The Toyota MR2 is a fairly unusual choice of weaponry for Australian circuit race drivers. Why? Well - despite the finesse of the mid-engine, rear-wheel-drive chassis configuration - the locally delivered atmo MR2s have nowhere near enough grunt to create much excitement. The standard 2.0-litre MR2 generates a high of 168hp but, without a really strong torque curve, it's a fairly disappointing low-to-mid 8-second 0 - 100 km/h performer.
When Raymond of Sydney bought this SW20 MR2 GT brand new back in '94 he soon fell in love with its driver involvement "but it felt like it should have had an extra 50 horsepower." This lack of power came to an abrupt end when Raymond took the car to a local workshop for a conversion to 3S-GTE power. The T in that engine code stands for Turbo - something that, in the early ST185-series, meant an output of 205hp. That gutless 3E-GE atmo engine was given the boot and in its place slotted an early 3S-GTE import engine endowed with a hybrid turbo, ARC intercooler and an aftermarket ECU (getting rid of the restrictive Toyota airflow meter). No question, the boosted 2.0-litre gave a whole lot more excitement under foot, but all was not particularly joyous - after the seventh engine rebuilt with Cosworth pistons and tough rods, Raymond said "enough!"
At this stage Raymond took the car to Paul Brell of BD4s Service Centre. Paul was very experienced with 3S-GTEs and MR2 - just check out his promo car, "A 1-OFF Creation".
The first thing Paul did was replace the ST185 engine with a late-model ST205 engine. The later version, we're told, received a new head casting and proves much stronger overall; Toyota had ironed out the early engine's little niggles. Not only did he start with a new slate, Paul also started over again with the engine internals and bolt-ons...
Most interestingly, the 3S's 2.0-litre capacity was taken out to 2.2-litres using an off-the-shelf HKS 2140cc stroker kit, which comprised a gorgeous billet crankshaft and new pistons. Paul added to this a set of Argo rods, just to be safe.
Up top, the DOHC, 16-valve Yamaha developed head has been ported and enhanced with HKS 272 cams, HKS valve springs and JUN titanium retainers. Blow-by oil is received by an AVO catch can, plus an oil cooler and thermostat can be found in the position of the original intercooler.
Forcing the power issue is a GT30/40 turbocharger mounted on a HKS 3mm stainless steel extractor manifold, teamed with a HKS 50mm external wastegate. Exhaust backpressure is simply not an issue thanks to a 3 ½-inch stainless mandrel exhaust with a HKS titanium muffler.
A massive new intercooler has also been fitted - a custom Airtech core, which is mounted horizontally in the boot. Airflow through the core is provided by a forward-facing WRX scoop on the bootlid, a pair of 12-inch electric fans underneath and an air exit passage cut into the rear bumper. This is one serious intercooling arrangement! A HKS air filter and blow-off valve round out the induction system leading up to the throttle.
One of the big advantages Raymond's car has over Paul's 1-OFF MR2 is its custom intake manifold, which was fabricated by Performance Metalcraft. This incorporates internal bell-mouth entries for each runner and a giant 85mm Edelbrock/Ford throttle body. As Raymond explains, "the car has made 375 horsepower at the wheels on C&V Performance's Dyno Dynamics chassis dyno running just over 1.1 Bar boost - Paul's car needs a fair bit more boost to reach the same sort of output."
We should probably reflect on that power output a bit more - 375hp at the wheels is roughly a 170 percent power increase over standard!
Engine management is the task of a MoTeC M800 programmable ECU, which takes an engine load input from a MAP sensor and enforces a rev limit at around 9000. A set of 1000cc HKS injectors, a HKS fuel pressure reg and twin Bosch Motorsport fuel pumps drink from a surge tank. Paul tells us one thing yet to be finished is the fitment of a fuel cooler; apparently the juice gets a bit hot after cycling through the fuel system. Delivering spark energy is a collection of M&W coils.
The RWD driveline is now slip-free thanks to the fitment of a grippy twin-plate HKS. The standard SW20 MR2 Turbo triple synchro transaxle is enhanced with a remote fluid cooler as well a TRD clutch-type LSD.
And as we all know - some from experience! - power is nothing without control.
With ample grunt on tap, Raymond spared no expense upgrading the MR2's suspension and brake package. The standard struts have been replaced by fully adjustable Drummond units (the first set made by the company), while adjustable GAB swaybars allow further tweaking of handling attitude. Furthermore, the suspension has been fully rose-jointed, bump-steer characteristics have been altered, the car has been corner weighted and castor has been increased by a massive 10-degrees - this, Raymond says, tremendously improved turn-in.
Paul has also added extensive bracing in the engine compartment, which tightens up the chassis in addition to the GAB front tower bar.
And no matter how quickly that stroked and turbocharged mill can fling the little MR2 to the next corner, Raymond can have confidence in the braking system under his boot - impressive 6-pot AP calipers and monster discs at the front and slightly larger rear discs with relocated calipers at the rear. Both ends employ Ferodo 3000 pads.
Apparently, Raymond has a fair collection of wheels at home but those seen here are 17-inch Volk products wearing track-ready 215/45 and 235/45 Dunlop D10Js. Seventeen-inch wheels, by the way, are the minimum size required to clear the giant front brakes.
Inevitably, there are a few telltale external signs that this isn't your average MR2. There's an aftermarket front 'bar, carbon fibre bonnet, carbon fibre side air intakes (for the air filter and gearbox fluid cooler), a cut-out in the front bumper (for the coolant radiator), adjustable rear wing and the aforementioned WRX intercooler scoop. Another tricky feature is the Ferrari-style louvered engine cover, which - according to Paul - lets the engine run a bit cooler. Looks killer too!
Indoors, the MR2's 2-seater cabin doesn't leave room for a great deal of space, but Raymond has made the most of it by fitting a half cage, Recaro carbon fibre race seat, race wheel and a few gauges - yet to be changed to a computer display with numerous sensor inputs.
At the time of writing the car hasn't made much of an appearance on the racetrack. Professional driver - Warren Luff - took the car for a spin around Wakefield to suggest some improvements and came back with one main point - "it has a lot of power!" Raymond tells us the car is a bit nervous cornering at high speed, but - as always - the car requires discipline to drive fast. Once he is fully accustomed with the car's somewhat accentuated characteristics, it will surely be one of the ultimate weekend racers.
This car finds its place in the garage just in case Raymond needs more of a speed hit after driving his rare ST205 Toyota Celica GT4 Group A and (modified) Japanese-import MR2 turbo on the street!
BD4s Service Centre