Downshift or exhaust brake?

opnspaces wrote:
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 downhill I have always downshifted and kept the speeds where I wanted them with only an occasional push on the brake pedal.

For those of you who have driven both, is a diesel with an exhaust brake that much better at controlling speed going down a grade? Or is this just another Ford vs Chevy type of question?

All an exhaust brake does on a diesel is plug up the engine on the exhaust side. On a gas engine you have the same thing it's just on the intake side and is known as a throttle valve or a throttle body. A diesel does not have this because the intake tract is wide open.

The reason an exhaust brake works better on a diesel is because of the compression ratio. It takes a lot more energy to compress an 18 to 1 cylinder with air in it than a 10 to 1 cylinder with air in it.