Big Boy MR2

Of all of the 2.0 litre turbos, one of the most overlooked is the Japanese market SW20 Toyota MR2 Turbo. And, curiously enough, the turbo ‘2 is one of the most potent - on paper, anyway. With the Celica GT4-type 3S-GTE pumping out 162kW and a kerb weight around 1250kg, the MR2 has a great power-to-weight ratio. Factor in MR traction and exciting handling and you can see how the little Toyota deserves more attention.

Well, here’s an example that has received plenty.

Owned by Gavin Lee of Melbourne’s Technic Tuning, this ‘91 SW20 MR2 Turbo was imported from Japan and arrived in the Gavin’s care in 2000.  “The car was completely standard when it arrived and I thought it went really well, especially through the twisties,” he says.

So where did the motivation to modify come from? Simple. Gavin has access to a fully equipped dyno workshop and simply cannot leave things alone!

Initially, the car was enhanced with basic bolt-on mods. A high-flow exhaust and air intake along with an aftermarket boost controller gave the car a great on-road improvement. This was highlighted with repeated low 13 second quarter mile passes - on street tyres.

Unfortunately, an engine failure occurred not long down the track.

“I think it made one too many passes,” says Gavin.

With a 3S-GTE full of melted pistons, Gavin gave it a full teardown and rebuilt it with more durable Aries forged pistons. Note that these deliver a static compression ratio of 9.0:1, which is higher than standard. Gavin says the aim was to achieve as much bottom and mid-range torque as possible - even if that meant slightly less top-end.

The Aries pistons join forces with Eagle rods and ARP rod bolts. The crankshaft was also lightened for maximum throttle response. A high-flow water pump was also installed.

On top of the strengthened 2.0 litre bottom-end is the Yamaha-designed 16 valve DOHC head featuring port work, 1mm oversize valves, mild camshafts, heavy-duty valve springs and a bucket-and-shim type actuation system. This is well suited to high rpm operation. The head is torque’d down onto a HKS 1.6mm gasket. An in-house fabricated catch can is also visible under the engine compartment lid.

Bolted to the exhaust side of the head is the Toyota cast iron manifold that’s been match-ported. The standard manifold flows enough for most applications, so why bother changing it? Gavin also refrained from selecting an oversize laggy turbocharger - a high-flow T04E with internal wastegate is enough to do the trick.

The turbine exhales through a 3 inch mandrel exhaust with a high-flow cat and a single MagnaFlow straight-through muffler. The front section of exhaust is thoroughly heat wrapped to improve performance and reduce under-lid heat. A large electric fan also serves to reduce engine compartment temperatures.

The induction system of a MR2 is difficult to arrange because of the mid-engine layout. Where are you supposed to pick up induction air and mount the intercooler?

Gavin solved these questions using a K&N filter mounted behind the right-side rear wheel and with a water-to-air intercooler from a late-model Celica GT4 Group A. This approach keeps the turbo to throttle pipe length to a minimum. The rest of the water-to-air system comprises a custom PWR front-mount radiator, a marine electric pump and a 5 litre reservoir. An A’PEXi twin-chamber blow-off valve is installed before the throttle.

The intake manifold is match-ported to the head and the standard throttle body is enlarged. Maximum manifold pressure is set to 25 psi using an A’PEXi AVC-R electronic boost controller.                        

Gavin hauled out the factory management system and put a MicroTech programmable system into action. Not only does this give more tuning flexibility, it also removes the restriction caused by the airflow meter and frees up some more under-hatch space.

Fuel delivery has been enhanced with 550cc injectors, an in-house adjustable fuel pressure regulator and a Bosch Motorsport fuel pump. The ignition keeps the standard dizzy arrangement working with a Fireball coil and MSD booster.                  

Driving through a lightened flywheel, 3-puck clutch and Exedy pressure late, the 3S-GTE delivers its goods through the standard MR2 Turbo 5-speed manual ‘box. The only change here is a TRD LSD.

At the time of photography the car was yet to receive its final tune but had already pushed out 220kW at the wheels - as measured on Technic Tuning’s in-house Dyno Dynamics chassis dyno. Gavin is hoping for a low/mid 12 second pass still using street tyres.                              

An effective brake upgrade has been to fit the discs and calipers from a post-1996 ‘Generation 3’ MR2. A’PEXi GT-spec and N1 performance pads are fitted front and rear.

The mid-engine, rear-drive chassis of the MR2 Turbo is reasonably well balanced but it takes great driver control to get the most out of it. Gavin has installed Bilstein dampers from the Generation 3 model and Eibach 25mm lowered springs. Just 25mm, you ask? That's right - the visual impression of a lower stance comes from the full TRD wide-body kit. This gives the MR2 a completely new attitude. Fitment of the body kit was also the perfect excuse to re-spray the car in an attractive custom red mix. Wheels are Buddy Club P1 Racing Series 2 18s wearing 235/40 and 214/40 Falken rubber.

The 2-seater cabin has also been upgraded in accordance with the level of performance. Cobra Daytona II seats provide plenty of comfort and support while a new dashboard houses a Tom’s 260 km/h gauge cluster. Electronic Defi boost and oil temperature gauges can be found on an A-pillar pod and an oil pressure gauge is mounted on the steering column. A Victor F1 steering wheel, Sparco pedals, TRD short-shift and a compact 8 inch sub-woofer sound system have also been squeezed into the cabin.

Gavin says his ‘2 is an absolute buzz to drive but, unfortunately, he doesn’t get the opportunity to take it out as much as he’d like. “It just sits in the garage doing nothing,” he laments. There’s plenty of potential for more power – the engine is built to handle it – but there seems little point in going down that road.

And here’s where you come in.

“If there’s someone with a real passion for MR2s I’d be wiling to sell it,” says Gavin. The price? Around AUD$33k.

If you’re genuinely interested, Gavin can be contacted on 0401 694 882 or 0438 38 6669.

Contact: Technic Tuning +61 3 9495 1683