To recap, Project Supra has undergone major surgery at Speed Force Racing. The 2JZ-GTE long block was completed using several high-end components, machine work, cryo treatment and thermal barrier coatings as covered in our April and May, 2005 issues. Finally, the time has come to talk about our turbo, fuel system and some preliminary dyno testing.
Sound Performance of Bloomingdale, Ill., is home to some of the most powerful Supras in the world. Larry Prebis and Gary Grossman head this well-known Supra tuning facility. SP sells a variety of custom-sized single-turbo upgrades for Supra owners seeking power levels anywhere from 500 to 1,500 whp. SP turbo kits include an SP-spec turbocharger, 321 stainless steel ceramic-coated header, 3-inch ceramic-coated midpipe and downpipe with wastegate recirculation and flex section, HKS GT 60mm wastegate, a 4-inch intake pipe and air filter, and oil feed and return lines with the necessary fittings. SP will soon have 4-inch midpipes and downpipes available for really high-horsepower setups.
Choosing the right turbo for this car was extremely important. Our goal is to achieve a safe 500 whp on pump gas and 750 whp on high-octane juice. At the same time we need a reasonable spool response for street use or on a road course. SP recommended the SP71-GTQ turbo upgrade to meet our needs. The SP71's compressor wheel is the only one in SP's lineup machined from billet aluminum. When asked why, SP's Larry Prebis responded, "In this specific case, we found that an extreme pressure ratio wheel intended for use in high-altitude applications just happened to work nicely with the Supra's particular engine design."
Since a billet wheel is much stronger than cast, the blades can be razor thin. This creates a turbo whine unlike anything else we've ever heard. It's awesome. Additionally, it's also lighter than a cast wheel, promoting quicker spool up.
Of course, with around a 500-whp limit, the stock fuel system had to be upgraded. Dual Walbro 255 lph high-pressure fuel pumps were ordered from Extremepsi.com, a company with a huge assortment of import performance parts at very reasonable prices. To get the pumps to work in-line, a "Y" connection needed to be fabricated. Tim Richards of Speed Force Racing welded a -8 fitting to the pump housing which allows the two pumps to dump into a single stainless steel feed line.
The -8 line was routed along the stock system's path, eventually coming to the Aeromotive 2,000 lb/hr in-line filter, which SFR plumbed into the fuel line as well. The Aeromotive fuel filter features a reusable stainless steel micron filter element, making costly fuel filter replacements a thing of the past.
From the fuel filter, the feed line continues and ends at the beautiful billet anodized HKS fuel rail. At the end of the line, the fuel empties into the combustion chambers via HKS 1000cc injectors. Granted, for this particular turbo upgrade anything above 720cc would have been sufficient but we wanted to have a fuel system that was also capable of supplying enough fuel for an even larger turbo-should we decide to test one. If you're planning to feed the fuel rail from one side, as we did, it's a good idea to feed the rail from the front-most port so the flow doesn't fight against acceleration forces.
From the back of our fuel rail we ran a -6 line to an AEM billet fuel pressure regulator. An Auto Meter 1.5-inch fuel pressure gauge was plumbed to an outlet port on the regulator so we could keep an eye on things. From the regulator, SFR routed a return line back to the fuel tank.