9.98 @ 138 MPH
The first update of Al Friedman's flame-emblazoned Mitsubishi Evo VIII appeared in the January, 2005 issue of Turbo after he swapped out the HKS 3037S turbo for a GT35R turbo. With the GT35R the 4G63 pumped out 667 whp. "My car was running very well," relates Al, "but I was being held back with excessive wheelspin and breakage of rear half shafts.
"I considered lowering the boost off the line with a speed-dependent boost map on my AEM stand-alone ECU, but the thought of cutting back on all that hard-earned whp didn't make any sense. If I wanted to go faster, I needed to make as much power as I could. Lowering boost was not an option.
Clearly, the solution was to find a way to get all the power to the ground and fix the weak links in the Evo drivetrain. My goal was to leave the line at full boost and hook up all 667 of those horses.
"My recent improvements have yielded 1.50-second 60-foot times on my 3,300-pound (with driver) Evo VIII, which remains a fully registered and insured road going car."
Potent 4G63 Diamond Stars have been putting the twist to driveline parts for decades. Many a chunk of driveline has found its end smoldering under a car just off the line at the drag strip. For the Evo it's half shafts that suffer. "Every time I would try and launch hard the rear half shafts were breaking off at the end near the outer splines." According to Frank at The Driveshaft Shop the outer splines are made from a slightly softer and cheaper material than on previous generation DSMs.
The Driveshaft Shop engineered a Stage 5 rear-axle system, using new hubs with upgraded splines and shafts giving the shafts a 1,000-whp capacity. "These are direct bolt-in propositions and have proven to be totally indestructible," says Al.
Another significant problem can be found in the stock engine mounts and suspension bushings which are quite soft. The mounts allow the entire engine and transaxle to pitch back and forth several inches at each shift. This causes a great deal of instability and weight transfer and also makes fast shifts difficult. Al tracked down Rally Group N engine mounts and suspension bushings from Ralliart. This made the engine and suspension mounts much stiffer and reduced movement of the engine during fast shifts.
Also, Al reports rear wheel hop, a common occurrence on stock Evos, was totally eliminated when he installed a set of AMS rear trailing arm nylon bushings. The stock bushings crack and break very easily under hard launching. The AMS nylon bushings are totally abuse-proof and improve the handling and launching characteristics of the car by removing a lot of mush from the rear suspension.
"I have been using an off-the-shelf Tein Flex suspension with great results," says Al. "However, more power resulted in more violent weight transfer to the rear of the car and actually caused the rear suspension to bottom out on the bumpstops. Tein USA came through with a re-valving of the rear shocks to match a set of stiffer springs. All Tein suspensions can be re-valved by Tein to match your particular application."
The front diff is another concern when the hammer drops. Al reports the stock 2003 Evo VIII front open diff is both a weak link, known to fail even on stock Evos, and also a real handicap when launching off the line as the inside tire just spins. He points to Quaife's just-released limited-slip front diff as a key component to his recent success.