engine rpm range

[TTennyson]

i need to know max. engine rpm so i can determine what tires and transmission i need to run

 

[cerberusiam]

Max engine rpm for what????



HP?



Torque?



Engine efficiency?



Are you towing? Daily Driver? Both?



Auto or standard trans?







If you would, back up a little and flesh out what you want to accomplish and what you have to accomplish it.

 

[TTennyson]

operateing rpm. i am putting 2. 5 ton rockwells in my truck they have a 6. 72 gear ratio and i currently have a 727 auto. i need it to still be able to do 60mph and if i run 52" tires that works out to 2500 rpm. id rather just run 46" tires but id have to upgrade to an od trans. so i need to know if a cummins will do 2500 rpm

 

[pepecat]

yes

yes it will, but it starts to defuel at 2400 with it maxing out around 2600 if you're luckily with little load. I'd put a 3200 rpm gsk in there and you'll be good all day long. 3600 is where valve float occurs, and you'll need hd valve springs. but that is already screaming. I run 727 non od and it runs fine all day around 2500

 

[TTennyson]

ok dumb question. whats a gsk? governer spring kit? and where do i get 1?

 

[Greenleaf]

It's only a spring. Folks refer to it as a GSK though. I think it's because some vendors sell you an o ring or three with the spring. Some don't. The spring is available at any Bosch dealer or if you feel inventive, at your local Home Depot or Ace Harware. If I was you, I simply obtain the 1-464-650-366 from your Bosch dealer.



GL

 

[cerberusiam]

Given the pump is good and set up correctly defuel should start around 2600 rpms and all in by 2900 rpms. Wear on the pump and such will move that around but you should be good at 2500. Mine will run that all day if needed and pull a shade over 3000 without the governor spring. The last couple of hundred rpms are pretty slow but by that time I am generally out of road and/or room anyway.



If you plan on working on the pump and have a friendly pump shop they can set it up to run more r's without the spring. The spring is a great add on but on certain pumps and in certain conditions it can lead to a runaway. When it is stalled carefully test your throttle reaction and idle down to make sure you are not on the verge.



Considering the size and weight of what you are turning you may be better off considering an OD trans with a lockup TC. That much rotating mass will raise havoc with a fluid coupling that is already sloppy.



Sounds like a cool project. Post some pics when you get it done. Good luck.