I used to run 20% fuel and now i changed over to this pink Omega Stuff (15%) AND could it be runnnig longer?...seems like it like an extra five minutes at least

It doesn't seem likley that a different fuel will add five minutes to your run time. My guess is that something or a few other factors are causing longer run time. You could be running leaner, causing more run time, but still five minutes is alot.

If you are gaining 5 minutes... hook me up!!

When you retune for lower nitro, you end up leaning it out to get it crisp. Here is your extra time.

Nitro supports the burning of aditional fuel with the same amount of air, so running less means running leaner to arrive at the ideal air/fuel [link=http://dictionary.reference.com/search?q=stoichiometric](stoichiometric)[/link] ratio .

[:@]


I hate stoichiometry!

Illl just act like i know what your talking about

Hope i can make it understandable:

Nitromethane requires less air to burn efficiently than does Methanol.
This means when you increase nitro content in fuel, you need less air to burn it efficiently.
Conversely, with a fixed volume of air, as you increase the nitromethane content in fuel, you need to burn more of it to burn it efficiently.

Our motors can draw a fixed amount of air into the combustion chamber on each stroke. To compensate for higher nitro content, we increase the amount of fuel burned in that fixed amount of air by tuning the hsn needle richer.

Therefore you are using more fuel on each stroke, and your runtimes go down, however you are burning more fuel, so you generate more power.


As an interesting aside. Methanol has a higher energy content than Nitromethane. You would think increasing the Nitro and decreasing the Methanol would cause you to lose power. In fact, because of the stoiciometric ratios of the two fuels, you can burn more nitro on less air, therefore an efficent engine burns a much greater quantity of the less energetic fuel, increasing generated power, but decreasing fuel efficiency.

ME TOO! I had that crap in Chem I last year.

But anyway, it does make perfect sense. I may end up dropping down to the 16% blend of Trinity MH. I don't need any more power, and a little more run-time is always good. I am out of fuel right now, so that would be a perfect time to pick it up.

gerwen:

Thanks. That is the best explanation I have heard. I know the basics of volumetric efficiencies in cars, real ones, but never new how the fuel effected that balance.

Now I know.

Got this off a website:

Stoichiometric or Theoretical Combustion is the ideal combustion process during which a fuel is burned completely. A complete combustion is a process which burns all the carbon (C) to (CO2), all hydrogen (H) to (H2O) and all sulfur (S) to (SO2). If there are unburned components in the exhaust gas such as C, H2, CO the combustion process is uncompleted.

I think I get it - kinda neat when you think about it.

Since our RC cars do not have a way to increase O2, unless you put a super charger on it, then it is the fixed amount. To burn the fuel properly, you need to either add more or less to get a perfect burn. By changing the amount fuel percentage, changes the Stoichiometric. You need to then adjust as you mentioned the HSN to match the air in the combustion chamber - Brilliant!!!

Thanks guys - I think I learned something today.