DM993tt

Cayman GTR??? http://www.farnbacherloles.com/perfo.../info/?id=2972

ausgeflippt951

So via that same logic, Harley Davidson makes some of the best motorcycles around?

There is a fine line when you deal with race car balance. In addition to the y-axis loads on tires (AKA downforce, lift, weight), you have lateral loads being placed on them as well (from cornering). With more of a weight bias on the rears, the lateral loads will be greater on the rear tires as a result. This uneven force distribution will necessitate the use for a different suspension geometry, overall width, and tire width. Porsche has recognized this and altered their design accordingly.

One disadvantage to such a dramatically uneven force distribution is a more "unconventional" feel when driven under the limit. a 65/35 car will feel much different than a 50/50. Not necessarily bad, just different. Same reason a lot of racers aren't too happy w/ the new R888s vs. the older RA-1s.

JackOlsen

Well, it would it if Harley Davidson had an absolutely unrivaled legacy of race victories over its long lifespan.

Suspension design is a big factor in building a great production-car platform for racing. Weight distribution is a much smaller one.

ausgeflippt951

Agreed. Which is why if you took the engine out of a 911, threw it into the trunk (front) and took it to the track, it would perform like crap. The car must be designed around the powertrain.

wanna911

Maybe for overall speed.

But for tire wear there is no question weight distribution makes a big difference, and that's big in the major series.

dbryant61

Personal opinion: I do not think it is possible to achieve the same trailing throttle oversteer characteristic that the 911 has without the 400 +/- pounds of engine mass behind the rear axle. While it is probably very freaky to drive for someone coming from a Bimmer 3-series, 944, or any other 50/50 car, it can be made to do things that other cars just cannot. Its a difficult instrument, but once mastered (not saying I am anywhere near that point), the rewards are great.

However, I've often wondered how a 911 would feel if you place the engine in the back seat. But I take it that was not an original thought - 914, Boxster, Carrera GT, Cayman....

wanna911

I am so familiar with my 911 I'm a little leary of driving anything that isnt (at least on track and at the limit). And yes the rear engine is predictable, and has it's advantages.

But as much as we know Porsche is all about beating the competition, even on the street, how long before there is nothing left to give from the configuration? Which could be very soon.

smlporsche

A slight rear weight bias is the best. In F1 there is no mandate as to where the engine goes but everyone has a mid engine configuration so the best engineers in the business do at least agree on that.

Any weight that is beyond the wheels is detremental and that is the current 911's shortfall comaprred to cars like the 430...

The wheelbase would have to be lengthened similar to the Boxster/Cayman which have a longer wheelbase that the 997's.

Alzen raced a GT3 engined Cayman S last year in Europe and did very well until PAG told them to get it off the track or they wouold loose all access to them. They're now back to Cup cars.

smlporsche

No more like this...

http://www.motor-sport-fotos-online....man/index.html

DM993tt

SWEET!!!!

Potomac-Greg

Actually, a cutaway of a 911 looks like a cutaway of any Audi, just backward. Since the earliest days of quattro, Audi has situated the bulk of its engine in front of the front axle; much like the 911 engine is behind the rear axle.

Audi has similarly found ways to make an ill-balanced car (60/40 wd) handle relatively neutrally. But with the latest A5 and A4, the drivetrain has been shifted back so weight distribution is better.

JackOlsen

There's really no way to compare 60/40 front weight distribution with 60/40 rear -- unless you're willing to go to front-wheel drive and have your rear wheels rotate for steering.

TR6

One huge advantage of the rear weight bias of the 911 on the track is that when you put the throttle down, the rear end just digs in and grips as you transfer weight rearward. Especially on a wet track, that rear weight bias can be a huge advantage when accelerating. When I try that in my BMW M Coupe, if I'm not careful, mashing the throttle down will break the rear tires loose with sometimes entertaining results.

jimculp

It's been done...and it ain't better.

Potomac-Greg

They both deviate from the mythical 50/50. There. I compared them.

Massive front bias creates a car that wants to go straight -- the mass wants to lead the contact patches.
Massive rear bias creates a car that wants to rotate - again, the mass wants to lead the contact patches.

The front heavy car is going the way its mass wants to go and is inherently stable (but boring). The rear heavy car wants to rotate which is inherently unstable (but fun). Like modern fighters, the ability to maneuver rapidly requires instability, which is why the 911 has always been a great track car, as long as you can keep it pointed generally in the right direction.

Audi's ability to get a 60/40 car to rotate is an engineering marvel, just as Porsche's ability to get a 40/60 car to stay pointed in the right direction.