High altitude tuning.

[cruiserdan]

I live at an altitude of just over 5,000 feet and 91 octane is the best available. I often encounter 90 octane at stations around 7,000 feet.

Typical octane rating reduces in relationship to altitude.

So, I am wondering if the 93 octane tune would be acceptable for a vehicle operated at ~5,000 feet on 91 octane fuel....?

Discuss....


D-

[Mike_Levy]

Log it. No way to know otherwise.

[cruiserdan]

OK,

I can log. once I log what am I looking for? I loaded it to see what effect it would have on the CEL codes I am currently dealing with.

I come from carburetors and pencils. I am attempting to learn.

D-

[Mike_Levy]

Log Knock Retard, Short term. And log the spark advance, rpms, fuel trims, speed I guess would help, throttle position.

[cruiserdan]

Copy.

I presume that if knock retard is not happening then the 93 octane parameters are acceptable for the available 91 at this altitude.

Of course if I travel to lower alittude, I will need to feed the car 93 or substitute the 91 octane tune for operation at such altitudes.

[cruiserdan]

double-tap

[airportdave]

I live at 6,000', and run the 91 tune on a mix of 91 and 87, with zero knock retard. I tried the 93 tune with straight 91 fuel, and also had no knock retard, but I didn't detect a noticeable power difference, so I went back to the 91 tune.