Picking out the right arrma infraction 3s upgrades is basically a rite of passage for anyone who spends more than a weekend ripping this truck around a parking lot. It's a blast right out of the box, don't get me wrong, but the 3S BLX platform has a few quirks that become pretty obvious once you start pushing it. Whether you're tired of the stock servo giving up or you just want to stop your motor from hitting sun-surface temperatures, there's plenty of room for improvement.
The Infraction 3S is designed for "street bashing," which is basically a fancy way of saying we're going to do high-speed drifts and burn through tires until the neighbors complain. Because of that, the upgrades usually fall into a few specific buckets: making it faster, making it stop breaking, and making it actually go where you point it.
The Tire Tax and What to Do About It
Let's be real for a second—the biggest "upgrade" you're going to be buying constantly is tires. The stock dBoots Hoons are actually pretty decent for grip, but they have the lifespan of a snowflake in a microwave if you like doing donuts. If you're looking for arrma infraction 3s upgrades that actually save you money in the long run, you might want to look at different compounds.
Some guys swear by the Gold compound Hoons for a bit more longevity, while others jump straight to GRP tires. GRPs are a bit of a staple in the speed run world. They're belted, so they don't balloon at high speeds, and they tend to handle the heat of a hot asphalt parking lot a bit better than the stock rubber. Just keep in mind that changing the tire diameter even slightly can mess with your gearing and top speed, so keep an eye on those motor temps after the first run.
Keeping the Heat Under Control
Speaking of heat, the 3S BLX system is notorious for getting a bit toasty. It's a compact chassis, and that motor is working hard to push a heavy-ish truck to 50+ mph. If you're running back-to-back packs, you're going to need better cooling. This is probably the most essential category of arrma infraction 3s upgrades if you want your electronics to last more than a summer.
A high-speed cooling fan is a total game-changer. The stock plastic fan shroud is okay, but swapping it for a twin-fan setup or a high-RPM aluminum fan (like something from Power-Up or even a decent 30mm or 40mm hobby fan) makes a massive difference. You'll also want a decent heat sink that actually has some surface area. If you can keep that motor under 160 degrees Fahrenheit, you're in the clear. Once you start pushing 180 or 190, you're playing a dangerous game with the magnets in that motor.
Fixing the "Mushy" Steering
If there's one thing that drives me crazy about the stock Infraction 3S, it's the steering. The stock Spektrum servo is well, it's fine for a beginner, but it's slow and lacks the torque to really snap the wheels back when you're mid-drift. If you want the truck to feel responsive, a servo upgrade is mandatory.
Look for something with metal gears and a bit more speed. You don't need a $200 crawler servo, but something in the $40 to $60 range with a decent transit speed will make the truck feel entirely different. While you're at it, check the steering rack. The plastic can be a bit flexy. Swapping in the CNC aluminum steering bellcranks removes that "mushy" feeling and makes your inputs feel way more direct. It's one of those arrma infraction 3s upgrades that you don't realize you need until you actually try it.
Drivetrain Durability and Power Delivery
The 3S drivetrain is mostly plastic, which is great for weight but can be a headache when you start upping the power or bashing hard. The power module is easy to work on, but those plastic spur gears can strip if your gear mesh isn't perfect or if a small pebble decides to ruin your day.
A lot of people jump straight to a metal spur gear. If you do this, just remember that you're moving the "weak point" further down the line. Usually, it's better to strip a $5 spur gear than to blow up your differential, but if you're precise with your mesh, metal is the way to go.
Also, don't ignore the shocks. The stock oil is a bit thin for high-speed street runs, causing the truck to bounce or "hop" when you hit a small pebble at 40 mph. Thickening up the shock oil or moving to some aluminum body shocks can help keep the tires glued to the pavement. A flatter, more stable truck is a faster truck, especially when you're trying to hold a long slide.
Gearing for Speed Runs
If you've got a big open space and you want to see how fast this thing can actually go, you're going to be looking at pinion gears. Arrma usually includes a "speed pinion" in the box, which is a great start. But if you've handled the cooling issues I mentioned earlier, you can push it a bit further.
Going up a tooth or two on the pinion will give you more top-end speed, but it'll also make the motor pull more amps and get hotter. It's a balancing act. If you're doing short speed passes with plenty of "cool down" time in between, you can get away with some pretty aggressive gearing. Just don't expect to do 20 minutes of non-stop drifting with a speed pinion installed; you'll likely thermal the ESC or cook the motor.
Protecting the Body and Chassis
Let's face it: the Infraction body looks amazing, and it's one of the main reasons people buy the truck. But since it sits so low, the front splitter and the underside of the chassis take an absolute beating.
One of the smartest arrma infraction 3s upgrades isn't actually a mechanical part—it's a set of skid plates or a chassis protector. A simple Kydex or stainless steel skid plate on the front and rear will save your chassis from getting ground down by the pavement. There are also "roof skids" and body protectors that can help keep that beautiful paint job from getting shredded when you inevitably flip the truck at 45 mph.
Electronics and Radio Gear
Finally, let's talk about the radio. The stock SLR300 receiver and SLT3 transmitter are functional, but the range isn't incredible, and the latency is noticeable once you get used to better gear. If you plan on doing long-range speed runs, upgrading to a radio system with better range and more tuning options (like end-point adjustments and steering expo) is a solid move. It gives you way more confidence when the truck is 200 feet away and moving at terminal velocity.
Some people also choose to swap the ESC. The stock Firma 100A is solid, but if you want to run 4S (which some people do, though it's "unsupported"), you'll need to beef that up. Even staying on 3S, a more programmable ESC can let you tune the "punch" and "brake" settings more effectively, which helps in getting those perfect drifts.
Wrapping It Up
At the end of the day, the best arrma infraction 3s upgrades are the ones that fix what's bothering you. If you hate how it turns, fix the servo. If you're tired of waiting for it to cool down, fix the fans. You don't have to throw the whole catalog at the truck on day one. Part of the fun is changing one thing, seeing how it handles, and then moving on to the next tweak. Just keep a spare set of tires handy—you're definitely going to need them.