Bones wrote:Thanks for that, I'll have a poke around at my local gardening centre although I did spot these on ebay
http://tinyurl.com/mm46qfWhat sort of pump do you use and how is the flow activated?
I cant use the kick down button on mine as car is too fast

The nozzles you linked are 180o rather than the full circle 360o type I use. These may be OK but you would want to watch which way you mounted them to keep the water dispersal as even as possible throughout the cylinders.
The pump I use is just a windscreen washer pump off a popular car here. It is made by VDO and I believe is used by several manufacturers It is known as a black pump due to the distinct black rubber cover it has on it.
Not sure if your car is a turbo but if it is you can just use a pressure switch to activate the WI. There are some adjustable switches made by hobbs that can be set from I think 2Lb upwards.
If you have an NA engine, you could try a pressure switch that is fed from the exhaust. I would tap the manifold and then run a copper or steel pipe to the remotely mounted switch. You may also be able to use a proximity switch on the throttle linkage. Mount a switch and a magnet so when the throttle is at half or above, the switch is near enough the magnet to be activated.
There are also Washing machine level switches which are basically very sensitive pressure switches. One of these strategically tapped onto the inlet manifold would most likely be able to be set between the difference in pressure in the inlet manifold between idle and higher revs even on a Diesel.
The only other thing I could think of is something with the Auto kickdown rod although I'm not sure your car has one.