Water Meth Injection nozzle size

[Cobber]

Ok time to put water meth injection on the car.

I have pretty much designed the tank and the Adaptronic will run the pump on a PWM output no problem.

The only bit I'm stuck on is what size nozzle to use.

I want to just put one nozzle pre supercharger behind the throttle body below where the brake booster hose is. There is a 1/8" port there ready for the job.

I have read several tech topics on the subject and they recommend to inject a 50/50 mix of water meth at around 15% of fuel burn.

Also if placed before a roots or twin screw supercharger a nozzle 1.5 times the required size is used for additional supercharger cooling.

My fuel burn at 7,000 rpm is 2985cc min, do I just get 15% of that figure and then add 50% to find the correct nozzle size?

15% of 2985 = 447 x 1.5 = 671cc/min

Closest nozzle to this size is 10gph 630cc/min

Am I close or is this miles out?

Anyone use these guys before?
http://www.alcoholinjectionsystems.com/index.html

 

[cribbj]

Andy, I inject around 600cc/min also, using a small Snow nozzle presupercharger, and two Snow nozzles post supercharger.

My post SC nozzles: one is mounted in the bottom of the manifold, and shoots up into the discharge of the SC, and the other is mounted in the rear wall of the manifold and shoots forward.

I wasn't getting the reduction in inlet air temps that I wanted when I was running only presupercharger, and even with the 2nd nozzle mounted, shooting up into the SC intake, I wasn't seeing a huge drop, but when we put the third nozzle in at the rear of the manifold, that's what did it.

 

[Zuffen]

I run a Snow system that turns on at 6psi and is at max flow at 12psi.

I use one 350cc nozzle pre throttle body and I wasn't all that happy with the cooling effects.

I now run an external W2A intercooler and still run the Snow as a) I have it, and b) it can't do any harm.

Your fuel burn may well be less than you think as 3 litres per minute amounts to 180litres per hour. If you were travelling at 200kmh at 7,000rpm you would be using around 90litres/100km.

Don't forget the injectors won't be running at 100% duty cycle so fuel burn will be less than your calculation.

Running too much water/meth will reduce power.

 

[JustenGT8]

I run x3 aquamist injectors, smaller but better atomisation i find. 2 pre SC and 1 post....haven't had a chance to datalog inlet temps since adding the extra one but i'll let you know when i do. In total i would be around 600cc/min but i'll do a bucket test and confirm that as well.

 

[XR8tt]

Keep in mind it's against manifold pressure..

 

[hypronet]

he is some info that may help that i will be using?

these 2 sites has water injection calculators on them, the second 1 is better to use?

http://www.rbracing-rsr.com/waterinjection.html
http://www.customperformancesolutions.com/waterinjectioncalc/

a doc that has some formulas on it
http://www.jurispro.com/uploadArticles/JohnBerningerArt1.PDF

they say that the % of Coolant to Fuel Ratio (Based on mass not volume). Should be in the 12.5% to 25% range.


____________________________________________
http://www.lextreme.com/forums/showthread.php?t=9037
:sgrin:There is No substitute for cubic inch, except for BOOST !!!!:sgrin::burnout:
"91 LS400" Argo rods, CP pistons 9:1, Custom Tighte Cams, Whipple supercharger 20psi, Torsen Lsd,
Dual TB's, Whiteline swapbars, 97 RZ Supra brakes, Airbag & controller

 

[JustenGT8]

he is some info that may help that i will be using?

these 2 sites has water injection calculators on them, the second 1 is better to use?

http://www.rbracing-rsr.com/waterinjection.html
http://www.customperformancesolutions.com/waterinjectioncalc/

a doc that has some formulas on it
http://www.jurispro.com/uploadArticles/JohnBerningerArt1.PDF

they say that the % of Coolant to Fuel Ratio (Based on mass not volume). Should be in the 12.5% to 25% range.


____________________________________________
http://www.lextreme.com/forums/showthread.php?t=9037
:sgrin:There is No substitute for cubic inch, except for BOOST !!!!:sgrin::burnout:
"91 LS400" Argo rods, CP pistons 9:1, Custom Tighte Cams, Whipple supercharger 20psi, Torsen Lsd,
Dual TB's, Whiteline swapbars, 97 RZ Supra brakes, Airbag & controller

Nice find, that 2nd calc is great for my aquamist injectors.

I dunno if it was more good luck than good planning but my current nozzle setup is bang on what the calc suggests Total rate needed is much higher than i assumed at 1100cc/min but they also rate the nozzles higher than i had done as well (i was very conservative as listed pressures aren't as high as what i run so i have to scale up).

I'll still test...and yet the test can't account for the 14psi MAP but near enough seeing pump pressure is 120psi.

 

[Cobber]

Thanks guys,

Looks like I am ball park with my first calculationand the fuel burn was based on 55psi fuel pressure and 9.5 ms @ 7,000 rpm.

I will end up getting a few nozzles anyhow as they are only $20 ea. I just wanted to know if I was ball park on my calculations.

John, I'm thinking the rear nozzle you put in may be closer to your air temp sensor as well?

I will just put one pre supercharger as I can't be bothered to take it all off to tap the supercharger manifold.

 

[cribbj]

Yep, the IAT sensor sits just off to the side of the nozzle, but it doesn't get hit directly with its spray pattern. In the pic below you can see the fittings in the rear of my Richwood manifold. From left to right are: IAT sensor, plug, MAP sensor, M/W nozzle, barb, barb, barb.

 

[Cobber]

Well there is a lot of reading to do there but it would appear that around 600cc min 50/50 mix is about right for my set up.

I did like the diy section of the RB racing link above posted by Hyponet but got somewhat distracted after that stage.

 

[hypronet]

hahahah the diy

i found the info on rb racing link to be great, boost pressure, pump pressure, pressure loss via nossle etc an the 2 diagrams on the bottom showing std an staged setup to be excellent.

But the calculation on the second link i found to be better to use as it works in ratio to fuel, but doesnt have stage settings like the other 1 does?

____________________________________________
http://www.lextreme.com/forums/showthread.php?t=9037
:sgrin:There is No substitute for cubic inch, except for BOOST !!!!:sgrin::burnout:
"91 LS400" Argo rods, CP pistons 9:1, Custom Tighte Cams, Whipple supercharger 20psi, Torsen Lsd,
Dual TB's, Whiteline swapbars, 97 RZ Supra brakes, Airbag & controller

 

[JustenGT8]

Some results. Last dyno tune i had 14psi with inlet temp peaking at 75 deg C

I added an extra injector and i have also upped the eth/water ratio to approx 60:40. Inlet temp have dropped to 55 deg C and below and boost has snuck up a little to 16psi. Car feels strong so pretty happy with that for now.

I need to get back on the dyno and see if we can't play with timing and mixtures probably need a tweak as well. I haven't had time to test the flow rate of the 3 nozzles yet either but theoretically approx 1000cc/min.

Hillclimb tomorrow so see how we go

 

[Cobber]

You added an extra fuel injector or water meth nozzle?

55c air temps post SC is very good, you would have to be happy with that.

Good luck at the hillclimb.

 

[JustenGT8]

Another aquamist nozzle. That's 0.8 and now a 0.7mm pre SC and a 0.8mm in the plenum post SC. I still want to up the plenum nozzle to a 1.0mm and run both 0.8mm pre SC. I suspect it's hurting power a little but safety 1st eh Need to get back on the dyno and see what we can tweak....this old roots SC may still surprise yet?