Not all Supra Turbos look like catfishThat a 1989 Supra, then a star of technological innovation, is now considered "old school" is an indication of just how perishable the modern tuner market is. More poignantly, "old school" is almost apologetic, an excuse to explain away older technologies and lower performance thresholds, given recent advancements in everything from tires to turbo technology. Duane Stephens makes no excuses for his MKIII Supra Turbo, nor should he. It makes the numbers, looks the part, and does both better than most, old and new.
Since Stephen's MKIII was featured in our pages several years ago, he's become something of a MKIII Supra-community celebrity, and for good reason: His is still one of the finest examples extant. That whole best-never-resting bit means Duane has come close to doubling the horsepower figure since we last saw the car, with matching trick bits throughout. The car was more of a car-show darling than drag-strip terror the first time around, a mistake that's since been remedied. Before driving down to the event, Duane smacked down an 11-second flat quarter-mile time at over 130 miles per hour, on slicks and without nitrous.
This car serves as a rolling billboard for Duane's company, Carbonfibre F/X Bodywerks Ltd. and as such, features a host of his production and custom body and interior parts. These are in addition to a sea of chrome in the engine compartment to better trawl in car-show judges. Which it does. Components rendered from carbon fiber include the hood, radiator block-off plate, headlight covers, armrest and dash kit, and Duane used fiberglass for his custom front bumper.
As if Japanese engineering needed a champion, Duane stressed the robust nature of his car and build by not just driving his 600-plus horsepower car over 1,300 miles from Vancouver, British Columbia to Southern California, but doing so in December, which meant snow-blanketed passes and other treachery, all dispatched without incident.
More than tripling the Supra's stock output requires more than quadrupling the 7MGTE's stock 6.8 pounds of boost with an appropriate growth of all parts whose contents are governed by the laws of fluid dynamics. The 7M's stock crank and rods are more than up to the task, and after balancing and shot peening, were topped with custom 8.4:1 compression forged JE pistons. If 7Ms have a chink in their armor, it's the head gasket, which Duane addressed with ARP head studs and a 2mm thick piece from HKS. Before it was cinched down, the long head was ported and polished and fitted with 1mm oversized valves, and stock cams fitted with AEM cam gears.
To provide an idea of just how forced the induction is on this 7M, the "low boost" setting, which means running on the wastegate spring, is 20 psi. GReddy is responsible for the most of the turbo's guts, including the manifold and RHC7 turbo, sized to start making the numbers earlier in the powerband of an engine that by design doesn't love to rev. A diameter of 3.5 inches is maintained through every part of the intake and exhaust track, starting at a Ron Ramirez intake manifold, through a Q45 MAF, custom intercooler, down a custom stainless-steel downpipe and exhaust, then out a Burns titanium muffler.
Knowing that his car would be seeing prolonged lateral loads during our testing (and with a long gaze at our USCC), Duane installed a fuel sump, which he then combined with a monstrous Aeromotive A1000 fuel pump and a -8 fuel feed line dumping through GReddy 720cc/min injectors. This system provides plenty of headroom should Duane decide to challenge the younger generation of Supras defined by four-digit dyno load blowing.
All electron guidance is still done by Electromotive's TEC-II standalone computer and coil-pack ignition system. Twin 10-pound tanks of nitrous separately feed a single wet NOS 60-shot fogger and intercooler sprayer. Again with an eye on prolonged track use, reduced intake charge temps are complemented with cooler fluids, thanks to a Fluidyne radiator, Earl's oil cooler kit, plenty of ducting and big electric fans.
The Dynojet we used was no friend to Duane's Supra: The roller was too light to properly load the engine to create its full 30 psi. At 23 psi, he generated 554 horsepower and 533 lb-ft of torque. With a 60-shot of nitrous, the numbers grew to 585-horsepower and 563 lb-ft of torque. At 30 psi, Duane reports the car makes 665 horsepower and damn near as much torque, and we believe him.
Tired of building and replacing automatic Supra trannies, Duane installed a factory 5-speed unit after installing shot-peened forks, heavy-duty bearings and a short shifter. Again walking the fine line between street and strip, a 6-puck sprung hub clutch disk from HPF was mated to a 3200-pound pressure plate from RPS.
