Altitude Change, Do I need to retune?

**WS6ICK** · 01-24-2009, 10:22 AM

This summer I will be moving from Colorado to Kentucky. The altitude where I live in Colorado is 6000 ft above sea level and the altitude where I am going in Kentucky is 450 ft above sea level. Do I need to retune it once I get there or will my stock MAF adjust for this? Also, how much differently will my car run at a lower sea level?

**0verkill** · 01-24-2009, 01:00 PM

i dont know about the tune but you should run alot beter down here. what part of ky are you moving?

**Firebirdjones** · 01-24-2009, 04:50 PM

I have been in the same boat. I moved from Ohio 4-500 ft above sea level and now reside in Prescott, 5,300 ft.
The real snag is that no matter what direction I drive from here the altitude changes from 8,000 ft. down to 1,000 ft where the race track is. UGH!!!

On my carbed cars I had to tune for a happy medium spot and left it be. Seems to be doing fine for those.

On both 4th gens I have left the tune alone since it has the ability to maintain a 14.7 AFR while cruising and that part seems to be fine as my gas mileage hasn't changed. The only part of the tune you will have to fiddle with is the WOT I believe. Since that is a set number that is commanded in the tune when the car switches to open loop. That is the way I understand it on these cars anyway. Maybe Frost will jump in here and verify but I'm 99% sure.

I have 2 tunes right now for each 4th gen, one has a little leaner WOT for running around up here, and the other is a little richer at WOT that I throw in for the track that is closer to sea level depending on the DA that day.
The amount of fuel needed at high altitude is much less. Your car will want more fuel when closer to sea level..

I can tell you from tuning carbs all my life that every 2,000 feet in elevation change requires roughly 1 jet size.

**WS6ICK** · 01-24-2009, 05:06 PM

Originally Posted by 01 T/A

i dont know about the tune but you should run alot beter down here. what part of ky are you moving?

Fort Knox area.

**SS02** · 01-24-2009, 05:26 PM

Did You have a Pro/Dyno tune before? That is a big change altitude, if you did then you will run different/worse. Much depends on how picky you are.

Yet it may run better going from up there to down there? It will change.