I have an SMC v2 kit and am interested in setting it up to run straight water. Is anyone here running straight water? I imagine that the jet that came with the SMC kit (7 gph) is probably too big for just water. Not sure what the right size would be for straight water, or how to calculate it?

Before someone tells me to just run alky or meth, I'm interested in participating in SCCA autocrosses with the car (alky or meth aren't allowed in street class) and would prefer to stick with pump gas while getting the extra power and safety of water injection.

Thanks.

 

Rich, I don't have your answer, but I wanted to clarify that alky/meth injection is not legal in any class. The karts are able to use methanol fuel, but they also can be the only things moving when it is their turn.

 

~10 to 15% water to fuel to fuel ratio.

assuming you are using stock injectors
560*4*0.10=224cc/min

224/63 = 3.56gph water @ 10% water to fuel ratio

 

agree with slowcar, 10% of whatever your fuel requirement is. Heat latency of water is twice as high as methanol so it requires much less of it to do the COOLING job.

 

I would keep pressure at least at 150psi or higher.

 

AT 10%, you can expect about 18 degrees centigrade temp reduction on intake air.

 

I don't know anything about this, but didn't you just change cubic centimeters per minute into gallons per hour without a conversion factor?

 

If you've maxed your 560cc fuel injectors, then 224 would be correct. Actual fuel requirement is needed however, to calculate the water needed, since more than likely the 'jet size' will be a fixed volume. That is unless you use something like Snows 25d2 controller which measures airflow and boost.

 

sorri about the quick math

1GPH = 63cc/min

 

9sec9, I'm a little confused by your suggestions. I have an SMC kit which operates at about 100 psi with the included jet. Are you saying that you need more pressure with water than meth/alky to sufficiently atomize?

Is it a bad idea to use a boost-based controller like the SMC with pure water? It would inject the same amount of water at 4000 rpm as at 7000 rpm, given the same boost level, though the amount of fuel injected would clearly be a lot higher at higher RPM. So I guess it would inject too much at low RPM and not enough at higher RPM? I suppose this is where systems like Aquamist triggered off the fuel injectors come into play. This is starting to sound more complicated to implement than I was thinking...

 

or better still, the aquamist 2D system. the high speed valve pulses insync w/ the fuel injector thereby maintaining a constant water to fuel ratio.

 

I am glad this question was asked. I am running the SMC kit also, and have been thinking about what to do for next autox season. I have come up with 3 choices:

1. Remove it all together and just run, it is the cheapest choice but I think I might miss the power.
2. Run water (which is legal) instead of alky, I would need to change the jet and get retuned for water (already have an alky and non alky map). Some of the power would be back but not all, would this be the best compromise??
3. Be able to switch the alky off and run a non alky tune when autoxing. This is by far the most complicated and possible expensive choice. It would be easier if there was an easy way to switch boost settings and tune the cheap ways to switch tunes (ecuflash) do not control the boost and if you are running an mbc adjusting everytime you autox could be annoying.

I am hoping the the COBB accessport comes out soon as it is supposed to be able to control the boost as well as allow easy flashing of the ECU. I think with that I would choose #3 and just set up a switch to turn the alky off when i autox but allow me to run it on the street and when I do track events. Any other thoughts or comments?

 

Ah! There's the conversion factor; I just missed it!

 

bullfrg, turning off the SMC should be easy, just remove the power line and/or fuse. Then you could turn the SMC kit off and run a low boost, no alky tune.

 

To make it even easier I was thinking of installing a little switch. Really the only issue is changing maps and boost, want to be able to change both, as changing the mbc all the time might be a pain in the butt.