1UZFE Lexus V8 Supra Transplant
Over the past 3 years or
so I have wired over 20 Lexus V8 transplants into a variety of
things, with a plan of using one in my 1934 ‘Ford’ Woodie
Project. Given the ever increasing timeframe of the Woodie
project, I figured it was time I did a ‘quick and dirty’
conversion of my own. This came about for a number of reasons:
- I was getting tired
of being hassled for not having one of my own.
- I needed to
actually complete a project - having had three projects die
in recent years I was beginning to feel like all my projects
- My daily Driver 4WD
turbo GT4 Celica despite being a huge amount of fun was
going to need significant TLC and $$$ to keep it going.
- A better tow car
would be handy.
- Because I could.
I seriously considered a
van or a ute from a load carrying etc perspective, but decided
against them due to:
- Initial vehicle
cost compared to other body options.
- Poor comfort
compared to a car (I was driving over 500 km a week to and
- Poor handling
compared to a car.
For the past few years I
have been eyeing up 70-series Supras (1986-1992) as a donor for
the Woodie suspension, gearbox etc. Consequently I had been
buying dead ones and stripping them for the bits I needed, along
the way discovering the subtle variances in hardware between the
A couple of years back I
happened to have a rolling Supra shell (less engine and
gearbox), Lexus V8 and a portable engine crane in the garage all
at the same time (as you do). One thing led to another and 30
minutes later I had the V8 sitting in the engine bay. Much to my
surprise it fitted in really nicely and looked like a conversion
would not be too difficult.
I thought nothing more
of it until about 18 months ago when it became apparent that I
would really need to do something about a new daily driver in
the near future.
So, last year I ended up
with converting both a 1990 Supra for myself and a 1986 one for
a friend. Mine is a 5 speed facelift wide body; his is an early
model stock body Auto. It is really interesting comparing the
two finished cars – but first things first.
Best engine (but also the rarest it appears) to use is from a
Soarer. This is because it has a rear sump, which clears the
front cross member. Some minor trimming needs to be done on the
engine mounts on the subframe to allow the sump to fit past on
installation – ultimately you effectively widen the gap between
them by ~20mm. The ironic aspect is that the sump clears fine
once in place (the engine is narrower where the mounts are
located), it is simply a fact of there not being enough width to
allow the sump to fit past while the engine is lowered.
I bolted the engine to
the factory W58 Supra 5 speed using one of my adapter plates, a
lightened billet flywheel and 2100 lb clamp clutch assembly. The
gearbox remained on its factory rear mount and retained its
driveshaft. I sat the motor on the subframe via a ~20mm thick
piece of wood and fabricated engine mounts to suit, ensuring the
engine was level and centred in the engine bay. This resulted in
the engine mounts being exact mirror images of each other.
I also mounted an
external slave cylinder on the same side of the V8 bellhousing
as had been in the car, which meant the standard plumbing mated
The factory brake booster was too large a diameter to clear the
rear portion of the right hand cylinder head cam cover.
Fortunately the large size of the booster is in part due to it
having to act as a vacuum reservoir for period when the turbo
engine is on boost. It turns out that a standard Hilux booster
turned upside down has identical mounting points and clears the
A critical step is
ensuring the new booster has identical pushrod lengths to the
old one (otherwise the brakes won’t work correctly). This is
achieved by measuring the original booster pushrod dimensions
and adjusting the new booster to suit. The factory brake master
cylinder was retained, with the net result being a slightly
heavier (but still very acceptable) brake pedal.
Despite the engine being
significantly lighter than the 6 cylinder it replaced the brake
balance remains fine. Note that the 2 litre turbo cars have
~270mm front discs, whereas the 2.5 and some later 3 litre
turbos have 305mm. I suspect the export 3 litre early models
also had the bigger discs, but the Japanese domestic did not.
Rear discs are the same on all models.
The V8 is a close fit in the engine bay, hence we used standard
mid sump ‘crown’ headers. These are very poor from a flow
perspective, but definitely compact. The left hand unit dump
pipe had to be shortened slightly to clear the firewall but they
otherwise fit well with factory heat shielding being able to be
retained. From the headers we fitted a 2½” system with an 18”
resonator located roughly under each front seat (there is a
suitable recess in the floor pan on each side) before merging
into a singe 3” pipe, with a final muffler under the boot floor.
