BMW i3-REx or Prius Prime
 

We have both and glad about it:

• BMW i3-REx - great around town and cold weather but a 'hanger queen' for maintenance. The problem being BMW spare parts are 1-2 days away, a built in delay. End of lease, they are easily found in the $15-23k range.
• Prius Prime - the +600 mile range makes it the road warrior and even around town, more efficient. But cold weather, under 50F, the Prime has a number of control laws that can trip up the owner and turn the engine ON. New, the lowest cost trim, the Plus, lists $28k with a $4.5k tax credit.

Bob Wilson

We can also get several other plugin hybrids with ranges around the Volt (more than the Prime and less than the REx).

I thought this was going to be a thread about "which car should I get?" and I thought to myself, "nice problem to have!"

Today we have choices not available in May 2016 and December 2016. These are the cars we own, 2014 BMW i3-REx and 2017 Prius Prime, so I avoid speculating about something I can't test. No doubt the Volt has fine specifications and meets the requirements of others.

In our case, the BMW i3-REx gave us our first dynamic cruise control and accident avoidance braking. These were so much better than anything we'd had driven before, they became a mandatory requirement. But every BMW repair has a minimum 1-2 day delay to get the parts. So we replaced our Gen-3, 2010 Prius with a 2017 Prius Prime that comes with TSS-P standard.

The cruel irony is I tested a 2016 Prius only to discover the one I wanted, the Level 2 ECO, was the only trim that did not have TSS-P. So I bought the BMW i3-REx for the same price as the Level 3 Prius offered and never looked back.

Bob Wilson

What repairs has the BMW needed?

From memory:

• May 2016 - took delivery and coded it to enable REX at 75% SOC for 463 mile trip home.
• June 2016 - arrived in Huntsville and took about 3-4 days to catchup on recalls. Also had two tires replaced under warranty and bought the other two so new rubber all around and four wheel alignment.
• July 2016 - added a 2" receiver hitch.
• September 2016 - winshield wiper came off of arm which snapped down and cracked the windshield. This time the part was ordered and three days later it went into the shop to pickup the next day.
• December 9, 2016 - motor mount bolt broke. This two week repair included getting a collant hose from Germany. The replacement bolts and motor mounts substantially increased the strength with a 1/2" bolt replaced by 3/4" bolt and aluminum mounts replacing the composite plastic and aluminum part.
• May 2017 - check engine light came on due to low oil level. There is no oil pressure indicator for the driver.
• February 2018 - OBD interface and BIMMERCODE to tune the car: enable 75% SOC enable of REx; increase usable fuel from 1.9 to 2.3 gallons; turn off passenger seat belt alarm so dogs can sit, and; default the middle power/efficiency power setting.
• March 27-29, 2018 - software recall, slow air leak right front tire, and fuel tank pressure sensor.

This was the first model year for the BMW i3-REx and many of these problems are 'infantile'. Some like the absence of an oil pressure indicator are design issues but I can compensate using an OBD scanner and BIMMERLINK. Happily, I have 24k miles on the tires and they look to go twice as far.

The design of the i3 is more interesting to look at, but sometimes I think that 650cc parallel-twin used in its genset is quite overkill.

It is hard for me to call just the engine because it is paired with a generator, the engine load. Regardless, the engine-generator are able to maintain 70 mph (112 kph) without loss of battery SOC. Faster, the battery drains. Slower, the gas MPG goes up.

Bob Wilson

Interesting.

Well, I'd be quite curious to see how it would perform if the driveline was more similar to the Prius' HSD instead of a serial-hybrid. Emissions certification for the engine also got me thinking, because that engine was originally meant for motorcycles and they're certified into less stringent emission standards (IIRC it's currently Euro 4).

USA EPA testing metrics displayed using crude table using Courier and "_" for " ":

|______metric|______I3_REX|_____I3s_REX
|___CO_(g/mi)|___0.0117600|___0.0097700
|__CO2_(g/mi)|___0.2943000|___0.2733000
|__NOx_(g/mi)|_181.1700000|_189.4700000
|___PM_(g/mi)|___0.0037000|___0.0012000
|__CH4_(g/mi)|____________|___0.0003480
|__N2O_(g/mi)|___0.0006600|___0.0006400
|__RND_ADJ_FE|________49.2|________46.7

Is there a vehicle you'd like to use as a reference?

Bob Wilson