Kain

With all this "the engine is in the wrong place in a 911" batter that I hear from some people, I was wondering if Porsche has ever considered or will consider making a mid-engined 911?

utkinpol

They do make 918 and Cayman.

Gabe Newell

And the Porsche 960:

http://www.automobilemag.com/feature...rrari_fighter/

MaxLTV

Engine placement in 911 is becoming less and less relevant for weight distribution, and it almost a red herring now (probably not completely though).

Yes, it did matter A LOT when the engine was so much of the total weight of the car - a big cast-iron cannonball in a tiny tin-foil-mobile - but now it's a rather light element in a fairly big and heavy car. Also, the placement shifted forward with 991, making it almost above the axle, with a heavy PDK transmission in front of the axle. So moving the engine in front of the axle will not change things dramatically because it will likely require moving transmission behind engine, canceling out much of the weight shift. It will also kill the rear seats for regular 911. So probably will not happen for 911 any time soon.

Mid-engine still has significant benefits - more space for suspension mechanics, ability to use bigger engines, easier to keep exhaust heat away from the engine, etc. So it makes sense that Porsche is going with this layout for 918 and 960, but keeping 911 as is.

Petevb

I don't agree.

Despite the "lightened" and shifted forwards engine the GT3 still has over 60% of its weight on the rear axle, very similar to previous GT3s and indeed early 911s going back into the late 60s.

Despite the "lighter" new motor, the addition of both water cooling and emissions equipment means today's engines are still over 100 lbs heavier than those in early cars (those cars never used cast iron, but started with aluminum before moving to aluminum plus magnesium for the block). While weight hasn't increased quite in proportion with the car, it's close. And the motor still starts entirely behind the rear axle line, the small shift forwards accounting for under .5% change to weight balance overall.

Engine placement and weight is still a critical issue for modern 911s, both for the weight balance and handling impact of the high polar moment. Zero question in anyone's mind that the 911 would be a significantly faster, "better" handling car if it was mid engined, and Porsche's CEO admitted as much.

Don't get me wrong, I'm not arguing for a switch to mid-engine. There are already plenty of mid-engined cars, and Porsche makes a few. Pretty sure Porsche realizes that a mid engined 911 would cease to be a 911 at all...

MaxLTV

I'm not saying it does not matter at all, rather that gains from mid-motor are decreasing, which makes it less likely to happen.

Few things to consider:

1. Most mid-engined cars have around 60% of weight on the rear:

Lotus Elise: 38% front , 62% rear
Lotus Evora: 39% front , 61% rear
MP12-4c and 458 - 38/58

The numbers I've seen from 991 are 41/59 from a guy who cornebalanced his and I've seen 42/58 mentioned in some porsche materials for GT3. Sportauto had a different number, so I'm not sure whom to believe.

2. The polar moment of inertia is not THAT much increased by rear motor. In fact, during normal driving, the pivot point of the car is just ahead of the rear axle if the car has no rear wheel steering. So rear motor is not that far from the center. Of course, mid-motor is right in the center. Some journalists when talking about polar moments of inertia assume that cars pivot around their geometric center, a point in the middle between axles, but that would require rear wheels steering in the direction opposite to the front wheels by an extreme angle.

3. Rear wheel steering (active or passive) in the same direction as front wheels shift pivot point back, possibly even behind the rear axle. Now Porsche seems to have a pretty good active RWS technology, that for all we know can put the pivot point right where it needs to make the car pivot around the engine. So now even fewer reasons to go mid-engined.

MikeBat

In the end, rear engine = 911.

Porsche has and will continue to develop cars with other engine placements, but the 911 is the 911.

reidry

+1

I find it highly unlikely that Porsche would ever market a mid-engine car under the 911 model number.

As has already been stated, Porsche has created several mid-engine cars under other model designations including the Carrera GT, Cayman, and the 918.

In general people asking this question are driving at the "will Porsche ever make a mid-engine car with the same power as the 911". As for that answer I think we will just have to wait and see. Porsche, or more properly, VAG the mother company is motivated by Profit and there are many factors driving sales / profit in the auto industry. Until now Porsche has take the approach that the 911 is a large profit center and that the model must have a significant performance and cost separation from any Porsche model that could be considered a rival.

We are slowly seeing that erode, the Cayman GTS coming in the Spring / Early Summer will likely perform at the same level or above the base 991 911 Carrera 3.4L car.

Ryan

911Jetta

I always hate hearing that comment from non-owners, and am somewhat confused when I hear that comment from 911 owners. The weight distribution is what makes the car so fricking awesome in the first place.

20,000+ victories an people still have a problem with its weight distribution?

