Contour Enthusiasts Group Archives Forums Modifications Forced Induction Tuning question concerning altitude???

Say I have a Contour/Cougar tuned for boost at 4,500 ft. above see level and then ship the car to a town at say around 500 ft. above see level. Let's assume that the car is chipped with an SCT 4 position chip (if that makes a difference). Any reason why the car would be running lean? Is there an alititude parameter in the tuning tables?

Yes, I know there is less oxygen the higher you go, so yes, it would run lean. However, I thought that modern cars adapted to this automatically???

There is a barometric pressure value that the car can learn. The SCT tuning recommends setting it to a fixed value. I'd guess you wouldn't want to do that unless you were boosted and maybe not even then.

Other than that the system works on the mass of the air. If the air is less dense then the mass is less. There should be no issues.

I know the ECU 'learns' altitutde, but you would have to have a fuel system that would keep up with the extra air at sea level.

I have thought A LOT about this b/c I am at 4500.

And you would also want to be careful with boost pressure as far as strain on the engine...psi is measure above atmospheric pressure. So 10 psi at 4500 is atmospheric pressure (which is about 12) plus 10. At sea level 10 psi is 14.7 plus the 10. SO obviously you will have more pressure in the cylinder.

As for having to get a cpmpletely different tune...not really. Of course there is only so much learning a car can do.

I own the car in question and bought it from a guy in Salt Lake City (roughly 4,330 ft. above sea level) and I live in the eastern panhandle of West Virginia, near Martinsburg (roughly 550 ft. above sea level). I was told that the car "ran beautifully", but I keep getting a recurring CEL for bank 1 & 2 running lean. There is no audible ping, but the car is definitely "off". Aside from the CEL for lean conditions, I have a misfire issue on cylinder #5 that I will have to try and track down. The previous owner assured me that he had fixed the misfire issue by replacing the injectors. Once I solve the misfire problem, I will take it to the nearest SCT dealer with a dyno and get the thing tuned. However, I am trying to determine if in fact the altitude difference would cause the CEL for lean condition. Based on what Warmonger said, I would imagine that the tuner of the car in SLC set a fixed value for the altitude and this is what is causing the lean condition. All I do know is that the car is no faster than a stock SVT and should be blowing it's doors off. I attribute this to the misfire causing the car to run basically on 5 cylinders.

Can I ask how much you paid for it? I know it is personal...it's ust that I was wondering b/c I was thinking of selling my SVT when I have my 3L turbo build done, and wondered what the market was like.

$11,500 ... but based on the problems and driveability of the car, I probably paid $3,000 too much! I'm currently trying to negotiate that the previous owner take the car back ... I'm sure we will work something out.

Is your car the one that was listed on FCO and, for a bit, over here?

I didn't know it was over here and yes, that is the one ... the one of fco.org

Geeze, where were you in March? I was ready to sell my SVT back in March for $14-15K the way it sat with all the old turbo stuff and the scratched bumper. NOw that I have fixed the paint and been doing more stuff I won't sell it, unless the price was right.