EMAX ECO II 2004

EMAX ECO II 2004
Image: racedayquads.com
Stator2004
KV options2000, 2400, 3000
Weight18.0 g
Shaft1.5mm
Max cells4-6S (2000/2400KV) / 3-6S (3000KV)
Configuration12N14P
Dimensions24.7x19.2 mm
Mount12x12mm
Winding resistance158 (2000KV) / 110 (2400KV) / 80 (3000KV) mOhm
Max thrust1170 g
Price (approx.)16.49 USD

At 18 g it is 1.2 g heavier than average across the 5 2004-class motors in our database (avg 16.8 g).

Thrust data (EMAX bench test)

KVPropBatteryThrottleCurrentRPMThrustEfficiency
1600 Gemfan SL4525-3 6S 40% 2.5 A 18200 244 g 4.07 g/W
1600 Gemfan SL4525-3 6S 50% 3.5 A 20300 312 g 3.71 g/W
1600 Gemfan SL4525-3 6S 60% 4.3 A 22200 376 g 3.64 g/W
1600 Gemfan SL4525-3 6S 70% 6.1 A 24800 482 g 3.29 g/W
1600 Gemfan SL4525-3 6S 80% 8.4 A 26800 582 g 2.89 g/W
1600 Gemfan SL4525-3 6S 90% 9.8 A 29400 665 g 2.83 g/W
1600 Gemfan SL4525-3 6S 100% 10.5 A — 695 g 2.76 g/W
1600 EMAX AVAN 5120-3 6S 40% 2.9 A 15200 308 g 4.43 g/W
1600 EMAX AVAN 5120-3 6S 50% 4.5 A 17400 415 g 3.84 g/W
1600 EMAX AVAN 5120-3 6S 60% 6.4 A 19600 543 g 3.54 g/W
1600 EMAX AVAN 5120-3 6S 70% 8.9 A 22200 685 g 3.21 g/W
1600 EMAX AVAN 5120-3 6S 80% 12.4 A 23600 825 g 2.77 g/W
1600 EMAX AVAN 5120-3 6S 90% 14.6 A 25900 915 g 2.61 g/W
1600 EMAX AVAN 5120-3 6S 100% 15.2 A — 951 g 2.61 g/W
1600 Gemfan SL5125-3 6S 40% 2.8 A 16100 294 g 4.38 g/W
1600 Gemfan SL5125-3 6S 50% 4.1 A 18100 378 g 3.84 g/W
1600 Gemfan SL5125-3 6S 60% 5.9 A 20400 496 g 3.5 g/W
1600 Gemfan SL5125-3 6S 70% 8.1 A 22800 630 g 3.24 g/W
1600 Gemfan SL5125-3 6S 80% 10.9 A 24800 759 g 2.9 g/W
1600 Gemfan SL5125-3 6S 90% 13.8 A 25830 880 g 2.66 g/W
1600 Gemfan SL5125-3 6S 100% 14.1 A — 935 g 2.76 g/W
1600 Gemfan SL5126-2 6S 40% 2.8 A 16300 297 g 4.42 g/W
1600 Gemfan SL5126-2 6S 50% 4.1 A 18300 380 g 3.86 g/W
1600 Gemfan SL5126-2 6S 60% 5.8 A 20600 495 g 3.56 g/W
1600 Gemfan SL5126-2 6S 70% 7.9 A 22900 615 g 3.24 g/W
1600 Gemfan SL5126-2 6S 80% 10.7 A 25000 765 g 2.98 g/W
1600 Gemfan SL5126-2 6S 90% 12.9 A 26500 868 g 2.8 g/W
1600 Gemfan SL5126-2 6S 100% 13.5 A — 915 g 2.82 g/W
2000 EMAX AVAN 5120-3 4S 40% 2.9 A 13200 224 g 4.83 g/W
2000 EMAX AVAN 5120-3 4S 50% 4.2 A 15300 300 g 4.46 g/W
2000 EMAX AVAN 5120-3 4S 60% 6.1 A 16900 389 g 3.99 g/W
2000 EMAX AVAN 5120-3 4S 70% 8.2 A 18800 490 g 3.73 g/W
2000 EMAX AVAN 5120-3 4S 80% 11.1 A 20800 615 g 3.46 g/W
2000 EMAX AVAN 5120-3 4S 90% 12.8 A 22100 695 g 3.39 g/W
2000 EMAX AVAN 5120-3 4S 100% 14 A — 715 g 3.19 g/W
