Surprising Power From VE SIDI

[gmh308]

What I find most surprising is the torque figure on the dyno sheet. Holden spec sheet says 290 nm at the engine for the SIDI, but this dyno manages to measure an average of around 650 nm at the wheels.
As dynos can only measure torque, and derive HP/KW from that via a formula, surely that throws some doubt on the dyno KW figures. The torque figure shown is simply impossible for this engine to produce without at least 1 BAR of boost without any losses.

Where is the flaw in my thinking?

gh

Well apart from Wonky's comment re ".....ignore the torque.....", unless the dyno was measuring torque at 1:1 gear ratio over all and roller rpm = engine rpm, it will be different unless a correction is applied.

For example 200Nm at flywheel, trans + diff multiplication 4:1 = 800Nm.

As power is derived from torque and rpm, the roller torque is higher, but the rpm is lower. So if engine was at 6000rpm, 4:1 ratio overall = 1500rpm wheel, assume roller diameter = wheel diameter, roller rpm = 1500 too.

(Nm x rpm) / 9550 = kw.

Simple example. Not meant to be accurate.