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TeamFroggy
Joined: 15 Jun 2004
Posts: 81
Location: Brisbane Qld
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The key to knowing how to tune a glo motor is knowing what the different components of the fuel do. Methanol, 65 - 80% of the fuel is the fuel and is very flamable. Oil, castor or synthetic or a blend, 12-20% of the fuel is your lube to keep everything slick. The bit that confuses most people is the nitro, without getting to technical, nitromethane on its own is not flamable and requires the methanol to make it burn, when it is burnt nitro releases gases that act like a chemical supercharger causing a bigger bang. To properly tune the motor you need to look at the combination of chemicals in your fuel, more nitro with the same amount of oil means less methanol to create the catalitic reaction and ignite the fuel. This reaction is only created between methanol and platinum ( the little wire in the glow plug), infact I have seen high compression 2 stroke glow motors fire with no power to the glow plug at all. So as the methanol content in the fuel drops you need to compensate with more surface area of platinum, thicker wire does this and is called a colder plug. The OS A5 plug is a colder plug than the good old #8. At revs, most hot plugs will usually be ok with methanol being as little as 50% of the fuel, the problem really arises at idle when there is just not enough methanol to create the catalytic reaction to make the plug glow, this is where the colder plug, with more platinum helps the engine run, the increase in surface area make up for the lack of methanol and generates the same amount of reaction.
Now for your particular aplication, Glen, I don't believe 20% nitro is to much for that motor, but I also do'nt think you would see a noticable difference in performance between 10% and 20%. Are you racing it at competition levels? If not then you are probably wasting money on nitro, it is the most expensive component of the fuel.
When you tune these glo motors, main (high speed) mixture is done first, as this meters the total fuel feed to the carby, any major adjustment here will sightly alter the secondary mixture. The secondary mixture screw, commonly called the idle or low speed mixture is done second. The idle that you mentioned Glen, seems to be the idle stop and will need to be adjusted if the car is idling to fast or slow. Changing the nitro content in your fuel wont require major adjustments on the mixtures and remember that any adjustments should only be very small. I make it a rule never to turn a needle more than 1/16th of a turn in one go. If your not sure on how exactly to tune the motor, go to the track with your car and ask a few guys what they think, often its a matter of listening to how an engine revs, idles and transitions between that tells the person what to do.
As for driving them, well I'm no expert but I get by and I could understand you needing to keep the power on to keep it straight. Cars just don't seem to do it for me, sure they are a bit of fun but theres nothing like the rush of flying a 6.5kg warbird with one wingtip about to scrape the ground on a high speed gallery pass. Like this http://202.173.151.96/forum/images/Flash%20Gordon/2006515162351_IMG_3789.jpg
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Regards,
Marshal J.
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Sat Jul 29, 2006 7:59 pm |
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RoboWars Australia Forum Index
-> Off-Topic
stick some naptha in the tank
but with it all tuned up it was still beating a few of the other 1/10th nitros weee. just need to learn to drive it lmao... keeps spinning out in the turns, seems like you need to keep the power on to keep it straight.
\
the 5% was going really really well and was about the same as most cars there except for ones that looked like those TC-3 cars with nitro motors in em which where pretty insane speed wise. hopefully ill get some form of power kick from the new fuel.
thankfully no damage at all except the exhaust pipe from the engine which got a bit of a ding at the end so ill peel that back out to shape and all shall be well.
