Japanese MR2 turbo information and trivia

FAQ

Ben Formesyn has a good FAQ at http://www.btinternet.com/~netsurf/mr2t/mr2tfaq.html This page is meant to supplement that FAQ (especially for later cars) not replace it.

Revision dates

Revision 1 begins about Oct 89
Revision 2, about Jan 92
Revision 3, Oct 93 (SW20-0087386 onwards)
Revision 4, Jun 96
Revision 5, Nov 97

Model codes

The model code for my 94 revision 3 Japanese MR2 GT (turbo) is E-SW20 ACMZZ. The chassis number is something like SW20-0093123.

Engine

1998 cc, straight 4 cylinder, twin cam, 16 valve, EFI, intercooled, twin entry turbo.

Power

Revision 1 & 2: 220 BHP. Revision 3 onwards: 240 BHP.

The 240 Brake Horse Power figure is sourced from a '245 PS' figure in a Japanese 1998 Toyota brochure.

Weight

1260 Kg (source: 'Japanese Performance' magazine, Jan 2000).

Curb weight of the american MR2 turbo T bar car is listed in an american 1994 and 1995 Toyota brochure as 2888 lbs. That's 1310 Kgs. Hardtop car should be very slightly lighter though. U.S. brochure also lists coefficient of drag (Cd) as 0.31

Top speed

About 150 MPH. (160 MPH if you want to exaggerate). Speed limiter @ 119 MPH is often removed as soon as cars hit UK soil as part of speedo conversion. A genuine 155 MPH is quite possible in uncontrolled conditions (wind, gradient, etc). Speedometers on MR2s (and a lot of other cars) are designed to read between 4% and 8.5% over, so 155 MPH would read as about 165 MPH. Gearing prevents the car going much faster than 155 MPH, which is about 6850 RPM in fifth with standard size tyres, well beyond the peak power at 6000 RPM. Heat saturation of the intercooler from the prolonged wide open throttle is probably also an issue.

Acceleration

1/4 mile time is about 14 seconds, this coincidentally is also the 0-100 mph time. 0-60 is about five and a half seconds (bit of a stupid benchmark for such a car). I have a Japanese TV clip that seems to show a standard '245 ps' MR2 GT hardtop doing a quarter mile in 13.668 seconds (I don't understand Japanese and can't be 100% sure its a quarter mile and not a shorter metric equivalent or something though).

Oil filter

Toyota part number is 90915-10004 and costs about 6 pound (June 2000). Toyota part apparently has an anti-drain back valve to assist cold starts. Position of the oil filter moved from top of engine to bottom of engine for revision 3 (maybe the anti-drain valve isn't an issue for the later cars?).

Coolant

Ethylene glycol based anti-freeze with corrosion inhibitors suitable for aluminium engines mixed with distilled, deionized or soft water. Use 'toyota forlife' if you wish, but you don't have to. Those unfamiliar with MR2s should read http://mr2manual.teq.org/co-5.html or the appropriate section in an MR2 engine repair manual describing coolant filling procedures (note: the Celica GT4 is different in this respect). Bleeding the air out isn't rocket science, but air-locks are a common cause of overheating problems, which could be very serious if the driver ignores the temperature gauge and other warnings such as the heater not blowing warm air. Its not a job a DIY mechanic should fear though as long as they are aware that air-locks sometimes happen (warning: never use a mains voltage inspection lamp under the car when draining the coolant).

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:

piston
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

Some part numbers seemed to be different such as:

turbo charger
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!)

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). All other information that I've come across seems to support this view.

Almost none of the part numbers in the revision 3 MR2 turbo engine were shared with the revision 2 engine.

Differences between revision 1 & 2 engines and revision 3

Just a quick list, do not take any of these as gospel:

position and orientation of oil filter changed.
different internal engine parts, e.g. pistons, con-rods etc.
turbo charger changed from Garrett CT26 to CT20 (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 intercooler.
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). Note 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.

(Please note a lot of significant chassis improvements were already made for revision 2, although revision 3 ABS is probably much improved.) 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).

Chassis number SW20-0087386 and onwards have the newer engines according to the Toyota Electronic Parts Catalogue for the Japanese MR2 turbos.

Engine Repair Manuals

As far as can be established, there are no Toyota repair manuals or supplements or wiring diagrams available for the exact car in the English language (May 2000). It is my guess that for the engine the best choice is the engine manual for the UK Celica GT4 (although revision 1 and 2 owners do have the option of american MR2 turbo repair manuals instead).

