W2 408 Dyno results today !

PRH said
Looking at these two shots of run #4......
Just picking a line...... peak hp @6000......
Fuel flow is 233.3lbs/hr, bsfc for that line is .540.
233.3/.540= 432.0hp, uncorrected.

If the efficiency of the motor was producing bsfc numbers in the .470 range, the uncorrected HP would be more like 496hp, with that same 233.3lbs/hr(or it would be using way less fuel to produce the 432hp).

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The thing I don’t think anyone mentioned yet is....... anything that causes the motor to make less power, makes the bsfc numbers look bad.
Even things that have nothing to do with the motor....... like poor air flow through the dyno cell.

We installed a 1" tapered spacer before pull #7 and that fixed the flatline. We tried 4 different spacers and even stacked 2 .
It was getting late and we never tried changing the jetting after pull 7. Maybe dropping 2 all around might help the afr and BSFC ?

I checked the rotational torque of the shortblock and it was 25 ft-lbs or less. Lowest my wrench will go... so I dont think friction is the issue. Could be the intake creating massive turbulance ?
The engine liked about 32* of timing so that should mean the chambers are efficient.