Power steering reservoir on turbo mkIIIs is located in an unfortunate spot where not only is it exposed to hot air blown through the radiator, but also it is blocking the same air flow from moving though around the turbo and thus helping to cool it. Unlike previous years, Supra model years 1991 and 1992 had an improved “power steering cooler”, upgraded with cooling fins vs. just a bent pipe running in the nose of the car. Apparently there must have been an issue with power steering fluid temperature that prompted this fix. In an attempt to remedy this problem on “Project Black”, a power steering fluid reservoir was replaced with a plastic unit from another Toyota car and moved away from the original location. The new placement allows for better cooling for both the power steering fluid and the turbocharger.
Fuel system is another area where mkIII Supras need some help. To ensure that there is enough fuel supply for the targeted higher horsepower, an adjustable fuel pressure regulator from Aeromotive was installed. A fuel pressure gauge mounted on the fuel rail provides accurate fuel pressure readings helping in setting of base line fuel pressure of 40psi. Base fuel pressure setting needs to be done with engine not running. With the ignition in “ON” position, connect “B+” and “Fp” points on the Diagnostic Connector under the hood to pressurize the fuel system.
To improve performance of the Supra ignition system, an HKS Twin Power DLI ignition amplifier was installed. The Twin Power ignition amplifier incorporates both the CDI and transistor method ignition to provide optimum spark duration and maximum voltage output, resulting in crisper throttle response and a smoother engine powerband. The effects of this upgrade were felt during first drive after the install.
A set of Bortex RPM 18″ rims from Enkei was wrapped in low profile Falken tires and installed on all four corners. Front brakes were also upgraded with custom combination: a pair MkIV Supra 12″ directional rotors custom fitted, in combination with Nissan 4 piston aluminum brake calipers installed using custom brackets from supracarparts.com. Custom made brake pads were utilized. Goodridge stainless steel braided brake lines replaced factory rubber lines to minimize the “spongy” feel of the brake pedal.
Since the original grey leather interior was in a dismal shape it was necessary to step up and replace it with custom leather. A two-tone red and grey design was chosen to coordinate with dashboard and trim colour and to add a little “spice” with an accent colour. Passenger and cargo area carpet was also replaced with a molded replacement piece. Extra padding was added to improve soundproofing. New floor mats were installed.
An excellent upgrade for manual transmission cars is removal of the throttle linkage assembly completely (look at the pics) and replacing it with JDM-style assembly which gets rid of the useless levers and springs. JDM cars being right hand drive never had this linkage, and trust me, the throttle response of the engine without it is so much better, you’d think it’s a different car altogether. The throttle pedal movement is a lot smoother and crispier, it gives you much faster response due to different ratios - it’s like a throttle pulley upgrade for Nissans. It’s one of the best feeling upgrades for the mkIII. It doesn’t give you more power, however power delivery is so much faster, that the car feels much stronger and more responsive.
Here is a photo depicting visual differences between Toyota Supra factory original pistons & connecting rods (on the far right) vs. JE pistons & Eagle rods (on the left). The piston skirt length and design is apparently different, and so is the piston ring thickness and location.
A set of Supra Japanese Domestic Market (JDM) power folding mirrors was also installed. A control module was mounted in the passenger side door, inside a space already allocated at the factory (much like the space for the power door lock unit on the driver side). Additional wiring was added. Original power mirror switch was also replaced with a JDM unit equipped with a “retract” button. For a complete wiring diagram click here.
Supra factory backlight tends to be a little yellow-ish. It is especially apparent when using Greddy Gauges. To minimize this effect we used a Green LED upgrade kit. It provides nice and green gauge light perfectly matching Greddy gauges (in this case Boost and Coolant Temperature). For those interested in changing the backlight to blue to match modern CD/mp3 players or gauges, a Blue Kit is also available.
Ignition Coil Conversion Kit for Toyota Supra Turbo 7MGTE 1987-1992. The kit allows you to convert your stock ignition system from the original factory coil pack and spark plug wires system to Coil Over Plug system without the use of high voltage spark plug wires. No more issues with different length/resistance of spark plug wires for each plug. The system utilizes the original 7MGTE igniter in combination with HKS Twin Power DLI ignition amplifier. Spark plugs are standard - either factory spec or lower temperature range for higher boost cars. THE KIT CONTAINS: Polished Aluminum Centre Plate, all mounting hardware, ground wire AND WIRING HARNESS connecting the new coils to the stock igniter wiring harness. NOTE: The system utilizes six MkIV Toyota Supra Twin Turbo ignition coils. Toyota/Denso Part Number 90919-02205. Also, the HKS Twin Power DLI module is used in the kit to provide optimum spark energy which DLI does by controlling the coil dwell time.
Here is another example of a mkIII Supra that started as a fine stock specimen. With 190,000 km and minimal wear it became a perfect candinate for restoration and mods. Factory original red paint was replaced with “custom” red. Grey leather interior received an upgrade to two-tone grey-red combination. Stock internals in the 7MGTE motor with a few BPU upgrades to improve performance. They included: custom modified polished 3000 pipe with removed bottleneck, large intake pipe with Greddy type S blow-off valve, K&N cold air FIPK air filter mounted on a polished Lexus AFM. Exterior upgrades included JDM style clear turn signals and colour matching body mouldings. This Supra was on the right track towards more upgrades…
The next step was to address a few quality issues. Brand new fog lights were purchased form Toyota to replace stone-chipped original units. Xenon-white bulbs replaced ordinary lightbulbs. Targa roof also received new treatment. New rubber seals were installed all the way around. Door seals were also replaced with brand new units. Same happened to the trunk seal. All new, nice and soft rubber. Next the old carpet went out, replaced with Black, molded 20oz cutpile factory-quality piece, with rubber soundproofing backing applied. Both, the cabin and trunk area sections were replaced. Brand new, factory Toyota leather shifter knob was also purchased and installed, matched with the black leather shifter boot covering a short shifter. It is a factory original unit modified the way that retains the original rubber bushings, helping with precise and quick shifts while retaining most of the original vibration-free feel. Center console armrest was also covered with new black leather.
One of the next mods was an addition of AutoMeter gauges. First a double gauge pillar pod from Lo-Tek replaced the factory a-pillar trim. Then a pair of 2-1/16″ (52mm) gauges was installed: a boost gauge and a coolant temperature gauge, both with dashboard cluster matching green backlight. It seemed like a great addition, however, because the needles were not illuminated, night time readouts were less than perfect.
To improve intake air delivery a K&N Cold Air FIPK kit was added. Installation was very easy, a drop-in application, although clearing the Greddy BOV was somewhat challenging. A polished stainless steel shield next to the intake was also added to reduce warm air intake coming through the radiator. Toyota factory Air Flow Meter (AFM) was polished to improve the appearance.
Only a couple of years ago this car was still a fairly stock version of the Toyota Supra Turbo. 130,000 km original mileage. No winters. Factory original Ruby Black paint, grey leather interior, stock internals in the 7MGTE motor. A few BPU mods were implemented to improve performance. They included: Suspension Techniques anti-sway bars, custom modified polished 3000 pipe with removed bottleneck, large intake pipe with Greddy type S blow-off valve, Fluidyne radiator, Greddy Turbo Timer, and TRD Style 320mm diameter steering wheel among others. Also present were front Greddy replica and rear Cusco tower braces to aid in torsional rigidity. The Supra was on the right track towards a few more upgrades…It shortly received reverse facing hood air scoop aiding in evacuating hot air from the engine bay, polished aluminum upper radiator pipe, TRD oil filler cap to dress up the engine bay as well as aluminum race-style pedals.