Nitro Car Basics

Many of those who are starting their RC hobby are facing a decision between an electric car and a nitro car. There are a few basic things to know about nitro cars’ features and maintenance routines. Nitro cars have a unique throttle response, longer runtime and they make that special sound that many people like so much about nitro cars. In order to have all of these, proper maintenance is required. Also, in order to maximize the life span of the car, special servicing routines during and in between runs are required. Bearing this advice in mind and following it, you should be able to avoid all the major pitfalls. What’s better than to drive the whole day without problems and enjoying the properties of your nitro car?

In this article, the focus is not on the engine itself, but the basics of the hobby as well as basic maintenance. With a proper understanding of how the car works and why it’s important to service it properly, you’re more likely to enjoy the hobby.

With nitro cars, it’s important to remember that it’s not all about the engine. In addition to a few special things when it comes to maintenance, the car requires all the same maintenance routines as an electric car does. In nitro cars, the bearings tend to wear out faster than in electric cars. This is caused by the warm engine and exhaust pipe and the vibration when the engine is running.  The bearings in transmission in particular wear out faster than in electric cars.

Take your time to familiarize yourself with the car and learn about the required maintenance routines and see how everything works during the first few runs, especially the engine. The tuning depends on the sound, throttle response and temperature of the engine, so make sure you have a peaceful spot on the track where you can study and observe your car during the first runs.

Note! Not everyone likes the sound of the engine, so please find out if there are any quiet time regulations in the area.

Functional principles

One of the most important things about combustion engines is that the engine requires the right ratio of fuel and air in order to run correctly. The tuning of the engine, the type of fuel and the air filter will affect how the engine works. When you’re starting the hobby, it’s good to keep in mind that the air filter must be replaced with a new one for every run. This is because when the air filter is clogged, the engine stops working efficiently, which will show as poor throttle response and increased smoking of the engine. When there’s a lot of dust in the air, it’s good to change the air filter somewhere in the middle of the day to avoid problems. 

Fuel also matters.

When buying fuel, make sure that you pick the right one for your engine – airplane and car fuels have their own mixtures. In general, you can find fuels with a nitro mixture of 16–25%. As a general rule of thumb, the traditional RTR engines run with 16% fuel and 1:8 engines with turbo plugs with 20–25% fuel.  However, you can always use fuel with a lower nitro ratio. With a higher ratio you might damage your engine. Check the car engine or the manufacturer’s instructions regarding fuel use.

Tip!  Also bear in mind that the fuel contains oil, which is meant to lubricate the engine as it flows through it. Oil is heavier than methanol, so when stored, the oil sinks at the bottom of the canister. So when you get back to the track, shake the canister before refueling your car.

Note! Don’t forget that fuel is toxic. Like really, really toxic. Handle it with gloves on, and make sure none of it ends up in your mouth or eyes.  So while refueling, keep your mouth closed and eyes far away from the fuel. And keep your hands clean too.

The most common problems with the engine are usually result from the things already mentioned.  As the fuel lubricates the engine, it must be clean. And the air filter must also be clean. All the dirt that goes through the engine in the fuel or the air will wear out the engine.

Tip! Every time you are changing the air filter or the glow plug, make sure to clean the areas around them first. This way you can make sure no dirt will not end up to the combustion chamber. When changing the dirty air filter or the glow plug, put the car on its side while changing them so the loose dirt on it won’t fall into the engine.

If you’re a beginner and notice the running of the engine changes during runs, try to avoid tuning the engine too much. If the running changes for the worse and the engine doesn’t rev up normally, the explanation can often be found in the air filter. Also make sure to check the mechanical condition of the car and that the driveline moves freely. Tuning should be done when the engine is in running temperature and with clean air filter.

As a general rule: do not tune anything if you don’t know what you’re doing.

For a combustion engine, it’s important that it runs in the correct temperature.  Every engine has it’s own temperature range in which it is designed to run. Check your car’s engine’s temperature range in the manual. The temperature is measured right on top of the glow plug or the bottom of the engine head. The running temperature is usually ca. 105–125°C.  If the temperature is above or below the range, the engine is tuned wrong and this will show in the way the engine runs. One of the most important tools for tuning the engine is the thermometer, which should be found in every RC hobbyist’s toolbox.

Glow Plug

One frequent problem that causes a lot of frustration is that the car won’t start up. Sometimes the car runs perfectly for a day and without any symptoms won’t start up again. For this reason, you should always have a spare glow plug because it’s often the reason why a car won’t start up again. There are many reasons why the plug stops working, but it’s also one of the parts that wear out fastest.

Stopping the engine

When turning off the engine, always follow the car/engine manufacturer’s instructions. If the manual does not say anything about turning off the engine, an easy way to do it is use a tool on the flywheel which will turn off the engine immediately. In practical terms, by pressing the tool on the flywheel you stop the running of the engine.

Memo list for when leaving for the track:

• Full battery on the transmitter or a new set of batteries
• Fully charged glow starter or at least a new set of batteries
• Change the air filter
• Thermometer
• Spare glow plug
• Spare air filter (oiled)
• Tools
• Fuel

Memo list for runs:

• Remember to observe the running of the engine during runs. If the engine stops running normally, the air filter may be clogged. Note! General note about the fuel mixture: There must always be a little bit of smoke, which means the engine is properly lubricated.
• The temperature: After reaching running temperature, measure the temperature a couple of times to make sure the temperature remains in the right range. Before you turn off the engine, measure the temperature as soon as possible after the car has stopped.
• If the steering feels sluggish or the throttle does not return to idle normally, it’s the first sign of low or empty batteries in the receiver -> recharge or replace.

Rules at the track:

• If driving at a track with other drivers with electric cars, follow the track rules regarding turns and run times. If there are no rules then agree with others on turns so everyone can enjoy their time at the track.
• To reach the running temperature, use a separate table. You can usually find one at the pit. Otherwise you can do this at the side of the pitlane. Other people may not like the noise and exhaust residue on the table or on top of their tools and equipment.

Memo list for the end of the track day:

• Drive until the tank is empty
• Remove the battery/batteries from the car
• Clean and inspect the car
• Check for possible faults
• If the car is stored for a long period of time – drop a few drops of After Run oil through the plug hole.
• Store the fuel in a cool and dark place out of the reach of children. Remember to close the canister properly.