Why the BMW i3-REx

Discussion in 'i3' started by bwilson4web, Nov 13, 2017.

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  1. bwilson4web

    bwilson4web Well-Known Member Subscriber

    No one asked but since we have both a 2014 BMW i3-REx and 2017 Prius Prime, this forum seems a little thin about this car too. The full details are found in this thread: https://priuschat.com/threads/why-the-bmw-i3-rex.165584/ so I'll try to be brief.

    In May 2016, we gave our 2003 Prius to our housekeeper. Our practice is to keep two cars so I went shopping for a replacement. I tried to get a 2016 Prius Level Two ECO but it did not come with Toyota Safety Sense P (TSS-P). The dealer had me test drive a Level Three with TSS-P but could only get 99 MPG and told the salesman, 'not good enough.' Back at the dealer, they offered the car for $28.5k which I knew was close to the $29.5k of an end-of-lease, 2014 BMW i3-REx, 6440 miles that had their TSS-P equivalent.

    I flew to Charlotte NC to pickup the BMW i3-REx; coded it to allow the REx enable at 75% SOC, and; drove it 463 miles back home filling up the 1.9 gallon tank 5 times. In September, my wife, her two dogs, and I drove 700 miles each way to Oklahoma over a long weekend. Again stopping every hour and fifteen minutes for gas and a wife/dog break, everything was fine until a planned trip in December when the motor mount bolt broke. The 2014, first model year car, the replacement was a 3/4" bolt replacing the 1/2" bolt and substantially stronger motor mount. But I had to revert to our backup, 2010 Prius and I hated the lack of TSS-P. By the end of the month, I sold the 2010 Prius and bought a 2017 Prius Prime that comes with TSS-P standard.

    The BMW i3-REx has +27,000 miles and the Prius Prime, +7,000 miles. Since we have two, plug-in hybrids:
    • 2014 BMW i3-REx - a pocket rocket with 72 mile EV range, this is the car when making more than 3 stops on a trip. It can also EV round-trip to all neighboring towns.
    • 2017 Prius Prime Plus - a calmer ride, more efficient than the BMW i3-REx, it is the first choice around town for 3 stops or less. But it is also the cross country car because the radar based, TSS-P works in low light and fog.
    So why not the Volt? The answer is TSS-P that consists of dynamic cruise control and collision avoidance. Although these can be custom ordered on a Volt, both the used BMW i3-REx and new Prius Prime came with it.

    At ~2,900 lbs with 168 hp rear wheel drive, this is pocket rocket. The carbon fiber body mutes outside noise and with the windows rolled up it is very easy to speed. Happily, the optically based, dynamic cruise control reads speed limit signs and shows the last value. Taller, the rear space handles loads easier than the Prime. Parts and tires are pricier but gosh it is a nice ride.

    Both cars can handle urban driving in EV but the BMW i3-REx excels. Both cars can handle cross country trips but the Prius Prime excels. With TSS-P, both are a joy to drive.

    Bob Wilson
    Domenick likes this.
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  3. Thanks for sharing.

    For anyone interested, TSS-P is a safety package that includes:
    Pre-Collision System -- This advanced safety system is designed to alert you, and may apply the brakes, if it detects a potential frontal collision with another vehicle.

    Lane Departure Alert -- A camera on your windshield may help you avoid the consequences of unintended lane departure by alerting you when it senses that you’ve veered from your lane.

    Automatic High Beams -- A camera on your windshield aids nighttime driving by using a camera to detect headlights and taillights of preceding vehicles, and toggling accordingly between high and low beams.

    Dynamic Radar Cruise Control -- This high-tech cruise control uses a radar behind the Toyota badge plus a camera on the windshield designed to adjust your speed, helping you maintain a safe distance from the car in front of you.

    Pre-Collision System with Pedestrian Detection -- This integrated camera and radar system is designed to reduce the likelihood of colliding with a preceding car or pedestrian.
  4. In find the whole business of "coding" the BMW i3 kind of fascinating. Did you do this yourself? I know there was a particular i3 enthusiast who was doing it on behalf of a number of new owners.
  5. bwilson4web

    bwilson4web Well-Known Member Subscriber

    When I bought the BMW i3-REx, I used DVDInMotion but it only handles allowing the 75% REx enable. This summer I've gotten BIMMERCODE which covers dozens of options of which I'm using:
    • 75% enable REx
    • usable gas from 1.9 to 2.3 gallons
    • default to ECO PRO, the middle of three driving modes
    • adding tire temperature to tire pressure display
    During the "Drive EV Week," I coded another BMW i3-REx in Huntsville and carry it in the car. This iPhone App also has a simulation mode to show how easy it is to use.

    Bob Wilson
  6. Ok, just searched for BIMMERCODE and now realize it's an app you can download. I didn't realize that was a thing.

    I find it weird that a third-party can legitimately produce software that alters the programming of your car. I was under the impression that, initially, the coding thing was a bit more "informal." BMW could try to have this sort of app removed if they thought it hurt its cars and/or business.

    I'm going to have to download it to check it out. Just wish I had an i3 to try it on.
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  8. bwilson4web

    bwilson4web Well-Known Member Subscriber

    Coding is pretty common in BMW performance circles and also found in the Toyota world too. In the case of the BMW i3-REx, CARB insisted to get the ZEV credits that the engine only come on when down to 6%. At high speeds or climbing a hill, the battery can dip down to 3-4% while the engine warms up leading to reports of 'dangerous slow down.' But outside of the USA, the owner can enable the REx at 75% for cross country travel.

    On the Toyota side, look for 'miniVCI' which typically comes with a pirated copy of the Toyota diagnostic software, TechStream. Just don't be connected to the Internet when using it because it will "phone home" and brick itself if there is no authorized, software key.

