Our Project Supra has seen several upgrades that kicked its performance level up several notches. Although it's fast and very entertaining to drive, I'm sure you know we didn't start a 2JZ-GTE-powered project to stop at 400 whp. The time has come to get into the next dimension of performance for this street machine. Time for asphalt-thrashing power!
Since day one of this project it was a given Project Supra would be sporting a single-turbo setup with more than enough power for the street and occasional time-trial. It took a while to decide on which turbo system to use but we eventually decided on Sound Performance's SP71-GTQ turbo kit.
Initially, we were going to test it on the stock engine but a compression test revealing a leak in cylinder four from either a burned up exhaust valve or bad ring threw a wrench in our plans. Since a repair would call for decapitation of the engine we decided to have it rebuilt from scratch altogether.
Our shop of choice, although a newcomer to this project series, is well known throughout the Supra community, Speed Force Racing. The Santee, Calif. shop has performed big jobs on cars ranging from BMWs, Porsches and Toyota Supras to Nissan 350Zs and Skyline GTRs. Armed with a plethora of fabrication, welding and machining devices, SFR technicians are fully capable when it comes to fab work. The shop's in-house fabricated intake and exhaust manifolds, as well as its turbo kits speak for themselves. But its experience with turbocharged vehicles and attention to detail made it especially easy to leave Project Supra in SFR's hands.
Over the next few months we'll go into detail over the parts and processes we chose to make this 2JZ-GTE engine extremely durable. This month we'll start with the short block.
Building a block capable of comfortably withstanding the pressures this 71 mm turbo will put out relies on several key components. This is not to say a stock 2JZ-GTE motor can't handle the horsepower from the turbo-featured on our March, 2004 cover, a Sound Performance-tuned car dynoed 980 whp on the stock block! Regardless, we're over-building this motor which could probably handle over twice the power we'll put to it just for peace of mind.
JE Pistons were our pistons of choice. Also seen on Editor Griffey's Project Scerious 2JZ-GTE-powered SC 300, JE Pistons have an undisputed tradition of winning. Using state-of-the-art CNC and FEA (finite element analysis) computer processes, these forged pistons withstand the tremendous pressures of race cars seen in NHRA, IHRA, NASCAR and IDRA. At just 335 grams per piston, the light weight reduces damaging tensile loads-the load realized when the piston is changing direction, or inertia load-on each connecting rod. Since Project Supra's pistons are 0.50 mm over bore, SFR had to machine the cylinder walls accordingly for a precise piston-to-wall clearance.
The pistons were sent out to Swain Technology for its Thermal Barrier Coating (TBC) on the piston dome and tungsten-molybdenum disulfide polymer matrix (PC-9) coating on the skirts. TBC is a 0.002-inch ceramic coating that protects the piston by preventing heat transfer through the piston and holding the heat inside the combustion chamber. Additionally, the rods, crankshaft and bearings stay cooler. Since the entire dome surface is coated, flame travel is improved for a better burn as well as helping to prevent hot spots, which can lead to pre-detonation.
Swain Tech's PC-9 coating on the piston side skirt is 0.0007-inches thick and has an extremely low coefficient of friction. The durable coating partially transfers to the walls during piston movement, reducing scuffing and friction.