First published in the January 2003 issue of Street Machine

This LJ GTR is visually sensational, coated in the deepest, glossiest, dog-donger red imaginable and slammed to the ground on Weld rims and fat rubber. Most of us can comprehend that kind of sweetness, but getting your mind around a 600hp Holden 202 is a little more difficult. If you doubt the power figure, just check out the 1200kg car’s current PB down the quarter – 9.92@135mph!

West Oz-based racer and mechanic for tuning shop Formaz, Mick Munro is here to tell you it is possible turn the humble 202 into a real screamer and you don’t need a truckload of exotic components to do it. Plenty of people told him it couldn’t be done and it would have been easier to go the tried and true V8 route, but he wanted to try something different so he hit the old 202 with some turbo boost.

Mick started with an early Garrett kit, using twin SU carbs for induction and no intercooler. This set-up ran as quick as 11.81@114mph, which is plenty fast, but Mick wanted more. He came up with his own a recipe for force-fed bliss, the key ingredients being a Garrett TO4B turbo, 42mm external wastegate, fabricated exhaust manifold, VK EFI inlet manifold, truck-based intercooler, Trust blow-off valve and a bunch of aluminium intercooler pipework. Mick complemented this with the appropriate fuel and ignition system upgrades and a Wolf 3D programmable computer.

Now he had the external goodies to make some serious grunt, so all he had to do was convince the internal engine components to come along for the ride. Don’t think for a minute that Mick had to spend a motza either, as the specs are surprisingly basic.

When it comes to building Holden sixes, Mick favours the Blue motor, the last of the line. The crank is a balanced factory unit, while the rods are shot-peened stockers. Most heavy-hitting turbo motors use forged pistons, but in this case the slugs are simply decompressed cast items as used by HQ racers, giving a compression ratio of 7.5:1. Rod bolts, rings and bearings are all ACL.

The valve train is a particular area of weakness for Holden sixes, so Mick took the tried and true path of using Yella Terra roller rockers, Yella Terra valve springs and hardened pushrods to toughen it up. Harmonic balancers have also been a problem for these engines since the XU1 days, so Mick fitted a Romac unit as insurance. Even so, Mick generally observes a rev limit of 7500rpm to keep body and soul together.

A key player in the combination is the Yella Terra 12-port aluminium head, which apart from being port matched, has been left in its out-of-the-box specs. A copper head gasket, o-ringed block and stud kit keeps combustion pressures sealed in.

The finishing touch is a Wayne Green cam, which Mick describes as a ‘secret little solid.’ With 30psi up its clacker, the humble little blue motor now makes plenty of grunt – some 403hp at the wheels. This translates to some 600hp at the flywheel, and helped drop times to 11.52@119mph. Nice, but nowhere near fast enough, the culprit being wheelspin. Mick grabbed the gas axe and started cutting out the floor of the genuine, rust-free GTR before he really stopped to consider what he was actually doing.

“I freaked out when I stopped and looked at it, but I don’t regret it now,” he smiles. He fabricated a rear clip and wheel tubs, bought a four-link kit from McDonald Brothers, and located the Ford nine-inch diff, complete with 28-spline axles, a set of 3.7:1 rear gears and a mini spool. Back on the track, the Torana could now put all those glorious ponies to good use and achieved its current best time of 9.92@135mph.

“Without a trans brake, I hold it on the pedal at the start line, bring the revs up to where it’s just coming onto boost at around 3500rpm,” he says. “The two-speed Powerglide has a 4500rpm stall converter, so I can hold it there,” he describes. At about the 100-foot mark, he palms it into second then sits back for the rest of the ride.

There is plenty of room for more. Mick plans to fit a monster TA45 turbo, bump up the compression to 9.5:1 and switch to methanol in search of even more grunt. By that time, the car should be knocking on the eight-second zone and Mick will look at turning Japanese.

“I’d like to try a 2JZ-GTE from the late model Toyota Supras,” he says. “They can make heaps of power with stock internals, so it would be interesting to push the limits!”

BOLT-ON BOOST

This is what was required to build the EFI turbo system for Mick’s 202 (note, prices are from 2003):

• A turbo. CAPA supplied a Garrett GT3040, rated up to 600hp for $2960
• A wastegate. Rare Spares 45mm Turbosmart unit for $740
• An exhaust manifold. Mick’s is made from 3mm mandrel bent steampipe. This kind of thing can cost $700 or more from your local turbo workshop
• An inlet manifold. Blue motor owners are lucky that the VK EFI manifold is a nice bit of gear from the box
• An intercooler. Around $1300 for a 600hp, custom unit from ARE Intercoolers
• A blow-off valve. Rare Spares Turbosmart unit from $329
• A big fuel system. Mick used six injectors from a turbo RX7 ($70 each) and a fabricated fuel rail. Other goodies include a Malpassi rising rate fuel regulator ($195), surge tank ($120+), primer pump (up to $200), and a pair of big mutha Bosch fuel pumps ($350+ each)
• A programmable engine management computer. A Wolf 3D like Mick’s cost around $1395 with handset, plus the appropriate sensors

MICK MUNRO
LJ Torana GTR