Could someone please tell me what the RPM should be for a 1980 300SD at 70 mph? I am getting about 3100 rpm, which seems high for a deisel. Thank You.
Cruising RPMs?
Feb 10, 2004
3 Replies
That is exactly what it should be.
205/70 tire rotation at 70 MPH is about 950 RPM x 3.07 (rear axle ratio) is 2,915, add 3% for torque converter loss and the engine is spinning at 3,000.195/70 tires are smaller and rotate faster.
I run 205/70 on my '80 300SD and it handles well.
I'm right at 3100 @ 70 MPH with my 85 300SD also, provided I'm running on level ground. It drops to 3000 down a 3-4% grade, which would seem about right.
My 1999 E220 CDI is at 2200 rpm's at that speed
Steinar
Join the Discussion
Have something to add? Share your thoughts — no account required.
Didn't find your answer?
Ask the community — no account required