One of Japan’s all-time best supercars is the JZ80 Toyota Supra twin-turbo.
Toyota held nothing back with the design of the 3.0 litre DOHC sequential
twin-turbo 2JZ-GTE engine; sure, it might have the same 206kW listed power as
the Nissan RB26DETT, but the Supra engine is convincingly better overall.
Anyone who argues otherwise simply hasn’t driven one!
So when Ivan Serensen of Toowoomba, Queensland bought this 1992/1993 Supra RZ
back in 2001, he was pretty much bowled over by it.
"It’s as easy to drive as any hatchback, the 6-speed is wonderful and it
feels great through the corners. I also love the shape," he says.
And, of course, there was plenty to talk about in the power department.
Ivan’s Supra arrived from Japan fitted with a HKS exhaust, HKS pod filter and
blow-off valve. Nothing extreme – just enough to let the engine breathe
unrestricted.
Interestingly, the engine developed a welsh plug leak with about 75,000km on
the odometer and the only way to replace it involved ripping off the
sophisticated sequential twin-turbo system. Not a fun job - not when it has to
go back together anyway... While Q Mechanical of Toowoomba had the turbos off
it was also apparent that the bearings were shot. It seems the car was poorly
maintained while in Japan.
Recognising his good fortune that the turbos didn’t let-go and cause engine
damage, Ivan treated both units to a full rebuild with steel turbine wheels to
replace the relatively delicate ceramic jobs. The resulting trade-off in
throttle response wasn’t noticeable.
Next, there was a strange intermittent problem with the ‘Check Engine’ light
coming on. Rob from Q Mechanical says this is a fairly common problem which can
be traced to a dry solder connection in the ECU. This took time to locate but
was a relatively easy fix.
By this time the car had seen some dyno time and it was obvious the bulk-rich
mixtures was reducing power. Rob tried one particular brand of aftermarket
computer (which, as it turns out, had never before been fitted to a Supra)
before moving to another brand which, at least, got the car running. The
programmable computer was piggy-backed to control fuel delivery only – Rob tells
us the Toyota ECU is very sensitive to tampering on the ignition side.
Unfortunately, the aftermarket management system lacked tuning resolution at
light loads – switching on the air-con or headlights caused the engine to run
lean. The only way around this was to tune the idle mixtures overly rich - a
band-aid fix for a fundamental problem.
At this point Rob spoke to Peter Hopkins from Advan Performance Centre in
Sydney and the decision was made to go for a GReddy e-Manage piggy-back
computer.
The e-Manage utilises the factory engine sensors and is installed as a
piggy-back to the factory management system. The base e-Manage allows adjustment
of only one variable – the input from the factory load sensor (in this case, an
airflow meter). The load input is altered at 5 rpm points using trim-pots in the
e-Manage body.
The e-Manage’s other features can be accessed only via the optional support
tool (which is a Windows-based software program). With the optional support
tool, the tuner has lap-top access to a 16 x 16 airflow adjustment map (based on
rpm and throttle position), real-time adjustment and map tracing, boost cut
limiting, basic data logging and more. Upgrade injectors and airflow meters can
also be accommodated.
Further, an optional injector harness and software package allows fuelling
adjustment in a 16 x 16 injector duty cycle table. An optional ignition harness
and software package provides a 16 x 16 timing map. Note that the injectors and
ignition can be driven directly from the e-Manage.
Rob says the e-Manage requires only slight modification to the vehicle’s
existing wiring loom and is easy to program via lap-top. The fiddliest bit is
installing each wire into the appropriate position in the harness plugs (the
wires and plugs are not connected when they arrive).
This Dyno Dynamics chassis dyno graph shows the before and after figures.
The red plot shows the Supra previously maxed at 175kW (234hp) at the wheels
and about 12 psi boost. Note the abundant grunt through the bottom-end – the
sequential twin-turbo system does a great job providing a meaty torque curve.
The blue plots – with the e-Manage fitted - show a peak power figure of 201kW
(269hp) at the wheels, an improved transitional stage between the primary and
secondary turbochargers and 12.5 psi peak boost (just 0.5 psi up on standard).
Note how power continues all the way to the rev limiter - we’re told ideal test
conditions have seen 216kW (290hp) recorded at the wheels.
With an easy 201+ kilowatts at the treads and a generous spread of torque,
Ivan is more than happy with his Supra’s ability to leap away from other cars
before they know what the hell is happening. Yep, more power would be nice but
now that he’s experienced ‘total torque’ there’s no way he’d rip off the
sequential turbo arrangement for a high-capacity single turbo. That’d be a
case of one step forward and two steps back. If anything, an upgrade
intercooler would be next on the ‘to do’ list.
For the foreseeable future, Ivan is content to continue cruising Toowoomba
claiming the scalps of cars with bigger power. The car is well-known by its
sinister black paint, distinctive rego plates, Veilside body kit and tri-spoke
18 inch wheels wearing 265 wide rear Michelins.
Inside, the fighter-like JZ80 Supra cabin scores carbon-fibre dash and
console panels, a carbon gear knob, aluminium pedals and a leather/timber Momo
wheel. There’s also a Sony head unit and red/black seat covers, which protect
the trim and complement the red rimmed wheels.
It mightn’t be the wildest Supra of all time but it does prove what can be
done with relatively few mods. The idea of buying the fastest production car you
can get your hands on and giving it some light tweaks never looked so good!
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Footnote
Unfortunately, Q Mechanical workshop closed shortly after our photo
shoot. If you are interested in the GReddy e-Manage, contact Advan Performance
Centre in Sydney. The latest models are also available with knock sensing, boost
control and other features.
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Contact:
Advan Performance Centre +61 2 9647 1326
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