Down Hill Braking on a Ford Chassis
Guru's, This may seem a silly question, but, on my DP when going down a long or steep grade, I just downshift my Alison to a lower gear and hit the exhaust brake as needed. I never have to use the ...
Forum Discussion
Terryallan wrote:
A diesel just free wheels downhill in any gear, unless it has some sort of add on braking. Where as a gas engine has compression on the back side naturally, and will in fact hold the vehicle to a lower speed, IF you down shift.
Actually, compression is NOT why a gasoline engine has better engine braking than a diesel. Remember, a diesel has HIGHER compression (usually around 17:1) than a gas engine.
The difference is that a gasoline engine has a THROTTLE PLATE, so there is a significant vacuum on a gas engine with the throttle closed. The pistons have to do a lot of work to pull the piston down against the vacuum of closed throttle plate.
There is no throttle plate that the piston has to pull against with a diesel engine.
