engine (rebuilt, still on stand): S5 TII, stock ports, hybrid turbo (Super-V compressor), stock ignition, free flow exhaust, big front mount, 4 x 750cc controlled by Rtek 1.8 (non-programable), 42 psi fuel presure, 12 psi max boost.
by my conservative calculations, have enough fuel for at least 325 (+) bhp (crank).
interested in this progressive system from Snow: https://www.snowperformance.net/Stag.../sno-20010.htm

At 12 psi, is 89 octane + water safe (contigent AFR stays in range which I think it does)?
If yes, at what psi should water flow start?
If not, and 91 is all I have, at what psi should water flow start?

 

 

As it is a rotary, I'd skip 89 and run 91 or 93 if you can find it regardless of the water injection. I'm assuming that by "non-programmable ECU" you aren't able to adjust or modify the fuel table? If this is the case you will need to run water only, and not water/meth as you aren't able to account for the AFR change you'll see from the addition of methanol. You'll want to target about 10% water by volume fuel so you'll need to do the fuel calculations for your max consumption then size your nozzle accordingly. If you have a progressive controller, you can probably start around 2-3 PSI and ramp up to full flow by 10-12PSI, but if it is driven by a simply on/off switch then I would set it to come on around 8 PSI. At such low boost levels you aren't going to really need to detonation safety down below that, and without a progressive controller you'll risk inducing ignition breakup due to the single flow nozzle sized for max flow coming on so early.

Skeese

 

 

"I'm assuming that by "non-programmable ECU" you aren't able to adjust or modify the fuel table?" Correct. Intent is for water only.

After further reading decided on the progressive AEM 30-3350 vice the Snow. Less $$ anyway.

 

Since I have 4 x 750 = 3000cc capacity, if ~ .85 DC @ max power = 2550cc fuel, nozzel should be ~250-300cc??