MFI Calc

Engine Tuning & Weather for Mechanical Fuel Injection Racing


Jet your car from anywhere with an internet connection. Have a smartphone? You now have a portable jetting calculator and weather station.

for racers

Free resources including a density altitude calculator, informational articles, and helpful links.

MFI Consult

Get your MFI fuel system setup programmed into MFI Calc. Even get your dyno data added. You get 1 year of access to MFI Calc too!

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What's New

April 2, 2024

We are live!

Welcome to our new site! If you are here from Air Density Online, we're glad to have you!

All links on Air Density Online should now redirect here. We have worked to make this transition as smooth as possible but there may be some hiccups. If you have any issues or if you wish to send any feedback, let us know.

March 11, 2024


Welcome to our new site! If you're new to this site and our partner site,, we're glad you're here. Our sites aim to provide information and tuning tips for racers and engine tuners in the motorsports world. Specifically, we provide information and tools for mechanical fuel injected racing.

If you're here from Air Density Online, this might look a little familiar to you. We hope so! We have kept the new site as similar to the old site as possible in order to make the transition as easy as we can. That being said, we plan on adding new features and making this more useful than the old site.

We will be officially moving all ProCalc & ProTune users over here at the end of this month. We will be in communication with those customers as we go. In the meantime, look around and don't hesitate to send us any questions or comments.

January 25, 2024

Coming Soon!

Get Ready! We're working on some big new things. Air Density Online has been a wonderful experience for over 10 years but times are changing. The jetting calculator portion is transitioning to it's own site with it's own features.

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