Johan GSi Kompressor


Based on a C20XE –88. Balanced and weight adjusted. Block O-ringed. Mahle forged low compression pistons, 9.0:1. ARP big end bolts. Balanced flywheel from Kadett Gsi 16v. 12-9 quality flywheel bolts. Ported coscast head. C20XE cams. CNC-modified inlet from Astra Gsi 16v. ETC throttle house removed and replaced with a CNC-machined supercharger-adapter in billet aluminium. Lysholm 1600 twin-screw supercharger.  Charge pressure (at this moment) ~1 bar @ 7000 rpm. The supercharger has future capacity for a charge pressure of ~1,7 bar @ 7000 rpm. Single throttle house from Omega 2,6i. K&N air filter. Custom built intercooler for high efficiency and low pressure drop. HKS racing recirculating blow off valve. TWM fuel rail. Bosch low impedance fuel injectors, 580 cc @ 2,5 bar. Malpassi 1:1 regulator, 3,5 bar fuel pressure. Modified standard fuel tank. Twin Facett “Red Top” pre-fuel pumps. Pre-filters from Volvo 340. 3 litre catch tank. Bosch motorsport 044 main fuel pump. Audi K-jetronic main fuel filter. Calibra Turbo watercooler. 75 degrees thermostat.  Saab 9-5 Aero oil cooler. MBE Systems 967 ECU (fuel & ignition). Distributor removed. Bosch direct ignition coil, double-fire type. NGK BCPR7ES spark plugs. Magnecor custom-made ignition leads (8 mm competition type). Bosch LSM-11 wide band lambda sensor. Lexmaul 4-2-1 system. 2,5” exhaust with Apple racing mufflers.


F28, 6 speed. Converted to FWD. Saschs updated sinter clutch.


Bilstein Sprint shocks, Irmscher group N springs. Powerflex polyurethane bushes.


Front: Saab 9-3 Turbo (290 mm discs and calipers) 5x110 hubs from Saab 9-3

Rear: Saab 900 Turbo (standard Gsi calipers) 5x110 hubs from Saab 900.

Discs and hubs CNC-modified –2mm (new ET = 51) and five cooling-strips machined at each side.


BBS RK II split. 8x17”, ET40 (modified from original ET35). 5x110 mm.


Bridgestone S-02 PP, 225/35-17”


Rieger Infinity 1 kit, Rieger grille, Vectra B doorhandels. Astra F white side repeaters.

Light window tinting at all windows except windshield.


VDO 7000 rpm tacho. VDO 300 km/h speedo. VDO oil pressure,  GIK chargepressure, Autometer Lambda, Knocklink knock monitor. Homebuilt board computer with big LCD-screen, shows information about fuel pumps running, fuses, oil temperature, inlet temperature, water temperature and a lot more. Using I2C and Dallas 1-wire interface. Momo steering wheel.


Johan Hallström, Sweden