's read high at the wheels so thats normal

[DCL]

That looks like a good results . I wouldn't worry too much about the actual numbers as many things can alter the results. I have seen 40 BHP difference on two different dyno's taken only one day apart. If they did a coastdown check, then losses will be about right. As a guide, my losses are generally around 11%.