Kevin Krupski’s Exceptionally Fast 10-Second Explorer ST

The Ford Explorer is probably one of the last Ford platforms anyone would venture to look at when choosing a performance vehicle. Aside from the Saleen XP8 or an occasionally hot rodder-turned-father modifying his 5.0-liter second generation Explorer, this line of sport utility vehicles were never considered something to go fast in. In recent years someone at Ford Motor Company decided to add the suffix “ST” and create an entirely new beast out of the Explorer. While the majority of Explorer ST owners simply enjoy the twin-turbo powerplant, others provide an exception to the “keep it stock” theology.

Kevin Krupski is one of these exceptions, although his original intention was far from what the build has become. When Krupski purchased the new family vehicle his plans were to simply add some tint and maybe a catback exhaust. After all, who doesn’t love a deeper depth of sound and some sun protection? After relocating for his job, which coincidentally aligns with Ford Motor Company, and being stuck at home through COVID, he found a forum full of exceptions that were also looking to modify their Explorer ST.

 

Explorer ST

Krupski decided to first try out the technology route before implementing any hard parts. Through the forums, Krupski made a connection with ZFG Racing. ZFG Racing was claiming 100 horsepower gains from a tune flashed into the vehicle using an HP Tuners RTD. An increase of 100 horsepower from a simple tune would tempt even the most conservative owner. Krupski decided he would bite the bait and try it out. Once the baseline tune was uploaded, he was disappointed that it wasn’t the whiplash inducing tune he had hoped for. However, ZFG Racing continued to read the data logs and make corrections before uploading a final custom tune.

I’ll never forget the first hard acceleration after I loaded the second tune. I liked it, no I loved it, and I wanted more. Kevin Krupski

Once that first taste of power was delivered, Krupski knew it was going to be a wild ride building his Explorer. He returned to his original exhaust idea, but found a dismal amount of aftermarket support. Apparently the aftermarket community felt the same about the Explorer as the masses. Krupski knew what he wanted, but had to find the fabricator to complete the job. A local search led him to FENFABrication where he was able to spec out a complete exhaust. Once completed, Krupski could not stop staring at the craftsmanship and contracted FENFABrication to handle the intakes, charge pipes, catch cans, and strut bars.

A shame these welds are rarely seen without the Explorer ST being on the lift.

Krupski could have called it quits at this point, after all, he had reached the destination he wanted from the beginning. However, the reception his build received online from other owners wanting to follow his footsteps, meant he knew he couldn’t stop the process. The next step was to proactively address the transmission and converter. Level 10 Transmissions handled the transmission build while Circle D Specialities installed a billet stator in the torque converter.

Building a vehicle can sometimes be a game of cat and mouse. Once one part is optimized, another component is maxed out and requires replacement to continue forward. A pair of turbos combined with a Whipple intercooler resulted in the fuel system needing a complete renovation. Once again the aftermarket offered limited resources. Nostrum High Performance stepped up and used Krupski’s vehicle as the product test bed to develop their new high pressure fuel pump and stage one injectors. Once the fueling was complete, the Explorer was strapped to Nostrum’s dyno and produced 657 wheel horsepower on e60 fuel.

Allowing the 657 ponies to stay planted on the pavement required more than a shock and strut replacement. Utilizing the skill of FENFABrication combined with products from Air Lift Performance, Slam Specialities, and Viking Performance, the team was able to set up the suspension for optimal 60-foot times. These products were all carefully adapted from the Ford Mustang catalog and fabricated to work on Krupski’s chassis. A set of 20-inch Magnesium Performance wheels, weighing in at a scantily 19-pounds each, sit on all four corners. Instead of shaving weight and compromising braking ability, Krupski purchased a Rotora big brake kit with eight-piston front calipers and four-piston rear calipers to bring his freight train to a halt.

Explorer ST

Massive eight-piston calipers hide behind the 20-inch wheels.

Once the engine was properly tuned and the chassis was finished fighting for traction, Krupski managed to knock off a 10.94-second ¼-mile pass while still using his all season tires! A 10-second pass was something Krupski had never imagined he could do in such a large vehicle. One might think that the build would begin to slow down after achieving such a feat, but Krupski has decided to push forward and continue to pioneer the Explorer ST platform.

To match the performance aspect, the Explorer is being fully vinyl wrapped in a bright KPMF Matte Iced Blue Titanium. The engine is once again seeing a restructuring of its setup with a custom turbo kit, exhaust revisions, and intake manifold modifications. The updated turbos are being replaced by twin Xona Rotor 5451S turbos combined with Turbosmart wastegates and blow off valves. The exiting exhaust gas path is not the only thing to receive a revision, the throttle body and intake manifold are also getting the upgrade treatment.

 

“These Xona turbos are good for 1100hp, which may sound crazy, but that’s what I thought about the power we are making now,” says Krupski. As Krupski remains the pioneer and guinea pig in the Explorer ST group, it’s exciting to see the minds of more Explorer owners change towards performance, rather than settling for stock.

Explorer ST

 

About the author

James Elkins

Born into a household of motorsport lovers, James learned that wrenching takes priority over broken skin and damaged nerves. Passions include fixing previous owners’ mistakes, writing, and driving.
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