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How To:- Rev3 NA to Rev3 Turbo Conversion


I wrote this a while back, It maybe of use to someone on here, I'm always happy to help anyone with a similar conversion, just pm/call me:

This Conversion was carried out in the Autumn of '03 by myself to my late 1993 (early Rev 3 G-Ltd) NA car. Donor car was a similar age/spec Rev 3 turbo, air con, no abs, etc. The wiring/age/spec similarities between donor and receiver made it a lot easier than expected!
I am not a mechanic, and had not attempted anything like this before.


More Power! I'm lucky enough that my MR2 is not my daily driver, I could live with the extra fuel/insurance costs etc, on a limited mileage policy. I was severely limited with the NA engine for future easy tuning options and I've always wanted (should have bought in the first place) a Turbo. I could have sold it and bought a Turbo but I've done so much to my car, it had such a low mileage, and was in such a good condition. I couldn't find another suitably priced within my price range.
Then I spotted the advert.. Rev 3 Turbo rear cut £750.!!!


The written off, Rev 3 Turbo hardtop, was roughly the same age as my Rev 3 G-Ltd and had extensive panel damage all round. I set off to the middle of SCOTLAND from NORWICH ( with a borrowed rickety old 6x4 unbraked trailer to pick up whatever I could fit in. It took best part of a day and a half to complete the acquirement, taking 8 hours to get back from Ayrshire to Norwich at a careful 50mph. Nearly drove me crazy!


The Conversion was done in my garage at home, I used normal home garage tools, socket sets etc, I already had a torque wrench and the only tool I needed to buy was a chain hoist from Machine Mart to use to lift the engines/body shell.

I made an engine dolly with a strong rectangular piece of wood with heavy duty casters bolted to the bottom of it.

The Plan was to swap over the whole lump in one, this lump consisting of engine, engine loom, gearbox with selector cables still attached, and driveshafts.

What made the whole job so much easier was that it was completely "plug and play". This was because the loom from the relay block in the passenger foot well back on the NA was exactly the same as that from the turbo, bar 1 pin, the turbo pressure gauge, and the same pin position on the NA cars loom was unused, thus the turbo loom simply plugged into the car at this position. I needed to swap the whole loom out from here back inc the rear lights as well etc, but it made the job so much easier, not having to do any wiring changes.

This was applicable on my car, may/will not be the same on all cars/all revisions. Even so, if you can obtain the loom from a donor car from this point, it makes a easy comparison point to make any wiring changes.
Car was positioned diagonally in the double garage with the main double beam, where I was going to support the chain hoist from, over the engine bay.

Battery, engine lid, engine side panels, exhaust, ecu, air filter piping, all removed, I bought some resealable bags with labels for all the nuts/bolts/parts that came off, labelling for refitting as they came off.
I drained the coolant then I just went around the engine, unplugging all the connectors, pipes, fuel lines, unbolting earth wires, fuse box, starter cable, anything that attached the 'lump' to the rest of the car, most can be done leaning over the car when its still on the ground with wheels on.
The interior central storage box and the armrest to the gear stick came off to give access to the gear control cables, and the trim down the passenger side to the passenger foot well came off to give access to the wiring loom. The wiring loom from the connectors in the foot well was then removed back to the engine bulkhead.

The car was then jacked up onto 2 ramps at the front, with axle stands on the sills supporting the rear of the car, any further more connections to the "lump" were removed, along with under trays, rear wheels, rear suspension sub frame, and the front engine mount, hubs were dissed from suspension components and hubs/driveshafts supported. Air con gas slowly released and the pipes to the lump dissed. Handbrake mount and cables also removed.
The lump was now sitting in the chassis with the only connections to it being the left and right engine mounts. The dolly was positioned under engine/gearbox and weight taken by chain hoist, last two engine mounts unbolted, whole lump lowered onto dolly, feeding the gear change cables through the bulkhead from the car interior.
Two engine mounting bolts were now used with a sling, to raise the rear of the car to clear the top of the old engine, old engine lump was then wheeled away!

Now the engine was out, it was so easy to drop the fuel tank to replace the fuel pump. Literally a ten minute job!


Then the old loom from the passenger foot well back was then completely removed, this came through from the car interior, into the engine bay and then out into the boot, the same item from the turbo was then installed once the engine bay had been cleaned, and the intercooler installed.
Now was a good time to fit any new pipes (for boost gauges) or new wiring for future use.
The donor engine lump was lowered onto the floor from its old rear cut chassis once all connections from itself to the engine bays walls had been disconnected, intercooler and loom removed, what was left of the old chassis lifted off by hand and disposed of.

The new engine lump was cleaned up, and given a full cambelt service, Inc all new ignition components. This was then placed on the dolly, moved under the raised engine bay which was then lowered back onto the axle stands. Then the new engine was lifted into its left and right engine mounting points and bolted in.
The rear subframe and remaining engine mount were fitted, then it was just a case of refitting and reconnecting everything, re bolting up the suspension with the turbo hubs, fitting the exhaust, wheels, refilling with coolant, etc.

After all this, it was time to put some petrol in it and turn the key, well it was a bit of suspense, but when I turned it, it burst into life first time and away it purred.
The first run revealed it was boosting exactly stock at 14.5 psi, on my blitz boost gauge, I later compression tested the engine and found all cylinders at exactly the service manual levels.

Parts needed for a Turbo Conversion:
Engine and all ancillaries
turbo+induction piping
ecu + engine loom.
Gearbox and driveshafts+Hubs, (turbo driveshafts are thicker than NA's)
Turbo exhaust.
Turbo Fuel pump.
If possible but not essential, the car loom from passenger foot well back and Toyota service manuals for 3SGE, 3SGTE, and SW20 Body.
So don't think a 3SGTE upgrade in out of the question, all you NA owners, It really is not that tough, or expensive!
If I was doing it a second time, I reckon a weekend would be plenty time as long as all the bits were to hand.
And the new engine, well I can't stop grinning when I plant that pedal ............ Boooooost!


Since the conversion I've installed:-
DIY ST205 Chargecooler
Blitz SBC-ID Boost control

I came 3rd in the recent IMOC RR day with 338Bhp 278lb/ft @ 17psi, which I was extremely pleased with as the only the item I had not done myself was the mapping of the Unichip.



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