I'm definitely not looking for a 50/50 (static balance) car:
- that has artificial steering feel because of the heavy engine in it's nose
- that has a rear end that gets light under heavy braking
- that can't put the power down coming out of a turn
- that looks like everything else on the market

Maybe a quick review of this video is what is needed for moments like this:

or this one...


Or this handy point-by-point guide.

Petevb

I agree that rear wheel steering, in particular, makes a rear engined car more competitive with a mid engined one. Otherwise, however, the fundamentals remain, and I think you're underestimating them.

It's true that mid and rear engined cars can have similar weight distributions. What this ignores, however, is how this is achieved. A very early 911 achieves its weight distribution by a long front overhang and putting weights on the front bumper. Slightly later the battery stood in for the weights, and today you've still got a forward located battery, long overhang plus radiators out in front of the front wheels, placed there partly to counterbalance the engine in the back and achieve similar balance to the mid engined cars you mentioned.

Any time you move weight to the edges of the car you're increasing polar moment, and we know how much: flipping the motor as in the Cayman reduces polar moment by over 25% (and moves 5% total weight to the front axle over the turning wheels).

25% is a lot by itself- if means you need 25% more energy to get the car turning at a given rate, but there's a second effect that's less obvious, and that's the longer wheelbase. Today the Cayman's wheelbase is only slightly longer than the 991, but it still gives the tires more moment arm (leverage) to act on the inertia.

Consider a car on a sheet of very slick ice. If you go to the nose of the car and push it sideways the car will spin around its center of gravity. The closer to the CG you push the harder it is to get the car spinning, and a shorter wheelbase does exactly that, so the combination of a short wheelbase and a higher polar moment is a double hit.

The reason we consider moment of inertia around the CG is because any rotation other than around the CG puts additional loads on the tires. Thinking back to the ice sheet example, if the car doesn't rotate around it's CG when pushed, that's only because of forces going through the tires.

That's important because those forces are what define our driving experience. If a car has a high polar moment and short wheelbase we turn the wheel and the tires have trouble getting the car to rotate. We experience that as understeer, which is bad, and then once the car is rotating the rear tires have trouble slowing it down again and we experience oversteer. If we could put the tires out at the far corners and concentrate all the mass in the center the car would react instantly and there would be no understeer or oversteer. A mid engined car comes significantly closer to that than a rear engined one. Thus we can calculate that given equal tires, etc, a Cayman could change direction roughly 30% faster than a 991 due to advantages we can quantify. That's quite a lot, in modern sports car terms, and while the equation has improved recently with the longer wheelbase, the longer overall length hurts polar moment nearly as much.

Porsche's CEO summarised all this as "The Cayman, as it is mid-engined, is conceptually better than the 911, so if you have the same engine in both cars then the Cayman would be the faster car, and that is not our intention."

Carrera GT

There's really "no such thing" as a mid-engined rear-engined car, but yes, there is, it's the 911 GT1 -- this is no news to Porschephiles of the 90's, where both 993 body (lovely) and 996 body (okay, wouldn't say no, can't say it wins me over even so.)

That said, a "GT1" wild card has been said to be on the table for quite some time. We'll have to wait and see (since it's a turbo configuration) what comes of rear steer and whatever comes in the "real" 991.x turbos, all of which should unfold in the seven years of the 991 evolution, which, happily, we're half way in and I think everyone is already looking for the .2 minor increment.

Tacet-Conundrum

Dare I say Porsche start making Caymans with the current Turbo engines or GT3 methodology in mind and see what happens? Then watch as the 911 sales plummet and Cayman sales rocket because its not that far off from the 911 on some.of the tracks that's the magazines test on.

That and that reason alone is why a Mid Engine 911 or Cayman with the 911s engineering will ever get a green light.

Drifting

Porsche is so tied to tradition that they will never directly do that, at least at the price of a 911. Porsche CEO said that this year.

However, their ego causes them to want to compete with Ferrari and Mcclaren, so they are making the mid-engine 960.

For the next 20 years from Porsche, I expect you can buy a mid-engine car in the low end or the high end of the Porsche range, but not the middle.

You'll have the entry level Cayman at 50-60K and there will be the 960 at the high end costing 250-300K. There won't be anything in the 90-190K mid-range except various versions of the 911.

fbfisher

I hope not, but if they do it won't be called a 911. If you think the noise was loud when the engine included water cooling, can you imagine the hand wringing and yowling that will ensue should the 911 come with a mid-engine. Holy cow.

By the way, I hate mid-engine cars and would never own one.

cparkin

they already did... see 911 gt1.