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

Me Again wrote:
4X4ord. 2 gear(2:1) in a Aisin and 4:10's out back is going to hold back a lot on the full exhaust brake setting. If the VGT exhaust brake makes 75HP of braking, then in 2 gear wouldn't that equal 600+ hp of braking at the rear wheels?

AT that weight, what speed would 600 hp hold.on that grade. You seem to be able to compute the numbers going up, so you should be able to computer them coming down. I know at 24,500 in 4th(1:1) and 3.42 out back, I had to step on the throttle once in a while on 6% grades to not slow down to much. Would that not be 225HP of braking at the rear wheels?

On a 6% grade a 24500 lb truck and trailer would require about 215 reverse horsepower to keep it from accelerating down the hill. At 55 mph about 100 of that 215 hp will be air and rolling resistance. The other 115 will come from the engine. Rotating the engine 2000 rpm might account for about 50 hp and the remaining 65 reverse hp could come from the exhaust brake.


In the case of Ron's unit I did some sloppy number crunching in my head without a calculater. The actual reverse hp to keep his unit held back is more like 430. At 35 mph air and rolling resistance don't account for a whole lot. So maybe the engine needs to make about 400 reverse hp.