THE CHALLENGER

We have seen a number of 1/8-scale vehicles
converted to brushless power, but this particular conversion strikes us as being the most commonsense for a number of reasons. First, the E-8IGHT weighs exactly the same as its nitro counterpart, so all the setups, shock oils and springs that work on the nitro car will work on the electric version. When much heavier battery packs are used, ?known? setups can no longer be relied on. Balance is also a critical factor, and this conversion very closely mimics the balance of the nitro 8IGHT. Last, the Mega brushless ACn Car8+ is a relatively low-rpm motor, but it seems smoother, and it definitely produces enough torque to create speed through gearing (as shown by its blistering 47mph speed run). Some brushless motors spin at very high rpm and must be geared down to produce torque and extend run time; the Mega takes an opposite approach. When paired with the 11.1V LiPo batteries (wired in parallel to provide 4400mAh at 11.1 volts), the Car8+ spins at only about 14,500rpm, although the motor is rated at between 20,000 to 30,000rpm.

The installation uses laser-cut plywood parts from Mega Motor USA. Universal reaction to the plywood by RC racers has been negative?
even after we explained that it?s light and strong and does the job. Car people want aluminum or carbon; we?ve spoken to Mega
Motor, and they may well release the parts in aluminum to meet demand. The Car8+ motor is simply bolted to the chassis in place of the nitro engine (the motor is designed to fit a Kyosho chassis, but it can fit other cars with the use of an adapter plate). The motor?s 5mm output shaft accepts Mega Steel Mod 1 pinions (made by RRP), which mesh perfectly with RRP?s steel spur gears. An optional 12V cooling fan is bolted to the motor?s finned aluminum heat-sink case. Plywood trays serve as mounts for the twin packs and for the (optional) fan that sits above the ESC. The batteries are secured using Velcro, but we would prefer a more secure and precise mounting system.

SAFETY FIRST

LiPo cells are reliable and safe when used correctly. But as it?s always better to be safe than sorry, we?ll reiterate a couple of key rules for handling them:

• Use only a charger that has a specific LiPo mode.
• LiPo cells should be charged at a rate of 1C (in the case of
  our 2200mAh packs, the correct rate of 1C would be approximately
  2 amps).
• LiPo batteries can ignite if overheated, overcharged or
  shorted, so it?s always good to use a charging/storing ?sack?
  such as the Li-Poly Sack from Racers Edge (racers-edge.com,
  item no. RCE2007, $28).

PERFORMANCE COMPARISON
For the sake of equality, we set both cars up as closely as possible (using a slight variation of Mike Truhe?s 2007 Nitro Challenge setup:our cars used thinner diff oil: 3/5/1, instead of Truhe?s 5/7/2). GRP mounted Cubic tires (GMH03A) to each car, and we tested them over several days at Wolcott Hobby & Raceway in Wolcott, Connecticut.

ACCELERATION
We had no doubt that the E-8IGHT would clearly win in this category, and there weren?t any surprises. Electric motors make maximum torque at their lowest rpm, whereas a nitro engine must build rpm to increase torque. So an electric power system will always out-accelerate a nitro system of comparable output. In a real-world application, the E-8IGHT is more of a handful to drive: it is less efficient at translating its considerable torque into traction at lower speeds, so it takes a gentler approach?and more concentration?to avoid unwanted wheelspin. By contrast, the nitro 8IGHT is more forgiving of an aggressive trigger finger, although it required more buildup to clear larger jumps. The E-8IGHT cleared virtually everything from a dead stop, including the Wolcott track?s quad-jump section?a feat out of the nitro car?s reach
Winner: E-8IGHT

SPEED
This is the most subjective category in this comparison, as gearing plays a large role in any vehicle?s potential for speed. That being said, with both cars geared for the track, the E-8IGHT?s best pass yielded a flat 47mph past our Stalker radar gun. The nitro 8IGHT blazes by just a tick below at 44.55mph. That?s a draw in our book, as both powerplants are capable of pulling taller ratios that would undoubtedly push them both well past 50mph. On the track, the E-8IGHT?s ability to get up to speed more quickly was negated by its reduced traction under hard acceleration, making its marginal speed advantage a wash against the grip of the nitro car.
Winner: Tie

