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spacer Ramjet Tuning

We have the capability to change the calibration and tune of your Ramjet 350 or Ramjet 502 MEFI ECM. The Ram Jet 350 and 502 engines used either a MEFI 3 controller for the older Ram Jet 350's and 502's or a MEFI 4A controller for the newer Ramjet 350's and 502's. The Ram Jet ECM's are locked with password protection from the factory, but we can unlock the controller and change the stock factory calibration to suit your requirements.

The older MEFI 3 Ramjet's used an open loop speed density calibration that had no feedback from an O2 sensor. The stock MEFI 3 Ram Jet calibrations from the factory were quite conservative and tend to run with very rich air/fuel ratios. This is not optimal for power or gas mileage.

The newer Ramjet 350 and 502 engines run a MEFI 4A ECM with a single narrowband O2 sensor and are set up to run in closed loop operation from the factory. These newer Ram Jets tend to run better than the older generation MEFI 3 equipped Ramjets, but still have their problems.

If you have modified your MEFI equipped Ramjet engine or are using a Ramjet intake and MEFI ECM system on a custom built motor, you could benefit greatly from a custom tune for your engine. The correct way to tune your Ramjet is to purchase our MEFIburn package and custom tune your engine in your car, collecting real data and tuning with a wide band O2 sensor to get your air/fuel ratios exactly where they should be under all operating conditions.

If you do not have the capability to do this or do not want to purchase the full MEFIburn package, we can give you a best guess calibration based on your inputs and our experience with other Ramjet setups. Obviously since we are not driving and collecting data from your vehicle we can not guarantee any calibration or modifications we make. That being said, almost any stock MEFI based Ramjet system will benefit from having the calibration modified to provide more optimal air/fuel ratios.

We can modify any parameter in these controllers, but some of the more popular ones are:

  • Idle speed
  • Fuel injector pulse width tables
  • Spark advance tables
  • Rev limits
  • Eliminate limp modes
A few points to mention:
There is no need to upgrade an older MEFI 3 based Ramjet system to a MEFI 4A based system. The MEFI 3's are great controllers and will run fine with the correct modifications to the calibration.
The proper way to provide you with an accurate calibration is if you collect data with a wide band O2 sensor setup and provide us that data. Even without this information, we will provide our best estimates on what you may need to improve drivability, based on your inputs.

Our price for a basic calibration upgrade is $500. Call or email us with your specifics and we will give you an accurate quote. This service is based on you mailing us your MEFI controller, us modifying the calibration and reprogramming your Ramjet controller, and mailing it back to you.

Click Here to Purchase the Tuning Service


OBD Diagnostics, Inc assumes no liability for any type of damages resulting from the use of this tuning service. Incorrectly changed parameters have the potential to cause damage to your engine or vehicle. Please monitor the results to verify that changes made are what you wanted. Use modified engine calibrations at your own risk!

Call Toll Free (USA Only) 888-469-3274

OBD2 | GM OBD1 | Marine ECMs | MEFIburn | J1939 | Ramjet

OBD Diagnostics, Inc., Redondo Beach, CA 90278
Tel: 310-793-2410     Email: sales@obd2allinone.com
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