Engine/Transmission (1998.5 - 2002) Engine vs. Turbo RPM

[Seed Guy]

Just out of curiosity does anyone know what the turbo RPMs are compared to the engine. For instances how fast is the turbo spinning if the engine is at 2K. Thanks

 

[B.G. Smith]

Rpms

I doubt that anyone other than the mfg. of the turbo could tell you other than an educated guess. For instance if you were driving down the hwy. running the engine at 2K with no load on the truck the turbo might be turning 8K with a boost pressure of 6 or 8 pounds, running at the same speed with the engine under full throttle and loaded the turbo might be turning 25,000rpm with 20# boost on a stock truck. Of course this is just a guess by me. bg

 

[Big_Daddy_T]

http://dodgeram.org/tech/dsl/FAQ/turbo_faq.htm this is alot of info.

edit: If i read right holset says 140000 rpm at 35 psi. Rpm isnt indicative of turbo rpm ,boost pressure is.

 

[andrewkoperdak]

Seed,

I don't think there is a direct ratio for RPM vs T RPM. Here is my thought. The turbo spins faster in relation to the amount of fuel you add. So if you run your RPM up to 2000 while sitting in the driveway it is not the same as when you are loaded and excelerating past 2000. Just look at you boost at a loaded 2000 ( say 30 psi) RPM and then do it again unloaded. Your boost for the second condition will be less. Boost is relative to the Turbo RPM. It has to spin faster as more explosive gases are expelled from the combustion chamber. I have read somewhere that the turbo can spin up to and perhaps beyond 20 thousand RPM. I am sure that now I that I have stuck my neck out here that someone will have a different opinion.

 

[Big_Daddy_T]

two hundred thousand.