When a go-fast workshop like Sydney's BD4s takes on a promotional car, you can bet that it'll be something extreme. A true 1-OFF to leave a lasting impression. Thomas - one of the directors of the business - snapped up this 1992 locally-delivered Toyota MR-2 after it had received a fair bit of mechanical lovin'. It had already been graced by a turbocharged version of the base 2 litre DOHC four - the 3S-GTE. The suspension and brakes - as you'll find out - had also been upgraded to race specs. All that the BD4s crew really needed to do was put some of their HKS goodies into place and it looked like a winner. Or, at least, that's how it first appears from the outside...
The already-worked Mister 2 that Thomas bought wasn't a car that needed merely a little tinkering on the side. It turns out that this sucker had been equipped with the 3S-GTE for good reason - the car had originally been used to race in the 1994 Aussie Cannonball Run! It was bloody quick too, crossing the line 7th outright. So - as you could imagine - there was a fair bit of healing and mending that had to be undertaken after the Great Race. The motor, for example, was purchased in many scattered pieces...
In the first instance, the 3S motor (the early ST185 model) was reassembled with a wheelbarrow load of good stuff - 8.0:1 CR Cosworth forged pistons, Carillo rods, a ported head (with stainless valves and heavier springs) and WRC-copy camshafts. The turbocharger was nothing more spectacular than a high-flowed stock unit. Paul (the other half of BD4s) says that this was a top motor, giving a really good spread of torque. But - unfortunately - the fellas had no end of dramas with it. The Yamaha-developed head was prone to flexing on the top of the block, causing a spate of popped head gaskets - a total of four! It was only by luck that the BD4s team acquired a later-model ST205 3S-GTE. It's appears to be pretty well similar to the ST185 motor, except it's proven heaps more reliable. Paul puts this down to differences in the DOHC cylinder head.
Note that the new engine hasn't seen as much internal working as the ol' ST185 motor - but it's plenty more powerful. How? Well, this engine is hung with a mega-serious turbo set-up - a full HKS kit, comprising a tubular exhaust manifold, 32/40 ball-bearing turbo and an external wastegate. Of course - being HKS - it's all top looking, top quality gear as well. And what's that big aluminium scoop on the boot lid, you ask? Well, open it up and you'll discover it's an air scoop for a monster 3-inch thick air-to-air intercooler. Interestingly, this is a fabrication by Melbourne's AVO workshop, originally designed for use on a Skyline GT-R. Induction air cooling is then further enhanced by a pair of 12-inch electric cooling fans underneath the humungous core. If you ever needed an example of a supreme intercooler configuration, here it is! Now - being a major distributor for HKS hardware - the BD4s guys were only too keen to display $1500 worth of HKS Racing blow-off valves on both sides of the 'cooler. Yep, these suckers are top shelf!
Yet another item that hangs out in the breeze is a moulded snorkel that puts induction air to the element of a HKS Super PowerFlow air filter. It's a set-up that works very well and looks ultra-trick. Blowing out all that the intake sucks in (and a little more) is a 3-inch mandrel exhaust off the turbo (with the first section of pipe heat-wrapped). Those dual polished HKS Super Dragger mufflers also fire out a wickedly aggressive exhaust note - especially when the car's steaming along on boost.
With a turbo system geared to see huge volumes of air shoved into the standard throttle body, the fuel and management systems were accordingly beefed up. 1-OFF features a MoTeC M4 ECU (with a stand-alone MAP load input) and a set of four 800cc SARD injectors. These are kept in supply of PULP thanks to a Nizpro fuel pump and a SX pressure regulator. There's plenty of scope for more power left in the fuel system.
As mentioned, the insides of the ST205 engine are pretty well stock. The only internal mods are a set of 272 cams, a port grinding job and - just to be sure - an HKS head gasket. Paul tells us the biggest limitation at the moment is the stock bottom-end. Still, wound up to a sunny 1.7 Bar boost, this motor has enough whack to stomp out a massive 270kW at the back wheels (on a Dyno Dynamics chassis dyno). On the road, it's a m-o-n-s-t-e-r MR-2. Boost creeps in late (at around 4500 rpm), full boost is reached at 5000 and, for the next 2000 rpm, it's 100% ballistic. Paul says that the turbo set-up can easily wind out to more than 7000 engine revolutions, but the mechanics much prefer to keep the stock bottom-end in one piece.
Copping the full 270kW force (plus drivetrain losses) is a Japanese-spec MR-2 GTS transaxle. This features a TRD LSD centre, and there's now a brass button clutch and a modified (for more clamping) pressure plate. Of course, a mid-engine'd, rear wheel drive, lightweight vehicle with 270kW at the tyres is a recipe for immense speed. It's also one that requires a fair hike in the how-do-you-slow-this-sucker-down department. 1-OFF is therefore pleasured with large diameter turbo brakes (which came standard on local models from '93 onward), HKS pads, HKS fluid and a set of braided lines.
Many car enthusiasts are well aware of the MR-2's unique handling traits. By all accounts, however, these oddities seem well and truly fixed. Warren Luff took Paul out for a quick spin around a racetrack and, apparently, Paul just about soiled his pants! With the car's competition-spec GAB struts, RS-R lowered springs and Whiteline adjustable front and rear swaybars, that's hardly a surprise. Especially when you take a peek at the rolling stock - Evolution Stitch 18s wearing sporty 215/35 Toyos at the front and 225/40 Falken GRBs at the rear.
From the outside, the BD4s MR-2 is over-the-top, overt and downright extravagant. If the lowered stance and 18s don't grab you as being anything out the ordinary, then the twin race stripes, stickers, external blow-off valves, scoops an' snorkels sure will! And on-board? Inside the MR-2 cabin is a couple of blue-winged Cobra race seats, harnesses, a suede steering wheel and an aluminium gear knob. It's the race essentials only - there isn't much room for anything else!
But is there overall room for improvement on this MR? That's a resounding "Yes!" according to Paul. The stock bottom-end has managed pretty well up until now - but there are plans to move to something a little more exotic. How does a HKS 2140cc stroker kit sound to you?
Like this MR-2 isn't a 1-OFF already!
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