Under Suzuki’s Scorch Racing S15-The DIY Time Attack Otaku

Under Suzuki’s  Scorch Racing S15-The DIY Time Attack Otaku

By Ellie Nikolova
Do you remember Under Suzuki from the winter time attack season here in Japan?  Under is Tomohiko Suzuki’s nick name, which came from the car’s prior understeer problems and his status as a self funded privateer. Suzuki san is the builder, owner and driver of the all-carbon Scorch Racing S15 Silvia, the fastest privateer time attack car on Tsukuba Circuit. Suzuki is aiming for victory this year in the WTAC (World Time Attack Challenge). He finished 5th last time and he is determined to become World Champion. With the RE Amemiya RX-7 and Top Fuel S2000 participating, the Cyber Evo back in the game and of course MotoIQ’s own Team America Skyline GT-R BNR32, it is going to be one very tough fight for sure!
The Scorch S15 is the fastest privately owned time attack car around the Tsukuba Circuit.  We have always liked this car's well balanced beauty and simplicity, getting speed with step by step refinement over brute force.
The Scorch S15's front aero has some influence from aeromaster Andrew Brilliant we think.  We can see some of his signature design cues.  The higher center and upward bend of the front splitter is not a mistake.  It makes the splitter less pitch sensitive, a good idea on a production based race car that runs on tires that prefer to be softer sprung than race slicks.  The Scorch S15 has a lot of chassis movement due to its softly sprung, DOT radial based race tire friendly suspension and the splitter shape keeps downforce more consistent as the car, pitches, squats and rolls.  You can't see it but there are diffusers in the front belly pan ahead of the front tires leading to the wheelwells to make more front downforce.  Usually front downforce and front aero balance is more difficult to get than rear downforce in a production based race car.  We understand that the Scorch S15 actually has a lot of front grip and the latest developments have been focused on increasing rear downforce and aero grip.
The Scorch S15 is a very simple car at heart.  No pedal boxes, long steering columns and rear set seats.  The unibody is largely unaltered.  The interior doesn't look like a high buck time attack car but a well sorted and clean club racer.
A Racepak digital dash and data logging system is used.  For engine management a HKS V-Pro is used in conjunction with a lot of stock stuff so it helps if the dash can be independent of the engine management with its own sensors and wiring.
The S15 is staged first on pregrid.  You can see the upraised center section of the splitter better here.  Also note the extensive hood venting.  This helps the air exit from the intercooler, oil cooler and radiator which improves aero by forcing air to flow over the car and reduces drag by reducing trapped air underhood.
The passenger side footwell holds an Odyssey PC925 dry cell battery, the relocated fuse and relay box and the V-Pro engine management system.  You can see the sequential shifter for the Holinger RD65 six speed tranny.  Surprisingly the stock steering column is retained.

 

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