2000 Gemfan SL5125-3 4S 40% 2.8 A 13900 213 g 4.75 g/W
2000 Gemfan SL5125-3 4S 50% 3.9 A 15600 277 g 4.44 g/W
2000 Gemfan SL5125-3 4S 60% 5.4 A 17500 358 g 4.14 g/W
2000 Gemfan SL5125-3 4S 70% 7.1 A 19300 445 g 3.92 g/W
2000 Gemfan SL5125-3 4S 80% 10 A 21600 574 g 3.59 g/W
2000 Gemfan SL5125-3 4S 90% 11.6 A 23200 638 g 3.44 g/W
2000 Gemfan SL5125-3 4S 100% 12.5 A — 670 g 3.35 g/W
2000 Gemfan 4023-3 6S 40% 3.4 A 22300 289 g 3.54 g/W
2000 Gemfan 4023-3 6S 50% 5 A 25400 379 g 3.16 g/W
2000 Gemfan 4023-3 6S 60% 6.1 A 26800 424 g 2.9 g/W
2000 Gemfan 4023-3 6S 70% 7.6 A 29300 513 g 2.81 g/W
2000 Gemfan 4023-3 6S 80% 10.6 A 32900 668 g 2.63 g/W
2000 Gemfan 4023-3 6S 90% 12.8 A 35300 736 g 2.4 g/W
2000 Gemfan 4023-3 6S 100% 13.4 A — 797 g 2.48 g/W
2000 Gemfan SL4525-3 6S 40% 3.9 A 20600 330 g 3.53 g/W
2000 Gemfan SL4525-3 6S 50% 5.8 A 23500 434 g 3.12 g/W
2000 Gemfan SL4525-3 6S 60% 7.3 A 25200 501 g 2.86 g/W
2000 Gemfan SL4525-3 6S 70% 9.8 A 27200 632 g 2.69 g/W
2000 Gemfan SL4525-3 6S 80% 12.2 A 30000 732 g 2.5 g/W
2000 Gemfan SL4525-3 6S 90% 16.5 A 32300 826 g 2.09 g/W
2000 Gemfan SL4525-3 6S 100% 17 A — 910 g 2.23 g/W
2000 Gemfan SL5125-3 6S 40% 4.5 A 18300 388 g 3.59 g/W
2000 Gemfan SL5125-3 6S 50% 6.8 A 20500 507 g 3.11 g/W
2000 Gemfan SL5125-3 6S 60% 9.4 A 22900 653 g 2.89 g/W
2000 Gemfan SL5125-3 6S 70% 12.5 A 25000 811 g 2.7 g/W
2000 Gemfan SL5125-3 6S 80% 17.4 A 28350 965 g 2.31 g/W
2000 Gemfan SL5125-3 6S 90% 19.6 A 29630 1050 g 2.23 g/W
2000 Gemfan SL5125-3 6S 100% 21.5 A — 1130 g 2.19 g/W
2400 EMAX AVAN 5120-3 4S 40% 4.4 A 15800 293 g 4.16 g/W
2400 EMAX AVAN 5120-3 4S 50% 6.7 A 16900 387 g 3.61 g/W
2400 EMAX AVAN 5120-3 4S 60% 9.2 A 18900 488 g 3.32 g/W
2400 EMAX AVAN 5120-3 4S 70% 12.6 A 20600 614 g 3.05 g/W
2400 EMAX AVAN 5120-3 4S 80% 17.5 A 22800 753 g 2.69 g/W
2400 EMAX AVAN 5120-3 4S 90% 20.7 A 25100 824 g 2.49 g/W
2400 EMAX AVAN 5120-3 4S 100% 21.8 A — 864 g 2.48 g/W
2400 Gemfan SL5125-3 4S 40% 4.1 A 15600 268 g 4.09 g/W
2400 Gemfan SL5125-3 4S 50% 6.1 A 17800 353 g 3.62 g/W
2400 Gemfan SL5125-3 4S 60% 8.2 A 19600 451 g 3.44 g/W
2400 Gemfan SL5125-3 4S 70% 11.5 A 22200 594 g 3.23 g/W
2400 Gemfan SL5125-3 4S 80% 15.1 A 24000 704 g 2.91 g/W
2400 Gemfan SL5125-3 4S 90% 18.3 A 25300 808 g 2.76 g/W
2400 Gemfan SL5125-3 4S 100% 19.2 A — 850 g 2.77 g/W
2400 Gemfan SL5126-2 4S 40% 4.2 A 15800 281 g 4.18 g/W
2400 Gemfan SL5126-2 4S 50% 6.1 A 17800 362 g 3.71 g/W
2400 Gemfan SL5126-2 4S 60% 8.2 A 19900 451 g 3.44 g/W
