RC Driving with Nitro Power

By Terry Dunn

Until recently, Terry Dunn had never owned (or even driven) an RC car with an internal combustion engine. And then he got his hands on the Kyosho Inferno NEO 3.0.

I've owned dozens of RC cars and trucks throughout my lifetime. Those vehicles covered a wide range of sizes, styles, and performance. But until recently, my RC pedigree was lacking in a very significant segment of the hobby. All of my surface vehicles were powered by electric motors. I had never owned (or even driven) an RC car with an internal combustion engine. That box has now been checked in a big way. In this article, I'll share my experiences uncovering the pros and cons of these screaming machines!

There are a few different types of engines that are used across the spectrum of RC vehicles. The most common engines for RC cars are 2-stroke variants that burn a special fuel containing nitromethane. For that reason, they are often called "nitro" engines. Some modelers also refer to them as "glow" engines because they use a glow plug rather than a spark plug.

About the Inferno NEO

My nitro-powered car is the Kyosho Inferno NEO 3.0 ($350). The Inferno is a serious machine! This 4-wheel-drive buggy weighs about 7.5 pounds (3.4 kg) and has a wheelbase of 12.8 inches (325.5mm). Its beefy nylon suspension components are attached to an aluminum chassis. The Inferno has traditionally been Kyosho's flagship 1/8-scale off-road racing platform. But this NEO variant is being touted as a backyard basher. That's great for me since I'm not into competitive racing.

The Kyosho Inferno NEO is a factory-built, nitro-powered machine that is ideal for experienced hobbyists.

With most versions of the Inferno, you must assemble a kit and provide your own choice of engine, radio equipment, tires, and other bits. That is not the case with the NEO. Not only does the Inferno NEO come with nearly everything you need to get it going, it is also pre-built at the factory. Even the body is painted for you. The only parts that I had to supply were eight AA-size alkaline batteries (four for the radio transmitter and four for the onboard radio receiver), a glow plug igniter (I'll explain later), fuel, and a squeeze bottle to transfer fuel to the car.

There are two schools of thought when it comes to factory-built RC cars. There is definitely value in assembling your own car from the ground up to understand how all of the parts work together. That knowledge gives you a leg up when performing maintenance or repairs, which are both integral aspects of RC car ownership.

The Inferno NEO is based on racing versions of the Inferno, but it includes budget-friendly gear to keep the price reasonable for bashers.

There is also benefit in having a factory-built car. None of my previous cars had things like the disc brakes or centrifugal clutch found on the NEO. Rather than having to figure these things out by trial and error, I was confident that they were set up correctly out of the box. I knew that the car would perform perfectly at the start and also provide a proper reference when it's time to fix things.

It is interesting to note that the all-in-one Inferno NEO is exactly half the cost of just a chassis kit for the current racing version of the Inferno, the MP9 TK14 ($700). I think the difference is that the MP9 includes a lot of high-end chassis tuning parts and weight-saving pieces. I'm sure that top-tier racers appreciate things like hard-coated aluminum shocks and lightweight bevel gear shafts. I am equally sure that bashers like me will not miss them.

What's Inside?

The included radio system is Kyosho's 2-channel 2.4GHz Syncro pistol grip unit with a matching receiver. I've used it with several other Kyosho vehicles and like it a lot. It isn't fancy, but it is comfortable and has the adjustment options that I typically use (trim, servo reversing, servo end-points). I noticed that the foam grip on the steering wheel slipped off easily. So I added a couple pieces of double-sided tape between the foam and the plastic wheel it sits on.

A big, fast car like this needs a beefy servo to command the steering. The NEO includes hi-torque servos with metal gears for both steering and throttle control. After installing the batteries for the transmitter and receiver, I performed a quick test to ensure that both servos were moving in the correct directions (they were).

I replaced the alkaline onboard batteries with a 4-cell pack of NiMH cells. I also added an inexpensive battery monitor to indicate when it needs to be recharged.

I noticed that the steering servo operated erratically when I turned the steering wheel right and left fairly quickly. It turns out that the onboard alkaline cells just couldn't deliver enough electrical current when the steering servo was under load. I swapped out the alkaline cells for a 4-cell pack of 1100mAh NiMH batteries. This power source has no trouble keeping the servos well fed. Be sure to factor that add-on into your budget. I also added a simple voltage indicator so that I can tell when the battery needs to be recharged.

The engine included with the Inferno NEO has a basher-friendly pull start just like your lawn mower! It displaces a whopping .21 cubic inches (3.4cc). It may sound small, but this engine can really get the Inferno NEO moving! Before you can do that, however, it is necessary to break in the engine.

The NEO's included engine uses a simple pull-start. Note the red glow plug igniter that is a necessary accessory for this model.

A clever feature of this kit is that it includes a removable plastic governor that fits inside the carburetor intake. This governor is used during break-in to limit the engine's power and prevent damage. You can then remove the governor to really cut loose.

Kyosho includes this simple governor to protect the engine by limiting power during the break-in process.

Now let's get back to explaining the glow plug igniter. It is a tool that connects to the outside of the glow plug and provides about 1.5 volts to the small coil within (making it "glow") which ignites the fuel in the cylinder. The igniter is only necessary when starting the engine. Once it is running, the heat from combustion of the fuel is sufficient to keep the coil element glowing.

The glow plug igniter I chose is the Kwik Start from Du-Bro, which includes a rechargeable NiCad battery and charger. The glow plug on the Inferno's engine is somewhat buried within a tall stack of heatsinks. I went with the XL version of the Kwik Start ($28) to make sure it would reach. I also picked up an 800cc fuel bottle from Du-Bro ($9). I use it to transfer fuel from the fuel container to the car's tank.

