Okay so I was wondering because of the thread I have about Tuning with elevation change how are these three things affected when there are a combination of these effects. Basically does elevation effect spool time or is the A/R somewhat more or less crucial with/out elevation? I have also seen the vacuum changes with elevation so I am just curious. Thanks guys

 

are you talking about the turbo a/r ratio or the air fuel ratio?
a/r ratio is a big deal as it affects turbo spool up time directly.
You need a lot of air to spool up a big a/r ratio turbo. So you need
the right combination of cubes and rpms. More cubes, you will spool it faster with fewer rpms.

 

I think he understands those facts, he is asking how elevation change is going to effect these parameters at higher elevations with less dense air...