The name K&N Engineering is synonymous with some of the most widely used aftermarket air filters, oil filters and cold-air intake systems. But, after the debut of this reworked 2003 Infiniti G35, the K&N name will soon be associated with racecar engineering, attention to detail and blinding speed. More than just your average, run of the mill, body kit-equipped tuner G35, K&N's time attack monster is a painstakingly planned out machine. Built for a single purpose, the K&N machine fires in anger one fast lap at a time, and at only one racetrack in the world--Buttonwillow Raceway.
Home of the annual Primedia Time Attack event, Buttonwillow's desert curves are the reason why K&N designed, fabricated, and built this G35. With a 1,200 wheel hp supercharged Viper in-house that has blasted the Silver State Classic and a tube-frame dragster assembled solely for the quarter-mile, K&N already knows a thing or two about building fast project cars. But to dominate the sport compact field, K&N decided to take the top times away from such time attack heavyweights as GM Racing's big dog Cobalt, the powerful Cyber Evo, and the color-shifting Signal Auto Skyline GT-R.
From the second we stepped into K&N's top-secret race shop facility, we knew that we were standing on hallowed ground. Three hydraulic lifts, a herd of machining equipment and a massive carbon-fiber autoclave rested within view. Hidden from view, even from the prying eyes of automotive journalists, were the laboratories where the military jet aircraft and M1 Abrams tank air filters are created. With a full professional race shop available, K&N Sport Compact Business Manager James Yim told us that the only unmolested parts remaining on the G35 are the headlights, e-brake, taillights, and spindles. Virtually everything else has been chopped, painted, reworked, or replaced with a bolt-on piece. And by bolt on, we mean CAD designed, machined from solid billet and then bolted on with aerospace-grade hardware.
A complete volunteer effort, the G35 was built after hours at K&N headquarters by employees James Yim, Max Lopez, Bret Kingsfather, Nestor "F&F" Cabrera, Julian Hinojos, Kevin Summers, Rene Torrez, Chris "White Snake" Neprasch, Jere Wall, Mark Keninston, Rick Daniel, and John Hudson. One of the very first Infiniti G35's to arrive in the U.S, K&N's model was a development chassis that arrived complete with what could be the world's only left-hand drive G35 dashboard covered in the same suede material that Japanese models receive. Not that it matters now.
Torn down to virtually nothing, the G35 was stripped of so many parts; K&N could easily build another G35 out of the pile. A custom rollcage was fabricated by K&N, with technical input on the design from scheduled driver Terry Borcheller. Borcheller, a veteran Grand-Am, World Challenge and American Le Mans champion, had specific requests about the positioning of the door bars for protection of his legs. Devoid of any interior for a reduction in weight, the only luxuries inside are a Sparco Circuit racing seat, Sparco harness, and the AiM Sports MXL Pista digital dash display/data acquisition system. Capable of displaying, recording, and uploading pressure, temperature, accelerometer, RPM, lap times, and split times, the MXL Pista system allows Borcheller to playback and analyze his driving after every session. Built to accommodate the MXL Pista, a custom fabricated carbon-fiber dashboard is fitted with a carbon-fiber center console that holds a host of switches as well as the HKS F-Con V Pro engine management system. Striving to loose as much weight as possible, the K&N G35 uses lexan windows and carbon fiber enclosed gutted door skins. With the engine bay completely bare, but with full glass and complete doors, the G35's chassis weighed in at 1800lbs. without breaking a sweat. When the car is ready to run, the plan is to have the Infiniti weigh in slightly under 2800lbs.
Tweaked by XS Engineering of Huntington Beach, California, the HKS F-Con tunes the crown jewel of K&N's masterpiece. Lifted from its resting place, the VQ35 engine was sent over to world-renowned Cosworth Engineering to be assembled and blueprinted. With plenty of Formula One, WRC, Champ Car, and street car building experience, Cosworth had no problem building up K&N's engine. But the three-day turnaround that Yim requested was impressive, nonetheless.
Disassembling the motor down to the bare block, Cosworth machined the 3.5L motor to accept larger 96mm bore forged 8.5:1 CP pistons with CP Plasma Moly ductile iron piston rings. The Pauter connecting rods are a 4340 billet vacuum chromoly forging, CNC machined, and fit with 220,000 psi tensile strength rod bolts. The crankshaft remains stock, aside from being balanced and micro-polished by Cosworth. Remarkably, the oiling system also remains stock, right down to the oil pan itself, and is deemed up to the task of lubricating this monster--aside from a blueprinted and balanced oil pump.
The cylinder heads were sent to BCE Racing Heads in Las Vegas, Nevada, for a port and polish job, then returned for final assembly. Supertech Performance double valve springs, titanium retainers, titanium keepers, and upgraded valves were installed to support Nismo 262 intake and exhaust camshafts. Supertech provided black nitride-coated stainless-steel intake valves and a set of drool-inducing Inconel exhaust valves. The same material that Formula One exhaust manifolds are fabricated out of, Inconel is ideal for turbocharged applications because it can withstand greater exhaust heat and helps reduce combustion chamber temperatures, allowing for more ignition advance and greater power.