Adding water after dyno tuning
 

What kind of nozzle size and pump pressure would be ideal for someone wanting to add just a little bit of protection after having already been tuned without WI. I am going to be running some events in the USA and the gas is quite different and I want to add a bit of safety to my set up. Rotrex'd soon to be 280whp ish hopefully (tuning is tomorrow, but I never started looking into WI until today :O)

Back when I was int he RX7 scene a lot of guys added WI to stock FD's to help keep IAC temps down and add some protection. All on the stock ECU without tuning for it. So I imagine the same can be done here.

As small as you can. Pump pressure is fairly standardized at 150psi, and typically the smallest nozzle available is 3gph. Go with that, or a 2gph if you can find it.

Most new kits will have a 150-250 psi adjustable bypass pump. You can find nozzles down to .5 gallons per hour. I don't know where to tell you to start. The company you buy the kit from should though.

I pulled the WI fuse when I dynoed. DO basic kit, 3 gph nozzle.

I was/am basically using it for the same reason you are. My timing isn't tuned for it, so it's just extra safety. Engine's lasted a few years now at 14 psi (knock on wood).

http://www.alcohol-injection.com/

is where i picked up some nozzles.

The external mount Devil's Own nozzles linked to above are nice. That is what I use.

i've had do in the past.
nice kits.
good prices.
i'd go with one of their smaller nozzles.