(moved/retitled) Safe RPM range to travel for extended periods?
 

The forum needs a general discussion area. Example: I will be traveling to California next month and I want to know what is a safe RPM range to travel for extended periods of time. My car at 60mph is roughly 2400. m46/D24

Engine peak efficiency is 2800, but you will have some aero losses, so who knows.
On flat ground, 4000 all day won't hurt anything.I normally run ~3200RPM at 75 so I don't get a big ticket.
If it heats up, slow down a little.
My car will heat up if cruising over about 90 for too long, but we have too much traffic for that here anyway.