Boost Solutions also heavily reworked the cylinder head to get the most out of the stratospheric boost flowing through its passages. The ports were matched and runners polished.
The engine was tuned first for 20 psi (base boost), and then we ran 24 psi, 28 psi and 32
A high-flowing exhaust system is key considering the volume being generated by the 4G63. B
Boost Solutions added 1mm-over stainless Ferrea valves, Ferrea dual valve springs and titanium retainers. Valvetrain orchestration is handled by Tomei Pro cams with 11.5mm lift and 260 degrees of duration that are fine-tuned with Tomei adjustable cam gears.
With the big boost on tap, Boost Solutions upgraded the 4G's internals and took the opportunity to bore and stroke the engine out to 2.3 liters. Custom Pauter rods and Ross pistons spin on a custom-built crankshaft of a secret identity. The reciprocating assembly was balanced and blueprinted. Key components were cryo-treated for enhanced durability.
The Rallye red EVO has minimal body tuning. A custom bumper frames the GReddy FMIC and a trick carbon-fiber hood saves weight and adds orifices for engine cooling. The wheels are the stock Enkeis from the factory but suspending them is a trick TEIN coil-over setup. TEIN Flex coil-overs, featuring the company's innovative EDFC that allows cockpit damper control on the fly, help the Mitsu resist lateral g-forces.
This car was originally supposed to appear in the May or June 2004 issue but the tuning regimen took some time and we wanted the car at 100 percent when it appeared here.
"The engine was tuned first for 20 psi (base boost), and then we ran 24 psi, 28 psi and 32 psi," relates Marinov. "The air/fuel ratio was kept very conservative at 10.9:1 and the tuning passes were made on C-16 race gas. On the first run, just to see how the turbo spooled, we did 411 whp at 10 psi letting off at 6000 rpm, just before the turbo really hit. At 32 psi we made a number of 700-plus-whp runs, topping out at 712. All the runs were turbo only.
"The EVO drives like a T88H Supra, just better because of the AWD," says Marinov. "It revs fast like a Hayabusa, even with the stroker kit and 8500-rpm redline. With the 150 nitrous shot, there is no lag."
The EVO's stock wheel and tire combo is hard to beat.
A Nitrous Express 150-shot setup is on call for spool-up enhancement.
We plan to do an update on this car if/when it runs at the track.