MFI Calc

Get the most power out of your fuel-injected engine
at all hours of the day at any track you race!

Join today and virtually jet your engine!

With an MFI Calc membership, you get 1 year of access to 4 fuel injection jetting calculators that will enable you to virtually jet your MFI engine according to the local weather and elevation. You also get weather - including air density and density altitude - at over 1000 race tracks around the world.

Why do I need this?

- weather changes throughout the day
Maintain your optimum setup from the cool early morning to the heat of the afternoon.

- differences between tracks
Adjust to different elevations and weather patterns easily when traveling to different tracks.

- gain control over your fuel system
Keep track of your system performance including system pressure and air/fuel ratio.

- save time
Know what your jetting is in the click of a button. No more time wasted on trial and error.

- plan ahead
Be ready to race right out of the trailer by planning the day before.

- test your system with nitro
Know how to adjust your setup with different percentages of nitro.

- portable, accessible from anywhere
If you have a smartphone, you have your jetting calculator with you everywhere you go.

- simple to set up
Set up your first baseline and you are ready to start running calculations!

What can it do?

- store 3 different baselines
Easily switch between your methanol-only and nitro setup. Or switch between your high and low altitude setup.

- add the current weather to your calculation
Browse the current weather at your track then click to add it seamlessly to your calculations.

- export data as a csv file
Maintain your records by exporting your data to a spreadsheet program.

- air/fuel ratio calculator
Find your optimum air/fuel ratio or test your modifications for air/fuel ratio changes.

- calculate main bypass and system pressure
Find out how much to adjust your main bypass. Find out how to modify your fuel system pressure.

- recalculate specific engine nozzles
Run calculations on specific nozzles to see how they compare to the rest.

even more...

- extensive user guide, helpful videos, faq's
- get more frequently updated weather
- get a customized setup with Consult Package


Get MFI Calc for 1 year:

Get access to the MFI Calc calculators for 1 year. Learn more


Renewing your membership?
Click here.

See MFI Calc in action!

I know my drag racecar with the MFI Calc setup can run my number

— Rich Hozak, Tuscon, AZ

I've taken the 13 gallon pump off the car. Back to my 7 gallon pump... Again, I know right where I'll be because of Thank you for such a great resource!

— Greg Means,

The calculator does what no one person can do...unless you have thirty plus years in racing and know over 1100 computations. Get it right every time...

— Mike Shriver, SpeedSports

I depend on the MFI Calc calculator app. for my fuel injection tuning. I do not have to rely on my engine builder or prior flow bench test any longer.

— Bill Ketterman, long-time drag racer

Get your car dialed in for any track, anywhere you race.

— Bob Szabo,

MFI Calc uses engineering principles such as air/fuel ratio in order to calculate the best jetting for your current environment. This enables you to get the most power out of your mechanical fuel injection engine in a repeatable manner.

No matter how well you have set up your fuel injection, changing weather and environment can make your car run poorly. Variables such as temperature, humidity, and elevation influence how much oxygen is in the air. These changes can affect combustion that, without adequate adjustments, can cause your engine's performance to suffer. Read our FAQ for more information.

Features include:
  • Air/Fuel Ratio Calculator
  • Calculate main bypass and system pressure
  • Re-calculate specific engine nozzles
  • Up to 8 cylinders with 4 jets per cylinder, 1 main bypass and up to 2 high speed bypasses
  • Ability to add percentages of nitro to your methanol setup
  • Up to 3 Baselines for storing different engine setups
  • Export data as a csv file
  • Access your calculations on your internet-enabled cell phone while at the track.
  • Ad-free use of the whole site
  • Track weather updated approx every 20 minutes

View screenshots from MFI Calc

air-fuel ratio calculator Results using the air/fuel ratio calculator populated with data from Baseline #3
weather at over 1,000 tracks Weather data for over 1,0000 tracks including air density and density altitude.
results of using the afr calculatorResults from the main bypass calculator using Baseline #2. Also calculate individual nozzles.

Get MFI Calc for 1 year:

Get access to the MFI Calc calculators for 1 year. Learn more


Renewing your membership?
Click here.

Get your setup

Bob Szabo in action

MFI Calc and Consult were created by father-daughter duo Bob and Jennifer Szabo in order to help racing teams get the best jetting for their MFI combination.

Bob Szabo is a retired welding engineer, long-time drag racer, and author of 6 books about racing mechanical fuel injection at Bob has decades of experience in the automotive industry and as a drag racer. He has put that experience together in order to assist racers with their engine setups.

If you would like further information or have any questions, Bob and his web-developer daughter, Jennifer, will be happy to talk with you. Fill out the contact form and they will get back to you ASAP!


The fine print:
-Payments are handled through PayPal. Upon successful payment you will receive an email that will direct you to complete the registration process. Please check your spam folder in the event that you do not receive your confirmation email.
-All payments are good for 1 year. You must log in and pay again in order to extend your membership. Memberships are not automatically re-billed.
-Your contact information, including your email address, are never shared with third parties. A reminder email will be sent when your membership is nearing it's expiration date and we reserve the right to send occasional announcement emails.
-Questions and comments can be sent via our contact page.
-You can view our full legal and privacy policy here.

© 2024