One of the most popular subjects in RC is speed. Experienced hobbyists love to point how the only two questions the uninitiated have when they see an RC running are: how fast and how much? Going fast isn’t just on the mind of newbs. Truth be told, we’re all interested in going faster. Racers quickly point out that it’s not how fast your car is that matters, what matters is how fast you get around the track. I know I’m guilty as charged, but if racers actually believed what they say, they wouldn’t be buying latest motors, speed controls and batteries every time something hot hit the shelves. Bashers, in contrast, readily admit they have a need for speed. The bottom line is that we’re all a little obsessed with speed, and more specifically, going faster. Check out these five top ways for going for faster with your electric ride.
Changing to a larger pinion will make your car faster. Most people learn that pretty quick and odds are you already knew that. A larger pinion will also make your electronics run hotter–specifically your motor and speed control. You’ll also lose runtime and acceleration. Pinions aren’t the only gears that can be changed on most RC cars. It’s often easy to swap out a spur gear. You’ll need to go smaller for more speed and it’s worth noting that the results will be far less noticeable per tooth count change. You can probably expect to gain 2mph from a single tooth pinion increase in most applications.
Increase Motor Timing
Increasing motor timing will increase rpm which in turn will result in more speed. Timing increases on brushless motors tend to yield more subtle results compared to brushed motors, but you will see positive results in both cases. You’ll have to watch your motor temperature and make sure it stays below 160 degrees F.
Changing tire size is like changing gearing. Taller tires cover more ground per revolution, so your car will be faster at the same motor rpm as it was with shorter tires. Off-road, the results will subtle–unless you go to a really huge tire. When racing on-road, specifically with foam tires, this is an important part of race tuning. A half inch increase (pretty significant) tire diameter will yield approximately an increase of about 4 or 5mph.
Higher Kv or Lower Turn Motor
This is the old fashion way to get more speed–add horsepower. Most brushless motors have Kv rating and the higher the Kv rating, the more rpm a motor will put out per volt. If the Kv rating isn’t listed, a turn rating will often be used. With brushed and brushless motors, a lower turn rating equals more rpm. Always check the limits of your speed control before installing a “hotter” motor. Increasing your motor’s Kv rating 2,200Kv can yield an increase of 20mph if your are using the same brand and model motor and have batteries that can supply the needed juice.
If you’re only going 25mph, aerodynamics aren’t going to play too noticeable of a role. If you’re going 50mph, aerodynamics will certainly start becoming influential on top speed. In addition to mounting a low profile, sleek body shell, mount it as low as possible and keep the wheel wells as small as possible. Open up the rear of the body to let trapped air to escape.
Higher Voltage Battery
Want to see some serious speed gains? Go from a 2S (2-cell) LiPo to a 3S (3-cell) LiPo. This jump from 7.4 volts to 11.1 volts can increase speed by as much as 25mph! Make sure your speed control can handle the extra voltage or the only thing you’ll be fast is going to the hobby shop for a new speed control. You’ll also want to make sure your chassis can accomodate the the larger pack.
Better Grip Tires
All the extra power won’t do you much good if you can put the power to the ground and put it to use. Invest in some high-quality aftermarket tires in a soft compound and you’ll be going faster.