JUMPING
This was a very difficult category to call, but in the end, the acceleration of the E-8IGHT gave it a very slight edge over the nitro 8IGHT. Both cars flew well and were easily adjusted midair by using the throttle and brake, but the E-8IGHT consistently cleared larger jumps, even if the length of the approach was diminished by a bobble or by an altercation with traffic. As mentioned in the acceleration category, the E-8IGHT cleared a long quad-jump section (which everyone else considered a triple-single) that the nitro 8IGHT just couldn?t complete. To translate this into an advantage, the E-8IGHT is more forgiving of driving error when precise timing is needed to complete technical jump sections.
Winner: E-8IGHT

TRACTION
Traction boils down to three variables: surface grip, tire grip and the forces that try to separate the tire from the surface. Of these forces, the one that comes most into play when comparing the nitro 8IGHT and E-8IGHT is torque. Torque is what produces wheelspin and loss of traction when applying the throttle, and as the E-8IGHT produces maximum torque at the lowest rpm, it?s natural that it would have less traction than its nitro counterpart. The Mamba Max ESC does its best to curb the initial hit of the motor (it also helps to dial the radio?s throttle channel to a negative value), but there?s just so much tire-shredding spank available that only a judicious throttle finger provides a workable solution. Driving the E-8IGHT simply requires more attention and a smoother application of the throttle to get the power to the ground.
Winner: Nitro 8IGHT

STEERING
Even with its electric powertrain, the E-8IGHT has virtually the same handling traits as the nitro 8IGHT, so the two cars are virtually identical in terms of steering response. Apart from an on-power oversteer that?s absent from the nitro car, the E-8IGHT exhibited initial and mid-turn steering on par with it. In contrast to the nitro 8IGHT, the brushless motor system provided a slightly noticeable coast-braking, which most drivers viewed as a positive trait and one that reduced the need to manually apply brakes when slowing for turns. With similar weights, balance and suspension setups, the electric and nitro 8IGHTs are essentially twins in terms of how they steer, although the E-8IGHT felt more aggressive.
Winner: Tie

BRAKING
We had reservations about the E-8IGHT?s braking ability, as the Econversion eliminates the mechanical dual-disc setup. The ESC applies brakes to the transmission?s spur gear, at which time, the stopping force is transmitted through the car?s center diff and apportioned to the front and rear wheels according to available traction and the shifting of the chassis? weight. As a result, braking balance changes with conditions, and most of the stopping force manifests
itself at the rear wheels. Surprisingly, the E-8IGHT stopped quite well and didn?t lose grip even when braking deep into turns. A stiffer center diff improves front-to-rear braking balance, while the opposite is true when the center diff is set more loosely. As expected, the powerful dual discs of the nitro 8IGHT proved superior, but both systems exhibited only minimal fade?a testament to the excellent Mamba Max ESC.
Winner: Nitro 8IGHT

AND THE WINNER IS ...

Although the scoring indicates a dead heat, we unanimously picked the nitro 8IGHT as being superior for track duties. Like all 1/8-scale buggies, the 8IGHT was designed around the power delivery of a .21 nitro engine. Its drivetrain, clutch and even its suspension and chassis layout are optimized for nitro power. While the electric powertrain is, on paper, a match for a big-block nitro engine, the increased torque of the brushless system did, at times, overwhelm the vehicle?s dynamics and reduce stability and grip. We?ve concluded that spending more time on setting up the chassis and suspension would narrow the gap. To be sure, it takes a different style of driving to pilot the E-8IGHT; the ?blip-blip? throttle action used for nitro must be replaced by a smooth, consistent pull of the trigger to avoid wheelspin.