What kind of jetting changes are needed when you take a car from sea level to mile high (5,125 feet/1,609 meters)? Well, none actually. But if you want it run good up there...you need to lean out the carburetor.

There is a 15% power loss at mile-high elevation, because the air is thinner. And more loss potentially if your jetting is off.

* Idle: Just turn the mixture screw in/adjust as normal
* Midrange: fit smaller main jets/larger air jets
* Power -- does the power jet need changing?

For hitachi carbs you can buy new jets from the Nissan dealer. Part Numbers are listed in the Jets listing.

For Weber DGV or DCOE, buy them from Redline.

Or use an altitude-compensating Hitachi, such as fitted to later B310s for USA.


FUEL
* Fuel sold in high-altitude areas may be blended to run lean, which means changing your jetting again!


TEMPERATURE
* If the temperature is the same as at sea-level, rejetting is called for
* If the temperature is 50F less, use sea level jetting
* Use a temperature-controlled air cleaner makes it consistent but you if you don't use that, you could actually gain back your lost 15% power when mile-high at below-freezing temps.

You planning on jetting to join the mile high club dd?
Or just a long road trip?

I was thinking of going to the Rally that Gary_P talked about. It is at 4,600 feet (1400m) -- short of a mile but still pretty high.

Which reminded me I've always wondered about this. All I can find about high-altitude jetting is some Jeep enthusiasts at some mt. named koziusku. That and a billion two-stroke engine pages.