Originally Posted By: javacontour
Well, it's higher than STL.
Humidity? Does that play a role as well. Dry, less dense air?
Originally Posted By: tempnexus
Even in Phoenix AZ? I mean they are not that high above the sea level.
Hotter temperature is less dense...drier is more dense...so, Phoenix is less dense in summer...
They refine and market the fuel for higher altitudes...which is fine for a normally aspirated engine.
But my old Volvo Turbo Wagon, which I owned when I lived in Colorado, would develop the same manifold pressure in the Eisenhower tunnel as it would at sea level. So, the lower octane was not ideal for that car.
Now, my Volvo V70 T5 (HP turbo engine) is currently in Colorado. I have a boost gauge (aftermarket) on that car, too. I can't tell exactly how the engine management system handles absolute manifold pressure, but it seems to generate the same numbers at full boost/RPM that it did in Virginia Beach.
With the same manifold pressure, I would think that the detonation concern would be the same. Granted, the Bosch ME7 system is far better than the Bosch CI in my 1985, with a multitude of sensors, including knock sensor, so I worry less...
But I agree with the OP - I should be able to get 93 out there so that I can get the best engine performance.
As an aside, nothing was more fun that taking my shoe-box shaped Volvo 240 turbo wagon into the mountains. Its measly 165 BHP wasn't competitive with a lot of cars at sea level...but once you got to 10,000 feet, the normally aspirated Corvettes and Porsches (at the time) were making even less as they wheezed along in the thin air and I took great satisfaction in passing them on mountain roads...