2400 Gemfan SL5126-2 4S 70% 11 A 21600 570 g 3.24 g/W
2400 Gemfan SL5126-2 4S 80% 14.8 A 23200 687 g 2.9 g/W
2400 Gemfan SL5126-2 4S 90% 17.6 A 25800 786 g 2.79 g/W
2400 Gemfan SL5126-2 4S 100% 18.8 A — 825 g 2.74 g/W
2400 HQ T4025-2 6S 40% 5.2 A 26600 351 g 2.81 g/W
2400 HQ T4025-2 6S 50% 6.7 A 28500 414 g 2.57 g/W
2400 HQ T4025-2 6S 60% 8 A 30400 471 g 2.45 g/W
2400 HQ T4025-2 6S 70% 10.3 A 33400 579 g 2.34 g/W
2400 HQ T4025-2 6S 80% 13.2 A 36800 728 g 2.3 g/W
2400 HQ T4025-2 6S 90% 15.3 A 38900 802 g 2.18 g/W
2400 HQ T4025-2 6S 100% 16.1 A — 827 g 2.14 g/W
2400 Gemfan 4023-3 6S 40% 5.4 A 25700 376 g 2.9 g/W
2400 Gemfan 4023-3 6S 50% 7.5 A 27400 442 g 2.46 g/W
2400 Gemfan 4023-3 6S 60% 9.1 A 29700 535 g 2.45 g/W
2400 Gemfan 4023-3 6S 70% 11.8 A 32400 659 g 2.33 g/W
2400 Gemfan 4023-3 6S 80% 15.1 A 35600 804 g 2.22 g/W
2400 Gemfan 4023-3 6S 90% 17.6 A 38200 885 g 2.1 g/W
2400 Gemfan 4023-3 6S 100% 18.8 A — 930 g 2.06 g/W
3000 HQ T3x3x3-2 6S 40% 5.9 A 30500 300 g 2.29 g/W
3000 HQ T3x3x3-2 6S 50% 7.7 A 33500 364 g 2.13 g/W
3000 HQ T3x3x3-2 6S 60% 8.3 A 34200 378 g 2.05 g/W
3000 HQ T3x3x3-2 6S 70% 10.7 A 37800 472 g 1.99 g/W
3000 HQ T3x3x3-2 6S 80% 11.6 A 40300 529 g 2.05 g/W
3000 HQ T3x3x3-2 6S 90% 12.2 A 41800 545 g 2.01 g/W
3000 HQ T3x3x3-2 6S 100% 12.7 A — 561 g 1.99 g/W
3000 Gemfan 3520-3 6S 40% 6.1 A 31500 345 g 2.55 g/W
3000 Gemfan 3520-3 6S 50% 7.5 A 34000 407 g 2.44 g/W
3000 Gemfan 3520-3 6S 60% 8.1 A 34600 414 g 2.3 g/W
3000 Gemfan 3520-3 6S 70% 10.2 A 38000 516 g 2.28 g/W
3000 Gemfan 3520-3 6S 80% 11.1 A 40500 582 g 2.36 g/W
3000 Gemfan 3520-3 6S 90% 11.8 A 41900 603 g 2.3 g/W
3000 Gemfan 3520-3 6S 100% 12.4 A — 636 g 2.31 g/W
3000 EMAX AVAN 5120-3 4S 40% 6.7 A 16700 378 g 3.53 g/W
3000 EMAX AVAN 5120-3 4S 50% 9.9 A 18600 477 g 3.01 g/W
3000 EMAX AVAN 5120-3 4S 60% 13.9 A 21100 629 g 2.83 g/W
3000 EMAX AVAN 5120-3 4S 70% 19.4 A 23000 796 g 2.56 g/W
3000 EMAX AVAN 5120-3 4S 80% 26.3 A 24800 980 g 2.33 g/W
3000 EMAX AVAN 5120-3 4S 90% 30.5 A 25970 1060 g 2.17 g/W
3000 EMAX AVAN 5120-3 4S 100% 31.6 A — 1170 g 2.31 g/W
3000 Gemfan SL5125-3 4S 40% 6.5 A 17800 370 g 3.56 g/W
3000 Gemfan SL5125-3 4S 50% 9.5 A 19800 476 g 3.13 g/W
3000 Gemfan SL5125-3 4S 60% 12 A 22200 598 g 3.11 g/W
3000 Gemfan SL5125-3 4S 70% 17.8 A 24600 764 g 2.68 g/W
3000 Gemfan SL5125-3 4S 80% 24.7 A 26400 920 g 2.33 g/W
3000 Gemfan SL5125-3 4S 90% 29.6 A 28680 1010 g 2.13 g/W
3000 Gemfan SL5125-3 4S 100% 30.2 A — 1090 g 2.26 g/W

