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Old 16th March 2014, 12:59
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Originally Posted by andrewhush View Post
Hi Towed

I remember reading that with interest. How effective has it proved. I remember having to be careful to use gentle throttle at lower revs in a higher gear to avoid pinking. Higher revs was ok though. Have you tried running for a while with it switched off to see if pinking occurs. Are you running standard static ignition timing and a standard distributor advance curve?

lots of questions, all answers greatly received

Hi Andrew, I'm running 13 degrees advance on the distributor as recommended by Triumph, and inadvertently ran it with 16 degrees advance for a while, which wouldn't be possible without the water injection system.

As for trying it without the system running, the original setup used a 35cc/minute nozzle that I'd calculated would deliver a suitable mist for my two litre mk1 lump with the 70psi fish-pond pump I was using. Unfortunately, despite having two filters in the system it clogged up on the run down to Goodwood last September. This resulted in the engine pinking like a can of spanners when pulling away from a standstill after running at 70mph for an hour, and the engine 'running on' after switching off the ignition when I arrived at the hotel.

Even after clearing the 35cc nozzle with an airline and flushing the system it kept blocking up in use, so I've switched to the next size up, which delivers 70cc/minute. This completely eliminates the pinking but with the triggering micro-switch set where it is at the moment the 3 litre tank empties in about 70 to 80 miles of driving, which is only about half a tank of fuel.

Plan is to alter the point at which the micro-switch triggers to make it kick in a little further into the throttle opening so it doesn't constantly feed the water in while cruising. That should conserve the contents of the tank but stop the pinking when pulling away or accelerating from low speed in a high gear.

The real test will come when I've got enough spare cash to upgrade the engine power - Ultimately I'm looking at fitting a mk2 cam, Witor flow balanced inlet manifold and raised compression ratio back to factory spec of 9.5:1. That should give me something like another 30bhp over the 79 it's got at the moment, and will be a much better test of the water injection's ability to prevent pinking.
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