Ford Repair: Performance, eaton supercharger, flow muffler

Question
I would like to increase the performance of a 4 liter 1994 Ford Explorer. 4 wheel drive with automatic transmission. I have K&N air filter, High flow caticalitic converter, & high flow muffler. I think my best bet would be a performance chip. Any suggestions? Recomendation on brand of chip?

Thanks, Bill Marshall

Answer
Bill-

  A chip won't help you much at all unless it's tuned to your car specifically on a dyno.  Off the shelf stuff might be good for 2-4 horsepower, but that's hardly worth dropping $225+ of hard earned money.  If I were you I'd get a power programmer if you want to retune the computer's timing and fuel curves.  Companies like Superchips and Diablosport make handheld tuners that let you continually alter your state of tune unlike a chip which is just one program.  I've seen those handheld units retail anywhere from around $200-$400 but they're well worth it as you can constantly change your tune if you add other modifications.  Other modifications would be a shift kit for the transmission.  It won't add power, but it will make the car move quicker thanks to quicker shifts.  If you've got some decent money burning a hole in your pocket, I believe BBK still makes a supercharger for the 4.0L engine.  Marketed under the name "Instacharger", they don't make a ton of boost, but will boost your power pretty significantly.  And it's based around an Eaton supercharger (same as the factory equipment on Thunderbird Supercoupes and later model Cougar XR-7s) so you know it's reliable.  I know they have made them for Rangers and I believe they make them for Explorers as well.  Hope this helps.

Steve