689WHP @ 40PSI
When news of the impending arrival of the EVO VIII hit the shores of America the tuning sector of the industry just about short circuited. The most euphoric of these celebrations was seen in the Diamond Star community where the market was shriveling like a grape in the sweltering desert sun. When Mitsubishi took the Eclipse "up market" and out of the tuner scene by going V6, Diamond Star tuners were left foaming at the mouth like ravenous pit bulls.
The EVO VIII brought about the triumphant return of the 4G63 turbocharged four-cylinder engine and DSM tuners had their savior. In fact, they had a leg up on the competition because the 4G was their baby ... their diamond in the rough (sorry). Further, they had in depth knowledge of drivetrain maladies and more importantly inroads to correcting these OE shortcomings. The pit bull had something to chew on...the tailpipes of unsuspecting WRXs.
One of these reinvigorated DSM tuners is Pruven Performance of Milford, Connecticut. Pruven and its prime mover, Dejan "Dan" Cokic, started the old fashioned way; with a car and a dream. Soon a hobby became a business and for Pruven the 4G63 was their rite of passage. Cokic made it to the top 13 fastest 2.0-liter Diamond Stars in the February 1999 issue of Turbo magazine.
Eventually his stripped down 1990 Eclipse GSX, which was painted orange with some "old school" flame graphics ran a 9.6 at 144 mph quarter mile without nitrous.
Fast forward to 2003 and Pruven was quick to acquire a Mitsubishi Lancer Evolution VIII. Initially, the car was bought for research and development and within the first week Pruven had the car running mid 12s.
After further experimenting, Cokic and his crew fabricated a turbo kit and went to the track with 480 hp at the wheels. The EVO produced an 11.1-second, 126-mph timeslip at full weight and full trim. All this with what Pruven calls, "a street turbo setup featuring a Forced Performance 3065 turbo."
Tuning can be a very Darwinistic exercise, natural selection, evolution and our favorite; natural progression. This usually means bigger, as in bigger turbos, bigger boost, bigger injectors and bigger tuning schemes. The unfortunate losers in this power play are the stock engine internals. Since Pruven was shooting for the moon the block was filled with the right stuff.
The 4G63's reciprocating mass is made up of Pruven-spec Arias pistons and Crower rods swinging on a strengthened stock crank. Basically, the same shortblock that Pruven would install in a customer car. The pistons are Silicon free, have different positioning of the ring lands than stock and the valve relief areas are significantly bigger. The slugs also feature heavy duty wrist pins compared to off-the-shelf units and a custom dish design. "These pistons took a few years to get perfect through many R&D sessions," says Cokic. "They could actually be called something like Version 7."
The block was O-ringed for improved sealing and topped with a reworked cylinder head. All porting and polishing was performed in-house at Pruven and the head has been fitted with 1mm oversized valves along with dual valve springs and titanium retainers. Valve actuation is handled by an eclectic HKS/JUN camshaft combination. "We have tried many, many combinations and found the combination of 280-degree HKS cams on the intake side and 272-degree JUN units on the exhaust side work the best for us. Seeing that we have the dyno at our disposal," says Cokic, "we have been able to test plenty of 4G63 cams over the years."
The turbo system was built in-house by Pruven's Ken Shelinsky. The most labor intensive portion of any turbo kit is exhaust manifold fabrication. Shelinsky paid special attention to exhaust runner length, placement of the turbo, 02 housing fabrication and numerous other factors. The weapon of choice was an infamous top secret Racing-spec GT turbo from Buschur Racing.Pruven also fabricated its own intercooler, along with custom intercooler piping and a custom intake manifold.
The intake manifold has a three-inch AccuFab throttle body attached to the turbo system's three-inch intercooler piping. It houses two fuel rails with four 740cc injectors in each rail. Four serve as primaries, which mean they work all the time for idle and cruising duty and the secondary four come on-line as the engine sees boost. Both rails share an Aeromotive fuel pressure regulator and are each fed by their own Walboro 255-lph fuel pump. The idea was to have an adaptable fuel system that could keep up if and when the crew wanted to swap to a bigger turbo. Mission accomplished.
Cokic and Shelinsky tag-teamed the tuning on Pruven Performance's all-wheel dyno via an HKS F-CON V-Pro. The V-Pro is HKS' answer to all Japanese cars that need a stand-alone ECU. Being such a critical product, only specially trained authorized HKS Pro Dealers have the codes needed to gain access to V-Pro tuning maps, and Pruven Performance is one of them. They turned the amp up to 11 and after a few pulls realized a very streetable 689 whp. "As you can see by the dynograph. The power just doesn't fall off, the 4G63 just keeps on giving," says Cokic.
During strip testing through most of the 2004 season, the EVO had nothing but clutch problems. "Finally, after some careful consideration and five devoured clutches, we opted to use the ATS triple carbon clutch kit," says Cokic. "At last we would be able to get to the track and not worry about breaking the clutch. The stock EVO has a pull-style clutch that commonly breaks on hard launches. Installing the ATS clutch cured this ailment because the ATS setup transforms the pull configuration of the OE unit to a push style. Consequently, there is no longer a retaining clip to break. We are running a Shepherd Racing transmission with upgraded internals to allow shifting at 9300 rpm and a custom ratio gearset tailored for the EVO's 570 lb-ft of wheel torque.
Inside, a six-point roll bar was crafted by Mike Carbone of MPH Fabrication of North Haven, Conn. The roll bar is absolute perfection as it follows the interior lines perfectly. Cokic says people have got in the back seat and not even realized a roll bar was there. Without a doubt, Mike will be adding on a full cage in the near future when Pruven gets back to the track with its new setup.
Under the banner of "Last But Not Least" the eye-catching appearance of this Evolution showcases the handiwork of DP Motorsports of New Haven, Conn. This car appeared in the Primedia booth at the SEMA Auto Salon and in the two weeks or so between that appearance and the photo shoot the car was transformed.
"We have always wanted flames on our shop cars, but have always put on vinyl graphics. This time, Steve and Cheli from DP Motorsports convinced us they could pull off something truly next level, and they made the car look unreal," says Cokic. "It was a really big risk to take due to the fact that it's a $30,000 car, and there would be no turning back. But after seeing the roaring flames, I wish we did it earlier. This paint looks phenomenal!"
The Pruven EVO definitely has the firepower to dominate the street and the crew plans to hit the strip to see what kind of timeslip the Mitsubishi can generate. We will be on the scene to bring you blow-by-blow results.