Good information so far...Where is your peak torque?
What is the vehicle going to see in terms of average speeds?
Do the two above match on a RPM calculator.
Ideally you want peak torque near you cruising rpm. Plug in the ratios and it will tell you. If you don't know your peak torque, post your CPL and someone will probably know it.
The Maximum overspeed (Cummins words) is 3750rpm, but using that extra 1000 rpm, will hurt your fuel mileage and longevity.What is the red line for these engines. I'm not talking about when does the govner kick in but I mean whats the red line on them? Also changing out the spring, is that hard? what rpm should it be put to.
No, the rpm range of the 4B (according to Cummins) is 850-2500 (on the governer), it's not a gas motor, it's designed to turn slow.ok so on my 3.0L right now my rpm range is from 1,000-5,500, on the 4bt its 1,000-3,700 then. Doesn't seem like a lot of RPM range to plan in. New valve springs will let me to get those higher rpms. I understand that the higher rpms will decrease gas mileage but I just wanted a little more RPM range thats all.