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Tilton Interiors Evo 9 Retires After 3 WTAC Championships

Retiring from the pinnacle of the global Time Attack scene, the Tilton Interiors Evo is a record-breaker backed by years of flawless teamwork

Alex Grant
Jun 22, 2016
Photographer: Alistair Ritchie

There's a lingering buzz of excitement mixed with a hint of relief in the Tilton Interiors pit garage. As the light fades over Sydney Motorsport Park, it's the end of long months and countless late nights preparing for the team's annual World Time Attack Challenge (WTAC) outing. And, yet again, they've made history. With eight years of Time Attack experience and record-setting, Pro Class leading performances at the two previous WTAC events, Kosta Pohorukov and his team have had plenty of time to get used to success. The '15 event was no different as the Evo stopped the clock at 1:23.7770—more than a second and a half faster than its nearest Pro Class competitor. To put that into context, driver Garth Walden came in only a second behind the F3 lap record (F3 is open wheel formula racing and has been regarded as the first big stepping stone for potential F1 drivers). And not with some single-seat track toy—the Evo is based on a production chassis, which, structurally, has hardly been modified. It's even using road-legal tires! "I think that's what makes World Time Attack so appealing," Tilton's project manager Charlie Dang tells us. "The cars are based on street cars, but the engineering, the trial and error, the thinking out of the box, it's out of this world. It's using the world of motorsport for grassroots racing." Probably a bit too grassroots at times. The team's Time Attack career was almost cut short when their original car was stolen back in '10. Charlie says it was a turning point that probably put them on the path to where they are today: "We already knew the chassis based on the earlier Evo, so we decided to build another one based on that car and, well, it kinda got out of hand. It went very competitive from then onwards, though we were always competitive."

Tilton interiors mitsubishi evo 9 farth walden Photo 2/26   |   Driver Garth Walden celebrating after recording a 1:23.77, a new WTAC and Sydney Motorsport Park lap record. The lighting fast lap is also 1.1 seconds faster than the previous year's time.
Tilton interiors mitsubishi evo 9 garth walden Photo 3/26   |   Three lap records, three WTAC titles... The Tilton Interiors Evo 9 is one of the greatest Time Attack cars of all time!

Stripped of its exterior panels and still just about radiating heat from its time on track, you get a real sense of the years of fine-tuning that have gone into getting it this far. There's not a square inch of the car that doesn't have a role to play, and a surprisingly large amount has changed since its last WTAC appearance, Charlie explains, adding that it's practically a different machine within that skeletal structure. Among the new additions is the huge BorgWarner turbo crammed into the front of the bay. Planned for the '14 event, it's the same unit fitted to Honda's IndyCar racer and part-spooled with a large tank of nitrous mounted in the passenger-side footwell. It's made the Evo good for 1,000hp at 40psi with minimal lag, delivered reliably through the handiwork of ABE Engines and a six-speed Holinger sequential transmission.

Tilton interiors mitsubishi evo 9 4g63 engine Photo 4/26   |   Tilton Interiors Mitsubishi Evo 9 4G63 Engine
Tilton interiors mitsubishi evo 9 4g63 engine Photo 5/26   |   Tilton Interiors Mitsubishi Evo 9 4G63 Engine
Tilton interiors mitsubishi evo 9 hypertune exhaust manifold Photo 6/26   |   Built 2.2L 4G63 receives an updated BorgWarner EFR turbo—acts as a small turbo with little lag, but still has the power of a larger turbo. The Tilton Evo pushes around 1,000 hp at 40 psi of boost.

Huge power is only part of the equation. Kosta struck up a relationship with Japanese company Voltex back in '12, which led to the Evo being shipped out to their wind tunnel in Suzuka for a bespoke aero kit. It turned out to be an investment worth making, helping to shave two and a half seconds off the previous year's lap times and an overall win on its first outing in '13. The car's return trips to Voltex, with several of the team in tow, have been a big part of the off-season development work ever since, and it hasn't slowed down. For '15, the Evo has a completely redesigned undertray, also specifically designed not to be vulnerable going over curbs, while the front diffuser, side skirts, hood and dual-plane rear wing are new parts, designed and built in time for its first track test at the EvoNationals. It's become a close working relationship, close enough that Voltex founder, Nakajima-san, and his employees are usually found in the pits making final adjustments. Relying on that level of detail meant the structure of the car could stay relatively untouched. There's no tubular chassis under the dry carbon panels, it still uses the stock suspension pickups and most of the parts that have helped Tilton set records are available to buy. The goal wasn't only to be the best, but to preserve that grassroots link to road cars - the 'spirit of Time Attack'—which was so important to Kosta. However, the downside is tight timescales. "We had four or five days of track testing, and we need a huge amount of adjustment to get it to work. If we didn't get the chance to test all the revised parts, we would have had a hard time winning. We were still only grasping the issues two days out from the event, and still adjusting on the day. That's Time Attack for you. There are always problems, especially when you're one of the first people to try new applications. We're dialing everything to 15 out of 10 when we're trying to make a time, so when we're testing, we need to make sure it's capable of doing its job under load," Charlie says.

