So I haven't bought Hpt yet but I have to ask if altitude becomes a factor when tuning a/f ratios. I live in Wyoming and live at ~5000 feet over the summer...but when I go to school I drive 350 miles and then am at 7200 feet for the rest of the year. So my question is do I need to tune at 7200 feet for driving there and have a tune for the summer at 5000 feet? Also I am workin with a '97 Firebird with the 3800 and plan on going FI here pretty quick with a turbo..Thanks in advance for the help.
Big time! The air is way thinner even at the altitude you're at in the summer. You'd be better off having 2 tunes. IMO
1997 Regal GS. SLP headers, CAI, cat back. S1X cam, 1.6 RR's, 3.5" pulley, ported S/C, LS1 valve springs.
Yeah....thats what i was afraid of....not so much just having to have two tunes...its just the fact that the drive to and from makes me lose that much altitude...i also manage to drive over a mountain pass or two at ~8200 and ~9700 respectively......so my question then becomes if i tune to 5000 feet how bad will 9700 feet treat me if i do not load another tune just to drive over the mountain? because i really don't want to have to stop each time i drop or go up a couple thousand feet to load another tune.......
No, you will not need a different tune. This ONLY applies to MAF based tuning. PE table raping and Spark table taping does NOT count! Tune the car at the lowest elevation you will be running most consistently, and then everything will fall in line regardless of elevation increase.
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1997 Regal GS. SLP headers, CAI, cat back. S1X cam, 1.6 RR's, 3.5" pulley, ported S/C, LS1 valve springs.
well thats good to know....and that applies to both N/A and FI vehicles correct?
Yes, James is correct. Going to higher altitude will just mean that less airmass is available similar to a throttle that isn't opened all the way. You will just get a lower MAP value at wide open, with a corresponding lower airmass. With a MAF sensor, it will just register a lower flow rate at WOT. Turbos, however, do a pretty good job of fixing this by just adding pressure to offset it.
As mentioned, tune your WOT fuel and spark for the worst case (lowest altitude) and drive it. The factory tune works fine at both sea level and 10,000ft so there's no reason a PROPERLY done aftermarket tune can't either.
alright cool....thanks for all the info guys
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