Downshift or exhaust brake?
I was just thinking after reading a post about gas vs diesel trucks where somebody mentioned they liked diesel because of the exhaust brake. I've never had a diesel, always gas. If I come up to a long...
Forum Discussion
Cummins12V98 wrote:
With trailer attached you should get more retarding HP.
With the trailer on behind there is a little more overall retarding horsepower due to added wind resistance and rolling resistance. As far as the engine holding back any differently there will be no difference. The engine will be turning the exact same rpm regardless of whether or not a trailer is hooked up and the back pressure created by the turbo will be exactly the same so the amount of force required to rotate the engine around will be exactly the same.
If you measured the retarding horsepower generated by an engine in a truck holding a trailer back going down a steep hill compared to the same truck without a trailer on that hill the truck/trailer combo would produce more retarding horsepower than the truck on its own because the added weight would push the truck faster down the hill which means that the engine would be rotating faster forcing more air past the exhaust brake (turbo) at a higher level of back pressure. The back pressure x air volume/time = power.
