I'm using a progressive controller, the usual shurflo pump with the shutoff bypassed, and a single 10 GPH nozzle. The progressive controller is set to engage at 1 PSI and max out at 15 PSI. My boost maxes out at 8 PSI, so the pump never reaches 100% DC.

I've been watching the IAT, knock retard, and wideband O2 readings via an AFR gauge, and a dashhawk. I've installed the faster Omega thermistor in the IAT sensor, downstream of the alcohol nozzle.

For the past several weeks, I've been running ethanol (Home Depot denatured alcohol to be exact) in the system. With this mixture, the IAT would drop about 20 degF (ex: 81 degF to 61 degF) within a second of the alky triggering. The IAT would then return to near ambient immediately when the alky was shut off. The AFR readings would drop to around 10.5:1, which is about 1.2 points below commanded AFR. (Command AFR and actual AFR are in agreement when not using alky)

I decided to top off my alky today, but this time, I used VP M1 methanol. I wanted to try meth since everyone raves so much about it.

I'm surprised by the results...

Using this mix of something like 60% meth / 40% ethanol, when the alky starts flowing, the IAT only drops a maximum of 5 (five) degrees. I used to see nearly this much drop in temp without running any alcohol at all. At first, this had me worried that maybe the alky system wasn't flowing. However, I did not get any knock at full boost and full load, and the AFR dropped to about 11:1. So alcohol was obviously injecting into the engine. The different AFR (11:1 vs 10.5:1) makes sense too, since it takes more methanol to richen a mixture than it does ethanol.

The car still pulls just as hard, maybe a bit stronger.

I'm really confused by the very slight temperature drop in the intake air. I expected it would drop at least as much and probably more than when I was using the straight ethanol mix.

Has anyone else tried both and measured a difference between them?

It seems to me that for the purpose of alcohol injection, the two alcohols are interchangeable. In my area, methanol is half the price of ethanol, but ethanol is much more convenient to obtain.

-Mike

 

Interesting and well-stated. How far away is your IAT sensor from the alky injection point? Might be useful to experiment with pure meth as a baseline as well.

Jim

 

Good info! If you could try meth 50-50 with water that would be great!

 

That is interesting, this is taken from another site I found which states it should be the opposite..hmmm.. tuning in for more testing!

Chris

"The most common types of alcohol used in water/alcohol injection systems are methanol grains. Methanol is produced primarily from natural gas, wood or coal. While ethanol is produced from sugarcane or corn. Methanol is far cheaper to produce than ethanol, thereby making it the more desirable between the two to use. Water injection is also often known as water/methanol injection, owing to the fact that the alcohol mixed into the injection solution is often methanol and not ethanol or isopropanol.

The main distinction between methanol and ethanol is that methanol has a lower caloric weight (or the amount of energy available to burn when combusted), higher specific heat (takes more heat to burn the mixture) and a high heat of vaporization (when vaporized can cool down intake air temps dramatically). Ethanol is generally the same characteristics and properties as methanol, but does not cool down the intake charge as well and as mentioned above costs substantially more then methanol. "

taken from this page address:

ethanol/methanol characteristics

 

That's why I'm thinking that if he read his IAT's as they were going into the cylinder, they would be at or lower than with the eth. I'm thinking it's taking longer to vaporize and produce the payoff in terms of lower IAT's.

Jim

 

I am curious why did you mix the meth with the ethanol? Why not run straight meth?

 

I'm guessing he had some left in the tank...

 

Methanol does have higher specific heat and heat transfer than ethanol:

SH:
Ethanol - 2.48
Methanol - 2.55

HT:
Ethanol - 0.14
Methanol - 0.25

Basically they will hold about the same amount of heat, but methanol transfer it twice as quick. Just does not make sense why you where seeing lower IAT with ethanol than methanol/ethanol mix.

Keith

 

I did some 'real' data logging last night with HP Tuners. Looks like my first post was misinformed, that's what I get for trying to watch the DashHawk at WOT. ;-)

As it turns out, the drop in temps is nearly the same. Anywhere between 9 to 13 degF in 1 to 2 seconds, for both mixes. Sorry for the mix up.

My IAT sensor is about 9 inches downstream of the misting nozzle. I mounted the nozzle on the backside of the MAF, attached to the air-foil/splitter in the MAF. I relocated the IAT downstream with a breakout cable. (The original IAT is in the MAF itself)

When I initially installed the kit, I started with 100% water. I wanted to make sure there weren't any leaks before adding alcohol. Later I switched to about 70%/30% alky/water. As I used it up, I would add straight alcohol, again because of the rave reviews about how great straight alcohol is. On this point though, I agree whole-heartedly! The straight alcohol got rid of all detonation and the car just pulls harder than it does with an alky water mix. It doesn't seem to care that the AFR is fat.

The reason I didn't switch to straight meth is because I was just topping off the tank. The pickup faces the front of the car (I know, I know), so I like to keep it at least 1/3 full so it doesn't suck air and lose it's prime.

I'm still of the opinion that the two alcohols perform nearly the same. I guess one advantage ethanol has is that it's not nearly as corrosive as methanol. This could become an important difference if one were to use a flex fuel injection pump and a fuel injector (like 160#)...something I've been contemplating since I'm not convinced the shurflo/check valve/misting nozzle setup is as rugged as a true EFI pump and injector.