Wild-Ass Rumor Of The Day: "CadiVolt" ELR To Be Rear-Wheel Drive?
TTAC has long held that GM should have initially sold the Volt as a Cadillac, putting its newest, most high-tech drivetrain in a luxury car that could support its high list price. Of course the bailout made a CadiVolt a touch too elitist, which led to GM canceling production plans for its Converj Concept coupe. But with plans back on to sell a Converj-inspired ELR coupe, a new question arises: can Cadillac really charge significantly more than the Volt’s $40k-ish MSRP without doing more than simply rebodying the Volt in Cadillac’s Art & Science styling? Automotive News [sub]’s Rick Kranz reckons Cadillac could do more, and thinks that the ELR could end up with rear-wheel drive.
Kranz writes:
GM has a new rwd platform that will be shared by the Cadillac ATS, a compact sedan that goes on sale next year. That could be the game changer for the ELR.
But there’s a potential packaging issue with a rwd platform: Can the battery pack be modified so the driveshaft can be positioned below it? I don’t know. The Volt’s T-shaped battery pack is below the rear seats and center console.
Certainly the battery pack could be raised, eating up some space in the passenger compartment. The trade-off would be rear seat comfort, especially headroom, aggravated by the slope of the roof as it approaches the rear of the vehicle.
I find it interesting that the ELR is being touted as a 2+2 instead of a true four-passenger sedan. A 2+2 generally limits rear-seat space to kiddies and grocery bags. There’s no room for adults.
Maybe that’s a signal that the battery pack will be eating up some of the rear-passenger space so the ELR can be offered as a rear-drive coupe.
Kranz is right about one thing: with the Volt as expensive as it is, a CadiVolt needs to be distinctive to sell. But if the battery pack needs to be raised to fit a driveshaft underneath it, the ELR’s handling will certainly be compromised. The Volt is a surprisingly fine-handling car, largely because its huge weight is kept low and central in the body. Raising that huge weight upwards could ruin any handling benefits obtained by rear-drive, making the distinction between the two cars largely academic.
On the other hand, a DOE EV stimulus from 2009 allocated $105m for
Construction of U.S. manufacturing capabilities to produce the second-generation GM global rear-wheel electric drive system.
At the time, that expenditure was something of a mystery, and we still don’t know what it means. But if GM has developed a rear-drive EV platform, that could underpin a rear-drive ELR without the downsides of using the ATS platform. But that’s one Wild-Ass Rumor to be sure…
More by Edward Niedermeyer
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A rear-drive plug-in hybrid and a front-drive flagship sedan. That's some solid thinking right there, Cadillac.
As interesting of an idea as it may be, there is one major problem with having the electric motors on the rear wheels (and not the front); stability. You can't recapture as much of the braking energy, which really is responsible for the hybrid's greater efficiency, because the rear tires do much less of the work when slowing a car down in the best of situations, and almost nothing (without skidding the rear end around) when it gets slick. Therefore you get much, much less regen energy back into the batteries from braking, and potentially at the risk of vehicle stability. The Lexus RX hybrid had some of these problems, especially when it was wet or snowy, where the rear wheels would lock up from regen as if the parking brake was pulled, or, conversely, be overpowered by the electric torque when starting off. This is besides the whole "cost of a new platform" argument, when they're still trying to pay off the original. The whole powertrain could move to the back, Corvair-style (which def would be possible with such a huge rear end), but that limits the utility of the hatchback since the front hood height is still limited by driver sight-lines.