Our Mk1 had had the 16v KR conversion approx 12 years ago but after years of enjoyable abuse the engine bores had seen better days. We looked at all the possibilities including 20vT and 9A 16v but things like total cost and overall power decided otherwise.
Besides we had a complete Corrado G60 at our disposal and so the inevitable happened but not the usual G60 conversion. We decided to convert the car to left hand drive and upgrade the whole braking system. Why left-hand drive?
• Better weight distribution
• Exhaust manifold will not touch the steering rack
• Removal of the horrendous brake bulkhead lever bar.
When we purchased the Mk1 originally it had no interior, so it was decided to use it as second 'thrash around' car, hence two buckets and harnesses. About a couple of years ago we decided to strip a little weight out of it by removing bumpers, headlining, dashboard and lots of soundproofing. This is free power!
The written off Corrado was completely stripped and anything we didn't require was sold. The brakes, engine, gearbox and complete loom were all kept for the conversion. At the same time the Mk1 had its engine removed along with the scuttle tray, brake servo and anything that wasn't required. Weight saving was always in the back of the mind. A Mk1 Scirocco 16v donated its steering rack and it was just a straight swap for the original one.
With the Corrado gone to the scrapper, the Mk1's engine bay was steamed cleaned and painted to smarten it up. The cable change gearbox was not used (for now) so therefore a Helix/Sachs clutch was bought in order for us to use the 2Y gearbox from the 16V. A standard clutch would have not lasted long with 200+ bhp. The flywheel had also been lightened.
For the engine mount on the cambelt side we decided to mount the original mount over the top of the water jacket plate using longer cap head bolts in the process. Some people cut and weld the engine mount to the water jacket plate but in the end you still get the same result. For added stiffness a Prothane insert was also used. The power steering pump was removed prior to engine installation.
With the scuttle panel removed it makes putting the engine in a lot easier. For the exhaust manifold we opted for a Supersprint Group A (60mm bore) racing item in stainless steel. Although not cheap at approx £400, the fitment and quality is extremely good. The Corrado radiator was used as it is the right length. The original mk1 radiator was now too long and also the water pipes didn't line up correctly. A BBM air filter is being used along with a charge cooler. The charge cooler requires a radiator to cool the water. A brand new early top fill radiator from a Mk1 Golf was used as this meant we didn't have to use a separate expansion tank for the coolant. The top fill radiator fits snugly in front of the Corrado radiator. The bonnet release was not used and was rusty, so we chopped this out to make room for the top fill cap. Below the radiators, a Pace electric water pump is fitted to pump the coolant around the charge cooler system.
When it comes to wiring most conversions are done with the G60 engine loom spliced into the original Mk1 loom. I suppose this is good if you are keeping the original equipment etc. In our case we have binned the heater and were going to use the Corrado clocks and switches so decided to get rid of the Mk1 loom completely and replace it with the 90-spec loom from the Corrado. It makes the wiring process a lot easier, as it is made up of lots of individual looms. The individual looms for the electric windows, heater etc can all be removed neatly simply by unplugging them from the fuse box. The only wires/plugs remaining from the Mk1 loom are the fuel pump wires, front headlight/sidelight plugs and part of the original rear light loom. These remaining wires have been joined to the correct wires from the 90-spec loom. The only minor problem we had was that although we flipped the front light loom upside down, so that the driver's headlight was still in front of the driver, the fuse box still thought the driver's headlight was on the offside. A quick look at the Bentley manual told us what wires went where on the fuse box and after swapping these around all the lights worked as they should.
If you are considering a G60 conversion then I can recommend purchasing the Bentley Corrado Manual. It may well be approximately £70 but it really does pay for itself in the long run.
With the removal of the heater and scuttle tray we mounted the ECU, charge cooler pump module and coil etc up underneath the dash panel with a piece of carbon now covering the hole where the heater blower went.
The original fuel lines have been replaced with a stainless steel braided hose from Sytec. The standard fuel filter is huge and is replaced with a smaller version again from Sytec. The filter has been mounted inside the passenger foot well to get it away from the heat of the engine. Mounting as much stuff inside the car means a lot less clutter in the engine bay.
One of our initial ideas when beginning this project was to install two alloy bottles to replace the existing washer and expansion bottles. Finding two exactly the same wasn't easy and they are also quite costly so we decided on a different solution. For the washer bottle we put a bottle back in the boot area, rewired the redundant rear wiper motor wiring so that now water is pumped from back to front with the same pulling motion of the wiper stalk. Replacing the expansion tank was achieved by swapping the Corrado radiator with another top fill radiator but this time from a Mk1 Polo. This top fill radiator is the smaller one out the two available and was used because it had to fit between the supercharger and the top hose from the other top fill radiator that sits in front of it. This one has a 380mm wide core and for reference the larger one that we use for the charge cooler setup has a 430mm wide core. The Corrado top hose just wasn't going to fit, so after a trip to my local breakers and a lot of bonnet opening I eventually found a hose from a Rover 75 that only needed an inch chopping off one end and it fits a treat. A Pacet fan was then attached to the new radiator using the Pacet Quickmounts.
With the removal of the heater a couple of years ago and now no expansion tank it meant we could remove the rest of the pipe work that wraps itself in front of the block. At the water pump end the hose splits with one half going to the oil filter housing, so a new hose was made in order to retain this. On the side of the head the plastic water inlet/outlet hose has now been replaced with a stainless steel blanking cap. This allows the standard o-ring to be used.