ZAPPED
Posts: 2
Joined: Sun Dec 16, 2012 3:49 pm

Handling

Sun Dec 16, 2012 3:55 pm

Well,

I just may inject a little maturity, experience, and wisdom to the i-MiEV discussion.

My first car was a Triumph TR3, the second a TVR 2500M. I’ve owned an E36 M3 Sedan (preferred by the factory racing team), a CTS-V (mistake), three Prii, a Cayman S, and an i.

Colin Chapman and Trevor Wilkinson would be ecstatic with the i. The wheels are pushed out to the furthest extremes of all four corners. Motor and transmission (and charger and inverter) over the rear driven wheels, with the battery mass located in the exact center of the vehicle. With a curb weight of 2579 pounds (less than a Tesla Roadster -2723 pounds), an extremely low polar moment of inertia, a low center of gravity (the batteries are hanging under the floor pan), and a front to rear weight ratio of 45/55 (identical to my Cayman), the i handles very well in transitions, and under steers (for the consumer’s safety) at the limit.

I think we will see a EV sports car built on the i chassis, one that costs closer to $30,000, not $110,000 (Tesla Roadster). Simply add more Kw for more torque, and a stiffer rear sway bar to reduce over steer. The i experiences wind buffeting due to a light weight cabin that is taller than it is wide. The structure is so tall that the driver experiences motion and tipping. A low slung sports car would easily eliminate that problem.
Last edited by ZAPPED on Mon Dec 17, 2012 5:16 pm, edited 1 time in total.

JoeS
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Location: Los Altos Hills, California

Re: Handling

Sun Dec 16, 2012 5:12 pm

+1
Even though I'm partial to FWD having owned a Lancia Fulvia Zagato and a bunch of Saab Sonetts, the iMiEV allows itself to be thrown about with abandon, the only prerequisite being to turn off ASC.
Add a low-slung lightweight very aerodynamic body and we'd have a great car capable of over 100 miles/charge with our existing battery pack.
Perhaps the first step for Mitsubishi is: http://www.gizmag.com/go/8256/
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

Don
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Location: Biloxi MS

Re: Handling

Sun Dec 16, 2012 9:11 pm

After 6,000 miles, I'm extremely pleased with nearly every aspect of my i and especially love that it's RWD, but it's handling isn't one of my favorite things about it - I find it understeers nearly all of the time and severely so at the limit. If I could make a major change to any one feature, I think it would be to re-engineer the suspension both front and rear to make it handle better. If they were to ever make a sportscar version of it, the first thing to do would be to toss the entire suspension and start over with a clean sheet of paper

I suspect most of my disappointment though lies with the fact that my i shares a garage with my 1994 R package Miata and there's no comparing the handling of the two cars . . . . not even a teensy tiny little bit

I don't complain much though, because great handling was the entire reason behind the engineering of the early Miatas and every piece of the suspension was designed specifically with that in mind - No struts or torsion beams anywhere on that car, whereas with the i, great handling probably didn't even make the top ten list of what they were going for when it was engineered. True, all 4 wheels are indeed pushed to the extreme corners of the car, but that wasn't because they were trying to make it handle - If it was, they wouldn't have stopped there

The i is very good at what it does . . . . but when I get the urge to go for a sporting ride, I'll leave it in the garage! :lol:

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1994 Miata 60K miles - Soon to be sold
1979 Honda CBX six into six

fjpod
Posts: 529
Joined: Tue Apr 17, 2012 2:31 am
Location: NYC

Re: Handling

Mon Dec 17, 2012 12:52 am

The height of the i makes it very easy to get in and out of. I like it this way as I use it as a city car only...for short stop and go trips. So besides the gas savings, cleaner environment, and less foreign oil, it is easy to park.

OK, I'll take a little more range, but leave the basic size and shape alone.

JoeS
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Re: Handling

Mon Dec 17, 2012 3:50 am

Oh dear, don't want to get into the perennial discussion of handling vs. roadholding, veering off into the differences between grip and adhesion and a zillion other subtleties. Enough on the Web about that already. http://en.wikipedia.org/wiki/Automobile_handling

Don, by every account the Miata is a superb-handling vehicle, with the differences amongst the MX-5's NA, NB, and NC extensively discussed elsewhere... I don't want to go there. Besides, I'm old-school, with my frame of reference being my own first car which was an Austin Healey 3000.

My bad, as perhaps I should have prefaced my remark by saying that we're simply talking about a tall econobox.

I recognize the necessity for Low Rolling Resistance (LRR) tires and accept the roadholding degradation that comes with them. Mitsubishi's use of unequal tire sizes is interesting, both by keeping the Rolling Resistance lower with the skinny front tires as well as their effect on handling, specifically understeer IIUC. They went to a lot of trouble to incorporate these very unique tires on our iMiEV.

Don, as you've pointed out in the past, the iMiEV's roadholding (and perhaps overall handling) could be altered and undoubtedly improved with different tires. That's been done successfully on the Gen1 Honda Insight, but I continue driving on the original LRR tires as efficiency is my priority with that particular car, just as it is with the iMiEV.

