From the outside, Electramotive Engineering’s small shops in El Segundo, California might appear modest. Not many onlookers would believe that some of the greatest cars in IMSA history were crafted inside its walls, but Electramotive’s 35 employees proved they had the talent to build a car that would quickly replace the Porsche 962 as the dominant car in the later stages of IMSA’s wild, unrestricted GTP era.
It all began with a production-based racer and its clever engine control unit. Electramotive’s Don Devendorf had pioneered electronic control unit development, winning the 1982 IMSA GTO championship in an electronically-controlled, turbocharged Nissan 280ZX. Several years later, Nissan assigned an ambitious project to Electramotive: build a prototype-style racer for IMSA GTP using the new Nissan VG30 V6.
In its earliest guises, the two-valve, 3.0-litre engine was frail and overweight. GTP power levels had risen to the quadruple digit mark by ’85, and the boost required to generate that sort of grunt proved more than the iron block could handle.
Aluminium block
Chris Willes was hired as an eager design engineer whose first assignment under boss, Wes Moss, and engine specialist, Joe Anahory, was to design an aluminium version of the VG30. Along with the expansion of oil and water passages and a re-design of the failure-prone main caps, Willes pressure tested the cylinders with strain gauge tests at 15 degree intervals throughout the combustion cycle. They needed to know it was robust enough before on-track testing began.
Testing helped the team determine that 800bhp would not put the motor under undue stress, but their greater reliability meant longer runs, which exposed another drivetrain flaw. The Weismann transmission, designed for a Formula 1 car, could not handle the GTP’s torque and weight.