Tilton interiors mitsubishi evo 9 stripped interior Photo 7/26   |   The Tilton Evo featured an unmodified unibody; however, a chrome-moly 'cage stiffens the chassis.
Tilton interiors mitsubishi evo 9 motec c187 dashboard Photo 8/26   |   MoTeC C187 display tells Garth Walden everything he needs to know in real-time.

Seasoned NSW-born driver Garth Walden's pedal work has an equally large role to play. Since the team took its first steps in Time Attack, he's one of the many members who've stayed part of the Tilton family on the journey through the ranks. "People think that we have contacted the best of the best, however that's far from the truth," Charlie says. "Kosta knew him through his involvement with Radical Australia. He's brought in people who he has been friends with from the start, and they're still the core people involved today, but we've had additional support as we've got more serious." That same core is almost certain to be trackside when the Evo's all-new replacement makes its first appearance in '17. But we'll let the buzz of this third successive win die down a little before pressing the team for details.

Tilton interiors mitsubishi evo 9 voltex front bumper Photo 9/26   |   Every panel is a custom carbon piece made by Voltex. While not pictured, even the roof skin has been replaced with dry carbon.

"We don't know what it will be yet. We're still researching and getting a feel for the options," Charlie says with a laugh. "We have to be competitive and come out with a briefing of our goals before we move forward. Like they say, measure a thousand times, cut once—or you lose a lot of money in WTAC Pro Class."

Tilton interiors mitsubishi evo 9 trunk area Photo 13/26   |   Tilton Interiors Mitsubishi Evo 9 Trunk Area
Tilton interiors mitsubishi evo 9 stripped interior Photo 14/26   |   Pretty much a skeleton when all the carbon panels are taken off!
Tilton interiors mitsubishi evo 9 alcon brake caliper Photo 18/26   |   Stopping with the very best parts—Alcon calipers with AP Racing rotors all around.
Tilton interiors mitsubishi evo 9 voltex staff Photo 22/26   |   Tilton Interiors Mitsubishi Evo 9 Voltex Staff
Tilton interiors mitsubishi evo 9 pit crew Photo 23/26   |   Voltex staff on hand at WTAC to make any last-minute adjustments to the carbon aero. Now that's service!
By Alex Grant
19 Articles
Tilton Interiors Evo 9 Retires After 3 WTAC Championships
Tuning Menu
Owner: Kosta Pohorukov
Hometown: Macquarie, Australia
Occupation: Owner of Tilton Interiors
Engine: 4G63 stroked to 2,200 cc; CP pistons; Cosworth crank, rods, titanium valve retainers; ACL Race Series bearings; Peterson dry sump; CNC ported head with 1mm oversize valves; Kelford cams; Hypertune exhaust manifold; 3.5-inch stainless downpipe; BorgWarner EFR 9180 turbo; HKS 3.5-inch titanium exhaust; Hypertune radiator and oil cooler; Turbosmart dual HyperGate 45mm wastegates, blow-off valve, intercooler, fuel pressure regulator; 2,200cc injectors; dual Bosch motorsport 044 fuel pumps; Royal Purple remote oil filter; Wizards of NOS nitrous injection; MoTeC CDI module; Braille lightweight fuel cell
Drivetrain: Holinger MF-E six-speed sequential transmission; custom flywheel; AP triple-plate clutch; Ralliart front and rear limited-slip differential; air shift paddles
Engine Management: MoTeC M800 ECU, C187 datalogging dashboard
Footwork & Chassis: MCA Gold Series custom coilovers; Whiteline 24mm sway bar; Racefab adjustable front arms; rose jointed suspension; MooreSport CNC front knuckles; KSP Racing Equipment rear knuckles
Brakes: Alcon six-piston calipers; 355mm AP Racing rotors, master cylinder, floor-mounted pedal box; Dixcel pads; braided brake likes
Wheels & Tires: WedsSport TC105N 18x10.5 et 12 TS TI Finish
Exterior: Custom wind tunnel tested dry carbon aero and three-plane rear wing by Voltex Racing; custom undertray; Voltex dry carbon rear clamshell and door skins
Interior: fully stripped; CAMS-spec chrome-moly rollcage; Racetech RT9009HR lightweight seat, six-point harness
Thanks You: Evolution Oz, The Low Down, Street Cover, Royal Purple, Voltex, Yokohama, TM Automotive, Garage 88, BorgWarner, Garth Walden Racing, Dixcel, ABE Engines, Hypertune, Insight Motorsports, MoTeC, Turbosmart, Kelford Cams, MooreSport



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