Japanese MR2 turbo information: differences and similarities
The big revisions were revision 2 for the chassis and revision 3 for the
engine (and ABS). The rest were mainly cosmetic.
- Revision 1 begins about Oct 89
- Revision 2, about Jan 92 (SW20-0059266 onwards)
- Revision 3, Oct 93 (SW20-0087386 onwards)
- Revision 4, Jun 96
- Revision 5, Nov 97 (ends sometime in 2000)
The model code for my 94 revision 3 Japanese MR2 GT (turbo) is E-SW20 ACMZZ.
The chassis number is something like SW20-0093123.
SW20 is commonly used to mean 'mark 2 MR2', even though in some markets some
non-turboed mark 2 MR2s had the SW21 prefix. The turbo engine in the MR2
turbo is known by the code '3S-GTE', but note there are a good few 3S-GTE
variants used in different cars over about a 15 year period.
Differences between revision 1 & 2 engines and revision 3
Just a quick list, do not take any of these as gospel:
(Please note a lot of significant chassis improvements were already made for
revision 2, although revision 3 ABS is probably much improved including the
addition of an accelerometer.)
Its rumoured that the USA never got the later improved engines,
even though the american version of the MR2 turbo was sold there until 1996
(in very small numbers after 1994 though).
- position and orientation of oil filter changed.
- different internal engine parts, e.g. pistons, con-rods etc.
- turbo charger changed from Toyota CT26 to CT20B (same intercooler though).
- boost pressure raised from about 10 to about 13 PSI.
- power output raised from 220 to 240 BHP.
- compression ratio slightly lowered.
- injector size increased from 430cc to 540cc.
- fuel cut threshold raised from about 12 PSI to about 18 PSI.
- head and inlet path completely redesigned. TVIS removed, 8 'independent
long ports' reduced to 4.
- throttle body increased from 55mm to 60mm.
- inlet valve lift increased from 8.2 to 8.7.
- different, smarter engine ECU, more tolerant of poor fuel, different
connector pin out.
- air flow meter removed.
- intake manifold inlet air temperature sensor added. i.e. after turbo and
- ECU now modulates the turbo VSV to achieve variable control of boost
pressure rather than either open/full or closed/reduced.
Control of boost now quite subtle when ECU is unhappy because of temperatures,
detonation, speed, etc.
- location of valve shims moved (someone said this was to stop problems with
them falling out). If the manual is to be believed, this makes adjusting the
valve clearances a much bigger job as on the revision 3 it
involves removing the
camshafts (might as well replace the timing belt whilst you're at it).
- exhaust valve clearance increased by 0.08 mm (probably. valve clearances
is one question I'd like answered direct from Japan. They are probably
the same as the UK GT4s, but it would be nice to be sure).
- oil pan changed from a one piece pressed steel part to a two piece affair,
the upper half being aluminium, the lower half being pressed steel.
- No. 1 compression ring now described as 'stainless steel' in GT4
manual/supplement instead of just 'steel'. Oil ring is described as
'stainless steel' instead of 'a combination of steel and stainless steel'.
No. 2 compression ring remains described as 'cast iron'.
- idle speed perhaps slightly reduced (need to check this out on a rev 1 or 2
car, my stickers say 750 rpm, I've a feeling rev 1 & 2 was 800 rpm).
- exhaust part numbers changed. Revision 2 part number for the front pipe
is superceeded by the revision 3 front pipe part number. Back-box part
numbers different. Unknown to me whether they are actually different.
- Coolant drain plug added on cylinder block (on older engines the manual
says to disconnect a by-pass hose when changing coolant).
Chassis number SW20-0087386 and onwards have the newer engines according to
the Toyota Electronic Parts
Catalogue for the Japanese MR2 turbos.
Differences between Japanese revision 3 MR2 turbo engine and UK ST205 (1994
onwards) Celica GT4 engine
Both engines are referred to by the same code: 3S-GTE. (However this doesn't
mean a lot since they've been making the 3S-GTE since the 1980s, in various
forms with various power outputs for various cars.)
The following parts have identical part numbers on the two cars:
Some part numbers seemed to be different such as:
- con rod assembly
- crank shaft
- cam shafts (both of them)
- block sub assembly (sorry I forget exactly what this means, just the actual
block itself probably)
- clutch friction plate
But I think you'll agree that the part numbers that match mean they are
very similar engines, if not identical. (Bear in mind it does seem that
Toyota may use different part numbers for identical parts). Other
information that I've come across seems not to contradict this view except it
does sound like the UK ST205 probably uses a steel exhaust turbine in the
turbocharger though where as both the Japanese MR2 turbo and the Japanese
ST205 use ceramic. Also, the UK ST205 probably has EGR
(Exhaust Gas Recirculation,
an emissions reduction thing), the Japanese MR2 turbo doesn't.
- turbo charger (but not on the Japanese ST205).
- engine ECU (obviously, although the connector pin-out is almost identical.
Probably the same PCB programmed with different software and with perhaps some
components left unpopulated).
- complete engine assembly (ST205 is 19000-88508, MR2 is 19000-88509)
- head sub assembly
- short block assembly
- intercooler (obviously!)
Almost none of the part numbers in the revision 3 MR2 turbo engine were
shared with the revision 2 engine. Revision 1 and 2 engines likely
have a similar relationship with the engines of the UK ST185 Celica GT4
as revision 3 does with the UK ST205.
Differences between Japanese and UK MR2s
An extensive list is yet to be produced, but most obviously its the level
of trim and extras. Hifi systems are different, seats are different, Japanese
have climate control and better ABS, that kind of thing. As far as I know all
MR2s were made in the same factory, so therefore plain economics dictate
that most of the mechanical parts are the same. Brake disks have the same
part number, brake pads look identical, rest of brake parts are likely to be
identical too. Wheels are identical. UK cars might not have the same shock
absorbers due to the lighter weight of their NA engine, not to mention rumours
of the ride being a bit softer in UK cars. Headlamps are slightly different
but are interchangeable. On the whole though the chassis are pretty similar;
claims by insurers or UK Toyota dealers that all the parts are different are
pretty much untrue.
Difference between Japanese GT and GTS models
GT seems to have steering front fog lamps, electrically folding
mirrors and some parts of the interior covered in dead cow as standard
instead of as options. i.e. GT and GTS are pretty much the exact same car.
Differences between revision 1 and revision 2 chassis
- Diameter of front brake disks increased from 258mm to 275mm.
Thickness increased from 25mm to 30mm.
Allowable wear increased from 1mm to 2mm.
- Diameter of rear brake disks increased from 263mm to 281mm.
Thickness increased from 16mm to 22mm.
(Allowable wear remains at 1mm.)
- Front tyres changed from 195/60 14 to 195/55 15. Rear tyres
changed from 205/60 14 to 225/50 15. Compact spare also changed due to bigger
- Suspension/steering geometry changed.
- Front strut bar changed so that caster is no longer adjustable.
- Speedo changed to use an electronic sender and not a mechanical cable.