Inliners International Forums General Discussion Engines re-jetting for altitude

When re-jetting a carb for higher altitudes do you increase or decrease the jet size?

Decrease. Less air means less fuel required.

Like he said, Less air , less fuel.

btw does anyone know a source for a drill index for jetting?

Larry

Is it kind of "trial & error" or is there some sort of formula? I'm interested in this, also.

When I went to GM school in Denver about 45 years ago, I believe they recommended 2 sizes leaner for Rochesters.

This is at 5000 foot altitude.

With exhaust analyzers today, you should get a much better result.

Will Willis