Manufacturer bench figures (4S, EMAX AVAN 5120-3, 100% throttle, 3000KV; manufacturer bench, throttle sweep 40-100%; 4S rows at 16 V, 6S rows at 22.2-24 V); real-world thrust varies with ESC, battery sag and prop condition.

ECO II 2004 vs other 2004 motors on 4S

The same thrust costs different power on different motors. Each line is one maker's own bench series (4S, its own prop), drawn as grams of thrust per watt against thrust, so a higher line makes that thrust for less battery current. Throttle percent is left out on purpose: it means something different on every maker's rig.

01234020040060080010001200 thrust, g g/W
MotorKVPropPeak thrust At 525 gAt 1050 g
EMAX ECO II 2004 3000 EMAX AVAN 5120-3 1170 g at 506 W 179 W (2.94 g/W) 480 W (2.19 g/W)
Diatone Mamba Toka 2004 2900 GF5125 1051 g at 506 W 193 W (2.72 g/W) 505 W (2.08 g/W)

Power at 525 g and 1050 g is read off each maker's curve, straight-line between its two nearest bench points; 1050 g is the highest thrust every motor here reached. Different props and rigs move these curves as much as the motor does, so compare rows on a similar prop. Peak thrust of every 2004 motor: 2004 motors compared. How to read a bench table: reading motor bench tables.

Thrust-to-weight with this motor

Four EMAX ECO II 2004 motors at 1170 g max thrust each give 4680 g: 2:1, the minimum to fly, up to 2340 g all-up; 4:1 (freestyle) up to 1170 g; 8:1 (racing) up to 585 g.

RPM & prop speed on this motor

Flies on these BNF quads

Props in this motor's class

PropSizeBladesWeight
Gemfan Long Range 5126-2 Durable 1.5mm T-Mount 5.1x2.7 2 2.6 g
HQProp DP 5.1x2.5x3 5.1x2.5 3 3.1 g
HQProp Juicy J37 4.9x3.7 3 3.4 g
HQProp Juicy J40 5.1x4.0 3 3.4 g
Gemfan 4935 Sbang 3-Blade 4.9x3.5 3 3.45 g

Where this data comes from

EMAX's own Specifications sheets (2004-1.jpg, 2004-2.jpg) on the maker's product page, read at full size 2026-10-20: 12N14P, Φ24.7*19.2mm, 3 mm bearing shaft with a 1.5 mm prop-adapter thread, 24#AWG 120 mm lead, bolt pattern M2 (12X12mm), internal resistance 200 / 158 / 110 / 80 mΩ (1600/2000/2400/3000 KV; this page sells the last three), No. of cells 4-6S (1600/2000/2400 KV) and 3-6S (3000 KV), weight 16.6 g (1600/2000 KV) and 16.4 g (2400/3000 KV), every one printed "(W/O Silicone Wire)". weight_g is the retail listings' "Weight (w/ wires): 18g", the weight with the cable; the maker's figures are the bare motor.

Related 2004-class motors

Guides