Mitsubishi Sigma GK

4G63 SOHC 8v Turbo Conversion

Vehicle Make : Mitsubishi
Vehicle Model : Sigma GK
Engine Model : 4G63 SOHC 8v Turbo
Transmission : 5 Speed Manual
ECU : EMS Stinger (Generation 1)
Brief Mods : Exhaust, Multipoint EFI manifold, Upgraded Turbocharger,

This vehicle came to RPW after having had the Starion Turbo 4G63T engine conversion performed replacing the 4G54 engine. A custom turbo manifold, Garret Turbocharger, front mount inter-cooler and modified intake manifold had already been fitted with some Nissan fuel injectors.

The ECU was a baseline EMS Stinger (Generation 1) which only provides multipoint injection (Every injector firing every ignition cycle) and very limited mapping points on the fuel curve.

Ignition is sequential ignition with RPW replacing the Starion Distributor with a later model Galant unit with crank / cam hall effect sensor.

Once all the teething problems had been rectified the vehicle was run up and placed on the dyno. Due to the severe limitations of the ECU, tuning was kept very conservative and boost retained at wastegate pressure only.

Once the ECU firmware is upgraded to the very latest EMS Stinger version, with significantly increased fuel load points and other improvements, including more programmable outputs, the vehicle can be tuned more accurately with higher boost levels.

On the road the car drove surprisingly well, with the attention to detail on the balance of the vehicle showing clearly.

Overall an impressive vehicle and a joy to see an older Sigma being loved again.