Steve Baur
Former Editor, Modified Mustangs & Fords
December 1, 2007
In about 70 seconds, we shaved off half of the tread life of the F-250's stock rubber. Yes, the SCT Extreme Race upgrade is a serious piece of tuning.

SCT's latest flash device, the Livewire, not only provides your fast Ford with improved power, it also records a number of performance measurements and datalogs many parameters. We've had the privilege of tweaking a 6.0L diesel, and today we bring you our test of SCT's 6.4L diesel performance tunes.

The 6.4L Power Stroke is pretty snappy from the get go, as the twin turbos spool up quite quickly and get the behemoth moving in a hurry. Our test vehicle belongs to SCT's Brad Grissom. The vehicle is a black '08 crew cab F-250 Power Stroke beast that's begging to be tweaked to unleash the Mr. Hyde within.

The Livewire is very easy to navigate, and we had the SCT Towing tuneup loaded in short order. Brad wanted us to start out with this program and work our way up toward the bad boy Extreme Race upgrade. Like its predecessors, this Power Stroke responds well to computer tuning.

The basic 6.4L Livewire unit starts off with a transmission tune that works with the stock engine tune. This was designed for those of you who are pulling 10,000 pounds plus more often than not. It increases line pressure to make sure your transmission can handle the rigors of hauling whatever you hook up to it.

Beyond the transmission tune is the Towing tune, which was a tad snappier in acceleration, along with a marked improvement in transmission shifting. The Towing tune offers an extra 50 hp and 90 lb-ft of torque.

Start by plugging in the Livewire and scrolling through the menu until you find the program vehicle option.

If you want to make your Power Stroke perform like a Mustang, then the Performance tune-up is your first step. Bolstering the Power Stroke's output with an additional 80 hp and 150 lb-ft of twist, the Performance tune will have you surprising a lot of pony car owners off the line, and it will certainly make pulling your trailer around much easier.

These days, the plume of black smoke from a turbo diesel engine generally means it has been tweaked for big power improvements, and for that, SCT offers the Extreme Race upgrade. Available in a separate tuner, the Extreme Race upgrade stacks the deck with a whopping 120hp improvement, along with an earth-rotating 230 lb-ft of torque. In testing at SCT's home drag strip, Orlando Speedworld, the team pushed the 8,000-pound truck down into the 14-second quarter-mile range with a best e.t. of 14.67 at 88 mph, which was nearly a 3-second reduction and 7 mph at the top end.

The air filter restriction gauge monitors the air traveling through the intake tract. If too much of a vacuum is noticed, it will close up and cut power. Then you must manually reset it by pushing the yellow plunger. This can happen quite often when you're at the track. We've heard of people disconnecting them, but it's up to you.

The Extreme package includes SCT's EGT sensor, which mounts in the driver-side exhaust manifold. If you have already purchased the basic tuner and want to upgrade, SCT can update your Livewire via e-mail and ship you the EGT sensor for an additional price.

SCT notes that you'll need to exercise some self-control if you plan to run the Extreme tune all of the time. Driving the truck hard constantly can quickly fill up the diesel particulate filter, and the truck will switch to the power-reduced Regeneration mode more frequently to clean it. This cleaning mode is something the truck is normally programmed to do, but if you load the filter up with soot, then it will do it more often. If you are a little easy on the loud pedal-which we found difficult to do given the amount of fun you can have at full-tilt-you shouldn't have a problem with the particulate filter.

Just fifteen or so years ago, performance enthusiasts thought fuel injection would be the end of automotive performance, and here we are pushing a couple of buttons and picking up an extra 120 hp. It sure beats bending over the fender all day to bolt on cylinder heads and a camshaft, doesn't it?