maximum flow for 0.4 mm, 0.5 mm, and 0.6 mm Aquamist nozzles

[mushin]

Originally Posted by Richard L

Mushin,

Unless you have your compression ratio decreased, you need to run at least a 0.7 or 0.8mm jet - no intercooler assumed.

Wow! Why is that? I didn't order any that big!

[Jason96SL2]

You're suffering from major inefficiency. Sounds like things are getting too hot for making good power. I would bet you could throw down 250hp with some dyno time and water. Intercoolers are cool too. I have one for my eaton.

[mushin]

Originally Posted by Jason96SL2

You're suffering from major inefficiency. Sounds like things are getting too hot for making good power. I would bet you could throw down 250hp with some dyno time and water. Intercoolers are cool too. I have one for my eaton.

That is definitely true. Coolant temp hits 250 degrees under WOT and high boost. I just thought that 0.7 to 0.8 mm would be too much for my application, but I guess not! I'm in the process of ordering 0.7, 0.8, and 0.9 mm nozzles from BKA Inc. here in the U.S.

[Jason96SL2]

Lemme know how it goes...I've been too scared to slap on the 14psi pulley on my M90 and I have an intercooler. ops: Those eatons make some crazy heat at higher boost pressures.

[mushin]

Originally Posted by Jason96SL2

Lemme know how it goes...I've been too scared to slap on the 14psi pulley on my M90 and I have an intercooler. ops: Those eatons make some crazy heat at higher boost pressures.

Sure will. I can't wait to take it back to Alternative Auto Performance for retuning once the kit is installed.

[cmetzner]

Richard -

I would like your feedback to see if I understand this correctly. I have an M62 sc on my 99 Miata. I have no intercooler, fueling is controlled by the Jackson powercard to run at 12.8 - 13.3 under boost. The sc boost is 6.5 psi with the pulley I have.

I use a .4mm nozzle on my 2d system. From the Aquamist site, I calculated that this would cool the air charge by about 80*F.

Mushin, it seems impossible/unlikely that you can get the cooling you need by WI alone! When I used larger nozzles to flow more water, the car balked off the line. And I am running much less boost than you.

Running that amount of boost you would want to inject more water but, Richard, isn't there a point where the amount of water needed would begin to drown out the combustion?

[robbilau]

Hey Chuck,

I've got an FMI crossover tube on order and I'm going to see how far I can go without an IC. I can meter the water in more ways than the 2d so I should be able to find close to the max cooling. The piping and jets etc will be in in a couple of weeks I think.

Anyway, if I remember we hooked your WI signal to a piggy injector, not so? Did you upgrade to the powercard since then? It seems odd you would bog with a 0.4mm jet as you shouldn't really have much until higher rpm.

[cmetzner]

Hi Robbie -

I upgraded to the jackson powercard. That meant that I had to unhook the piggy injectors.. That meant that I had to tap the water injection into the stock fuel injectors.

The car does not bog down with the .4mm jet, it was bogging down when I was using the .8 or .9 jet.

I was advised by turboice or the forum admin on this site (can't remember which) that my water % should be about 3% - 8% of fuel. He said this because I am not replacing fuel with water. My fuel is set by the powercard at 12.8 - 13.3 under boost. I cannot change the map in the powercard.

He said (whoever "he" was) that because I was using the WI as an intercooler only and not leaning the fuel as I was adding water that I should be at 3 - 8 % water.

I was also advised by another that I should begin injecting at about 2psi. The car runs best injecting at 2psi; with a .4 or .5 jet and stock heat range plug.

I will be interested to hear your results. I have no way of measuring the air temp. I am first going to spend the money on a new clutch before the gauges.

This summer I will probably change the pulley on the sc to get to 9psi. The powercard handles fueling to 8psi. So, I will have to hook up at least one piggy injector. I have heard of people running 6 cyl cars to 10psi on water alone with good results.

[robbilau]

That sounds reasonable. But I don't think you are running rich enough at 12.8 - 13.3 to restrict yourself to just using the 3-8%. That's right around the correct AF for max power on gasoline. Some of the stock import turbos run very rich under boost - up to 10:1 - to cool combustion. That's really the case where you need to lean up the fuel for power as you add water for knock suppression. You can generally run up to 25% water compared to fuel depending of course on the heat of the air etc.

So I think you could run up to the .5mm or .6mm jet. Let's see, the stock injectors are about 270cc/min. With the .6mm jet you have 250cc/min which is 23% of fuel flow which is about as high as you want to go. So your 0.4mm jet is probably quite well suited at about 15%. You might switch up to progressively bigger jets up to .6 as the summer heat grows if you find they help.

In terms of what can probably be run on water I had a tech from MoTeC help get my car baseline tuned. He typically tunes drag cars and is well known in those circles. While getting boost control sorted we hit over 15psi by mistake (fun mistake, I must say) and he remarked out of the blue that I could probably run 15psi on 91 octane with water injection.

[cmetzner]

Thanks for the info. From what I gather from different sources, I can use the water only instead of an A/W intercooler at the modest boost that I plan to run.

My plan was to use a larger jet in summer. BR Performance is also selling a heat shield for the header. The sc sits right on top of the unshielded header.

When you run 25% water do your plugs show any signs of fouling? Do you use the stock heat range plug?

I think my car balked because I was using the 8mm jet and a spark plug that was one level cooler than stock. Even NGK says one heat range cooler for every 75 -100 hp added. I am right on the edge having added 65 - 75 hp.