RPM question for those with 6.2 diesel

[Grantshire]

What is a good 65 mph cruising RPM for the 6.2 diesel? Mine is a non turbo military 6.2 with a NV4500 behind it, if that matters. I want to make sure I don't over rev or lug the engine with my upcoming axle & gearing swaps. My current tires are 38's but I plan on going to 40's soon.

[poolmike]

My buddy had a service truck that we used to run at 3,000 all day long on the highways. Never had any problems.

How far are you from Springfield?? I'll be passing thru there tomorrow.

[Grantshire]

My buddy had a service truck that we used to run at 3,000 all day long on the highways. Never had any problems.

How far are you from Springfield?? I'll be passing thru there tomorrow.

My gas engine Suburbans cruise nicely with good fuel economy at 2000 RPM's at 70 mph in OD. The M715 has a NV4500 behind the 6.2 and I will run 38-40" tires on modern axles (60/14 bolt combo) that will need to be geared correctly for the above outlined drivetrain. If the engine were another small block gas engine I would shoot for 2200 RPM's at 70 in OD. I just don't know if the same number hold true for a diesel. 3000 seems too high to me.

I am about 90 miles south of Springfield off I-95 near Richmond.

[ncjeepers]

Hey.
The 6.2L's are high reving compared to the other diesels.
My CUCV Blazer has 3.08's on 31" tires, runs as fast as you care to go in one on the highway, and gets around 20mpg around town and on the highway.
If I were you, I'd try to keep the gearing close to that, which comes in around 4.00 on 40" tires. I'd say it'd be pretty happy around 4.10 or 4.56 without an overdrive.

[rollie715]

I'm sure there's a limit, but with the shorter stroke in the 6.2's they will handle higher rpms' better then the newer 6.5's

[Tanner]

Check out Cabell Garbee's website for Equations - http://www.garbee.net/~cabell/equations.htm

We're working on a 6.2/Spicer 3053A swap into my M37 - running 5.89's & Michelin 1100x16 tires...

Tanner in Raleigh, NC

[Kamikaze12volts]

if it can help .... a site that a loved for that ... Just fill the blank spaces

http://www.rocky-road.com/calculator.html

[devildog]

You should aim for 1800 RPMs at 60 MPH. Your best mileage and power will be in the 1800 to 2200 RPM.

[Tanner]

word is that over 2500rpm, you're just making noise... power dropoff

Tanner

[Grantshire]

You should aim for 1800 RPMs at 60 MPH. Your best mileage and power will be in the 1800 to 2200 RPM.

Thanks, this is the information I was looking for. I have run rpm calculations on dozens of combinations but I did not know what the ideal 6.2 rpm range for power and economy.