How do you tune a RC nitro engine?

Answer 1

it is easiest to have a temp gun you can get one at any local hardware stores. first thing to do is locate all of your needles on your carburetor the main needle or high end needle is typically the needle located right where your fuel line enters your carburetor because it is the MAIN needle it controls the fuel flow next to be located it your low end needle usually found on the slide of the carburetor or if it is a rotary carb usually it is on the side of it as well (Note: if there is no needle on the rotary part of your carb it is because it has a preset low end setting.) then see if you have a mid range needle usually most RTR cars do not come with a mid range needle but it is usually on the opposite side of the low end needle then last but not least find your idle needle it is almost always on the front or back of the carb it will pointed at an angle into the case of the carb. next step is to close your main needle all the way then take it 3 full turns out (Note: this will in most cases make your engine run very rich which is easier to work with that way you know which direction you need to go with your main needle) then take your low and mid needles to flush with the carb case and/or slide of the carb or rotary then completely close the slide of your carb or the rotary and turn your idle needle until there is about a three millimeter gap between the case and slide or rotary. next step is to start your RC car and drive it around for a few seconds to build up the heat in your engine for accurate temperatures and like previously noted most likely be rich which is where your temp gauge comes in handy see what your temperature is your goal is to be within the range of 210 degrees to 240 degrees lean it out if necessary until you get in that range if you are already in that range you do not have to adjust if you are above that range you will need to richen your engine up. by turning your needles clockwise you will lean out that particular needle and if you turn it counter clock wise you will richen your engine. after you have reached that temp range it is time to tune your low end bring your car to a total stop and floor the gas if it bobbles with a big cloud of smoke you are too rich and will need to lean it out a little but if it bobbles and puffs no smoke and takes a while for your engine to come back down to its true idle you will need to richen your low end until it is a clean take off with a consistent line of smoke next is your mid range needle which is rather difficult to tell if it is in perfect tune but once you get your low end set right in the previous step and the transition is not smooth you will in most cases have to richen that needle but you may have to lean it out depending on wether the smoke line goes from one size to a bigger size then smaller you will need to lean it and vise-versa and then next to last you will need to set your idle by bringing your car to a complete stop and letting it idle if it is trying to die then you need to turn your idle needle clockwise to raise your idle or if you car is trying to keep moving while your just sitting there you will need to turn your idle needle counter clockwise to lower it and you want your idle to be low enough to have your car stay still when your idling it but you don't want it to be almost dyeing when its just sitting there and las but not least you will ned to drive your car around for a few minutes then temp your engine again and don't be surprised if your temp has changed from the previous reading because every adjustment will effect your temp and then you will need to fine tune your main needle and only do your main needle and remember you want it to be running in the same temp range as previously mentioned. remember always use small increments when your adjusting your needles think of your needle as a clock adjust the needle as if if was the long hand on the clock going from one number to the next in small steps and always remember your tune will change from day to day so never expect it to run the exact same from day to day.