If you do not have
access to a crown exhaust manifold the standard ones can be
shortened to fit. Extractors would be better but need huge
effort to make given the tight space to work in.
In both cars the factory radiators were retained. My car was a
1JZGTE 2.5 litre twin turbo; Jason’s was a 1GGTE 2 litre twin
turbo. The radiators appear identical and easily cope with the
cooling load. I run the factory variable speed computer
controlled hydraulic fan, using the 1UZFE on engine components
and ECU, with the 1JZGTE fan, reservoir and fluid cooling
system. Jason has 2 x electric fans mounted behind the radiator.
Aftermarket flexible hoses were used, with a slight complication
arising from the radiator and engine fittings being different
diameters. New hoses and tight hose clamps resolved the issue!
The factory power steering in both cars was retained,
effectively by splicing the V8 power steer pump into the car
system with new hydraulic hoses. My car has variable assist
speed sensing steering, which works flawlessly. Both cars
utilise the cooling loop in the bottom of the radiator
originally intended for automatic trans cooling. My car was
converted to 5 speed during the engine swap, whilst Jason
installed a HD aftermarket trans cooler.
Jason actually used a mid sump crown engine, which supplied the
correct gearbox, headers and (lack of) hydraulic cooling fan
system, but the sump location required significant cross member
and oil pan surgery – use a rear sump if at all possible. His
engine choice resulted in the oil filter being located towards
the rear on the left side of the engine block. This is
accessible from under the car, but it is tight.
My car has the factory
front mount, which is great for access, however, it interfered
with the sway bar. Ironically the bend in the sway bar to clear
the original engine sump posed the problem.
I modified a rear oil
filter mount from a Crown to fit, however, the fuel lines from
both the car and my engine were in a similar location and
ultimately the front mount filter was a better solution than
trying to re-route the fuel lines. I had a sway bar custom made
without the kink. This cost $300 and clears the oil filter fine.
The rear sump engine has fuel supply and return low on the LHS
of the engine block towards the rear. This lines up very well
with the factory car lines but leaves little room for hands to
get in to access a rear mounted oil filter as detailed above,
especially with the clutch slave cylinder ending up in the same
vicinity. Jason’s mid sump engine has fuel supply and return on
top of the engine, which were reached by extending the flexible
hoses, thus leaving room below to access the oil filter from
under the car.
I would still prefer to
use the rear sump engine given the easier and neater fuel and
oil filter access, and accept the cost of a custom sway bar. The
factory fuel pumps are more than adequate.
Jason retained the factory aircon, effectively splicing the V8
compressor into the original system. The system has yet to be
final plumbed and charged, but there is no reason to expect the
climate control system would not work.
The heater was successfully connected using a common ‘hockey
stick’ shaped hose (I think from a Holden) cut to length and a
modified factory hose.
Jason’s car uses a standard Crown transmission however he
swapped the tail housing for the Supra unit. This provided him
with a speedo drive on the correct side. Whilst the back of the
trans was off he also changed the driven gear to suit the final
diff ratio so the speedo remained accurate. The trans bolted
straight up and the stock driveshaft fit. The entire Supra
shifter assembly was used to shift the Crown trans.
The trans dipstick
became a challenge to bend to clear the firewall, especially
with the fuel lines in the way. If I did it again I would
investigate the viability of swapping the Supra trans oil pan
(and dipstick tube) onto the Crown trans to see if it cleared
Note you should use a
Crown trans as it has a standard yoke. A Lexus trans (with a
rubber donut output) will require a custom driveshaft and
possibly a modified gearbox mount. We also used a SC/LS400 ‘U1’
bellhousing as opposed to the Crown ‘U2’; this enabled the
engine and trans to both be upright as opposed to having them
skewed ~7 degrees to each other.
Being originally a 2 litre, Jason’s car came fitted with a 4.55
ratio open diff. This was swapped for a 3.9 ratio 4 spider LSD.
Given that my car was originally a 2.5 litre twin turbo it came
with the rare 3.9 ratio Torsen LSD. Generally 2.5 and 3 litre
Supras have a 3.9 ratio diff, with some 3 litres running a 3.7.
