Methanol injection itself doesn't make power. On a forced induction car, it cools the charge and allow you to add more timing. It is the timing that makes the power. On a N/A the air charge isn't hot enough for it to make a difference.
It allows for more timing and should prohibit any detonation. On an N/A motor, it really doesn't matter whether or not you use water or a water/meth solution. The results should be the same. Read up on it, it is not new technology. The military used it as far back as WWII and Holley offered it for carbeurated motors in the 70's. Bottom line is that you shouldn't have to spend the extra cash on 93 octane gas. If you drive enough like I do, it will pay for itself in due time. Water is cheap!
About the only way you would lose power is if you had too big a nozzle. For instance, on a N/A motor such as ours, you would only use a single-stage unit with a rather small injector nozzle. If you were blown or turbo, then you would possibly use a dual-stage and/or a larger nozzle. The intercooled turbo diesel's (such as a 7.3L Power Stroke) would use big nozzle's and a dual-stage setup and would see gains in excess of 50 horses (many claim even more).
You set it up based on a vacuum switch (or a boost switch if forced induction) and can adjust to where you want it to kick in. Keep in mind that your air charge becomes more oxygenated with the addition of water and that is good. However, if you add too much then I guess it would decrease power. Just stick to the recommended nozzle size and you'll be fine.
There are several companies out there that offer this product and I poured over each site before I made the purchase. I was introduced to the idea back in the 70's when the NASA engineer next door made his own about two years before the Holley carb folks introduced theirs. He had one on a Vega of all things and was looking for increased mileage. I think he should have put it on his wife's Olds big block!
Go to the local auto parts and pick up a $0.99 bottle of wiendshield wiper fluid . Get the one that protects against the lowest possable temp, as it will contain more meth.
Meth is high octain fuel...im pretty sure it equevelent to like 110 octain. You can add quite abit of WOT timing with a little of that . That mixed with water will keep detination AWAY! Its should last a LONG time too if its only setup to comeone @ WOT...we are talking probably well over 1000miles for the adverage driver. 500 for me . I would do it, but i would need to send my chip to Tim for a retune.
You are correct, windshield washer anti-freeze is what I use. I mix it 50/50 with purified water (so as not to clog my injector). I even utilize my windshield washer tank for my injection fluid. You simply "tap" the bottom of the tank and it serves both purposes. It lasts a long time for a single stage setup like mine.