For myself, I had very low expectations of the iMiEV in either handling or roadholding. That's not what I bought it for, as its controllable electric drivetrain coupled with its wonderfully functional overall package were the deciding factors.

What I've been very pleasantly surprised by is the iMiEV's overall handling relative to my initial expectations. ZAPPED explained it nicely in his original posting on this thread.

Besides, not my area of expertise. 'Nuff said.
EVs: 2 Wht/Blu SE Prem., '13 Tesla MS85, 3 156v CorbinSparrows (2 Li-ion), 24v EcoScoot(LiFePO4)
EV Conv: 156v '86 Ram PU, 144v '65 Saab 96
Hybrids: 48v1kW bike
ICE: '88 Isuzu Trooper. Mothballed: '67 Saab (orig.owner), '76 MBZ L206D RHD RV

Don
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Location: Biloxi MS

Re: Handling

Mon Dec 17, 2012 9:25 am

Joe,

I agree with nearly everything you said - I didn't buy it expecting great handling either and looking at it sitting there, I'm amazed that it handles as well as it does. It is a great around town econobox with emphasis correctly placed on good all around visibility, ease of entry and exit, comfortable room for 4 adults and spacious cargo room . . . . well, as much as you could reasonably expect for a car it's size anyway
JoeS wrote:Mitsubishi's use of unequal tire sizes is interesting, both by keeping the Rolling Resistance lower with the skinny front tires as well as their effect on handling, specifically understeer IIUC. They went to a lot of trouble to incorporate these very unique tires on our iMiEV.
I kinda doubt they went to any trouble at all. It looks to me like they basically took an existing RWD ICE vehicle (and it's suspension, wheels and tires) and dumped in the battery, motor and trans and didn't change hardly anything thing in what became a completely different car, with a lower center of gravity, more equal weight distribution and a completely different drive system. Then, they made major changes by completely redesigning the entire body for the North America version, again not changing much of anything suspension-wise from the basic ICE they were building years ago

I understand they were likely trying to keep the costs down and they were probably trying to spend the money where they had to just to make a completely different, totally electric car, but I certainly wouldn't offer up any kudos for purposely designing a suspension just to fit this all new, low CG, less rear weight biased car - I don't think they did that at all. I think what we got suspension-wise was just enough to hold the wheels on the car and most of it was just carried along from the car it used to be. True, it didn't work out all that badly, but I don't believe a great amount of thought or engineering went into it - I think their time, efforts, engineering and money was all spent elsewhere

If they ever sell enough of them to recoup what they spent bringing it along this far, I expect the wheels, tires and suspension will get much more attention in the second generation car . . . . at least I hope so

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1994 Miata 60K miles - Soon to be sold
1979 Honda CBX six into six

peterdambier
Posts: 284
Joined: Thu Oct 04, 2012 3:26 am
Location: Bergstrasse, Germany

Re: Handling

Mon Dec 17, 2012 2:06 pm

I guess the understeering can be helped. There is a switch to get rid of the nurse who controls the breaks and thrust.

Yesterday we tried melting snow for the first time and I was impressed. Snow was days old and melting. We found a lot of space were others did not dare going. Getting out again after hours of parking and late at night was no problem. Other cars got stuck with one wheel freewheeling.

Comparing my old VW Beetle and NSU Prinz 4 is not fair. They all had the engine in the back but the NSU was easy to control although oversteering and the Beatle was lost when it began swinging. All I could do was hit the breaks let it go turning and wait until it got to a stand still whatever directing it deemed apropriate to face. The i-MiEV would never lose its dignity as long as the nurse was watching.
Peter and Karin Dambier, DL2FBA, www.piraten-fraktion-bergstrasse.de

ZAPPED
Posts: 2
Joined: Sun Dec 16, 2012 3:49 pm

Re: Handling

Mon Dec 17, 2012 2:53 pm

My Bad,

I looked underneath my i and found each front suspension has a McPherson strut with the sway bar serving as the fore/aft locating link. The rear lacks a sway bar entirely, utilizing a three link DeDion tube/Watts linkage.

I think adding a rear sway bar would be entertaining.

alohart
Posts: 377
Joined: Wed Apr 25, 2012 10:15 am
Location: Honolulu, HI, and Uppsala, Sweden

Re: Handling

Tue Feb 05, 2013 5:39 pm

With a F/R 45%/55% weight distribution, almost exactly the opposite of the Leaf, installing the same size tires, maybe 165R65x15, if a suitable low-rolling-resistance tire is available, would help tremendously with the i's overcautious understeering. If that's insufficient or not possible, then adding a rear anti-roll bar could reduce or eliminate the understeering, but a custom (i.e., expensive) anti-roll bar would likely be necessary.

With its weight concentrated low (probably a relatively low center of gravity despite its height) and a mid-engine design (low polar moment of inertia), the i could be made to corner quite well.
Aloha,
Art
Honolulu: 2014 BMW i3 BEV (formerly 2012 i-MiEV SE)
Uppsala, Sweden: 2000 Honda Insight

Llecentaur
Posts: 239
Joined: Thu Dec 27, 2012 7:56 am

Re: Handling

Tue Feb 05, 2013 8:46 pm

Do you think that adding a little negative camber to the front wheels can help understear ?

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