We are now able to offer a 2GR V6 conversion into a Toyots SW20 MR2 and are prototyping the same engine into a MR2-Spyder . The engine and related electronics are from 2009 Australian Aurion sedan.

What you need

For this conversion you either need a complete donor car or : engine package as removed, air-box with intake piping, plastic incoming fuel line, security ECU with matching key & transponder, air-con compressor pipes, engine ECU & matching harness, special harness for the security system & the electronic throttle pedal, V6 (MZ or VZ) flywheel and clutch

Dependin the customers needed, a matching gearbox (see below)

Gearbox & axles

After studying the gearbox situation, we found the early SW20 turbo box will not bolt up adequately without welding and machining. For everyday road cars we beleive a late model V6 gearbox is a better choice due to a combination of better ratios and it bolts up much better. The V6 Camry gearbox however requires complete dismantling & the shifter mechanism reversed (we have made tooling to do this job) .

Depending on the exact gearbox and car models, the spedo may need to be changed in the gearbox.

There are a number of other minor changes.

• The MR2 clutch slave cylinder hits the block and grinding the block away will remove part of the factory engine number. Spacing it out away from the block will result in a poor shaft angle and likely a short cylinder life, so that idea was rejected. For road cars where the engine number must remain, the SW20 clutch cylinder and bracket can be relocated with a specially made adaptor, and the untrained eye would never notice the change.
• none of the various 3SG rear engine plates will suit the V6, so we will leave it out. as its mostly a seal plate, this wont be a problem on this conversion as the V6 box seals against the block OK.
• the axle seal plate on the side of the box, hits the block. this can be fixed with minor grinding of the plate and block. This plate on the V6 box is not the same as MR2 as it is missing 1 bolt that is part of the engine mounting bracket. The MR2 turbo plate needs to be fitted.
• The support bearing on the long axle has to be moved 8mm to allow it all to align with block mountings. A apcer is made that fits behind the ebaring and the circlip groove re-cut in the axle

Wiring & electrics

We have found out the Australian built Aurion has unique harness/ECU, so info from other conversions in the USA and UK is not 100% useful.

The engine loom has a few un-used plugs for radiator & air-con fans that we tape up securely, as removing them totally from the loom would take many hours. Various sections of the 3SGTE harness are removed and others merged with the 2GR harness to make connections into the fuse box etc, much easier. The Australian Aurion engine operates with a complex security system which must be retained and integrated into the MR2 to get the engine running. The only alternative to this is to use a non-standard computer, however this will preclude fitment of the Government approved modification plate, so we cant do that if its a road registered car.

The stock tacho has to be modified to suit the new ignition signal.

Engine

A kit comprising specially made exhaust manifolds and engine mounting brackets can be bought from the USA. The manifolds have no provision for oxy sensors (essential-engine wont start without them), so these are relocated further down the pipe. Each pipe has sensors either side of the catalytic converter, with 1 pair being special wide band ones. Because they are heated sensors, the location proved not be a problem.

The water transfer pipe on the V6 needs to be modified to accept a 3SGTE sender unit for the dash gauge and accept a hose from the stock MR2 water filler. Other hoses require very minor alterations.

These V6 engines are fitted with a return-less fuel system and we change that, rather than convert the tank and hoses to the Aurion system. We retained the snap-lock connector on the end of the rail, but add an external adjustable regulator to incoming line. This takes a bit of experimentation to get pressure right.

Fitment

With the gearbox mounted, the entire package fits into the bay OK, with more room in some places than the stock GTE engine. The alloy casing around the Toyota mount needs to be machined down for more clearance. With this mounting arrangement, changing the serpentine belt will always require mount removal. A much shorter belt is used as we dont keep the Aurion power steering pump

The alternator power output wire hits the metal insulation plate on the firewall, and we have to "massage" the panel to give clearance. The air-con compressor is a very tight squeeze.

The plastic cover over the engine can be refitted if the drivers side is modified to clear various hoses found in the MR2 body. A short length of new vacuum line is required to joint the intake manifold to the MR2 brake booster pipe over by the right strut tower. An engine bay cooling fan from a NA model, can be fitted where the inter-cooler used to be. The engine bay cross brace has to be packed upwards at the strut end to clear the plastic cover.  

Driving

Performance is shattering. The custom exhaust make a glorious noise but will still pass a noise test.

Conversion

if you want to do conversion yourself, then please do your own research & experimentation using the above as a guide. Various MR2 forums not cover this conversion quite fully. We are unfortunately unable to respond to email or phone requests for free advice on wiring problems, emisions , computers etc.