Toyota part numbers are as follows:

RM164E - 3S-GE, 3S-GTE, 5S-FE engine repair manual (as mounted in ST182, ST184, ST185 UK celicas), Nov 89. Price: 15 pound 10 pence (May 2000).
RM266E - 3S-GTE engine repair manual supplement (as mounted in ST185 celica GT4), Aug 91. Supplements RM164E. Price: 10 pound 60 pence (May 2000).
RM396E - 3S-GE engine repair manual (as mounted in ST202 UK celicas and SW20 UK MR2s (non turbo)), Oct 93. Price 45 pound 41 pence (Dec 2000).
RM398E - 3S-GTE engine repair manual supplement (as mounted in ST205 UK celicas), Feb 94. Supplements RM396E. Price 15 pound 14 pence (Dec 2000).

So if its not obvious:

for revision 1 you'll want RM164E (and possibly a RM165E supplement which I don't own so can't comment for sure).
for revision 2 you'll want RM164E and RM266E (and possibly RM165E).
for revision 3 you'll want RM396E and RM398E.
for revision 4 & 5 you'll probably find RM396E and RM398E to be appropriate. I haven't heard of any engine differences between revision 3 and the later revisions.

I own all of the above manuals/supplements. The manuals are big thick books about an inch thick. The supplements are more like the thickness of a thick magazine.

If a UK toyota dealer can not be persuaded to order a repair manual even when you give them the part number, its perhaps best to take your business to a more helpful dealer.

Selected pages of a american turbo engine and body repair manuals are at: http://mr2manual.teq.org/

Body Repair Manuals

You've a choice between manuals for the UK non-turbo MR2 or the U.S. MR2 turbo. The latter are available by mail order from companies in the U.S. Don't forget american cars are LHD and I think they never got the later revision engine.

The exception is the gearbox. As far as I can guess the only English language documentation for the MR2 turbo gearbox will be for the american turbo. The UK non turbo MR2 gearbox may be similar to some extent but they are not identical though.

Toyota part numbers for the manuals for the U.K. cars are as follows:

RM182E - MR2 chassis & body repair manual SW20 series (for Europe & Australia), Dec 89. Price: 30 pound 90 pence (Apr 2001). Note, as a bonus, to my slight surprise this manual does cover transmission, clutch and electrical wiring diagrams, even though separate publications are listed for some of these and the situation may be different for the US repair manuals. Of course non of these things are identical on the turbo car, but in the absence of anything else it gives you a rough idea.
RM282E - MR2 chassis & body supplement SW20 series, Dec 91. Supplements RM182E. Price: 13 pound 97 pence (Nov 2001). Covers bigger brakes & wheels, power steering, revised geometry & suspension, airbag, updated electrics & wiring diagrams, etc.
RM379E - MR2 chassis & body supplement SW20 series, Nov 93. Supplements RM182E and RM282E. Price: 24 pound 15 pence (Aug 2001). Covers suspension, power steering, airbag, updated electrics & wiring diagrams, new front & rear bumpers/spoilers/lights (diagrams only), R134a air conditioning, etc. Note that the revised bigger brakes are covered only in RM282E and not in this supplement, making this book seem a bit expensive.
BRM025E - MR2 repair manual for collision damage SW20 series, Dec 89. Price: 15 pound 60 pence (Apr 2001). Contains some really useful information for proper crash damage and panel replacement repairs etc. For example the location, type and quantity of welds needed, body dimensions, etc.

So if its not obvious:

for revision 1 you should get RM182E.
for revision 2 you should get RM182E and RM282E
for revision 3 you should get RM182E, RM282E and, if cost is not an issue, RM379E.
for revision 4 & 5 I'm not sure what the situation is.

I don't think you need part numbers to order american repair manuals from american Toyota dealers, they don't seem to have an attitude problem about manuals over there.

Electrical Wiring Diagrams

The only accurate wiring diagram will be in Japanese. The american wiring diagram is good enough to be very helpful though in a lot of cases. For example in the past I've found this particular gif from http://mr2manual.teq.org/ewd.html to be very useful even if its not 100% accurate for my Japanese rev 3 turbo: http://mr2manual.teq.org/images/ewd_03.gif (380K and the quality of the scanning makes it very difficult to print, but its still been very useful in the absence of anything better.)

You may be able to find some pin-out information of ECUs by taking the cover off and reading the screen print on the PCB. Follow this link for the pin-out information screen printed on the PCB of my engine ECU.

Scans of Japanese MR2 turbo wiring diagrams can be found at: http://gtfour.orcon.net.nz/diagrams.htm

Removing trim

Plastic fasteners that are used to hold in trim such as the carpet in the boot can allegedly be removed by pressing the centre in. This is a useful thing to realise as Toyota allegedly charge 90p each for them.

Difference between GT and GTS

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.

JASMA

Often owners may find 'JASMA' stamped on an aftermarket exhaust that was on their car when they bought it. JASMA is not a exhaust manufacturer, its some sort of organisation that certifies exhausts meet noise standards etc. It stands for Japanese Automobile Sports Muffler Association.

