But the difference is that the heating block/head would not require cooling - it would remain substantially at the same temperature and just be used to flash the water spray to steam. The hot steam would then be ejsvted in the exhust cycle ready for the next injection. I like the idea but think that the running speed would be limited. I've actually been thinking of a similar effect by injecting water into a petrol engine. Similar effect except that the burning petrol is used to vapourise the water. It is a recognised technique for efficiency improvement. The benifits are quoted as reducing engine operating temperature while increasing mpgs. Most benifit is obtained if the timing is advanced somewhat. Apparently the optimum mix is about 1/20 to 1/10 of the fuel so the effect is not massive. (maybe 5% improvement) I just have to be able to measure the fuel usage on the fly and meter the water appropriately. And not care too much if I damage the engine, which is a sticking point at the moment. RP On 23/09/05, Howard Winter wrote: > James, > > On Tue, 20 Sep 2005 14:15:32 -0700, James Newtons Massmind wrote: > > > >snipped -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist