I would like to join the
I would like to join the others who have taken issue with this article's description of the i3's performance with the REx engine on. I'm an i3 owner (though only as of a couple weeks ago) and have driven a total of about 150 miles with the REx engine in operation.
First, power (at least for the short bursts when I've needed to use it) is excellent. Just yesterday, faced with a situation where an uphill freeway onramp went from two lanes to one lane and driving with the gas engine on, I punched the accelerator to get past a large truck before losing my lane. The car took off like a rocket. (Impossible without an A/B comparison to say whether the power was identical to that of all-electric mode, but it was PLENTY sufficient.) Later on that same trip, with the gas engine still running, I encountered an amber light that I noticed a little bit too late to stop. I punched it again. Again, the car shot forward quickly enough to give me a thrill. If the car's power is compromised in range-extended mode, I haven't yet experienced it. Perhaps sustained high-power demands, like a long and steep uphill grade at highway speeds, will tax the system. I haven't encountered that yet. I have also driven the i3, loaded with some heavy boxes equivalent in weight to that of 3 or 4 occupants, in range-extended mode cruising at 60 to 70 with flat stretches, mild grades and rolling hills. There was no apparent power or performance limitation, other than the obvious feeling that there was more weight in the car, in those situations either.
Second, the relayed blog post purportedly from a BMW i3 REx owner, describing "the car's behavior as "hysterical" when the range extender comes on" does not reflect my experience in the least. For me, there has been no change. At speeds below about 20, I'm just barely aware of a small vibration and engine noise coming from the back of the car, and I can detect when the gas engine shuts off when I stop at a light. At all other speeds, I don't notice it at all. I haven't seen any change at all in the dashboard instruments--no repeated messages about getting juice, no suggestion of local charging points. Period. None. Sure, you can use the car's electronics to find nearby charging stations, but that's no different than it is any other time.
Bottom line: based on my experience so far, the i3's only real limitation in range-extended mode is the size of the gas tank. The tank is too small (I would even accept the word "pitiful" to describe the tank size) and if the theories being bounced around the web are correct, we have inflexible CARB regulations to thank for that!