I just drove from texas to San Diego in a 1200$ rx7. Ran great but what I noticed is that the temp gauge (S4 would sit at the half way mark in texas (60degrees) and slightly creep up a little when held at 4k rpm's. It would drop after I went back to 3k.

Once I came off to SD which I think is a few thousand feet lower and the same temperature I noticed the temp gauge took a dump. It hung lower then half way.

What effect does elevation have on temp ?

 

Usually not much, are you sure it wasn't just colder in SD?

 

lower elevation = denser air, thats the only thing i could think of. I'm at sea level and my temp gauge never gets above 1/4 the way up.

 

None, but the boiling point changes with changes in pressure.

 

And hopefully you were well below boiling point at all times...

 

The lower elevation has denser air which means it has more mass. More mass means more efficient cooling.

The other thing that will affect efficiency is the humidity. More humidity=more mass.

Elevation affects the boiling point of open systems, i.e. a pot of water. The cooling system of a vehicle, if properly maintained, will boil at the same temperature, regardless of elevation.

The amount of work required to reach elevation, and the reduction in air desity can cause a cooling system to overheat, when it normaly wouldn't at a lower elevation.

Spent too much tome up and down the mpuntains.

If your temp guage is running at half through west Texas, maybe it's time for a flush, fill and thermostat.

 

Humidity affects cooling, but negatively, not positively as you imply. Moist air can't absorb as much heat as dry air.