Thread: Injection vs E85

also consider what source you are using for methyl alcohol and how pure it is. I know that fuel line de-icer is 99% pure.

Valuecraft washer fluid from Autozone is supposedly 40%. Take a gallon of that and add a bottle of Heet, and you got a pretty dang close to 50/50.

because i have the autronic and can run up to 8 injectors, i was actually thinking of fabricating up a small tank in the boot, with its own fuel pump then hooking up an injector just before the throttle body, just get a fuel rail and fpr from a wreckers, then cut the other 3 injectors off and running methanol in the tank.

Coheed, if you don't already, get an EGT controller. Run both set-ups, and see which one produces lower EGT's. It would be a great test with valuable data.

When you do this you can compare it to mine.

At my power level my injectors prob won't like running E85. I think I have a car to test though! It already runs a water/meth kit on it. Just a basic cooling-mist kit. We wanna test this car on E85 soon to see what it does.

EGTs can give us nice data, but E85 has a lot lower burn temp already. I don't know how this would play out with the water injection though. It would be really interesting to see how they compare.


I always had an EGT bung on my manifold but never got a chance to see the EGT data. I never thought of it as a necessity. If I had every guage in my car that was needed it would look like an airplane ****pit at this point lol.

If there is one person here who can claim the benefits of injection, it is JP. Stock motor VE running injection at just about 500whp right now.

E85 its way better than meth water inj(super e85 race gas plus ethanol even better. but It will depends on what % are you using in the injection system
From my understanding and experience.

100% meth
This is great with 93 oct but you will need to run aprox 2 times more quantity (than water) to take the same heat out of the combustion chamber.
Meth is combustible and has a lower viscosity than water, This is 1 of the reasons that meth has a better distribution over water, and better atomization too wich means it can take a little more heat from the combustion chamber.
Another good thing with meth is the high oct value 115 aprox .If you use 100% meth is a lot easier to tune .
Depending on the setup I recomend at least a m6( 384cc)nozzle to run strait meth.

100% water

Water is not combustible so it has an infinite octane rating since we can not make it to knock.Water provides better heat absorption than meth or ethanol.
What I found to run very nice with water its to tune a setup just for knock supressor this is easy to. Water work best for very high boost lean a/f target mixed with race gas.
Depending on the setup I recomend at least at m3(192cc) nozzle

50-50 water meth-ethanol.

This could be see to the be the best of both worlds, takes the benefits of both meth and water, cooler air temps, higher oct (115) better atomization from meth and better cooling in the combustion chamber less egt from water...
I would recomend here a m5(320cc) minimun.


Originally Posted by Richard L
The following charts are calculated based on:
10Kg of air, Gasoline's latent heat capacity of 350KJ/Kg
Water's latent heat capacity of 2256KJ/Kg
Methanol's latent heat capacity of 1109KJ/Kg

Injection water at different ratio to fuel at 100% water and 75% Water/25% Methanol. You can see the at 100% water injection, only 3% of w/f fuel ratio is enough to replace 2.5 point of a/f ratio (dotted line). As soon as 25% of Methanol is added, the a/f ratio is dropped to 12.0 - loosing some cooling capacity






Each of the following chart show a 25% percent increase in Methanol concentration of the mix






lastly, just methanol is added and no water. The chart on the right is 100% water






The two charts show (first and last) that you will be required to inject twice the amount of methanol to equal the latent heat of water alone. Methanol is relatively low cost and very effective as a coolant so what is the problem?

When higher concentration of methanol is injected, you need to lean your engines a/f ratio to accommodate the extra fuel or your engine will bog down and loose power. Consequentially - one runs the risk of putting the engine into heat stress if the supply of methanol is suddenly interrupted. Injecting water does not affect the a/f ratio. It appears that 50/50 mix has the best of both worlds.

In either cases, having a good w/a injection system with reliable "system fault" diagnostic capability is essential especially if you are running a high concentration of Methanol.

Don't get me wrong, alcohol/water injection is great, I've made that much power on a stock DET with injection.

I will take E85 over injection based on my experience though.

I did play ALOT with mixes fuels and water with my old DE (550plus whp ) what works wonder its race fuel with water.
cheers man.

I figured that the Injection would be best because you don't sacrifice gas mileage while using it. E85 pumps here are way too far apart, so it is extremely difficult to justify going with E85. Water/Meth seems very promising, but we will have to see the knock threshold of both to come to a final conclusion.

I would go with a Apexi AVCR or similar boost controller set with a scramble boost function, then get a injection kit that sprays when you hit a certain psi level. So daily you can drive around at 15psi or so, then when you want some more juice you can hit the scramble boost to hit at 24psi or so; then with the water injection set to come on at 17psi it will automatically spray when you hit the scramble boost button.

Then I could still get 275 miles/tank and have 500whp on tap anytime! Much better and cheaper than running E85 all the time.