Ever since Lexus
offered the GS300 in the U.S.- the dawn of Lexus Tuning was at hand. Looking enviously at the Japanese Specs-
Toysport had drawn plans on what
can be done. The GS300 known as the
Aristo in Japan is available with Toyotas’s 2JZGTE Twin-Turbo engine. This is Toyota’s premium performance
engine. These engines are rated at 280 HP (primarily for insurance purposes and
agreement among Japanese engine manufacturers). The US 2JZGTE (with 550cc injectors vs.
Japan spec 430cc) is rated higher at 320HP. Since we have done an SC 300 2JZGTE U.S.
conversion before- a walk in the park, we thought.
The owner who used to
drive Honda/Acura had bought the Lexus after he crashed and witnessed how flimsy
the Honda/Acura bodies were. He
“upgraded” into a Lexus, but wanted more- a real Grand Touring
car.
NO- a 2JZGTE with the
factory Twin-Turbo will not work, despite all those pictures in the
magazines. The rear turbo hits the
firewall and short of removing the AC / heater behind it- a single turbo was the
only way to go. We had originally
looked at the GS300 engine bay (and all the Japanese Aristo pictures), but the
firewall shape is imperceptibly different- it protrudes an inch too much. To use
the 2JZGTE factory twin-turbo for these older GS models the only was is to make
new turbo manifolds.
Since we were
committed, more frustrated, in making a street scorcher and the engine was
already in- we dropped the factory twin-turbos and opted for the HKS turbo kit.
We first tried the HKS T51R-KAI (800 HP) kit, but the manifold had fitness
problems in the chassis. We settled
on the HKS TO4R (650 HP) single ball-bearing turbo kit. The stainless manifold fit perfect- but
the down pipe in the kit was unusable- a new one had to be fabricated. After the conversion on an SC we had
done, this project have become a total complete custom turbo
install.
We were originally
concerned about driveability, but the HKS TO4R was remarkably smooth engaging-
the ball bearing unit really adds a lot in the power delivery. Of course there was more than enough HP,
considering the owner only wanted about 400.
We retrofitted to the
Japanese oil pressure driven engine fan…because we had the parts lying around-
works wonderful and quiet. For the
drivetrain we upgraded to the factory turbo automatic transmission, which
required a modified and reinforced propeller shaft.
We planned on a street
legal conversion for this car, but when we lost the factory turbos…plans quickly
changed. We are making the correct
manifolds to use the factory twin turbo set-up- and meet all the smog
requirements. The 2JZGTE installed
in this car is a U.S. model and so- it has to have the factory
turbos.