Confirmed: Next-gen Porsche 911 to use KERS throughout entire model range

Aiolos

Aiolos

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This is pretty cool actually. I like the idea of the flywheel in an everyday car. :thumbup:

It means that you can have the regular engine with less power and emissions to satisfy your wallet, the government, and the environment, but you can have an extra bit of power to pass another car when you need it (which is the whole reason I could even justify having a big engine in my [future] daily driver that didn't double as a track car) :cool:

Source: Carpix via Autoblog

The next generation Porsche 911 will be a significant departure from all previous generations, though to the untrained eye that could be a hot-air boast. The chief novelty of the 991, confirmed for us recently by Porsche sources in Germany, is that the entire range will benefit from a KERS device, such as what was used by a couple of teams in Formula 1 in 2009 and then immediately banned by the FIA for the 2010 season as an unfair advantage, only to be allowed again for this 2011 season.

The Kinetic Energy Recovery System takes brake energy recuperation to a whole new sophisticated level, putting it on reserve for when you want the pedal on the metal for quick overtaking. But it's not stored in any additional onboard battery system ? instead, it is meted out via a dedicated special flywheel system.

The chief giveaway that Porsche is definitely planning the KERS strategy is the added wheelbase length of four whole inches together with added vehicle length of 2.75 inches. Just the right amount of distance for incorporating the new flywheel technology between the gearbox and engine.

Though the starter 991 911 Carrera is earmarked to have 350 horsepower from a smaller 3.4-liter flat-six engine, the KERS ingredient will give the car acceleration figures comfortably quicker than the 4.7-second 0-to-60 time of the current 997 911 Carrera. And this direction ensures that the new 911 can still emit less noxious stuff, go faster, go farther on a gallon, and, according to our sources, even weigh around 100 pounds less as Porsche rolls out more and more lightweight materials usage where we've never seen it before.
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Not sure if want?

It's cool, and yay for Porsche experimenting with new things, but...throughout the whole 911 range? Really? I'm...not sure about that one.

I hope it's an option. It's a cool option to have, but I'm not so sure about them including something new to a road car as standard (sans a delete option) across the whole range.
 
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That 911 does look wrong, looks like they moved the engine further in front or something similar. Anyway, the only 911 I'm interested in is the GT3/RS.
 
immediately banned by the FIA for the 2010 season as an unfair advantage, only to be allowed again for this 2011 season.
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Got this far, decided the reporter didn't have a fucking clue, stopped reading.
 
I can see the benefit of lower overall horse power and using KERS for quick bursts instead. The problem is a lost of buyers buy from a specs sheet.
 
I'm not sure how I feel about the new sharper back end. But more power and less weight is a good thing.
 
argatoga said:
I can see the benefit of lower overall horse power and using KERS for quick bursts instead. The problem is a lost of buyers buy from a specs sheet.
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It's also a lot lighter.
 
I can't believe that even with the announced weight reduction, it's growing in dimensions. Isn't the Porsche already longer and taller than the Corvette?
 
^ only by 1 inch either way. The wheelbase is almost as short as an Elise though (92 inches). The Corvette is 105 inches.

But that only really illustrates how much weight is hanging out on the ends of the car past the wheels.
 
MadCat360 said:
^ only by 1 inch either way. The wheelbase is almost as short as an Elise though (92 inches). The Corvette is 105 inches.

But that only really illustrates how much weight is hanging out on the ends of the car past the wheels.
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So are you saying that those aspects within the dimensions of the car aren't really important (the over hang)? I'm asking because I simply don't know?
 
czelaya said:
So are you saying that those aspects within the dimensions of the car aren't really important (the over hang)? I'm asking because I simply don't know?
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The wheelbase vs.total length has some interesting impacts.

The Exige actually has a not-insignificant rear weight bias. The weight is still more centered in the chassis than in the 911 (mid-engine rear bias vs. rear-engine rear bias), but the rear bias is there. Combine that with the relatively short wheelbase, and you get a car that changes direction very effectively. The 997 wheelbase is actually only slightly longer than the third gen Miata's wheelbase, as well. All three of these cars can transition very well and can quickly become a handful, if set up to allow that (yes, I'm serious. If you don't believe a Miata can be a handful, I invite you to drive mine with the rear swaybar attached). This means a more careful, more smooth touch from the driver is required to lay down power, relative to something like a Corvette. I enjoy this, but that's just a personal preference.

On the street, however, these long overhangs are a significant disadvantage. When Nugget had his 997 C2S Cab, his car sat higher than my (lowered) Miata. Yet my Miata (with a similar length wheelbase, but ~14" less total length) scrapes much less frequently on driveways here in Houston. The GT3 RS, with its significant overhang and low height, simply cannot go to many places. A Corvette would have an easier time with these driveways than the Porsches, as its total length and wheelbase are closer (like the Miata's).

It's misleading to judge a car's handling behavior by its length, rather than it's wheelbase, but total length still has an impact (especially as related to wheelbase).
 
czelaya said:
So are you saying that those aspects within the dimensions of the car aren't really important (the over hang)? I'm asking because I simply don't know?
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No, a car with more centralized weight is usually more ideal.

If you compare two similar cars, say, the Formula Skip Barber and the Spec Racer Ford, you find very similar weight biases, curb weights (the SRF is a little heavier), grip levels and handling traits.

