Iron Viper

Deep front chin splitter with integrated intercooler and brake-cooling duct channels
Front fender louvers to reduce lift and extract heat from brake/oil cooler zones
Wide rear diffuser with layered carbon fins for high-speed stability
Adjustable carbon drag wing on reinforced uprights for trap-speed control

Designed for the night strip—burnout smoke hanging under stadium lights, then a full-throttle run where aero and cooling matter as much as power. The wide track and rear aero package are there for the far end, not the parking lot. This is a build that reads best between the beams, with the Christmas tree reflecting off carbon edges and heat haze.

Front: Forgeline GA1R 18x10 ET-30 with Nitto NT05 335/30R18 drag radials
Rear: Forgeline 20x15 ET+5 with Mickey Thompson ET Street 345/45R20 slicks
Widebody-clearance alignment with straight-line stability bias and scrub managed for steering effort

RB25DET stroked to ~3.2L with forged rotating assembly and drag-focused oiling
Roots-type supercharger conversion for immediate boost and consistent hit off the line
Front-mount intercooler with short, serviceable charge routing through widened front architecture
Drag-spec ECU strategy: boost-by-gear, launch control, and simplified harness for reliability

Widebody built from thick thermoformed fiberglass with carbon reinforcement at flare edges and mounting points
Chassis seam welding and localized gusseting to control torque twist during hard launches
Custom rear multi-link/traction geometry with adjustable links to tune anti-squat and tire load
Ceramic-coated side-exit exhaust packaging for heat control and quick service access

Iron Viper is what happens when an S15 stops caring about apexes and starts hunting time slips. The familiar Silvia silhouette is still there, but it’s been stretched into a full drag-body with a 2020mm front and 2050mm rear track, big enough to plant real tire and stay calm when the boards are coming up fast. The widebody isn’t cosplay—multi-radius flares, brake and cooler extraction, and a chin splitter with proper ducting all exist to keep the car straight, cool, and repeatable.

Under the cowl hood is the heresy: an RB25 that trades “single turbo hero” for instant-hit boost and brutal consistency. A stroked, forged 3.2L with a roots-style blower and drag-spec control strategy is built for launch violence and quick resets, while the chassis gets the kind of reinforcement and geometry you need when the car’s job is to leave hard and never wander.