All turbo Supras are born big-boned, so selecting suspension components that can handle serious load without upsetting the car's luxocruiser status is quite a balancing act. Duane chose well, basing the setup around Tein's 22-way adjustable HA coilovers. Suspension bushings, squishy when stock and mucous-like when old, were swapped out for polyurethane bushings from Energy Suspension and A1 adjustable toe links help Duane prep for the car's various dynamic duties. Also installed to battle heft are anti-roll bars from Suspension Techniques, which better transfer load into a chassis stiffened with a 6-point NHRA-legal roll cage and strut-tower braces from Cusco and Tom's.
Being a musclecar guy, Duane ensured that his Supra, perfectly capable of ripping up a road course, can still cut 1.52 60-foots at the drag strip. To that end, Duane had a set of CFX trailing arms custom made with spherical rod end bearings to better withstand repeated, hard launches on slicks.
Since we last saw the car, Duane invested in a huge, custom front brake setup using four-piston AP calipers and 13.2 inch, 2-piece, lightweight KVR rotors. To continue Jenny Craiging the Supra's unsprung weight, a set of 17-inch forged TRD wheels arrived from Japan. 255mm-wide Dunlop SP9000s in the rear put up a valiant effort against the big twist routed through a TMS carbon-fiber driveshaft, but full throttle in any of the first three gears shaves rubber.
Despite big numbers and bulletproof reliability, Duane is assembling a new 7M using more forged bits and six lovely titanium rods. With more nitrous and new cams on top of the current turbo setup, his goal of 750-plus horsepower is reasonable. And to make the rest of us jealous, Duane recently expanded his stable of Mark IIIs by taking advantage of Canada's 15-year rolling importation law, adding a right-hand drive,1JZ-powered Supra.
MkIII Supras are often overshadowed by the larger-than-life MkIV, but given the latter's ridiculous $30K used price tag, eyes and wallets are returning to what are comfortable, swoopy, turbocharged, RWD bargains, yours for less than the price of a roached Civic. And, if modified as finely as Duane's, just as relevant as anything produced today.
Duane Stevens 1989 Toyota Supra TurboEngineEngine Code: 7MGTE
Type: Inline six, iron block, aluminum head
Internal Mods: 8.4:1 JE pistons, shotpeened and beam-balanced rods
External Mods: Greddy IHI RHC7 turbo kit, ceramic-coated exhaust manifold, 40mm wastegate, Type-R blow-off valve, 3.5-in. stainless-steel custom downpipe, custom 30x14x3.5-in. intercooler, Ron Ramirez custom intake manifold, Q45 88mm throttle body, custom 3.5-in. stainless-steel exhaust with Burns titanium muffler, AEM cam gears, NOS single fogger, intercooler sprayer and purge kit, twin 10-pound nitrous bottles, tig-welded fuel sump, Flexalite fans, Fluidyne radiator, Earl's oil cooler and filter relocation kit, GReddy catch can
Engine Management Mods: Electromotive TEC II standalone engine management, AEM UEGO wideband
DrivetrainLayout: Longitudinally-mounted inline-6, rear-wheel drive
Drivetrain mods: Hurst line lock, shot-peened forks, heavy-duty bearings
SuspensionFront: TEIN HA coilovers, Suspension Techniques anti-roll bar, Energy Suspension bushings, Cusco strut-tower brace
Rear: CFX custom trailing arms, TEIN HA coilovers, Suspension Techniques anti-roll bar, Energy Suspension bushings, A1 adjustable toe arms, Tom's hatch brace
BrakesFront: AP Racing 4-piston calipers, KVR 13.2-in. rotors with custom Caliper type, rotor size, lines, pads, etc
Rear: KVR carbon pads, Russell stainless lines
ExteriorBody: CFX carbon-fiber hood, radiator block-off plate, CFX fiberglass bumper
Wheels: 17 x 8-in. front, 17 x 8.5-in. rear TRD Sports T3 forged aluminum
Tires: 235/40R-17 front, 255/40R-17 rear Dunlop SP9000
InteriorCFX carbon-fiber armrest and dash Kit, 6-point rollcage, 5-point RCI harness, GReddy turbo, boost controller, oil temperature, oil pressure and fuel pressure gauges, Momo Race steering wheel and shift knob, Taylor stainless-steel battery box