But the SB F2000 has more centralized weight, whereas the SRF has more weight out by the wheels.

The result is that the SRF has more of a tendency to rotate due to this additional "leverage". It has more rotational momentum in a slide and is harder to keep from spinning out during a moment.

The Exige vs. 911 situation is also really interesting, because they share their weight bias, but it's more complex I think.
 
MadCat360 said:
The Exige vs. 911 situation is also really interesting, because they share their weight bias, but it's more complex I think.
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It absolutely is more complex. On this subject, I am going to steal from another person, another post, on another board?

Porsche 911 F/R weight distribution 38/62%
Lotus Elise F/R weight distribution 38/62%

From: http://www.lotustalk.com/forums/f100/weight-distribution-91279/
Now, I'm no expert but I understand most of physics (I think) enough to at least help....or not, it remains to be seen. Anyway: It is true that simply looking at the weight distribution % of a vehicle doesn't really say a lot about how it will handle. And I think the statement about "center of mass" is the right idea, but what it's really about is "moment of inertia." This has to do with how hard is it to change an objects angular momentum, ie: how hard is it to stop it from (or start it) rotating by applying a force at any given point. For instance, a dumbbell usually has 50/50 weight distribution, but has a very high moment of inertia. Why? Because most of the weight is at the outer reaches of its total length. Now lets say we have a steel rod the same length as the dumbbell and a weight is placed so that it is in the center of the rod such that the rod and weight have the same mass as the dumbbell. They both will have 50/50 weight distribution but the rod with the centralized weight will have a much much lower moment of inertia when compared with the dumbbell.

So that's the super simple example. Cars are, of course, much more complicated but the concept is the same. You want a low moment of inertia for two reasons: So you can turn the car easier (that would be changing from 0 angular momentum to some non-zero value) and so you can stop it from rotating (spinning) easier. However, There are definite benefits to having rearward weight bias in a car -- better braking and you should be able to apply more throttle when exiting a turn.
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Even small changes to the polar moment of inertia matter significantly. Just as an example, comparing my NA to my NC, the weight distribution is roughly the same (slight to the front, but both claim 50/50 with rounding). However, the engine in the NC is just a bit further back - a matter of inches. I felt this difference on a test drive back in March 2006, in about 5 miles of street driving on a car off the dealer lot (with my mother in the passenger seat). The change in feel was sufficient for me to notice it in these relatively mild conditions.

As a result of the different polar moments in the cars, the 911 and Exige do reward different behaviors. In the 911, going through a tight corner, I'll rotate heavily in the entry and use a severe late apex, using compression braking (or even a touch of trailbraking) to rotate the car. This involves a lot of sliding in the rear, and that heavy engine way back there holds a very stable slide until rolling on the throttle transfers weight to the rear. The Exige doesn't reward this extreme-late-apex behavior. It doesn't hold the slide like the 911 will. When the back starts to come around in the 911, it's a long, graceful slide when compared with the Exige's quick rotation behavior. The Exige is quick - quick to rotate, quick to correct, quick to rev, quick to brake, etc.

That makes it sound like the cars are very different. They're not. When compared with other cars - Corvette, Ford GT, Cayman, etc., they're remarkably similar. But there are some critical differences.
 
Has it been confirmed that it would be a flywheel system? A hybrid with regen-braking is a "KERS" system.
 
NecroJoe said:
Has it been confirmed that it would be a flywheel system? A hybrid with regen-braking is a "KERS" system.
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kynetic energy recovery system. even if they have a little monkey charging batteries under breaking, the term would still be correct...
 
equiraptor said:
It absolutely is more complex. On this subject, I am going to steal from another person, another post, on another board?

Porsche 911 F/R weight distribution 38/62%
Lotus Elise F/R weight distribution 38/62%

From: http://www.lotustalk.com/forums/f100/weight-distribution-91279/

Even small changes to the polar moment of inertia matter significantly. Just as an example, comparing my NA to my NC, the weight distribution is roughly the same (slight to the front, but both claim 50/50 with rounding). However, the engine in the NC is just a bit further back - a matter of inches. I felt this difference on a test drive back in March 2006, in about 5 miles of street driving on a car off the dealer lot (with my mother in the passenger seat). The change in feel was sufficient for me to notice it in these relatively mild conditions.

As a result of the different polar moments in the cars, the 911 and Exige do reward different behaviors. In the 911, going through a tight corner, I'll rotate heavily in the entry and use a severe late apex, using compression braking (or even a touch of trailbraking) to rotate the car. This involves a lot of sliding in the rear, and that heavy engine way back there holds a very stable slide until rolling on the throttle transfers weight to the rear. The Exige doesn't reward this extreme-late-apex behavior. It doesn't hold the slide like the 911 will. When the back starts to come around in the 911, it's a long, graceful slide when compared with the Exige's quick rotation behavior. The Exige is quick - quick to rotate, quick to correct, quick to rev, quick to brake, etc.

That makes it sound like the cars are very different. They're not. When compared with other cars - Corvette, Ford GT, Cayman, etc., they're remarkably similar. But there are some critical differences.
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You have polar moment of inertia confused with the mass moment of inertia.
 
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