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
Lynnmor wrote:4x4ord wrote:Lynnmor wrote:
You are testing the exhaust brake like it has an on off switch and no ability to modulate according to speed and deceleration. Doesn't the computer change the rate of braking as programmed?
On the Ford, one push of the exhaust brake button turns the exhaust brake to full on. Push the button a second time and auto mode is activated. I believe the Ram is the same.
So pushing the button once the exhaust braking will be a constant value from high speed right down to a stop?
No. When the exhaust brake is turned on, the turbo vanes move out to their maximum position and will choke the turbo down to generate back pressure. The faster the engine revs the more air is forced past the turbo so both air volume and back pressure are increased with rpm and the retarding horsepower will rise. Again back pressure x rpm = retarding power.
Edit: If the maximum permitted back pressure is generated by say 1500 rpm then additional rpm will increase the retarding horsepower even though the back pressure will remain constant.
