To counter the effects of lower air density at altitude, can I simply swap the standard pulley that comes with the Comptech kit for a higher boost pulley? To maintain the sea level performance of an AP2 with the standard Comptech set up, what diameter pulley would I need at 5000ft elevation?

 

So long as you make sure your AFR's are okay by going to a tuner I suspect putting a 7lb pulley on there would be as fine as it is anywhere else. I wouldn't go higher than that without an EMS of some sort.

GL!

 

I went with the 7 lb pulley from the start and I am at 2600 feet. I don't know if it 'compensates' for the altitude per say. Anything else you will be driving at that altitude will be dealing with the same problem.

I can tell you this; on the drive during SacS2KDays V, my car felt awesome at sea level. I loved it. Then I found out the great equalizer- altitude. At Mt. Rose (10,000 ft.), my car felt like it was having a hard time breathing, but I was still faster then the other S' that wanted to run when we got to the freeway.

 

I'm thinking about trying a 3.5" pulley. I'm guessing that it will be good for only 7psi or less at 5000ft.

 

Yeah, FI cars tend to cope better with altitude but you'll still lose plenty if you're way up there...