Unless by some miracle E85 shows up around here I plan on running meth injection on my turbo blow thru project. I've researched and everybody has a different opinion on the best placement for the nozzles. I would think in the hat directly over the carb would be best, one nozzle, and I also thought about putting one in the front and rear of the 1 inch spacer plate. I guess you could monitor IAT's in a rear intake runner. Where have you blow thru guys had the best results? I would think you'd want to spray as close to the intake runners as possible to get the best results.

 

I'm in the same boat, with no E85 available near me.

Rodney from ProMeth will tell you to place the nozzle as far away from the TB or carb as you can. Says the turbulence helps with droplet size. I was interested in individual port nozzles and he talked me out of it. System worked great, made over 800 hp on 93 pump. Tuned at home by regular guy me,LOL.

Even after that, I'm still thinking about going port on my current combo...I just want to try it.

Edit, just realized you're talking 100% Meth, so I don't think the distance is as important since the meth will flash to vapor much easier than water.

 

I was thinking about injecting pre turbo into my blow through setup when I got to that point. Cool the compressor and everything on the way to the cylinder.

 

I'm thinking the set up would be Meth at the compressor and water at the ports. ?

 

Don’t want to use too much meth with carburetors though. Seems like 20% meth 80% water is the general consensus. Meth does the most cooling though.

 

I'm wondering how much difference it will really make. I was spraying a LOT of meth on mine at one time and I had more issues with manifold air/meth distribution into the cylinders and I was spraying about 20" pre-TB. I even started designing a direct port setup until I thought about the cost. Distribution was so bad to two cylinders it convinced me to go flex fuel.

If you plan to spray 100% meth then, IMO, under/over each of the carb venturies, like a N2O setup, would be best.

ks

 

Most carbureted intake manifolds struggle with even distribution anyway, especially out of the box. Custom porting and a wet flow bench is probably the best and only way to sort that issue out. Running a little bit you probably won’t notice, but I could see large additions pooling up or favoring runners and make a mess of things.

 

Carb manifolds are wet flow and have a much better time with it than a modern dry flow manifold does. A dry flow manifold can have a really bad time with water meth, port injection works a lot better on something like an LS3 manifold.

Ideally you want to do the cooling before the carb, as you will get further cooling at the carb. What I am not sure about is if the charge cooling that happens at the carb could be significant enough to pull part of what is already vaporized back into a liquid (condensation). You might drop 80° at the carb. Because the conditions are so dynamic there isn't a simple calculation that's going to give you the answer, you are going to have to try and see, and its going to vary with track temps, atmospheric pressure, boost, humidity, etc.

My intuition is the opposite of @Briansshop, if you were going to split the water and methanol I would think you want the water at the turbine (or after the intercooler if you are using one), it is harder to evaporate, takes more time. Then you hit the fuel cooling charge at the carb, then the meth, which is the easiest to evaporate. If you did condense water out of the charge at the port that might not be as big of a deal, it will vaporize when the compression stroke happens.

 

I wasn't going to split it and from talking to a few people doing it straight meth works best for octane and cooling, never done it so I don't know. I ran mechanical injection and meth for over 20 years in all my dragsters so that is the only experience I ever had. The first idea I had was one ove the carb and one in the charge pipe 18 in or so from the carb, second was 2 nozzles, front and rear in the carb spacer. Installed in the spacer you'd have to have them where every cyl would get the equal amount. I see where Devils Own has a spacer deal with 4 nozzles in it and I think with small enough nozzles, that idea would be best. Either way, with this set up on a Hobbs switch coming on at 4 lbs, you'll have to tune for it. When the time comes I'll post my results and if I didn't have to drive so far to get E85, I wouldn''t have to worry about any of this.

 

Also, I was thinking 2, #3 nozzles, Devils Own is supposed to have really good nozzles but I wonder if McMaster Carr's are equal.

 

My thinking was based on the thought that the water doesn't do much cooling until it get exposed to the extreme heat in the chamber,where as the meth can cool the "cooler" air in the charge pipe since it doesn't need as much heat to vaporize. The split system was just thinking out loud though, I'm going to go with 50/50 W/M in the ports just before the head.

 

@Briansshop I'm curious how you do with that, I've thought about this as an option instead of race gas or E85. Is it in your build thread?

 

Some info on it might be in there. My last 2 builds were om 93 and W/M. No issues. Lightning was on 20-22psi boost. Simple,a couple nozzles in the intake and it turned on a 8 psi.