Known problems

Solid, non-metallic paint fades somewhat.
Rear boot can let in water, probably from water sprayed off from rear tyres onto wheel arches and underneath of car, rather than leaking from the top.
Toyota CD players may spit out CDs.
Wipers may have problems staying smoothly on the screen when being used at high speed, regardless of brand or whether they have the little spoiler thing or not. Stiffer spring tension in the wiper arm is thought to help.
Radiator drain and bleed valves may start leaking, requiring the O ring seal to be changed.
Catalytic converter cores can start to break up after a few years and can block the exhaust somewhat, leading to poor performance and poor fuel economy.
Old / contaminated clutch fluid can cause problems when it gets warmed by engine heat. If the clutch pedal acts improperly, try changing the clutch fluid first of all.
Front fog light screws are reported to be prone to corrosion related seizure. Might pay to grease them up, before you need to replace a bulb.
Engine number is virtually impossible to see whilst engine is in the car.
Coolant header tank level is difficult to see. Shinning a torch down the neck in the dark might help, but you're probably better just using a piece of tube to gauge the level - push it down the neck whilst blowing down the other end until you hear bubbles or something.

Speedometer accuracy

Speedometers often may be a little inaccurate. The repair manual for the UK car says the allowable reading at 100 MPH is 104 to 108.5 MPH, i.e. they are designed to over-read. Also needles may be placed in the wrong position if speedo faces are changed etc, as zero is alleged to be behind the stop. As far as I can establish so far, each 1100 rpm in fifth gear corresponds to pretty close to 25 mph with standard 225/50 15 rear tyres. E.g. 2200 rpm is 50 mph, 3300 rpm is 75 mph, etc.

Tyres

Revision 1: 195/60 14 front, 205/60 14 rear.

Revision 2 onwards: 195/55 15 front, 225/50 15 rear.

These sizes give about the best handling, deviate from them with caution. Minimum speed rating is V. Bridgestone S03s (made in Japan) are a popular choice with MR2 owners in the UK.

Your door sticker should give you more reliable information. Generally you can fit better or, within reason, bigger, but using smaller than the manufacturer's recommendations is probably illegal and may affect your insurance.

Tyre pressures

According to the Toyota manuals for the U.K. car:

14" Wheels: 29 PSI (200 kPa) front, 32 PSI (220 kPa) rear.

15" Wheels: 30 PSI (210 kPa) front, 35 PSI (240 kPa) rear.

The Japanese door sticker on my revision 3 turbo seems to specify 2.0 Kg/cm2 front, 2.3 Kg/cm2 rear. By my calculation thats 28.4 PSI front, 32.7 PSI rear. However I don't see any reason to use lower pressures than the UK model which is lighter and slower, assuming the speed limiter on the Japanese car isn't operative. 4.2 Kg/cm2 (59.7 PSI) seems to be listed for a 135/70 16 tyre, which I pressume is the compact spare? Please note my use of the word seems, I can't read Japanese.

Wheels

Front: 15x6 JJ 45 Rear: 15x7 JJ 45

- or at least those are the numbers cast into my stock toyota alloys on my revision 3 turbo. (Revision 1 is different with 14" wheels.)

Currently the second hand value of original toyota MR2 15" alloys is less than 150 pound, probably due to the amount of people fitting 16" and 17" aftermarket wheels for their cosmetic appeal. OEM 14" wheels are virtually given away, sadly.

Note 14" wheels wont fit on the front of revision 2 onwards because of bigger brake disks. Similarly compact spares from revision 1 wont fit later cars. A standard 15" OEM front alloy wheel will fit on the rear of revision 2 onwards cars, and seems to work fine for emergency use but bear in mind that its probably illegal and may affect your insurance even if it probably is a lot safer than a compact spare. A standard front 15" alloy plus tyre weighs about 16 kilograms.

Fuel consumption

I get about 15 MPG but thats with the throttle to the floor as much as possible, which isn't that bad if you consider the amount of power being put out. Something like 24 MPG might be more typical. Some might claim as much as 30 MPG, but I think you're looking at a lot of motorway miles at 70 mph to get that, which perhaps isn't an appropriate use for such a car.

OEM brands / contractors

air filter	denso
brake calipers	aisin
brake pads	aisin
distributor	denso
drive belts	mitsuboshi
electronics	denso
engine	yamaha
engine mounts	toyo
fuel filter	denso
ignition leads	yazaki
oil filter	denso
radiator cap	denso
steering rack	koyo
stereo	matsushita
suspension	bilstein
tyres	yokahama

Mailing list

http://www.imoc.org.uk/

Author

Robin Arnold - arny@rat.ltd.net

http://www.mr2turbo.info/