My Electric Tiger E-Boxer GPR-S

Well, I just took delivery of my new all electric GPR-S from Electric Motorsport Co. LTD (EMC). EMC integrates electric propulsion and drive train into the Tiger Boxer frame. EMC's base bike is integrated with a 19HP E-tek-R Motor. The first option is a SepEx based motor with 25HP. Next is the AC version with ~ 30HP which is the one I purchased. Mine is the first AC based DOT approved (for use on highways in the United States) bike produced by EMC. ThunderStruck Motors of Santa Rosa, CA supported EMC with the electric integration of this AC based bike. ThunderStruck Motors and EMC have a host of the National Electric Drag Race Association (NEDRA) drag race records for electric motorcycles which gives them great electrical engineering credibility. It does not, howerver speak directly to the capability of my AC GPR-S as an AC based GPR-S bike has not been raced by either company. The closest version raced was a 72 volt SepEx powered bike with EMC's owner Todd Kollin at the controls. He took the 1/8 mile CV/H class on October 12, 2008 at the Kick Gas Festival in Barona CA. at 56.26 MPH and 11.73 seconds.

Enough about the Companies and on to my first impression review. My bike is integrated with 20, 50AH HiPower LiFePO4 batteries, a Curtis 1234 controller and an AC-15 motor. The bike is silver and about "250CC" size weighing in at 280 pounds. It comes with a backlited LCD dispay which shows speed, odometer, trip odometer and time. Mine also came with a Curtis Spyglass which also shows speed as well as BDI% (remaining battery), AMPS, Volts, controller temperature, and RPM. The bike has regeneration which provides very nice braking and gives a little energy back when stopping or going down hill. Some other characteristics and performance points are listed below:

1. Naturally, the bike is dead quiet at a stop, but generates a little more turbine like noise than I anticipated by the motor / drive train. The motor is hard mounted to the frame and some of the motor noise resonates through the frame. It's probably about the 75-78db level. It's a little louder when just taking off (5-15 MPH)and then quieter when cruising (40MPH). above that it's mostly wind noise (at least in the helmet I where).

2. The regen is very strong. Under normal conditions in the housing area you don't use the brakes at all until you get below 3 MPH to get to the final rest. You can reduce power and not turn on the regen (or not hard), but when you turn the throttle all the way off it acts like a brake with about the same decel you would brake with under normal conditions. The brake lights are activated by either applying brakes or throttle off (regen activated). The Spyglass indicates -14 AMPs when the regen goes on above 30MPH.

3. It was a very windy day with wind steady at 15 gusting to 20. I could feel a little buffeting but it wasn't bad and tracked pretty straight.

4. A range test was completed with about half the miles being completed on 35MPH streets and half on 45MPH streets. There were 66 slow 90 degree corners / stops that required accelerations. The accelerations were all at a reasonable, keep up with traffic “g” level, except for one “maximum effort” acceleration from 0 to 45 MPH where I wanted to get ahead of an approaching car. Range on the bike was about 42 miles.

5. With the lights on while riding I could easily see the numbers on the main gauge which has MPH, Trip, Odo and clock.

6. The craftsmanship, fit and finish of the bike is excellent. The only issue I have identified so far is the hinge that holds the electrical cord cap is weak (the black access port on top of the tank). People will be breaking these off. The paint quality is excellent. The electrical setup looks to be done with quality parts and workmanship. I wouldn't quite call it aircraft quality integration, but it's as good as my '08 Toyota Camry Hybrid.

7. The kickstand is great. It has a little handle that sticks out that makes it easy to kick it up. And it goes up and down a lot easier than the ones I rode in motorcycle school (which was a new bike with 600 miles). Martin G (EMC tech) also showed me a neat trick if the bike is sitting in a parking spot and you want to turn it 180 degrees to get out of the spot. You stand on the kick stand side, hold the bike by the handlebar and the seat handhold, pull it up to balance it on the kickstand and walk it around counterclockwise to the new heading. He said he made sure they bought strong enough kickstands to do that.

8. The acceleration is relatively soft off the line but then comes on strong. The softness is caused by a "gear soften parameter" setting in the Curtis controller. That has various settings that control the degree of softness during takeoff and creates the ability for a very smooth and controlled take-off. There is good power after 20MPH and clearly acceleration per degree of throttle increase is much more at 35 MPH than it is at 5MPH. Softning is ramped out with time during the acceleration.

Story and pictures by Chuck J.