By E.K. Cozzene
photographer: Henry Z. DeKuyper
746 WHP @ 45 PSIBig Al Friedman's flame-embellished Evo VIII was last updated in the September, 2005 issue. At that time, Al had just become the first Evo VIII to run 9 seconds on all turbo. He was running the GT35R turbo which has become the most common turbo upgrade on high-power Evos in the U.S. due to its excellent power-making potential and decent street driveability. Big Al's Evo VIII has made more power and gone faster with a GT35R than any other Evo VIII in the world-667 whp without nitrous yielded a 9.98 in the quarter mile and a record 144 mph trap speed. The previous update explained all the details of how Al pushed the GT35R in to 9's and got all the power down to the ground.
The combination has proven to be very effective at the track this year. Al has tallied four wins and two runner-up finishes out of seven races he's entered. Al says Exedy Racing Clutches deserves a lot of credit for the success during this year's racing season for its continued support and sponsorship of what has now become the Exedy Evo VIII.
New Modifications"At one point, going 11 seconds was my goal," says Al "Having gone 10s and now 9s it's like an illness. You can never have too much power. Tuners can never have enough power and always are looking to find more. Of course, I wanted more power and I was very shortly going to come into conflict with the law of diminishing returns. The first 50 whp is fairly easy and straightforward, the last 50 whp materialized into something very difficult and expensive.
"We were up against the very edge of how much power we could make from the GT35R. I made this assessment based upon examination of the datalog files, which revealed we had reached, and pushed right up against, the comfortable limit of detonation activity. Further, the data showed way too much backpressure in the turbo housing and manifold to support the kind of power we wanted. The boost was turned up all the way and it would not go any further. The GT35R was maxed out, it was time to move beyond the familiar and comfortable. Simply put, we had gone well beyond the turbo's volumetric efficiency."
GT40R"It was David Buschur of Buschur Racing who gave me the suggestion to try the GT40R, a hard-to-find turbo from Garrett. The GT40R, which we obtained had a divided turbine housing which afforded us the opportunity to run a true twin-scroll setup. On a four-cylinder engine one exhaust pulse is created every 180 degrees of crankcase rotation. Keeping each pulse properly timed as it reaches the turbine wheel helps speed spool up and makes slightly more top-end power. This technology is employed on the stock Evo VIII engine in the form of a totally divided exhaust manifold and twin wastegate flappers.
"No one has released a turbo upgrade kit using the GT40R so I asked my good friends at Pruven Performance in Milford, Conn., to fabricate an exhaust manifold which employs twin scroll technology, totally divided exhaust flow into the divided turbo housing and twin TiAL 44mm external wastegates. The manifold itself is made with special 8-gauge stainless tubing supplied by Buschur Racing, which has proven to be totally indestructible.
"Theoretically, the GT40R is capable of 70 to 80 more horsepower than the GT35R. Realizing that theoretical gain would prove to be very costly and time consuming. As soon as we fired up the car on the dyno with the new turbo we realized that we were going to run out of fuel. The 1,000cc injectors immediately hit 100 percent-plus duty cycle. So a four pack of 1,600cc injectors from Marren Motorsports were sourced. But it was soon discovered that an injector driver box was needed to work in collaboration with the AEM EMS system in order to properly control the larger, low-impedance injectors.