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Firstly, i apologise for my short replies as i am at work, thus not having much time to reply indepth.

What we were doing was determining whether water injection was a viable option with the turbo MX5 SP program. This has various factors such as whether or not it is warrantable and just simply how much water would be used, to determine how big the tank needed to be.

The DIY water injection and fuel testing was carried out on a different vehicle with 11.5:1 compression. This was also done to see if it was viable and warrantable. Whether it was 98 ron only or it was able to use regular ULP and water injection.

As for failsafe measures these were taken into an account and the manufacturer of the valve admitted to having a faulty batch. We dropped their support for the project after that and other quality and supply problems.

My first and final (boosted) setup was a tank in the boot, internally baffled capacity was around 8 litres from memory. Attached to the tank was a pump, similar to that of a bilge/marine pump supplying about 4 litres a minute, this gave excellent line pressure. This was controlled by a hobbs pressure switch which was activated at 6psi (there was also a switch in cabin to turn the unit on). Then up to the actual nozzle which was a brass fitting which was modified by hand until the desired spray was achieved.

The idea of water injection was then canned by the manager of the program and so then we tried water/air and air/air intercoolers, eventually the program went for air/air. And this was the warrantable product that was sold.

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Going with the minimum customer involvement has to be the way to go for reasons I stated earlier. Hard enough to get people to fill the fuel tank except the car stops, so how would they be with water to stop the engine dying? Warranty department would be kept very busy.

That doesn't mean WI isn't worth using for those after the extra edge or added protection, and anyone willing to go that little bit extra will maintain fluid levels for their performance, especially those of us who race.

The V8SC team I have worked for are meticulous about pulling apart everything conceivable the night before the race and checking and checking and checking, and then something just up and breaks anyway.

Exactly, car people are meticulous when it comes to maintence. A large percentage of MX5 owners (the relevant target audience) would check the water level as they are enthusiasts. On the other hand there is the hairdresser element of the market share, who only put petrol and air fresheners in the car.

If it was tuned to run water injection and it ran out we would be in trouble, but if the water injection was there just to add a safety buffer (like it is on my car) it would fine.

My fear is bad fuel from the servo, which i have had before. Foolish to push that far in the opinion of some but this was so bad the engine was producing no power and lotsa black smoke and burned $20 worth in 30km of driving in town.

Refuelled at a different servo and it was back to normal.

Had a bad batch a few weeks later and about 3 km away from the servo the engine detonated and cracked 4 pistons. I'm a bit more cautious now after a refuel but you could never prove conclusively for a reasonable cost the fuel was faulty.

Water will just protect it a bit more.

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