altitude change problem
 

When I race at Tuscon, el. 3300 ft and DA of 5000 ft I can hook the car and am consistent with 60 ft times. 10.8's at 125 mph(5200 da)
I'm having a problem blowing tires off in Phoenix that is 1200 ft and usually has a DA of 2500-3000 ft. best 10.68 at 125 mph(2200 da).
What should I do different in Phoenix?

Re: altitude change problem
 

I'm guessing your tune up is set for Tucson? Im usually .25 to .28 faster in Phx. and about 3.5 MPH faster also. Im the opposite and set up for Phx air Sounds like its lean and excessive timing in Phx altitude in which helps bottom end power but hurts the rest of the pass. Just guessing

Re: altitude change problem
 

Looked up in my log book and found similar DA numbers and at 3000 difference I was .22 faster in Phx. I have changed timing and opened valve lash to compensate when its really bad in Tucson.
Also converter acts different and track prep will come into play.

Re: altitude change problem
 

Thanks Jeff, I was considering adding a carb spacer in Phoenix, along with a couple thou tighter lash. Tire pressure and shock adjustment don't seem to help. I think the track is worse at WHP.......just guessing....Ill try a bit less timing also

Re: altitude change problem
 

If your there for Drag and Drift night, it's the track. At Team races and big events it hooks pretty good.