gunzo

iTrader: (2)

Richard I hope you can pipe in on this .. your Aquamist forum is closed for whatever reasons ( I can't get in) and I know the info I want is somewhere inside there ..


Fact or myth 1
We use water for in cylinder cooling and I read in your forum (and the MF2 manual) that water is the best in terms of extracting heat from the engine

Fact or myth 2
We use alcohol to increase the octane level (methanol = 120 RON, Toulene= 126RON, isopropyl = ?? RON etcetc) so that we can run more aggressive timing using these as fuel to raise the octane level.


So question is .. is there a better option ??

Run alcohol to increase octane so I can run more aggressive timing
OR
Run water to reduce temperature using it as buffer to delay detonation (end result is run more aggressive timing).. I also understand that using water is almost similar as retarding the effective timing??? meaning you're worse than before if you don't advance timing??
OR
Run both in a 50/50 mix.. and accept a slightly lower ability to remove heat but add a buffer of increasing octane ??

I am asking because I've finally run low on 50/50 mix of meth/water (YEA !! 3 gallons does last a long time ) and I've just topped up with pure water only..
so I guess I'm running more like 15% methanol and 85% water

1st full boost run and the engine retarded timing due to knock .. and I can hear it audibly the knock at 5000rpms ..

So now I'm at a loss .. I always thought water should be better than alternative fuel..

Ultimate CC

iTrader: (122)

For me it depends on where you live, here in the northeast I have found that its optimal to run about a 75% mix...where are you from?

blackevo110

denatured alcohol doesnt increse your octane enough to advance timing but a little bit. I personally run a 50/50 mix of meth/distilled water.

Why are you so concerned with "heat"- meth is an alcohol and naturally a cooling factor.

Richard L

iTrader: (5)

Hello Gunzo,

We are upgrading the water injection forum due to an attempted attack last month. We are taking this opportunity to moving the database to a more stable platform. It will take some time to re-organize. It will be back for sure.

Water and methanol injection does the same job in different ways, they both perform in-cylinder cooling and knock suppression well.

Water has a higher latent heat value than methanol, you need to inject twice the amount of methanol by mass to extract the same amount of heat during combustion. This is why all pure alcohol injection systems require a bigger jet. By volume, you need to inject 2.5 times more than water.

Effect on knock suppression is totally different. Water suppresses knock by quenching peak flame front temperatures hence regulating the frame propagation speed – (too fast burn promotes knock). In-perfect charge distribution produces lean and rich pockets. Lean pockets burn at a higher temperature (oxygen-rich = faster) compared to fuel-rich pockets (excess CO slows down burn speed).

Alcohol suppresses detonation by increasing the knock threshold value of a given fuel grade. Since large amount of alcohol is required to control in-cylinder temperatures, air/fuel ratio will be affected significantly. Some fuel has to be removed to avoid over-rich mixture.

As far as power production capabilities is concerned, both methods will yield good power increase, but is done very differently:

Methanol increases octane to allow high boost whereas water can allow very high boost at very lean conditions, power is being produced by increasing the effective compression ratio without the penalty of high EGT. Alcohol power increase is purely based on raising the octane value and cooler EGT.

Water alone has a higher potential of extracting more power in extremely applications such as the WRC cars where CR ratio of 10:1 at pressure ratio of 4. Some reference below:
http://www.i-club.com/forums/showthr...ght=subaru+wrc

In Diesel application, the extreme use of “effective compression ratio” is being employed in this example below where power is being limited by excessive EGT. Water/steam allows the serial turbo configuration running in excess 80psi absolute, extracting a targeted 750 BHP at 710degC EGT instead of 550BHP at 750deg C EGT. Abstract below:
http://www.aquamist.co.uk/dieselmax

I hope you are able to identify the merit of both systems and use it according to your needs.


Richard

PhoenixEvo

iTrader: (1)

Good thread

Ultimate CC

iTrader: (122)

Richard, awesome post as usual

UCB

iTrader: (12)

If you are tuned for 50/50, I certainly wouldnt run anything else than that though

HxllxMan

iTrader: (6)

Isn't 100% Methanol bad for the engine?

Richard L

iTrader: (5)

Please read this first before using isopropyl as your source of alcohol injection
http://enginehistory.org/Frank%20WalkerWeb1.pdf

Evo_Jay

iTrader: (17)

Richard that was a great informative post but can you just simply tell us what one is better??
Maybe what one is better for road race and which one for drag??
Also, Is one of the method easier and more stable to tune??
And any other things a regular car would like to know when making a decision about what to inject.

Richard L

iTrader: (5)

EVO kit,

I am stepping into deeper waters, slowly. So here are my opinions:

Richard that was a great informative post but can you just simply tell us what one is better??
I hate to sound like a politician, I think 50:50 is best for day to day street use. Due to the physical properties of the two, you have a wide effective temperature span. Please read on...

Maybe what one is better for road race and which one for drag??
I still opt for 50:50 for both. Since you want a specific answer, I will try:
I will go for 100% water in both cases, more importantly for the latter, you need to carry a great deal of methanol on board if you have long track time. I have to be clear, we are using pump fuel in both cases. If the race is very extreme, pure methanol injection has a limitation on octane enhancement, this be because only the first 5-10% has good effect on octane boosting, beyond this initial lift, it is only good as a fuel with a great deal of latent heat value.

If methanol is so good as a power added, as many vendors like to claim this (in their signature on the bottom of the post), fill your car up with E85 fuel and see if you improve your track time. Discussion Forum is a great place for participating vendors and customer interacts. There are many any mis-information lurks below, take all advice as a pinch of salt. Dyno-graphs and ¼ mile slip is only a sales tool, good results are a combination of careful ECU mapping and sound mechanical preparation.

Also, Is one of the method easier and more stable to tune??
50:50 for sure. There are not many tuners willing to take the water injection tune to the limit. That is, you need to go beyond the melting point of your engine components and brings it down to acceptable working temperature, this type of tuning is rarely done for practical reasons. Alcohol tuning on the other hand is simple, blessed with higher octane and more liquid to evaporate to cool your combustion chambers. Beware, loosing alcohol will rob your engine with high-octane fuel as well and a very large chunk of cooling capacity. Failsafe is vital with alcohol injection. One last thought, you really need a 3-D alcohol injection system to tune a alcohol rich engine properly. Load and RPM transient response time is very important.


And any other things a regular car would like to know when making a decision about what to inject.
A regular car without some form of management system should not be tuned beyond 10% over its rated power, you are really asking for trouble. I think if you want to inject something, go for water only, lift a few psi over stock when water flow is detected. As for fueling for that extra boost, the in-built fuel dumping technology from the manufacturers will take care of that, just let water do the cooling. If 100% alcohol is injected instead of water, the a/f ratio will be too rich to give you any meaningful results.

Evo_Jay

iTrader: (17)

Thanks for the response. The last question of mine was suppose to be like this....

"And any other things a regular car guy would like to know when making a decision about what to inject."

nutrulz

iTrader: (14)

Great info, best in the Alky injection forum. Could you give more specific info on the water injection tune. I was tuning with water and still getting knock on 91 oct. and 23 psi of boost with EGTs peaking @ near 1600F. What gives?

Richard L

iTrader: (5)

I need to think about this first

Richard L

iTrader: (5)

My first thought,

1) Knock is probably due to high egt.
2) High egt is the result of a slow burn or retarded timing.
3) Injecting water into a rich a/f ratio will produce slow burn.

Need some input form you:

4) What is the afr are you reading water injection?
5) What is your ignition timing at WOT
6) What tools do you use for alter your fuel and ignition?