Breakfast at the Autocross

Sunlight shimmers off the old El Toro Marine base’s acres of tarmac, and the orange cones of the autocross course are almost glowing. The HKS supercharged 350Z is growling at 4,000 rpm as I release clutch and jump on the gas. Brief rear tire spin, then rapid acceleration; a quick shift to second, then I’m on the brakes for the first turn. Threading the course quickly requires dancing on the brake and accelerator pedals. With HKS’ supercharger and suspension, the 350Z is working well, producing grin-inducing g-forces and acceleration.

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The company is known for its intake, exhaust, suspension and turbocharger systems for the sport compact market. New products from HKS were the GT Supercharger, being introduced for the Nissan 350Z and Infiniti G35 and FX35, and the Hipermax III suspension kit for the 350 and G35. For the demonstration runs, quarter-mile and autocross courses were set up. Stock and modified versions of the cars, along with a race-prepared 350Z, were on hand. For the quarter-mile, we drove stock and supercharged FX35s and the 350Z track car. Over by the autocross course were a pair of 350Zs and G35s in stock and modified forms.

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First stop, the quarter-mile: With none of the runs being timed, we didn’t flog the stock FX off the line., so the big crossover left the line a bit slowly. Once the V-6 is in the sweet spot, however, it manages to get through the quarter-mile at a speed of about 80 mph. Not too shabby…but not neck-snapping either.

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The extra torque was evident as soon as I left the line. As the big crossover’s transmission shifted up through the gears, the torque kept on giving. At the end of the quarter-mile, the speedometer only reads about 87 mph, but the first part of the trip was faster than in the stock FX. Very useful power for those short freeway on-ramps. HKS’ street kit, which has CARB approval pending, is a fairly low pressure setup with 7.25 psi of boost. The kit includes a piggyback electronic module to control fuel and timing maps.

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Now we’re talkin’. An OK launch, but gobs of torque make up for it, and I’m grabbing gears in quick order. I’d be pushed back in the seat except I’m already strapped in by a racing harness. If not for a bobbled gear shift, the speed at the end would have been higher than the approximately 105 mph. The 350Z was setup with a Pro Kit GT Supercharger with 11 psi of boost, complete HKS engine electronics and a purpose-built motor rumble under the hood. The custom exhaust has more open mufflers and no catalytic converters. HKS fitted the car with the Hipermax III Sport suspension.

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On to the autocross course, where Nissan’s kissing cousins, the 350Z and G35 Coupe awaited. After a ride through the course, we took two laps in each car. First up, the stock G35, and we learned that what makes it a good near-luxury coupe doesn’t suit the kinds of transitions encountered through cones. The car must be coaxed through, and doesn’t respond kindly to abrupt inputs. Still, after a decent first lap, I quickly figure out where I could go faster and how. Or so I thought. Accelerate to the first corner, slam on the brakes … uh, no anti-lock? Nope.

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Having learned my lesson about these G35s and antilock brakes, I approached the next two laps with more finesse and less brute. With the stiffer suspension, the transitional response of the G35 was much improved, with less understeer. The extra power from the supercharger helped on corner exit, but too much throttle would break the back end loose. Rolling on the gas in the right amount, however, was just the thing to bring the back end around the final corner and accelerate through the slalom to the finish. The luxo coupe looked pretty respectable on the tight autocross course.

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The 350’s shorter wheelbase was immediately apparent. The car was much more nimble. The stock suspension might have been a bit stiffer than the stock G35’s, but body roll and some understeer were apparent on the first lap. With adjustments to my driving, the stock setup worked pretty well when taking the body roll and understeer into consideration. There’s enough power in a stock 350Z to get the car out of shape on a small, tight course, but more torque coming off the slower corners would have been welcome.

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Autocross courses are all about handling, both steady-state and transitions. Out and out power isn’t as useful as low-end torque, which superchargers excel at providing. The HKS kits worked really well on the 350Z, transforming the car from okay to one that can handle all the autocross elements equally well. It should be noted that this car also had a very aggressive limited slip differential, a significant advantage in autocross, and Advan Neova tires which have proven themselves in national autocross competitions. The stock car had the very good Bridgestone Potenza RE040 tires, but they’re not as competitive as the Neovas.