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Welcome to (or Ford 4L or Ford 4.0, whatever you want to call it.) I've been driving a 4.0 V6 OHV equipped Ranger for 10 years now and am very surprised at how little info there is on the net for this engine/vehicle combination. So I put up this site to let others know what I've learned. In those 10 years, I've also made some mods to my Ranger that would be good for any Ranger, Explorer or SportTrac with the 4L V6 engine, and I've included them as well.

Common problems and solutions:

  • Hesitation, sputtering, etc. - HOT!
  • Overheating
  • Bad Gas Mileage

  • Air Box Mod for 10hp - HOT!
  • CAI, Cold Air Intake- actual data
  • Mass Air Sensor
  • KN Air Filter
  • Exhaust
  • Headers
  • 160F-180F Thermostats
  • Stealth: Avoiding unplanned meetings with Officer Friendly.

    I bought the PVC fittings here.
    I bought some flex PVC pipe here.
    I bought my clone golf clubs here.
    I bought the headers & MAS here.
    I bought my truck tires here.

    What I believe & why:

    Disclaimer: This website is a Ford fansite. It is not authorized, nor endorsed by Ford Motor Company. No affiliatation or association exists between (aka and Ford Motor Company. All trademarks are property of their respective owner(s).

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    Why CAI (Cold Air Intakes) work:

    Everyone knows, you get 1% horsepower change per 11 degrees Fahrenheit temperature change of the intake air. Thus, if you raise the air temps by just 55F, you lose about 5% HP due to a less dense air charge. So keeping a "cold air" system is absolutely critical. In fact I think the under hood temperature difference is way more than 55F. The factory thermostat has a 212F setting and that means that all the air coming through the radiator is at least that hot. Add to it the radiant heat from the engine and headers (or exhaust manifolds) and you can see it could be as much as a 100F difference, which would be a 9% loss in HP. So there is no way I'd ever use one of those cone filters which draws air from inside the engine bay. That's why I did the air box modification.

    Temperature Different Results:


    The above was driving around in city traffic, average speed about 45mph. The engine was at operating temperature (180F thermostat). "Underhood temp" was taken from behind the headlamp (where all the cone filters pick up air) and the wheel well (where I put my air intake) while driving. In fact, sitting at a light, not moving for 60 seconds, there was over a 50F difference, (underhood went to 134F) and sitting stopped for 5 minutes put the underhood guage off the meter (140F max.) Once I started to drive, then the temps dropped back down to about a 40F difference between outside air and underhood air. The difference between outside air and wheelwell air always remained about 7-10F. Also, I run a 180F thermostat. The factory is 212F. So if you have not changed your thermostat, the air coming through the radiator will be 212F, not 180F making the underhood temps even higher and the temperature difference even greater.

    Think about the drag racers who sit waiting for the start. If you use an underhood air intake, your launch horsepower will be down about 10% just from sitting during the burn out, staging and waiting for the lights to come down. (Underhood temperature difference could be well over 100F!) The launch is the most important part of the race and to be down 10% in HP is something no serious racer would accept.

    Thanks for visiting

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