Getting Started

The manual explains the break-in process but leaves out a few details. Even things like knowing which type of fuel to buy (I used fuel with 20% nitromethane) can leave a rookie stumped or making a poor decision. If you're not familiar with the operation of nitro engines, you'll probably want to have an experienced buddy help you out. My misspent youth included plenty of time with nitro engines on RC airplanes, so I felt confident that I could sort things out. And I did…eventually.

I'd love to tell you that the Inferno fired up (get it?) on the first pull. But that was not the case. It took me several minutes of fumbling though silly mistakes and basic troubleshooting before I got the engine running. But once started, it ran perfectly. Kyosho suggests running five tanks of fuel to break in the motor. For the first two tanks, I simply started the motor and let it idle. Each tank lasted for nearly an hour! I completed the break-in process by driving the Inferno around for three tanks of fuel with the governor still in place.

You can access the fuel tank and glow plug with the car body in place. However, it is necessary to remove the body and the carburetor air cleaner to prime the engine. I usually keep those parts detached until the engine starts. Then I kill the engine, replace the filter and body, and restart the engine.

The pull start is convenient. I like that I do not have to lug around a separate starter. Every now and then, the starter rope does not retract on its own. I can coax it back by jabbing the rope spool with a stiff wire. It's a simple fix, but annoying to do in the field.

Even after the break-in, I sometimes had trouble getting the Inferno running. In hindsight, success all boiled down to being very consistent with my preparation and approach to starting. Now that I have a system worked out, things have gone much more smoothly.

Driving the Inferno

There are a few factors that make driving the Inferno NEO a unique experience for me. Near the top of that list are this car's speed and power. I've driven a few large, powerful RC cars before, but this one stands out to me. It looks and feels like it could power right over (or through) just about anything. The wail of the engine and trail of white exhaust smoke add to the aura. It's fun to take the wheel of such a machine.

The Inferno is fast, powerful, and fun to drive. Its performance and noise demand special consideration when choosing where to operate it.

While the NEO qualifies as a basher, it is not the kind of car that you can simply fire up in your backyard or empty corner lot. You need to make sure that there is adequate room to let the car rip without having any people or things in the way. The car itself is super-tough, but I worry more about the fragility of the things it might crash into. I've been limiting myself to abandoned parking lots and large, grassy fields, being careful to keep my distance from pedestrians and dog walkers.

Another important consideration when running the NEO, or any other nitro-powered RC model, is noise. There is no other way to put it: this thing is loud! In addition to its volume, the note of a small, screaming 2-stroke engine can be very harsh. While you're having fun zipping around your yard or street, your neighbors may only hear infinite pairs of fingernails and chalkboards. In fact, my RC airplane club recently lost our flying field due to noise complaints. It's no joke.

The NEO comes equipped with a full set of all-terrain tires. I have driven on pavement, grass, snow, and some really soupy mud. The tires have performed quite well in all situations. I was especially surprised by how well the tires worked in snow. They kept the NEO racing forward until I ventured into the really deep stuff. I'd like to get a set of paddle tires to try in those conditions.

The included all-terrain tires work well on many surfaces. The Inferno will even power through snow!

With the stock set-up the NEO does not accelerate as fast as some of my brushless-powered electric rigs. But it's no slouch. That is especially true on pavement. By the time it hits top speed, it is really cruising! A lot of the suspension and handling adjustments that have evolved on race versions of the Inferno are integrated into the NEO. I've found the box-stock setup to be quite good. It has a fair bit of understeer on pavement, but that is easy to manage with the throttle. I think that the handling is very neutral on off-road surfaces with no obvious tendency to under or oversteer. Plus, it handles jumps like a champ!

Each tank of fuel typically lasts around 10 minutes. One of the advantages of nitro-powered vehicles is that you don't have to carry spare batteries or chargers for multiple runs. You just refill the fuel tank and go. Since the NEO's tank can be refilled without even removing the body, I can top it off and be back in the groove in no time. My total run time on an outing is only limited by the amount of fuel I have on hand. The charge state of the receiver battery is hardly ever a factor.

For those who like numbers, I've done some simple calculations. The Inferno's tank holds 100cc (3.4 fl oz) of nitro fuel. A gallon of 20% nitro fuel typically costs around $30. At that price point, each 10-minute drive with the NEO burns about 80 cents' worth of fuel…not too shabby.

Final Thoughts

Driving a nitro-powered RC car provides additional sights, sounds, and even smells, over electric models. It is pretty exciting stuff. There is no clear edge in performance with either power system. The biggest difference between nitro and electric power is whether you want to carry extra fuel or extra batteries for additional driving.

While the Inferno NEO is a turnkey basher and it is easy to drive, I would not recommend it for rookie hobbyists. It is a complex machine that demands a fair amount of know-how to get it going. It also requires routine maintenance to keep it rolling. Beginners should start out with something simple and work their way up to a 1/8-scale nitro buggy like the Inferno.

I think the NEO is perfect for hobbyists like me, who are already comfortable driving and wrenching on RC cars. It provides a smooth transition into the world of nitro power. I am excited to continue exploring the Inferno's capabilities over the winter. I may even take it to a race track in the spring!

Terry is a freelance writer living in Buffalo, NY. Visit his website at TerryDunn.org and follow him on Twitter and Facebook. You can also hear Terry talk about RC hobbies as one of the hosts of the RC Roundtable podcast.