In hindsight a 3.7 might be a better ratio (they are relatively
rare) as the V8 easily has the torque to pull a taller final
drive ratio. Then again, the acceleration wouldn’t be quite so
Note the manual and auto
cars tend to run the same diff ratio for a given engine. In
theory Jason’s Supra is running the exact same overall gearing
as the Crown sedan (it has identical tyre size), however, the
Supra is ~200kg lighter hence the ability to run a taller diff.
The V8 trans also has (I believe) a .70 top gear, whereas my W58
has a 0.78, which results in my car pulling slightly higher revs
Both car’s suspension was left stock; Jason’s car had
functioning TEMS (Toyota Electronically Modulated Suspension –
kind of electronic active shock absorbers) whereas mine had
factory standard suspension. Both cars ended up approximately
12mm higher front ride height after the conversion due to the
lighter engine etc. The suspension has been left alone, with
just a wheel alignment. Ideally I would put lower springs in,
but end of the day the car is just a daily driver and it handles
fine. The slight increase in height is not really noticeable.
Both cars use the factory plastic intake resonance box directly
off the throttle body. This required a seam on the rear to be
filed down to clear the brake booster. The unit was used as it
resulted in the hose connecting the air flow meter to the engine
to clear the strut tower. The AFM was attached via a 45 degree
80mm diameter silicone bend to the resonance chamber.
A K&N type air filter
was fitted below the right headlight ahead of the radiator
support panel and connected to the AFM via some plastic adapters
and hose from Supercheap Auto in Jason’s case and via some 3”
aluminium tube and cheap silicone bends from Repco in my case.
Basically after I plumbed my system Jason found the Supercheap
components and achieved the same outcome for 1/3 the cost!
The difference in
performance between having cold air induction vs. engine bay
induction was quite noticeable. The AFMs are not attached to the
car, being held in place by the pipe work. There is a convenient
hole in the radiator support panel to pass the tubing through.
The factory V8 alternator fitted fine, and so the output and 3
pin control plug were spliced into the original car loom. The
battery was able to remain in its stock location.
Both cars use factory engine management, spliced into the car
wiring. Jason’s auto relies on the secondary speed sensor (in
the speedo head) to trigger the trans shift points. This is
because the primary sensor (in the trans) is actually for the
ABS system, and the signal is processed via the ABS computer
before being fed to the trans computer. Given the lack of the V8
ABS system we had to rely on the back up sensor. This works
absolutely fine, but produces and error code to tell you the
primary sensor is MIA.
I won’t go into any more
detail on the EFI wiring, other to say it was fairly straight
forward (in relative terms!), especially as both cars were
injected originally, hence the power feeds and fuel pump control
systems were largely all there. We took the opportunity to
integrate high security rated alarms into the wiring, which will
make the cars extremely difficult to steal. Hopefully.
I aim to fit factory cruise control, using basically the Supra
vacuum based system with the V8 actuator spliced in. My car
wasn’t fitted with cruise initially and none of the wiring is
present, so I will have to recreate the entire system using
parts from one of the donor cars. I fully expect it to work, as
I have wired 2 x Surfs with factory cruise spliced into the V8
and they worked fine.
Both cars drive ‘like a bought one’ and apart form the blue
silicone hoses in the engine bay and some misc. brackets for the
fans in Jason’s car could just about pass as factory in
appearance. Ironically all the components were in production at
the same time – Toyota could have easily built a V8 Supra in the
early 1990s, and based on our experiences it would have been one
hell of a car.
The handling and braking
performance of both cars is improved due to the lighter weight
over the front wheels and the engine centre of gravity being
further back to boot. My original 2.5 litre twin turbo engine
made slightly more power and torque, but the auto robbed it, the
lag was horrendous and the power curve didn’t have a lot of
The V8 manual is
effortless, instantaneous and fun. It is also around 15% more
economical than the 2.5 turbo auto. Both Jason’s car and mine
return similar economy, however, I have a marginal performance
End of the day, a fairly
straight forward conversion, especially considering the rest of
the vehicle is more than adequately engineered for the task.
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