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suggestion, do or don'ts, please.
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? |
Not an authority or tuner but since you’ve not gotten any other response I’ll weigh in... I think the first thing to decide is nozzle sizing. A guess based on estimated power (similar to my car) is a M3...but I’m not progressive. I think there’s still a formula in the sticky’s. FWIW I start at about 1 psi on stock ignition. Never had any break-up or perceived any power loss. I run 93 when I can get it, 91 when I can’t, and can get by on 89 but only when I absolutely must. Still, knock values don’t change dramatically. |
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 |
To clarify, I use 89 only when the alternative is to run out of gas and I also stay out of boost. And for some WI isn’t just for knock suppression.And getting break-up at 1 psi with a hobbs switch hasn't been my experience, but you're right, yrmv. |
"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. |
Originally Posted by Skeese
(Post 12325904)
... "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..."
Skeese |
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