    Bob Wilson
  9. So, apparently Toyota frowns on this activity. Surprised BMW seems OK with it.

    Besides "performance chips," I didn't realize this was so much a thing.

    I am familiar with CARB regs being responsible for BMW selling it with dangerous settings from the dealership. Some reviewers and early owners felt it very unsafe driving on the highway after the battery had been depleted. New owners now, I guess, will (hopefully) run across the app when researching the car.
    bwilson4web and WalksOnDirt like this.
  10. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    This is the first time I've ever heard of this, too. I didn't realize there was an upgrade app anybody could download and install, even if it's *cough* unofficial *cough*. Nice to see that upgrading your American BMW i3 REx to what I'm guessing is full European capability (but is it?) isn't just for hackers anymore!

  11. There are some great options in this too, unrelated to the range extender. Indeed, it works on other BMWs and Minis as well, so pretty handy.

    Can set a maximum stereo volume when can is turned on. (great for families with driving teenagers who always 'forget" to turn down the volume before turning off car.)

    I could go on and on, but if interested, just check out the Bimmercode website. Click on the model of car for list of tunable options.
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  13. bwilson4web

    bwilson4web Well-Known Member Subscriber

    Coding a car to customize is usually found in the diagnostic software used by any manufacturer. Third-party, independent repair shops often have a paid copy they use to work on cars. So those would be the folks to approach about what customizations exist.

    Bob Wilson
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  14. Feed The Trees

    Feed The Trees Active Member

    From what I understand on the i3 it isn't so much a custom programming that you can do, it's just toggling features on and off. Lots of cars have these kinds of things as they make 1 software package to suit both the compliance needs of various countries and local taste for features. Speed governors, rev limiters, etc have long been removable on many cars, it's just getting easier.

    I remember back in probably 2007 when I had a bad sensor and needed to get a smog check done, I had my laptop with me and right before they did the test I reset the fault code which took about 20 minutes before it fired each time. Made it through the test and driving home came back on.
  15. bwilson4web

    bwilson4web Well-Known Member Subscriber

    Expressing my decision tree for using either the BMW i3-REx or Prius Prime looks like this:
    1. +100 mile trip - Prius Prime due to superior gasoline highway mileage and range, +56 MPG Prime and 600 mile gas segments vs. 40 MPG and 75 mile gas segments BMW i3-REx.
    2. +50F and 3 stop trip - Prius Prime due to more efficient EV operation but cold weather induces unplanned engine operation.
    3. -50F or +3 stop trip - BMW I3-REx because it does not have the cold induced engine operation and three times the EV range of the Prime.
    Either car works and can backup the other. If I had to choose, the Prius due to reliability, TSS-P, and long range legs. In this case, the Consumer Reports score is accurate:
    • 77 - Prius Prime
    • 66 - BMW i3-REx
    Bob Wilson
  16. sipabit

    sipabit Member

    Anyone who is comparing the two to decide which to get should get the Prius Prime. If you don't know why you want an i3, it's not for you.
    EVilCHARGERfan likes this.
  17. Srivenkat

    Srivenkat New Member


    I have a 2010 Prius and I am currently looking to get an i3 with the tech package that includes Driving Assistant Plus. But it looks like the collision avoidance offered by the i3 is limited to 35 MPH. Is this true? Is there a way to raise the MPH bar?


  18. bwilson4web

    bwilson4web Well-Known Member Subscriber

    That is a speed differential and sad to say the Prius Prime has a similar limitation. My speculation is the object detection range limits how much speed difference can be detect safely enough to react.

    Bob Wilson
  19. Srivenkat

    Srivenkat New Member

    Thanks for the info, Bob. So I understand this correctly, if the vehicle ahead is travelling at 65 MPH and the i3 at 75 MPH, the i3 will apply brakes to avoid collision, if the i3 gets close enough to the car, if I am NOT using cruise control?
  20. Viking79

    Viking79 Well-Known Member

    Several edits, reread: Also, download the BMW i Driver's Guide App (note the "i" version).

    I have a 2015 BMW i3 REx with Tech/Driver's Assistance package.

    Does the system brake at speeds above 35 mph, and does it work when ACC is deactivated. No and Yes. This is separate from ACC. ACC will slow down for anything it recognizes as a car or vehicle as long as that vehicle is moving in front of you, brake force is limited in ACC, so a big speed differential could be a problem (more than maybe 10 or 20 mph).

    Speed: "Appropriate braking kicks in at speeds of up to 35 mph."
    Cruise Deactivated: "The front-end collision warning is available even if cruise control has been deactivated."

    So the warning system works at all speeds, the braking only at slow speeds.

    What I noticed on my drive back from CA: Sometimes on a turn the warning system has a hard time detecting if an oncoming vehicle is in your lane or not, especially with a large truck on a two lane that might be over the lane markings a bit. The system sometimes flashed the indicator on the dash and activated a light amount of regen to grab my attention and to improve my reaction time. This happened at speed (like 65 mph). However, it is just a warning, the driver has to take action.
    Last edited: Apr 19, 2018
  21. Srivenkat

    Srivenkat New Member

    Thanks, Bob.
  22. Srivenkat

    Srivenkat New Member

    Thanks, Viking.
  23. bwilson4web

    bwilson4web Well-Known Member Subscriber

    I defer to @Viking79 as I pretty much drive 'Prius-like' using dynamic cruise control to maintain following distance and local traffic to handle the speed.

    The only times I see the alarm is when someone force merges into my lane ... usually on the way to another lane. My experience has to do with approaching cars stopped or turning. So I'm using the vehicle indicator to tell if the car 'sees' the car(s) ahead and whether or not my car brakes to a stop without my intervention.

    Bob Wilson

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