SKMetalworks

iTrader: (7)

With my stock 1.6l motor, 2860, and 10psi im a little bit concerned about detonation. I think a good idea add injection as a safety net. I do like adding octane but that would cause me to alter my AFR and it something fails then my motor is in grave danger. Right now i have a 4gph nozzle and im wondering is that too much? How much water is needed for hydro-lock?

Joe Perez

iTrader: (8)

Depending upon which research you believe, 4 GPH is far too little. From the standpoint of what's common to see on a street-driven Miata, it's certainly within the realm of reason.


Assuming the engine is running, quite a lot. The unswept volume of the engine is ~45cc. We'll say that you're at 3,000 RPM, which is probably at the lower end of of your boost threshold. That's 90,000 intake events per cylinder per hour, or 360,000 intake events / hour for the whole engine. Multiply by 45cc, and you'd need 16,200,000 cc / hour, or 4,279 gallons / hour of water delivery to actually hydrolock the engine, assuming we define hydrolock as filling the entire unswept volume with water.

Now, obviously you can still do some damage to the engine with much smaller volumes of water. It's quite likely that just a few hundred gallons per hour would raise the effective compression enough to bend some rods.

But not four.

SKMetalworks

iTrader: (7)

For a track car that will see abuse what size would you recommend?

magnamx-5

iTrader: (7)

ahem are you intercooled? do you have adequate fueling to begin with etc? 4 gph nozzels scale with the pressure you thow at them as well so realistically it will be just fine even running it without intercooling, and given enough headroom on the pumps line pressure you could even go as high as 14 or so psi. So long as you **** is moving ie running i doubt very much you could hydrolock below 10 or so gph. I dont have joes imperical data. But if you are intercooled then you might as well cut back abit anyway most sucessfull WI only people run about 20-25% of there fuel volume in WI the IC folks seem to have a sweet spot of around 10%

SKMetalworks

iTrader: (7)

Will be intercooled v-mount. I have 460cc injectors. The reason i want to run pure water is to not effect my tune in case of failure. Ill try the 4GPH and see what happens. Thanks for the insight guys.

Dust

You could probably get away with some methanol without effecting your AFRs too much. If you are that worried about blowing up your engine. Tune without it. That ways it's just a big ole bandaid.

SKMetalworks

iTrader: (7)

Id need less than 10% methanol, and water is just so easy to come by.

Dust

The methanol is a safe guard. How cold does it get where you live? Plan on using the kit in the winter?

SKMetalworks

iTrader: (7)

Not much below freezing. Year around. Methanol Richens up your tune when spraying. Where i want to have a 11.5-1 AFR i would have to remove some fuel in my map to compensate. I have stated that i do not want to change my tune. I just want to add water only to decrease my IAT's.

Dust

See what your tuner thinks. Most have said that less than 30% won't play with the AFR too much. Not trying to push you towards spraying methanol. Just trying to make sure you know what you are leaving on the table.

magnamx-5

iTrader: (7)

you will be fine dude you arent spraying a **** ton anyway dont be such a panzy.

SKMetalworks

iTrader: (7)

Previously i was using 30% and where i would be 11.5 without injection and under 10 while spraying.

Thank you for the kind words.

Dust

Ok, thanks for posting the info.

RotaryMiata

Pure water all the way, pre-turbo, through a BETE PJ Fog Nozzle. Water droplets less than 50 Micron. Go with 2 (2gph) nozzles over a single 4gph and get better atomization..