Quote:
Originally Posted by bobcowan
If you're concerned about it, consider EFI. If programmed correctly, it will adjust for altitude on it's own.
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Let me elaborate a little. Some of the aftermarket EFI setups go to Alpha N to solve issues. Alpha N mimics a Carb and will not compensate for elevation changes. Some of the people with 8 stack EFI look alike systems have said they were using Alpha N. Also huge cam engines often go this route.
Map systems kind of compensate. They check the Map when the engine is started to determine atmospheric pressure. So if you shut the engine off and restart it after an elevation change it is perfectly adjusted. If you do not shut the engine off, the O2 sensors will compensate by trimming the fuel in, slowly over time. However the narrow band that the O2 sensors operate in is only used at idle and cruise, at WOT the O2 is not used.
MASS FLOW systems truly 100% compensate for elevation all the time. Very few aftermarket EFI systems are Mass Flow. Also tuners have a nasty habit of turning the feedback off on high performance stuff to solve some problems.
So EFI can be the solution, but you still have to make sure of what you are installing and who is tuning it. Personally I feel a good EFI system is the best solution, but that qualifier GOOD is important.
PS
There are some MAP systems that have two MAP sensors. One connected to the manifold and another to measure atmosphere. These would not have to be restarted and would compensate very well. The systems that Ford put on the Mustangs in 1986 thru 1988 did not have this. Thought I should correct myself.