If I can't reach my goal of 700whp on 91 and water, then I am just going to run a second map for 100 octane and water. Which I have no doubt will get me to my goal, and I will accomplish it running fuel threw my injectors and not my intake

If there was only 87 octane fuel available, then I could see the benefits of running 100% meth, but with the higher octane fuels we have available, there really is no need.

Also for the guys making around 500-600rwhp, A properly setup high quality water injection system will be fine for pump gas to reach those levels safely.

In short, if you are using water injection as add safety/protection, I don't see the benefit of running methanol (because its not needed, not because it won't increase the octane level)

As Uprev stated, Simple is best.

-George

 

I can drive just a couple of miles to pick up a fresh batch of Meth, and one gallon at a time if I so choose, but I guess that's why I live in So. Fla. and not in downtown Cleveland.

Moreover, I have an on/off switch going in my car with multiple tuning maps. When I'm running around town, I'll be running a conservative map and the meth system will be turned off. When I go to the track, I'll switch to a tuning map that is tuned based on meth or meth/water injection. After I'm done for the day/night, I'll switch back to the conservative map, turn the injection system off, and drive home.

As you said, some people want to keep it simple. But if you want simple, why mess with any type of secondary injection at all? Why even bother taking a +/- 300 hp car up over 400 hp. Just go buy one that does it stock.

What it really comes down to is the individual setup and hp goals. As I indicated, for some people water injection may be adequate to achieve their goals. For some, however, it may not. That is when methanol can be a valuable tool.

 

I know what Geroge/GTM is planning to do and I will wait for the results....and I agree with ttg35fort ...simple is not a word I would use with meth or water injection. I too (like George) is happy with 700+ whp and running this much whp I would not feel safe without running meth.

 

Mix it 50/50 by volume, have it tuned that way, and continue mixing it that way every time. I've tuned cars at 100% water to 100% meth and everywhere in between. As long as you keep the ratio constant every time you fill the tank you'll be in good shape.

We use a 2.5 gallon gas jug, get gallons of distilled water from the supermarket, dump the gallon of water in the mixing jug, then pump meth into the empty gallon (from the water) and fill to the same level the water was at, then dump that in the 2.5 gallon mixing jug. This makes it easy as pie so you can't screw it up.

 

Thank you rcdash. Good catch. I forgot to mention that the timing was fixed.

I wouldn't say that there were "problems" with the report, however. It didn't have all of the information that we want 64 years later, but keep in mind that the experiment was performed and targeted for WWII era piston powered aircraft. Piston aircraft typically keep a relatively constant RPM, and I would assume that back then fixed ignition timing was probably the norm on these aircraft.

If I could find similar experimental data performed on a VQ35 motor, or at least a modern automobile engine using pump gas, I certainly would have posted it. On that note, I GREATLY LOOK FORWARD TO GEORGE'S DATA!!! George, I'm no longer in CA, but if there is information or research that I can help with, please do not hesitate to ask!

Now back to the report. Even though the experiment was not optimized for our cars, it still is a very valuable tool that should not be overlooked. rcdash, think of this report like a pre-clinical study. It does not give us all of the answers we want, but it gives us knowledge that we can use to proceed further with our own tunes.

Although the compression was 7.0, don't forget that they were running very high boost, anywhere from 1.5 to 5 bars. The real key is the mean effective pressure (MAP). Even at a 7.0 compression ratio, at 5 bars of boost they were able to get way higher MAP values than most of us will ever see in our cars, yet they were also able to investigate much lower boost levels.

As we both noted, they were using aircraft fuel, which has much higher octane than pump gas. Thus, we must keep this in mind when considering the results. Nonetheless, I think that some of the results they identified can be extrapolated to our cars. Here is what I learned:

1. The effectiveness of water injection over having no secondary injection at all decreases as the intake air temperature decreases. Those who have high intake air temperatures, (e.g. a center mounted I/C with a stock G35 bumper) may see significant performance increases from straight water injection. Although those who already have low intake air temperatures will see some gain with straight water injection, they will not see as much benefit from straight water injection as those with the high intake air temperatures.

