We may not have had enough time for a full test of the 2012 Fisker Karma in the short time we had it, but a suspension walkaround takes almost no time at all, especially now that we have our Rotary 2-post lift.
The Fisker is so new that Rotary doesn't yet have a lift point cheat sheet on it. The Karma's owner's manual was AWOL, too, so we went ahead and used subtle marks left behind by what we presume was Fisker's own shop equipment. Going slow in cases like this is key.
As a series plug-in hybrid, this unique machine is sometimes powered by electricity stored in a large lithium-ion battery running down the center of the car, between its four seats. Other times it's powered by a 2.0-liter direct-injected turbocharged four-cylinder engine and generator set that's mounted longways between the front wheels. In Sport mode both of these happen at once for extra ooomph.
In all cases the Karma is driven electrically by a pair of motor-generators that sit between the rear tires. There is no driveshaft; it's all done with wires.
The front end rides on a double wishbone suspension of Fisker's own devising.
Aluminum abounds, mostly in cast form. The upper wishbone (green) has the classic A-arm shape, while the lower one is more L-shaped. A coil-over monotube shock handles the springing and the damping.
The steering tie-rod end (yellow) mounts quite low on the front knuckle, but that's because the front-mounted steering rack (green) is positioned quite low on the front subframe. There's lots of steering rigidity here; the steering rack itself is hard-mounted to the front subframe, which in turn is hard-mounted to the chassis.
An EPS unit supplies the power assist, though the column-mounted unit is not visible here. The Fisker's steering response is quite direct, but the EPS steering effort tuning is probably heavier than it needs to be.
The bottom end of the Sachs-made front monotube coil-over mounts to the lower arm with a simple tie-bar...
...with long bolts that go all the way through.
Front camber and caster are easily adjustable via a pair of eccentric cams built into the inner attachment points.
The pivot axis of the aluminum upper control arm is tilted back to provide a dose of anti-dive geometry.
Karma's front stabilizer bar is mounted ahead of the steering.
Another look without arrows this time.
A car-spanning cast aluminum front subframe cradles the 2.0-liter turbo-4 engine. There's nothing in the central tunnel but batteries, so the entire exhaust system lives in front of the firewall.
After exiting the turbo and catalyst, the exhaust dumps into a central muffler before splitting in two, with each half flowing through another silencer to exhaust pipe. The dual exhausts exit from a cutout low in the front fender, ahead of the front door and behind the front tires. Each front fender sports a small grille opening directly above the exhaust pipe to help expel exhaust system heat.
Here's a closer look at one half of the exhaust system.
Little noise comes from those exhaust pipes, which are dormant half the time anyway when the Karma runs on battery power. At those times this speaker is one of two that emits an artificial noise to alert pedestrians at speeds up to 25 mph.
The front brakes are impressive-looking Brembo 6-piston fixed calipers with a removable bridge bolt for easy pad swaps. They squeeze two-piece floating calipers with an aluminum center hub.
But they don't do anything below 0.25g of deceleration in order to let the rear-mounted motor generators recover all the braking energy they can. An initial 100% rear brake bias sounds weird at first, but 0.25g stops are mild enough that it doesn't feel all that odd.
The calipers are nevertheless prefilled to move the pads up against the rotors during such stops just in case you press harder or if the stability control needs to kick in for any reason. They also work in normal fashion when the battery is full and has no room for any recovered energy.
A computer sorts it all out, but you'd never know it. These brakes feel powerful and sure-footed. At some future date we'll drive the car harder on the test track, but we don't expect to be disappointed except maybe on one front: the Karma weighs between 5,200 and 5,300 pounds. It's unlikely to set any stopping distance records.
Another double-wishbone setup with lots of aluminum bits supports the Karma's rear end.
Here we can see the upper arm (yellow), the lower arm (green) and the toe link (orange.)
The Fisker's toe-link sports a turnbuckle (yellow) midway along its length for easy adjustment. And check out the general massiveness of the double-shear outer attachment at the hub end (green). Probably has to do with the grip potential of the massive 22-inch wheels and Eagle F1 Supercar tires back here.
