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Old 24-07-2012, 02:32 PM
nutron nutron is offline
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Join Date: Jan 2008
Posts: 53
Default Re: one more nozzle sizing question

The restriction to how much water you can run is the cylinder temp, not the fuel quantity. As long as the compressed charge is above the auto ignition temperature of diesel it will ignite even in the pressence of water. Unless you have a temperature probe in the cylinder you will not be able to accurately gauge the temperature but you could try to calculate the cylinder temp from compression ration and boost pressure and determin roughly the amount of water/methanol in what ever proportions you use would reduce the temperature below the auto ignition point. Personally I think you would blow your piston rings, head gasket and valve seals before you reached that point with a 50:50 mix of water/methanol in a diesel. I ran 1.5ltr/min of 50:50 in my 1.9CDTI at 2000+rpm with 14-32psi of relative boost pressure. My piston rings and valve seals were fine but I eventually cracked my aluminium head between the valves. There were no noticable symptoms of this but during dismantling to fine another fault which turned out to be the EGR charge cooler rupturing, I found four cracks between pistons in the head.

On an 8ltr engine, you could flow the limit of the pumps happily.
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Vectra 1.9CDTI 235whp/380lbft (270bhp/405lbft) NOS+Methanol
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