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Old 03-30-2013, 04:41 PM   #102
reid-o
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Join Date: Dec 2005
Location: Mililani, Hawaii
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Quote:
Originally Posted by manitou View Post
On reading more about this it looks like it raises the octane level but slightly lowers the density of the air. Am I correct in this? What tuning changes did you make after installing it, added timing and or more boost?

This is especially intriguing because of the TMIC I am running with the speed density tune. Even if the tune was left as is, the benefits that I see are that it will cool the intake air and the ECU will make less negative timing corrections on higher boost.
Tuning depends on the volume of liquid of course. I started with a traditional pump and nozzle and saw slower spool with what I "felt" was better top end. I leaned it out as that's typical for post intercooler install.

I then moved to the air atomizing nozzle type making it fully mechanical. It's basically like an HVLP gun, using pressurized water on one side of the nozzle and air on the other side to disperse the mixture into a fine mist.
The spool decreased. I have logs of it on and off--spool reduced by both time and RPM. Wet compression increases the efficiency of the compressor slightly, and you get the benefit of detonation resistance from the water as well. It's just more finicky with the amount of injection, placement and water droplet size.

http://www.rx7club.com/auxiliary-inj...esults-987107/

I saw the same effect of this user here with the traditional pump and nozzle. I think the reason why these tests show reduced spool is that the progressive nature of the water injection has poor atomization till the high point, and then as the atomization increases, the turbo shaft speed accelerates normally. Spool suffers as the larger droplets slow the rpm of the compressor. You can see the effect of the increased top end with no tuning though. I actually use 50/50 as it helps with atomization--alcohol is less dense and thus helps the atomization and cooling further, but I feel like the increases are all over the curve.

You'll also notice that the post intercooler injection didn't raise power without tuning, but we all know that in the hands of a good tuner, power can go up.

I'm sure that with an Aquamist kit, which has constant pressure at low flow, and thus the same atomization at low and high, you would see similar results to the air atomizing nozzle. I just like that it's mechanical and simple.

For your setup, I would just be worried about nozzle placement, as you want to mount the air atomizing nozzle close the compressor. Wet compression works on a different principles than traditionally mounted water injection. Theoretically wet compression would have the greatest effect on turbos at the edge of the efficiency island, but I would argue that it can help any turbo. I can feel an increase in torque when it kicks on. PM me and I can show you pics of my install. Don't want to ruin your thread.
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Last edited by reid-o; 03-30-2013 at 04:48 PM.
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