I have a 2004 Ford with the 4.0-liter 6-cylinder sohc engine. It is rated at about 180 bhp. I noticed in the February 2009 issue of Road & Track that the new Mustang offers a 4.0-liter sohc six, but now with 210 bhp. Given that these engines are not exactly the same, what kind of changes have been made to raise the horsepower with the same displacement? More importantly, can these changes be retrofitted to the 2004 engine?
MARINA DEL REY, CALIFORNIA
Are you sure about the 180-bhp rating? Our research shows the 4.0-liter at 207or 210 bhp for years before and after 2004. Hardware changes of note are a plastic, equal-length-runner intake manifold in 2002 and a new calibration, improved emission controls, new camshaft and new spark plugs in the 2006 Explorer engine.
It sounds like a lot of trouble to change these parts out for a negligible power gain. More aggressive aftermarket parts might seem an easy solution, but most of these would incur emissions legality issues, however.
Better yet, just bolt on some real power and torque with an emissions-legal Explorer Express (888-397-5673; www.explorerexpress.com) Roots supercharger for the 4.0-liter. At around $4000 the supercharger is simpler to install and provides power gains you can really feel with no compromises in daily-driver operation.
Was this article helpful?