Horsepower is horsepower?

blt2ski wrote:

4x4ord wrote:
A pick up truck with a diesel engine rated at 400 hp @ 2900 rpm and 800 lb ft of torque @ 1700 rpm will will pull very similar to a near identical pickup truck with a 6.8 l V10 gasoline engine rated at 362 hp @ 4750 rpm and 457 lb ft of torque @ 3250 rpm if both trucks have the same transmission but the gasoline equipped truck has a 6.73 rear axle ratio vs the diesels 3.52. The gasoline engine will put power to the rear wheels at the lower rpm range and the diesel more power to the rear wheels at the high rpm range.

Shouldn't that last sentence be the diesel at lower rpm, the gas at higher rpm?!?!?!??? Otherwise I would agree if at sea level. at 10K feet elevation, the 6.8 will be sucking for air! unless it had a forced induction intake,ie super charger, then both should be about the same up to 10K' or so when a turbo/supercharger start to wain in power levels at 2-3% per 1000' elevation gain as a natural aspirated rig will.

Marty

Actually Marty I did mean to say the gasoline engine will put more power to the rear axle at the low rpm range but I might not have explained myself very clearly. The idea is that because of the different axle ratios, when the diesel is running in its low rpm range (1700 rpm ) the rear axle will be turning at the same speed as the rear axle in the gasoline powered truck when its engine is turning 3250 rpm. At 1700 rpm the diesel makes 800 lb ft of torque so... 259 HP to the rear axle (disregarding the driveline inefficiencies). The gasoline engine at 3250 rpm makes 457 lb ft of torque or 283 HP to the rear axle. At the high rpm range of the two engines, the diesel makes 400 HP at 2900 rpm and the gasoline engine would need to turn 5545 rpm to keep up with the diesel, way faster than its peek power rpm of 4750 rpm where it only makes 362 HP.