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Re: Who here actually drives an EV/HYBRID?

Posted: Fri Mar 20, 2020 1:22 pm
by BTZ201
My daily commute is about 90 miles. I drive a 2015 bmw i3 with range extender. It serves its purpose ok. My workplace has a couple charging stations I am able to use.
However I would not recommend it as a commuter. Windy days can be dangerous, I have been blown into a completely different lane on the freeway.

Re: Who here actually drives an EV/HYBRID?

Posted: Fri Mar 20, 2020 10:08 pm
by PackardV8
BTZ201 wrote: Fri Mar 20, 2020 1:22 pm My daily commute is about 90 miles. I drive a 2015 bmw i3 with range extender. It serves its purpose ok. My workplace has a couple charging stations I am able to use.
However I would not recommend it as a commuter. Windy days can be dangerous, I have been blown into a completely different lane on the freeway.
Interesting. I put a lot of seat time in an i3 without range extender and never noticed any crosswind sensitivity. Wonder if the COG/COP is radically different?

Re: Who here actually drives an EV/HYBRID?

Posted: Wed May 06, 2020 6:40 am
by Monzsta
I've got a '13 Volt. Little known secret, you can get into the PCM with HPTuners and rummage around a bit. I've remapped the pedal so all drive modes are like sport, and removed some of te torque limiters so when the engine is running it's a lot faster than stock. Sadly you can't get into the hybrid control module, where the settings for the electric side is. I even looked into swapping a HCM from a '16 Caddilac ELR, which has the same powertrain, just turned up for more performance. Volt is 157/295 hp/tq, ELR is 233/373. That's built in performance, but GM doesn't allow this due to their "Global A" archetecture.

Re: Who here actually drives an EV/HYBRID?

Posted: Wed May 06, 2020 7:09 pm
by gruntguru
BTZ201 wrote: Fri Mar 20, 2020 1:22 pm My daily commute is about 90 miles. I drive a 2015 bmw i3 with range extender. It serves its purpose ok. My workplace has a couple charging stations I am able to use.
However I would not recommend it as a commuter. Windy days can be dangerous, I have been blown into a completely different lane on the freeway.
Some tinkering with wheel alignment (toe front in, rear out a little, rear camber -> neg, front -> pos) and tyre pressures (increase rear, reduce front) might help.

Re: Who here actually drives an EV/HYBRID?

Posted: Sat Jun 13, 2020 11:49 am
by BTZ201
Sorry for the delayed response.
I recently replaced the very worn rear tires and had a 4 wheel alignment done at the dealer. Factory specs. It has helped with normal driving but not for cross winds one bit. These cars are very light weight. Tall and flat on the sides. My commute has some very flat wide open areas for several miles in spots that happen to get a lot of gusty winds.
No fixing a light weight sail with alignment specs.
Dont get me wrong, its a good little car, I actually chose it because it accommodates me well, I'm 6'2" and 260# and I am very comfortable in it.

Re: Who here actually drives an EV/HYBRID?

Posted: Sat Jun 13, 2020 1:27 pm
by PackardV8
BTZ201 wrote: Sat Jun 13, 2020 11:49 am Sorry for the delayed response.
I recently replaced the very worn rear tires and had a 4 wheel alignment done at the dealer. Factory specs. It has helped with normal driving but not for cross winds one bit. These cars are very light weight. Tall and flat on the sides. My commute has some very flat wide open areas for several miles in spots that happen to get a lot of gusty winds.
No fixing a light weight sail with alignment specs.
Dont get me wrong, its a good little car, I actually chose it because it accommodates me well, I'm 6'2" and 260# and I am very comfortable in it.
FWIW, the i3 ReX weighs about 3200#, which is above average for its side area. JMHO, but it's the skinny tires BMW uses to eke out the max range. The very tall, very narrow, very high pressure (175/50R20 (f) and 195/50R20(r) and 41 PSI) which some ReX had are what is making it feel less than planted in crosswinds.

Re: Who here actually drives an EV/HYBRID?

Posted: Sat Jun 13, 2020 3:01 pm
by Kevin Johnson
BTZ201 wrote: Fri Mar 20, 2020 1:22 pm My daily commute is about 90 miles. I drive a 2015 bmw i3 with range extender. It serves its purpose ok. My workplace has a couple charging stations I am able to use.
However I would not recommend it as a commuter. Windy days can be dangerous, I have been blown into a completely different lane on the freeway.
https://bimmerlife.com/2019/12/07/incre ... of-i3-rex/

You can see in the reflections on the side of the car that a large concavity is present that would capture the crosswind and generate a torque.

