4000KV motor on a 2S LiPo
A 4000KV motor on 2S turns about 29,600 RPM at 7.4 V nominal and 33,600 RPM on a fresh 8.4 V pack. Geared at 12:1 on 4.3 in tires, that is a 31.6 mph ceiling.
HOOVO 7.4V 70C 6200mAh 2S Lipo Battery Hard Case with Tracxas
- 2S
- 6200mAh
A 2S LiPo is 7.4 V nominal and 8.4 V full, which is what sets the RPM on this page.
$39.70 listed price, changes often
Check price on AmazonWhat RPM does 4000KV make on 2S?
| Pack state | Volts | Motor RPM |
|---|---|---|
| Nominal (3.7 V per cell) | 7.4 V | 29,600 |
| Fresh off the charger (4.2 V per cell) | 8.4 V | 33,600 |
High KV on 2S or 3S is the normal 1/10 brushless setup, from the Slash to the Granite. KV is unloaded RPM per volt, so real RPM under load is lower. See RC motor KV explained.
What top speed can 4000KV on 2S reach?
Theoretical ceiling in mph by final drive ratio and example tire diameter. Real cars usually reach about 85 percent. Measure your own tires and use the top speed calculator for an exact figure.
| FDR | 3 in 1/18 to 1/16 truck | 4.3 in 1/10 short course or stadium truck | 5.5 in 1/10 monster truck | 4.4 in 1/8 buggy | 6.3 in 1/8 monster truck (3.8 in wheel) |
|---|---|---|---|---|---|
| 6:1 | 44 | 63.1 | 80.7 | 64.6 | 92.5 |
| 8:1 | 33 | 47.3 | 60.5 | 48.4 | 69.3 |
| 10:1 | 26.4 | 37.9 | 48.4 | 38.7 | 55.5 |
| 12:1 | 22 | 31.6 | 40.4 | 32.3 | 46.2 |
| 16:1 | 16.5 | 23.7 | 30.3 | 24.2 | 34.7 |
| 25:1 | 10.6 | 15.1 | 19.4 | 15.5 | 22.2 |
| 40:1 | 6.6 | 9.5 | 12.1 | 9.7 | 13.9 |
Other cell counts for 4000KV
Other motors on 2S
- 1600KV on 2S
- 2000KV on 2S
- 2200KV on 2S
- 2400KV on 2S
- 2700KV on 2S
- 3000KV on 2S
- 3300KV on 2S
- 3500KV on 2S
- 4600KV on 2S
Motors near this KV and packs for this cell count
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Frequently asked questions
How fast is a 4000KV motor on 2S?
The motor spins about 29,600 RPM unloaded at 7.4 V. Road speed depends on gearing and tire size: at a 12:1 final drive with 4.3 in tires the theoretical ceiling is 31.6 mph, and real cars usually reach 80 to 90 percent of that. The table on this page shows the ceiling across common gearing and tire sizes.
Can I run a 4000KV motor on 2S?
Only if the motor and ESC are rated for 2S and the full-charge RPM of 33,600 is within the motor's maximum. This pairing stays under 50,000 RPM, which most suitable motors handle. Gear conservatively at first and check temperatures after a few minutes.
RCCarCalc is researched guidance, not professional advice. Figures come from published manufacturer specifications, listings and verified owner reports, not hands-on testing. Speeds are theoretical or as listed; real results depend on gearing, battery, tires and terrain. See how we research.