2. Injection using a 70/30 meth/water ratio will allow for higher torque/hp levels over straight water, especially if one already has a good I/C. Is this ratio right for everybody? Of course not. Some people do not need any secondary injection at all, and not everyone is looking to achieve the highest hp they can. It all comes down to the individual tunes. IF you can acheive your hp goals with straight water, that is obviously a much better choice. In comparison to water, Methanol is toxic, expensive, and (unless you are using windshield wiper fluid) you cannot pick it up at your local supermarket. (I'm lucky I guess, I have a race fuel dealer just a few miles away).

Here is what is still unknown, at least to me:

1. Will 100% methanol provide higher torque/hp than a 70/30 ratio? If so, is this limited to a certain range of intake air temperatures (e.g. below a certain temp.)

2. How does a 50/50 ratio compare to a 70/30 ratio in our cars?

3. Is straight water injection adequate to be able to obtain 700 hp in a VQ35 motor without knocking?


Hopefully, George's data will further enlighten us.

 

I have not seen an appreciable difference at 50/50, 70/30 or 100% meth, except when intercooling was poor. Then 100% meth worked better. This may seem counterintuitive, but the cars with poor intercooling had to overcome the risk of detonation due to higher intake temps (despite water/meth injection) and the higher amount of meth with its extra octane worked better.

I confirmed this on a non intercooled 4 cylinder setup (stock 7.8:1 CR engine, 33 psi on GT35R, NO intercooler). It was a beater of mine we were doing some testing on. I won't show the whole engine bay, but you can see the GT35R outlet, charge pipe w/Tial BOV, going right into the throttle body:



[img]

 

That wasn't the point, it does degrade, people don't respect that degredation in the tune, and water is pretty easy to find anywhere at any time. Those were my points.

Use as much meth as you want, but it's not a good choice for most people.

 

You're one of the lucky few. Why even bother with water injection? Because it works, it's not that expensive, and you'd have a hard time not mixing it right or running out of it.

 

I think Coolingmist already beat you to it.

http://www.coolingmist.com/detailmain.aspx?pid=10055

You might be able to mount the injectors on the plenum so that each injector sprays into a respective intake runner in the plenum.

The biggest concern that I would have is that if one line got clogged, you might not know it until it is too late. I would want a fluid flow sensor on each of the lines, but that would be expensive.

 

Well there are certainly benefits to be realized even at stock boost when intake temps are hot...

I was actually asking where in the intake system physically is your METH injector located? In the neck of the cosworth plenum?

ttg35fort, I agree with all of your conclusions - the degree to which they hold true may vary and as you noted, water may be enough to reach many people's goals. There's no question METH provides benefits beyond what water alone can provide. It'd be great too see some data that plots out where it's not necessary versus absolutely required to attain specific cylinder pressures without detonation/pre-ignition.

 

But the same can be said for meth in my case also.... Its not that expensive... you dont have to mix it.... and I wont run out of it.

Its easy for me to find in FL, AZ or TX....

Water does one thing...it cools intake.....Meth does 2 things...I am sure I dont have to list them.

 

Sorry Raj....its 15" from the TB on the intake pipe. You can see it in the picture below. The GTM IC temp gauge has 2 probes. One probe is placed before the injector and the other after....just before the TB so that I can tell how much the meth drops temp.

http://www.cardomain.com/member_page...1_406_full.jpg

 

How much of a temp drop do you typically see in that short distance?

What happens when the BOV opens during a shift and you let off? You've got a 100% methanol suspension and compressed air that needs to vent... That's one way to keep the engine bay clean!! Looks like the BOV is away from the manifold. That would be my only worry really with your set up.

 

I will let you know when I get to ATL....I have never tested the car with the GTM gauge to see the difference. As far as the meth...before I had it installed...when its hot outside (95 +)the boost would drop off....but with the meth it would reach preset boost and sometimes go over