F350 Super Duty vs 3500 Denali vs The Ike Pulling 30k lbs

4x4ord wrote:
^^^ I think if the fan on the GM was cutting in and out we would have heard it. I kind of think it was either always on or always off. The thing that is hard for me to understand is this: The Ford is supposed to make 1050 lbft of torque at 1600 rpm which is 320 hp. It is rated at 475 hp at 2800 rpm. The power very likely builds quite uniformly over the power band which means it likely gains about 13 hp per 100 rpm. This means the Ford should be capable of making around 398 hp at the 2200 rpm it ran at.

The GM is supposed to make 445 hp at 2800 and 279 hp at 1600. Therefore the Duramax builds about 14 HP per 100 engine rpm. If we say the Duramax ran at about 2600 rpm it should have been able to generate about 420 hp at that rpm. The time difference up the mountain between the two trucks indicates the Ford was putting out about 63 more hp than was the Duramax. If the Ford was making 398 HP the Duramax was only making 335 ..... yet it should have been capable of making 420.

Not sure if an elevation glitch, but TFLT's Duramax dyno is very poor:



As per this dyno, above 2300 rpm or so it makes a constant 320 rwhp.

If we believe their 2020 PS's dyno of 469, which is nearly identical to the crank rating, at 2200 rpm the PS is making ~390 rwhp, or 70 more than the L5P.

Pretty close to your 63 hp calculation!