Arm
Posts: 50
Joined: Tue Jan 07, 2020 5:53 pm

Snappier Acceleration Off The Line

Tue Jul 07, 2020 1:35 pm

Feels like the new i3's are neutered off the line. Real shame. I've an i3s and it should really haul butt when off the line...instead it doesn't move until you pass 5-10 MPH. Clearly it's an electronic limiter in play.

JohnWasser
Posts: 68
Joined: Sat Mar 07, 2020 6:15 pm

Re: Snappier Acceleration Off The Line

Wed Jul 08, 2020 7:19 am

The prototypes had a problem with the driveshaft splines shearing when full torque was allowed.

https://cleantechnica.com/2018/01/06/on ... gs-baffle/
If you were in the ActiveE program, you may recall that the early version of software did allow Launch-mode. Not long later, issues started showing up with the motor’s output shaft’s gear teeth (splines, actually) and the gearbox’s counterpart were showing premature excessive wear and failure. BMW replaced the $30,000 motor in every ActiveE in the test program. Ow.

Soooo, I’m guessing that BMW is forbidding a Sport-mode until those high-torque low-rpm components are beefed up — probably in the next generation of motor, which may exclude the i3 entirely 🙁

jadnashuanh
Posts: 5108
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: Snappier Acceleration Off The Line

Wed Jul 08, 2020 8:58 pm

FWIW, the tires may be limiting things. I know that I was in a show covered parking lot one time and floored it. The car barely accelerated at all but the tires were not spinning. Electric drivetrains don't like the shock of intermittent tire grip/slip, and the computer may be really aggressive on detecting and stopping tire slip.
Jim DeBruycker
2011 535i x-drive GT, 2014 i3 BEV
Soon (hopefully!) A 2021 X5 45e will replace the above

Arm
Posts: 50
Joined: Tue Jan 07, 2020 5:53 pm

Re: Snappier Acceleration Off The Line

Sat Sep 05, 2020 9:25 am

JohnWasser wrote:
Wed Jul 08, 2020 7:19 am
The prototypes had a problem with the driveshaft splines shearing when full torque was allowed.

https://cleantechnica.com/2018/01/06/on ... gs-baffle/
If you were in the ActiveE program, you may recall that the early version of software did allow Launch-mode. Not long later, issues started showing up with the motor’s output shaft’s gear teeth (splines, actually) and the gearbox’s counterpart were showing premature excessive wear and failure. BMW replaced the $30,000 motor in every ActiveE in the test program. Ow.

Soooo, I’m guessing that BMW is forbidding a Sport-mode until those high-torque low-rpm components are beefed up — probably in the next generation of motor, which may exclude the i3 entirely 🙁
I find that baffling since they are able to make ICE vehicles with 4 times the power of this car and not seem to have drivetrain issues. It doesn't make sense to me as to why they can't make it work

JohnWasser
Posts: 68
Joined: Sat Mar 07, 2020 6:15 pm

Re: Snappier Acceleration Off The Line

Sat Sep 05, 2020 10:45 am

Arm wrote:
Sat Sep 05, 2020 9:25 am
I find that baffling since they are able to make ICE vehicles with 4 times the power of this car and not seem to have drivetrain issues. It doesn't make sense to me as to why they can't make it work
They CAN make it work, but not with the design of the original part. We'll probably never know why those original splines weren't up to the task.

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