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
OK, I found this on the TDR site.
https://www.turbodieselregister.com/threads/boost-readings-with-the-exhaust-brake-on.238694/
Claims 5-7 PSI of boost on VGT turbo's, which is pretty low.
"The boost is from 2 reasons. The main one is the turbo is spinning fast enough to move a bit of air. The seconds is the restriction from the turbo. The airflow that is making 5-7psi would not be enough airflow to make 5-7 psi if there were not an exhaust restriction that is leaving up to 60 psi in the cylinder. Boost is not a measure of flow, but of resistance.
You can still only have 60 psi of back-pressure, and that is what is creating the retarding horsepower.
There are other features, like cam profile, that will effect retarding power as well."
https://www.turbodieselregister.com/threads/boost-readings-with-the-exhaust-brake-on.238694/
Claims 5-7 PSI of boost on VGT turbo's, which is pretty low.
"The boost is from 2 reasons. The main one is the turbo is spinning fast enough to move a bit of air. The seconds is the restriction from the turbo. The airflow that is making 5-7psi would not be enough airflow to make 5-7 psi if there were not an exhaust restriction that is leaving up to 60 psi in the cylinder. Boost is not a measure of flow, but of resistance.
You can still only have 60 psi of back-pressure, and that is what is creating the retarding horsepower.
There are other features, like cam profile, that will effect retarding power as well."
