Sea level to 4500' whats happening

[s_morrison57]

Hi
I took my 87 930 on a run to the mountains and went from sea level to about 4500 feet and was wondering what happens to the engine and am I doing any harm buy going on the boost at this elevation. The car is set up for sea level and passes the local emmision test. Does the elevation change effect the mixture, ie: a lean condition and is it OK to drive it hard at that elevation with a sea level tune up done by a local P shop. Thanks

[Turboo934]

Higher elevation makes it run richer.Being at 7000 feet I've had to lean her out.

[JFairman]

There's alot of mountains in Germany and surrounding areas and people drive where they want to go. It's not a problem.

There is less oxygen up there and the car will run richer because of that but not so much you have to avoid driving up there. The airflow meter will compensate for the thinner air to some extent but CIS mechanical injection doesn't have a MAP sensor that recalibrates itself to barometric pressure in a fraction of a second just before every instance you start the car for a new base AFR setting like a newer motronic or similar EFI system does.

If you stayed up there than the car would be better if you leaned it out. Possibly just a CO adjustment, and maybe an adjustable WUR steady cruise control pressure adjustment to make it closer to perfect.

Turbocharged and supercharged cars are the best cars going in the mountains because the compressor scoops up the thinner air, compresses it and blows it into the cylinders.
You'll have more turbo lag than at sea level, but the turbo will help compensate for the lack of air and make alot more power than a anormally aspirated motor at high altitudes.