Fastest 1/5 Scale Gas RC Cars: Speeds, Engines and Upgrades
1/5 scale gas RC cars use two-stroke petrol engines, usually around 23–32 cc, to drive large off-road buggies and trucks. Stock speeds are typically in the region of 35–50 mph, depending on model, engine, gearing and tyres. Among the best-known fast models are the Losi 5IVE-T 2.0 (4WD short-course truck), the HPI Baja 5B buggy and similar 4WD 1/5 models. With bigger engines, pipes and gearing, modified cars reach much higher speeds, but tyres, heat and safety become the limits.
By Kyle HilsonUpdated: October 20263 min read
Fast models
| Model | Drive | Notes |
|---|---|---|
| Losi 5IVE-T 2.0 | 4WD | Short-course truck; often cited around 50 mph+ with tuning |
| HPI Baja 5B / 5T | 2WD | Commonly cited around 35–45 mph stock |
| Rovan, King Motor and other Baja-compatible models | 2WD/4WD | Budget alternatives; speeds vary |
Speeds from dealer and community reports, checked October 2026, not our own measurements; they vary with engine and setup.
What limits speed
A 1/5 car weighs 10 kg or more, so engine power, gearing and traction all matter. Taller gearing raises top speed but slows acceleration and makes the clutch and engine work harder. Tyres can balloon or come off rims at high speed. Off-road suspensions and bodies aren’t built for very high speeds on tarmac, and stability falls. Fast cars in general are compared in fastest gas RC car in the world.
Engines
Most stock 1/5 cars use around 23–30 cc air-cooled two-strokes with Walbro-type carburettors. Bigger-bore engines (32 cc and up), performance pipes and porting increase power. Fuel is petrol mixed with two-stroke oil. Tuning the carburettor is explained in Walbro 1107 carburettor.
Common speed upgrades
- Tuned pipe for more power.
- Larger engine or big-bore kit.
- Taller pinion/spur gearing.
- Stronger clutch springs and shoes.
- Belted or glued tyres to stop ballooning.
- Stiffer suspension and lower ride height for on-road runs.
Safety
- A heavy car at speed can seriously hurt people; run only in open, empty areas.
- Fit and test a radio failsafe that cuts the throttle.
- Wear hearing protection near loud tuned engines.
- Handle fuel safely and refuel with the engine off.
- Check local rules on noise and where you can run.
Maintenance for speed
Fast runs stress everything. Check the air filter, clutch and bearings, keep the engine clean and well tuned (slightly rich is safer than lean), and look for cracks in suspension parts. Engine overheating from a lean mixture is a common cause of seizures.
Electric alternatives
Large electric cars now often match or beat gas cars in speed, with less noise and maintenance but expensive batteries. If outright speed is the goal, high-voltage electric cars are usually faster. See fast RC cars 100 mph.
Measuring speed
Many top-speed claims come from GPS units strapped to the car on a long, smooth surface, which is the most practical way to measure it yourself. Run in both directions to cancel out wind and slope, and take the average. Speedometer apps that estimate speed from video are less reliable. Remember that a 1/5 car on a long straight needs a lot of room to slow down, so plan a safe stopping area before going for a speed run.
FAQ
What is the fastest 1/5 gas RC car?
The Losi 5IVE-T 2.0 is often cited among the fastest stock; modified cars go faster.
How fast is the HPI Baja 5B?
Commonly around 35–45 mph stock.
Can a gas RC car do 100 mph?
Only heavily modified ones in special speed-run conditions.
Are gas RC cars faster than electric?
Usually not; high-voltage electric cars are often faster.
More on this topic: the complete RC Cars guide covers the basics behind this article.
About 20 years in RC. Mostly boats in the NAVIGA Mini Eco Expert class, with many self-made parts; also a King Motor Baja 5B, a home-built electric plane, home-built nitro planes he has flown, and an RC helicopter. More about SwellRC
