Hi All,

I'm just about to finish my custom plenum, and want to figure out the best place for the meth injection nozzles.

Instead of in the intake elbow, I was thinking the runner's would be an even better spot. But my question is, should I go with 2 nozzles, one at each outer runner (like in red below), 2 nozzles on the inner runners, or 4 nozzles one on each runner?



Is this even a good way of doing it, orientating them so they point in the same direction as the flow in the runner, or should I bet letting them spray into the plenum or intake elbow?

And what nozzles are best, I want a total of 1200 to 1400cc? is there anything that comes with a -4AN input side, and a 1/8th npt output side to screw into the plenum?

 

I know you guys are smart and have opinions on this

 

Also, does anyone know if there are any nozzles that are -4AN instead of 1/8npt? I'd like to connect my braided line straight to the nozzle instead of using an adapter.

 

I mounted my nozzles in the intake pipe right after the IC exit. You get better atomization.

 

Is there any evidence that it provides better atomization?

 

I'm not really into this topic, just reading in for now...

But what I've always wondered about this position -> the ECU doesn't know the actual intake air temperature, so how do you guys (which are running this position) are compensating for this?

 

As long as you are getting a similar drop in temperature every time it turns on, when you are tuning the car, you monitor everything else. Once you are done tuning, your computer has no idea that temps are coming down, but that's ok because your tune was made with this in mind.

 

Visiting different forums and experience from manufacturers that seemed to be the conclusion.

 

I just thought mounting that early in the flow would leave a lot of things (i.e. throttle body plates) for the water/meth to collect on and drop out of the airflow.

 

I dont think it will collect, the air is rushing so fast there is no time for it to collect and "drop out", besides even if it did where would it go? the intake is closed.

Are you going to be using the meth as a replacement for fuel? If so I think your idea to at use least 2 injectors directly spraying into the intake runners is a good idea to help insure you get an even amount of meth to each rotor.



John

 

I guess you're right. I'm going from 100% meth and using windshield washer fluid instead, so my fuel curve won't be dependent on it.

Since I've spent all this time making it custom, i want to make sure these go in the best spot possible.

 

I vote for just after the ic exit as well if your going for simple AI. I had my two nozzle bungs welded into the IC cold pipe just before the BOV.

 

what about none simple A/I

 

Since your NOT using it as fuel, another vote for pre-TB. With a properly sized nozzle I don't see it 'dropping out' of suspension either. And IIRC there was some talk in the stickys of it needing a little time to abosorb the charge heat.

 

Thanks, I'll search for that now.

I know I'm not currently using it as fuel, but if I want to change in the future so I can go higher boost, I want to be able to.

It seems like I'm hearing that different places are optimal for fuel vs. non fuel. I had thought no matter what you just wanted even distribution to each rotor.

Injecting prior to the throttle puts it in the flow of air, but air coming around the intake elbo is swirling and I don't think anyone knows how the atomized fluid moves in it. It could be coming in at one point and going mostly into one rotor.

 

It is my understanding that the high pressure of the fluid being injected through a nozzle is what does most of the atomizing. What happens after is just a bonus.

I would think if if the fluid goes "in at one point and going mostly into one rotor" we would see more blown engines as there are many people who are using AI to prevent it. By injecting a few inches before the throttle body you are allowing there to be more time for the mixture to evenly dissipate throughout the charge air.


I think you are trying to solve a problem that we do not have.




John

 

AI injection location is important and varies depending on the injectant.

if you are injecting 100% meth it is important to inject it far enough upstream so it can "flash" you do not want to inject it just prior to the combustion chamber.

water is the opposite... water works almost all in the combustion chamber so it can be injected in the stream post TB.

water meth combos can be injected where 100% water is injected as the meth is modest...

i understand that some inject preturbo water and that is an entirely diff situation as the compressor atomises the water etc ect.

hc

 

Thanks Howard, any chance you have ever seen a nozzle that has a -4AN connection on it?