Camber adjustments are made with an eccentric mounted at the outer end of the upper arm.
The Karma's rear stabilizer bar (yellow) sweeps in from behind to meet a drop-link that connects to the lower arm. But the interesting thing to note here is the large-diameter rear shock. This is something Sachs calls a Nivomat, an automatic self contained load-leveling monotube damper.
A Nivomat auto levels entirely via hydraulics within. Why put one here? This is not a minivan or SUV. I asked someone at Fisker and they told me they wanted the Karma to sit low, and it fact it does. But it also seats four. Getting away with both requires impossibly stiff springs or some sort of load leveling scheme.
I've personally worked with Nivomats before. It's a good solution to that sort of problem, especially when you don't want the complexity and cost of an air suspension system.
The point where the Nivomat coil-over mounts to the lower control arm (yellow) is mighty beefy, with a wraparound arm to put the joint in double shear. The more lightly loaded stabilizer bar link (green) just above can make do with a single shear joint.
The all-aluminum rear subframe (yellow) is welded up from several pieces. In addition to carrying the suspension, it cradles the electric motors and rear differential.
The differential and electric motors reside in a common housing. Imagine a regular ring and pinion diff, with power coming in through the pinion shaft. Now imagine that shaft being long enough to punch through the back of the differential housing and out the other side. Place one electric motor on the front and the other one on the back and you have the Fisker power unit.
Both motors act as one, turning the pinion shaft together. Any differential action required is meted out with gears in the usual way. Yes, it is a limited-slip diff.
Also, these are motor-generators, meaning they generate electricity to plow back into the battery under deceleration.
Pretty neat stuff.
The Fisker's pedestrian warning system (hear it here) makes noise at the back of the car, but these rear bumper inserts are fake speakers.
The real speaker is hidden dead center under the rear bumper, close to the rearmost of the two electric motors.
Four-piston Brembo calipers do the braking chores in back, but, like the front, they don't do much until the regenerative braking system tops out at 0.25g of deceleration.
All of this interesting hardware rides around on meaty Goodyear Eagle F1 Supercar rubber. Up front you'll find 255/35R22 W-rated tires on 22-by-8.5-inch rims. The rears are 285/35R22 on 22-by-9.5-inch wheels. I still don't have a scale at the shop, so I can't tell you what they weigh. I know, I know.
I didn't know what to expect before I put the Karma up on our Rotary lift, but after doing so I think they really have something here. I really have to hand it to them. None of what we've seen is parts-bin stuff. They really have designed an entire car.
Yes, it's heavy. But it is a couple inches shy of 200 inches long and is over 78 inches wide, which makes it slightly shorter and somewhat wider than a Maserati Quattroporte. And as a plug-in hybrid it carries around two kinds of propulsion in the form of a turbocharged 2.0-liter four up front (with intercoolers, the works), a big battery in the middle and two large electric motor-generators in back. And don't forget the weight of the third generator connected to that front-mounted engine and all of the power electronics and battery cooling subsystems.
We have a pretty good idea how well it goes on gasoline and electricity, but we have yet to test how all of this hardware works when pushed to the limit. Stay tuned.
eidolways says:
08:38 PM, 12/15/11
Man, if I had the money... That car's just a technical tour de force, even if it isn't necessarily the most practical thing in the world.
iancar says:
08:47 PM, 12/15/11
Honestly, I seriously doubt that Fisker or Tesla can survive more than 10 years into the future. Gasoline is still far too cheap for the mainstream to jump into the "NEXT" generation technologies.
Mike Magrath replied to comment from iancar
10:16 PM, 12/15/11
These are my thoughts exactly. Unless the government steps in an taxes gasoline to high heaven, there's no NEED for anyone to switch. They'd have to, what, double the price of fuel to get major change?
-mm
sharpend says:
12:48 AM, 12/16/11
Very nice.
Minor point, typo about the rear tires. The rear size is actually 285/35R22.
viss1 says:
06:09 AM, 12/16/11
Cool stuff.
Nivomats are a neat invention. In the same packaging as a regular shock, they provide constant ride height with little or no penalty in dampening vs. a normal shock. You'd want something more sporting in a more focused sports car, but even some Challenger R/T's used them. Of course the limitation is you can't swap springs to reduce ride height (because the shocks will just rise to compensate).
throwback says:
06:58 AM, 12/16/11
Another great job Dan. i still don't understand why Fisker went with 22" wheels. Surely 20s would ahev been enough.
rioranchonm says:
07:43 AM, 12/16/11
I want that Rotary Lift. How about a write up about it.
maxx18 says:
08:20 AM, 12/16/11
@throwback, I recall reading some time ago that the decision to go with 22" wheels was for clearance on the front end. The steering rack and cradle sit very low.
_c_ says:
09:20 AM, 12/16/11
@ Magrath-
Lithium ion battery density has doubled in the last 12 years. If battery capacity doubles within the next decade (http://www.technologyreview.com/energy/27049/page1/, http://www.techspot.com/news/46278-breakthrough-could-bring-tenfold-increase-in-battery-life.html), there will be no need for any government subsidies, as it is much cheaper to run a car on electricity than gas. Overall costs of ownership are lower for electric vehicles as well.
evodad says:
09:23 AM, 12/16/11
@iancar, perhaps they have international goals to help there business being that gas is a lot more expensive in many places outside the US (looking at you Europe, Australia, etc.)
empowah says:
10:01 AM, 12/16/11
I like it because it's unique and genuinely jaw droppingly good looking. A Panamera may be more practical, but I'd be more proud to own something like the Karma. It's got presence.
The fact it's electric is actually a competitive advantage, because if they just tried to make a better Aston Martin or Porsche with $100K, a tiny company like Fisker would fail.
And at 5,200 lbs, hey, at least it weighs less than a single-engine Continental GT.
thenewblack says:
10:43 AM, 12/16/11
I can absolutely see many wealthy movie stars and tech CEO's buying these.
mfennell says:
10:52 AM, 12/16/11
All those suspension castings are Fisker-specific? I am really surprised.
I did not expect it to look like a full-blown production car underneath.
greenpony says:
11:25 AM, 12/16/11
Mike Magrath says: "They'd have to, what, double the price of fuel to get major change?"
And people like me would be stuck paying thousands of dollars extra every year because batteries simply don't have the range or the rapid refuel time. Honestly, rather than trying to tax the hell out of everything that anybody doesn't like, why not just design better infrastructure so that people don't feel required to use gasoline, or required to drive long distances, or whatever. The system can be improved without just resorting to tax tax tax. I don't know about the rest of you, but with health insurance costs spiraling upward, basic need costs increasing, taxes & fees ballooning, and employee raises flatlining, the LAST thing this struggling economy needs to a higher fuel tax.
csubowtie says:
11:56 AM, 12/16/11
Cool stuff. It's obvious Fisker did it's own engineering on this car. However, it's also obvious they are a new company. A lot of that stuff looks well thought out, but not very refined. It reminds me of something a prototype shop or college team would put out. It's got all the performance and technical stuff right, but the manufacturing is cruder. Not complaining though. They need to have a car and a company before they can worry about refining things. I bet once they get this car on the market and selling, the next generation can have some manufacturing engineering poured into it to make it cheaper, lighter, etc. The pains of a new company.
mk40 says:
02:59 PM, 12/16/11
I don't think EV was ever intended to place all ICE cars or is it the mainstream solution that will do away with ICEs once and for all.... at least not any time soon. I don't think anyone is really saying that. But every bit helps and we need various efforts to chip away at energy challenges. 1 think a goal of 1 Million EVs on the road that the US admin has set is realistic when you consider the new battery technologies being developed, other improvements in technology and lower price of each sucessive gen of EVs.
It really is too early to make a fair judgement regarding EVs. No one is even saying it will work for everyone, but if it works for some people and they use no oil then why not? Again, it's going to take many different alternatives and technologies to deal with our energy challenges and we really need to pursue multiple avenues.... Then at some point in the future some of them may emerge as more viable for the mainstream than others, but can't be sure unless you try different ones. An even if something turns out to not be viable for the "mainstream", but maybe 5 or 10% of people adopt them, that's significant. If 5 or 10% of population adopts some combination of EVs, pluggin hybrids and regular hybrids then that makes a substantial difference in oil consumption.
miamifan1 says:
05:35 PM, 12/16/11
I'm blown away by the thoroughness of the design, too. Except for dead give-aways like the welded rear subframe and what appears to be off-the-shelf extrusions in the front chassis, it's a bespoke design.
