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Engine Ecstasy - VVT-i Supra Turbo

We all know about the JZA80 Toyota Supra - but we've gotta have a bit of a rant over the latest VVT-i twin-turbo engine...

Words by Michael Knowling, Pix by Julian Edgar

Click on pics to view larger images


This article was first published in 2002.

We'll apologise for rabbiting on in advance. But we've got to tell you, the post-1998 VVT-i version of the Supra 2JZ twin-turbo 3.0-litre six is - without doubt - the best production turbo engine we've ever driven.

The Best

Stroke it along gently and the VVT-i 2JZ-GTE six behaves as 'proper' as a top-line Mercedes. Despite having 209+ kilowatts on tap from only 3-litres, there's absolutely no hint of lumpy camshafts or an all-or-nothing turbo system. The only on-going reminder of the engine's potency is its throaty exhaust burble from out back. It sounds sensational.

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Throttle response (via the ETCS-i electronic throttle) is immediate and comes backed with a progressive snowball of torque. And, no matter what revs you've got the thing lumbering at, there's never a time when you have to row down through the ratios to find accelerative urgency - certainly a rare enjoyment in a turbo car.

On paper, the sequentially-turbocharged 3.0-litre VVT-i 2JZ-GTE is credited with a long-trunk'd 451Nm of torque at 3600 rpm; to give you a comparo, an R32 GT-R makes 355Nm, an Audi S4 twin-turbo 2.7 boosts its way to 400Nm, a Liberty B4 generates 320Nm and an Evo 6.5 kicks out 373Nm.

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N-o-w do you get the picture how much grunt the mega-Supra has on-call!?

Largely thanks to its sequential turbo operation, the RZ's low rpm torque is amazingly strong - but keep your foot buried and you'll find there's bountiful Nm to be enjoyed in the top-end too. Maximum power output is a foregone conclusion - it's the Japanese regulation 209kW (which the Supra attains at 5600 rpm). As is common, though, the general consensus is that 209kW figure is a bit understated...

The Advantage of VVT-i (Variable Valve Timing - intelligent)

Toyota's 'basic' twin-turbo 2JZ-GTE produces 209kW at 5600 rpm and 440Nm at 3600 rpm. The VVT-i variant has identical listed power and generates only an extra 11Nm; so what's the big deal, you ask?

Well, the VVT-i system's emphasis is on economy, emissions and, most importantly, driveability - giving maximum throttle response and a linear spread of torque from idle to the 6800 rpm redline.

The Supra's VVT-i system infinitely adjusts inlet cam timing over a full 60-degree range. Cam orientation is determined on the fly with rpm, throttle position, engine load and coolant temperature inputs taken into account. Physically adjusting the camshaft angle is a piston-type actuation system that's hidden inside the bulge on the leading end of the cam cover.

You can find similar VVT-i systems fitted to various other Toyota-developed vehicles - everything from a 1.3-litre Echo to the Lexus LS430.

Note that - even without VVT-i - the Supra's sequential twin-turbo system enables the 2JZ to deliver a stupendous amount of torque down low. The non-VVT-i engine can crank out an incredible 380Nm at only 1300 rpm...

Quite obviously, this was an already brilliant engine to start with!

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Our test Supra RZ-S (supplied by Melbourne's Sports and Luxury Cars) could shift its 1500kg mass quicker than we thought it would with 'only' 209kW under the bonnet. This really becomes apparent in high gears, where the car accelerates tremendously smoothly - power simply builds and builds to the point where the flashing-past scenery takes your breath away. The standard 180 km/h speed limiter cuts in when the ball's only starting to roll.

Thankfully, power delivery has been sorted so there's absolutely no 'rush' anywhere in the rev-range - something that could otherwise send such a car spearing off sideways into the scenery...

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Having said that, the Supra RZ's biggest shortcoming is its lack of traction. Our test vehicle came with the standard 6-speed Getrag gearbox, which is combined with a Torsen LSD (note that a 4-speed automatic option was also available on the RZ-S). No matter how tricky its Torsen LSD is, however, the standard 245/45 16 rear tyres are easily toasted.

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Light-to-moderate wheelspin flashes a traction light in your face and the control system does a fine job of trimming torque in the search for adequate grip. We're not sure whether the traction control system controls boost, cam timing, ignition timing and/or the electronic throttle, but - whatever it is - its operation is quite subtle. It doesn't completely-and-utterly turn the power tap closed.

Severe wheelspin (which is easily induced on a greasy or wet road) is dealt with in a very different way. The traction light goes into disco mode and the system automatically reverts to 'snow'. Snow mode dramatically reins back the rate of torque increase at the back wheels, virtually eliminating any chance of wheelspin and - in the process - knocking a heap off performance.

Of course, if all this electronic intervention sounds like a cold blanket for fun, you can always switch the traction control system off!

Oh, yes, and the rest of the car...

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Toyota's imported JZA80 Supra is well known to AutoSpeeders, so there's not much point in going back over old details. In short, it still looks sexy, it's still got appalling interior room and dreadful visibility. We'd never contemplate buying a JZA80 Supra if we had to carry any more than 2 people or a semi-decent amount of luggage.

As we've already established, the good ol' rear-wheel-drive chassis may have intrinsic limitations (ie lack of traction), but the purists love the RZ's tech-specs. Alloy double wishbone suspension front and rear provide balanced handling, and later models also come equipped with REAS - Toyota's reactive absorber system. Dissipating forward motion into heat are ventilated 322mm front discs with 2-pot calipers and solid rears with single-potters. ABS is standard.

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But, of course, it's the late-model Supra RZ's motorvation - the torque - that really grabs you by the shoulders. Infinitely variable inlet cam timing, DOHCs, 24-valves, EFI, air-to-air intercooling, sequential twin-turbochargers and electronic throttle control - this is one of the most sophisticated powerplants on Earth and, damn it, every hour of its development has been well worth it.

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And if you can't afford to buy the whole car, keep a keen eye peeled for one of these engines in half-cut form at your local Japanese import wrecker!

Contact:

Sports and Luxury Cars
+61 3 9753 5799

www.sportsluxurycars.com.au

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