Mitsubishi Magna 6G75 with Twin Turbo Conversion

Street Driven Touring Spec Turbocharged Magna

The Original RPW Twin Turbo magna was successfully raced for many years at Drag Events, Circuit Racing and local rally sprints. But time and wear, with its regular street duties wore the vehicle down till it was no longer viable to keep the vehicle on the road which was disappointing but necessary.

With our love of Magna’s, David decided to purchase a Silver Ralliart Magna and start from the beginning again, with some extra’s, with the focus again maintaining a street driven vehicle. The Ralliart Magna with its upgraded interior, Climate Control, Cruise Control and of course, the Evolution Lancer styling was definitely a good upgrade over the previous basic specification Magna.

The majority of modified items from the original magna were swapped across. The original plan of simply transferring the Twin Turbo 6G74 engine was performed initially but once it was up and running, further idea’s came into our heads and we decided to go next step forward.

Recently finishing a Supercharged Stock 6G75 engine pushing 350kw in an AWD magna, the choice was easily made and the 6G74 engine was pulled out and a slightly modified 6G75 motor refitted. The heads were removed, reconditioned and fitted with the valve springs, cam gears and camshafts from the original engine, The distributor was removed and fitted with the 6G75 cam sensor mated up to the up spec Haltech Elite 2500 ECU Package. A decompression plate was fitted to reduce the higher compression 10.0: 1 engine back to 9.0: 1 to make it more turbo friendly.

The remaining Twin Turbo gear was fitted across, and then placed back into the car. New intercooler piping was made with aluminium pipework although this pipe work is planned to be redone by more professional welders. Painted black the plan was retain a stealth look (and hide our bad welds).

With the combination of the larger capacity engine, higher flowing heads with larger valves, the motor had a much greater potential for not just more power, but great low rpm torque, reduction in turbo lag and overall improvement in driveability. With this in mind, a custom 5th gear made for the gearbox which reduced the rpm’s by 500 rpm for the same road speed to aid with fuel economy.

Other tweaks included complete conversion to Coil over Plug Ignition, Active knock sensor control via the Haltech, and duel channel wide band control with individual fuel trimming for Left and Right hand banks and best of all, Fuel Flex setup for E85 Compatibility.

The vehicle was up and running but was only road tuned, but straight away the vehicle was amazing to drive and the larger capacity with the same size turbo’s was fantastic for boost coming on earlier.

At the same time, the koni suspension was replaced with K-Sport coil over suspension and immediately made a huge difference to the way the vehicle drove on the road. Unfortunatly the vehicle never made it to the dyno with a core plug corroding and causing a coolant loss resulting in engine damage.

The engine is now out of the vehicle and is being rebuilt with forged internals and to be fitted with an ARP Main stud kit. Other upgrades include a newly designed duel plate clutch kit since it had become too difficult to retain driveability and consistency with the single plate clutch system.

Below are the existing modifications to date

Engine Modifications for Turbo Conversion

  • Stock 6G75 3.8 Litre Engine Assembly
  • MLS factory head gaskets with 1.00mm Decompression Plates.
  • Upgraded valve Springs, Stage 1 Turbo Profile Camshaft and Vernier Camshaft Gears
  • 3.5″ Mandrel Bent high flow exhaust system from cat back with Lukey Ultra Flow Stainless Steel Muffler

Turbo Modifications

  • Twin Garret GT-28 ball bearing turbo’s – 330hp each
  • PWR front mount inter cooler kit
  • GFB Return style blow off valve
  • Aluminum mandrel bent inter cooler pipes
  • Stainless steel braided Teflon oil fittings, water fittings etc
  • Mandrel bent 2 1/2″ dump pipe off each turbo, Ceramic coated.
  • Ceramic Coated turbo manifolds for further heat reduction
  • 1000cc Injectors into stock fuel rail no mods required
  • Fuel rail modifications with conversion to twin inlet and outlet system into single Powerflow Fuel Pressure Regulator
  • Walbro 550hp internal fuel pump (Largest available to fit to this car)

Electronics

  • Haltech Elite 2500 plug and play ECU system
  • Full idle speed, air conditioning control, future launch control
  • Upgraded Coil over Plug ignition coils
  • Haltech Duel Channel Wide Band Sensor Kit
  • Boost Control via 3 Port Solenoid

Suspension

  • K Sport Coil over Strut Kit
  • White line front sway bar kit
  • White line front strut brace
  • White line Anti Lift Kit
  • Modified rear lower control arms for additional Toe set adjustment

Driveline

  • Quick shifter Rally Spec
  • Fidanza lightweight billet flywheel
  • 8 paddle clutch semi ceramic clutch disc with 35% heavier cover plate
  • Future planned Duel plate clutch kit.
  • Quaife ATB Differential
  • Replacement 5th Gear for improved cruising efficiency
  • Polyurethane Performance mounts on front of engine.
  • Brembo Front and Rear brake upgrades incl rotors

Results

Once the new motor is completed sometime in 2019 the vehicle will be back up and running with a petrol and E85 race fuel tune. It will be interesting to see the results.