Re: Who here actually drives an EV/HYBRID?

Posted: Sat Jun 13, 2020 3:09 pm
by BTZ201
Listed at 2899#, just about right with me and my lunch box= 3200#😀
Jack I definitely agree, the tires are a lot to do with it, they are more like motorcycle tires they are so skinny.

Re: Who here actually drives an EV/HYBRID?

Posted: Sat Jun 13, 2020 3:54 pm
by Kevin Johnson
BTZ201 wrote: Sat Jun 13, 2020 3:09 pm Listed at 2899#, just about right with me and my lunch box= 3200#😀
Jack I definitely agree, the tires are a lot to do with it, they are more like motorcycle tires they are so skinny.
I was going to bring up driving a Renault R8 with R15 4.5" wide rims and 80 series 135 tires that needed particular pressures front and rear to prevent jacking the rear end around (rear engined and swing axle) during panic stops. There were often strong winds in the Altamont Pass that made things exciting.

I think BMW optimized forward movement. Simple as that.

Edit: I am guessing the batteries are at floor pan level. This would change (lower) the center of gravity of the car. The concavity on the side panel has a negative tilt and so the lever arm around the CG would be accentuated. It really does have the properties of a sail.

Re: Who here actually drives an EV/HYBRID?

Posted: Sat Jun 13, 2020 7:04 pm
by gruntguru
BTZ201 wrote: Sat Jun 13, 2020 11:49 amNo fixing a light weight sail with alignment specs.
Maybe not, but your problem is not caused by a large sail area combined with light weight and skinny tyres. This is not a large car and it is not a light car - especially not compared to a vast array of earlier European and Japanese models.

The problem is weight distribution and pressure distribution. If the centre of pressure lies ahead of the CG the car tends to yaw away from the crosswind. This was common with rear engine cars like the beetle. The i3 has 52% rear weight and with range extender 55%. There's a big hint there.

Incidently, all the suggestions I made in my previous post are back-to-front. Unfortunately, the correct changes (more front grip) will also reduce understeer which may make the car unstable/unsafe.

Re: Who here actually drives an EV/HYBRID?

Posted: Sun Jun 14, 2020 2:20 am
by Kevin Johnson
I agree that the yaw will be influenced but a roll is introduced as well. If the side of the car had a convexity rather than a concavity I do not think there would be an issue.
Come_Sail_Away_With_Me.gif
2017-BMW-i3-new-battery-1.jpg

Re: Who here actually drives an EV/HYBRID?

Posted: Sun Jun 14, 2020 3:44 pm
by BTZ201
Big wind gusts actually feel like the car is going to flip.

Re: Who here actually drives an EV/HYBRID?

Posted: Sun Jun 14, 2020 4:17 pm
by Kevin Johnson
BTZ201 wrote: Sun Jun 14, 2020 3:44 pm Big wind gusts actually feel like the car is going to flip.
That would be a way to describe a roll.

You could perform an experiment with shape-able foam to reject the roll hypothesis. Might damage the finish on your ride as well -- but SCIENCE, right? :lol:

Re: Who here actually drives an EV/HYBRID?

Posted: Sun Jun 14, 2020 6:39 pm
by gruntguru
Yes a big lump of foam and some tape. My money says it will make no difference.

There is a list of drag coefficients here https://en.wikipedia.org/wiki/Drag_coefficient no side-on coefficients for cars unfortunately but a parachute (i3 side panel?) is about 1.3, same as a flat plate.

Another thought. This car has a very low centre of gravity so it is likely the suspension has quite low roll stiffness and low roll centres. This would allow the body to roll more in the presence of cross winds.

The BMW i3s sits lower, runs lower profile tyres and stiffer suspension. You could investigate upgrading to some of these parts. IMO stiffer sway bars would be the best option.

Re: Who here actually drives an EV/HYBRID?

Posted: Sun Jun 14, 2020 7:06 pm
by gruntguru
https://www.bmwblog.com/2015/12/26/bmw- ... r-springs/
On the stock suspension the i3 has a fairly comfortable feel, even though high winds can give the car some significant body roll.