jdm_vtec

I've been thinking about building a basic Methanol/Water injection system for my setup.. but I was wondering; If it cools the IAT, adds octane, etc. it's obviously going to handle more boost during injection, so if the car is tuned at it's peak setting, say 18 psi for pump gas/street trim.. Would it be necessarily DANGEROUS to tune the cars max output during injection?

for instance, lets say I have it tuned without injection up until 13 psi, at that point the injection kicks on, and one day i'm boosting and the reservoir is dry at 18 psi.. I was thinking, just tune without the injection and then run it for safety, but that wouldn't really yield enough gain to be productive. any input??

carzntune

Having it tuned for safety can prevent a bad tank of gas from popping your engine. I believe a bad tank of gas put a hurting on my original setup. I think it's a great idea and why I've had it added to my car. Even using it solely for safety, you still have to tune the car. Meaning you can't tune for no spray then spray without additional tuning.

Tuning it for power places you at the very same risk but at a higher power level. The AEM system has built-in safeguards against running out of meth/water. A low fluid light and a trigger to be used however your tuner chooses. I'm sure other systems do as well.

This is my understanding of the options. There may be a happy medium to gain some power without pushing it. That's a tuner question.

Attaus

carz is right. You can hook up a low fluid sensor to an AEM unit as a fail safe.. or as I always say, check the damn thing before you use it!

It's like being worried that you'll run out of gas.. it pretty ridiculous when you realize you can check how much is in it at any given time.

If you're worried, get the extra large container and only use the advanced tune when it's near full.

50% meth/50% water allows you to run neutral timing, if not advanced, and slightly more boost. So yes, it's worth it.

DOHCter

You guys should be running straight methanol injection and ditch the water mix. If you read up on the reason for running water mixed, it was to cool the cylinders of "air" cooled aircraft engines. Since cars of today are well regulated, water cooled machines, running pure methanol give you extra added benefits. It ups the octane rating of your existing gasoline, and it also cools the intake charge significantly. Read up on the other forums, such as the turbo buick ones and other sites who have been running methanol long before any import tuners decided to up the anty. You won't be dissapointed in running it straight.

Vince64

ok, lets break it down a little bit

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by From Aquamist forum &raquo;</TD></TR><TR><TD CLASS="quote">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/s...u+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. </TD></TR></TABLE>


Also most WI systems out there are not compatible with 100% meth. Straight meth is also highly toxic and very flamable. Please dont mess around with 100% unless you know what your doing.


Modified by Vince64 at 8:12 PM 3/16/2008