Look how well the bodywork fits - Germanic in its assembly. Look how tidy the undercarriage is presented! Surely in this hidden region you'd see the parts-bin shortcuts and sloppy construct. Flat-out shocked, over here.
I bet Lotus couldn't do this good a job.
I keep looking for some other OEM tags in all those wishbones. None to be found...
PS: awesome pics! loving IL right about now!
miamifan1 says:
05:37 PM, 12/16/11
PS: awesome pics! loving IL right about now!
can you guys start taking macro shots of the whole under-car?
can someone say 'screensaver'??!!
nimisys says:
07:48 PM, 12/16/11
There is no column mounted EPS. it uses an Electro-Hydralic power steering system. The pump is integrated into the bottom of the reservoir under the hood.
smallfield says:
11:07 AM, 12/18/11
Nice walk around.
"I want that Rotary Lift. How about a write up about it."
+1 - I'd like to hear the prep, install process and operation. I guess a lift for me is like a dream car, but you guys write up things I can't have all the time and I like to read about them.
With 5200 lb curb weight I expected cast iron everywhere :), but seriously it seemed like they didn't even work on reducing it. Now that I see the weight consequence is really due to having range extension. Pretty much sells me on a Tesla type product. I imagine if the whole engine/generator for the I-4 is ahead of the firewall there is a real front bias to weight distribution as another unpleasant side effect of dual drive modes.
Keep my old now low value car if I need to go far and have something with 200 mile EV range to use daily. Hopefully Tesla can make their product look this well put together. Overall a good first product made from a startup.
nimisys says:
06:59 PM, 12/18/11
Weight balance is about 52/48% front biased. You have to remember that electric motors are HEAVY and this thing has two. That rear drive module is not going to weight significantly less than the ICE up front. So they really do balance out. Also the battery pack is going to account for 600lbs of the vehicles weight. There is probably a solid 2400lbs in powertrain/drivetrain components between the ICE, Battery, Motors and supporting systems.
duck87 says:
08:25 AM, 12/19/11
Pretty standard double wishbones front and rear. However, the front lower control arm tie bar for the monoshock is pretty... odd compared to the standard single pass through bolt (and those threads are too long). I see some opportunities for weight reduction with the rear aluminum subframe. Really, with lighter and smaller wheels, some chassis design refinement, and even such basic things as a lighter exhaust (it's a 2 litre engine, you don't even need something that complicated!) would reduce the weight at least into the 4K range.
I posted this in the last suspension walkthrough but I never got an answer so I'm hoping someone can help: A lot of people are claiming that front vs. rear steer offers more "feel". Can you explain to me why? From my understanding back in Formula SAE, it was mostly for packaging considerations, and geometrically the two are quite similar when you work it out (except for which links are in tension and which are in compression, and the angle of the joints). So why would there be a difference?
rioranchonm says:
09:11 AM, 12/20/11
@smallfield: "I guess a lift for me is like a dream car"
I think it's completely doable for a home mechanic. If you check out the prices this one is only $2,159: http://www.rotarylift.com/templateProduct.aspx?id=732
So an install guide from IL and review would be great.
jsanfroop says:
10:08 AM, 12/21/11
Thanks for the photos! I can't help but wonder what happens during an accident or when people drive into curbs. The front especially looks like that kind of loading may result in damage to the main aluminum chassis?
Did you get a closer look at the chassis side of the rear toe link?
It looks like the rear subframe itself may play a part of the suspension, it appears to have many bushings and capacity for movement, I wonder if that was part of the plan or if they just kept adding bushings for NVH.
Also, I must say that from a build perspective this appears to be an engineering sample rather than something that would have rolled off the line at Valmet.
Always enjoying Suspension Walkaround, just need to get a Lotus in there as well :)