Petevb

The RS has tire load ratings 10% higher than the 918 despite being 15% lighter, so yes, I think it will have much more downforce.
High downforce isn't difficult to achieve if you're willing to take a drag penalty- see the RSR or the aforementioned Viper ACR, quoted at 1200 lbs at 150 mph, though in practice almost certainly less. Bolt on big wings and you'll make downforce, it's just mileage and top speed that will suffer. I now expect the RS to have lower top speed than the GT3, have a worse lift to drag ratio than the 918, but make boatloads of downforce. I could easily be wrong- we don't even know if the tire numbers are accurate- but that's where I'd put my money.

As far as the design, aerodynamically the current 991 generation has about as much in common with the original 911 as a bird does with a brick.

Macca

Pete. Ive been asking around an although most of my PAG contacts have been quiet since the "GT3 Action Group" time, its been confirmed to me that the picture below of the Minichamps 1:43 model is indeed 100% cosmetically accurate to the final customer cars we will see shortly launched to the public. To get the type of down-force you refer to I would have thought perhaps front dive planes would be required? the 991 GT3RS is clearly wider at the front and rear axles than the 991 GT3 with conforming bodywork. The wheels on the model are clearly staggered sizes and again confirm what I have been told which is that the wheel design is identical in style to the existing GT3.

I think downforce and grip will definitely be increased significantly. It will be fun to finally find out!

MileHigh911

Just guessing here: Perhaps Porsche has finally figured out how to add aero downforce with diffuser technology?? The rake of the wing on the 991 RS videos is not that great. By using the side scoops to run air into the engine compartment, and exiting out the rear low, maybe they have finally figured out how to keep engine airflow adequate, and use efficient downforce methods to not increase drag? just thinking outside the box, as the overall design of what we have seen so far is not that much different than the gt3, besides the air scoops.

Jon70

Macca,
Dive planes were on the most recent test mules. I think they are likely to be added to the final design. Porsche is probably just trying to finalize the aero.

I can't wait for this thing. If the 918 seats are available for the US cars (as seen in the model above), then I doubt I'll be able to resist.

Macca

Jon. You are right., That is a very recent addition to the testing mules. I wonder indeed if it will make it into production. I guess the design team have had a little more time on their hands for the RS than is typical this time around...

Macca

It does look very close to production ready this recent mule doesnt it...just ear away the camo over the roof and front fender vents and you are basically there...

What we see here is a 90% finished proto. The cover over the hood is a red herring I feel and no hood treatment exists (although the hood itself may be composite). There are vents above the front wheels on the fenders both sides of the car which are clearly covered with camo. The roof is double bubble likely composite. The rear spoiler isnt a production ready item but in this example the wheels look to be. The dteering wheel will feature a yellow centring strip before presentation and teh car will feature light weight one piece bucket seats in nomex fabric at least for ROW supply. Door cars will be simplified and lighter. Brakes will be steel (possibly 410mm) with PCCB as an option. The front dive planes are new and may or may not make the production variant. The hard formed panels on this mule including front and rear bumpers look to be final items sans camo IMO....

Jimmy-D

Does any one have a confirmed launch date? Although a little to hardcore for me I am excited to see this beast. It will certainly be a marvel.

Petevb

The dive planes make less downforce than you'd expect. The front splitter makes a much bigger difference. It's a little smaller than I might guess for the expected downforce levels, but it looks deeper like a Cup's which is good. The fender louvers are also important for reducing lift, though they don't really look large enough or well placed to vent a front diffuser as efficiently as some designs.

The 911 has it relatively easy vs most cars, as you're generally limited by front downforce, and the 911 needs to make relatively less as it has less weight forward. This means it can make higher total downforce vs something like a Vette for a given setup. The front is significantly more aggressive than the GT3, so downforce is well up, but it's hard to say how much...

Assuming the louvers are covered, the front dive planes might be temporary, making up for lost front downforce so the car can be tested with correct aero balance.

isv

Are those load ratings actually confirmed for the 991 RS? I have to admit I find it slightly hard to believe the increase in load ratings over the 918 (which is already a decent amount heavier and produces a considerable amount of downforce with a very high top speed) is all downforce related as that means a staggering amount of df which at road car ride heights/suspension settings and wing size regulations is going to be very hard to achieve I would have thought. For comparison a Mclaren P1 which has a claimed 600kg of downforce with a non road legal suspension setting and dual element rear wing has much lower load ratings than those on the 991 RS...

az audi

Could a higher load rating be as a precaution, expecting these cars to see longer periods of track time, adding to the life of the tire (not specifically tread life) and ability to withstand more abuse or higher temperatures?

A question I want to research: with other cars, even other manufactures, do load ranges change from base model to the most powerful model?

Nizer

Load ratings were increased on prior RS per Michelin (https://www.michelinapex.com/message...email.thread):

997.2 GT3 F: 91 R:102
997.2 RS F: 93 R: 105

991 GT3 F: 91 R: 103
991 RS F: 99 R: 108

What's interesting here - remember these numbers are preliminary and could be full of inaccuracies - is the relatively even front/rear load rating increase (+2/+3) for the 997 RS over the 997 GT3 vs the relatively larger jump in front load rating for the 991 RS over the 991 GT3 (+8/+5). Comparing RS to RS the increase is +8/+3 front/rear. This suggests that if these factors are related to aero gain then there's more happening at the front than the rear for the new RS over the base model. This makes sense given the visible changes, with the rear wing very similar to that on the 997 RS, albeit a bit wider, while changes at the front include a deeper spoiler, fender vents, and potentially dive planes.

Another interesting thing to note, again assuming these numbers are accurate, is that the 997 GT3 front tire carried the same load rating as the 991 GT3. One would think that if these load factor changes were purely aero driven then the wider front end of the 991 GT3 would require a higher load rating tire vs the 997 GT3, all else equal.

As for bricks and birds, I haven't done much work with either so I can't speak to the comp. My point on the 911 shape vs clean sheet is that the basic 911 shape of downward sloping tail - still present today, albeit highly massaged and modified - is not inherently good at generating downforce. Hence the reason why all modern RS models and modern 911 racers sport monster wings where many of their competitors not married/handcuffed to the basic 911 shape can generate adequate downforce without them. That same relatively unchanged shape also limits the ability to incorporate underbody aero such as venturi or diffusers effectively. But I suspect you know all this

MayorAdamWest

Given what all time test mules look like, I'm pretty sure this model is nothing more than someone's active imagination. For instance, there aren't air outlets on the front quarter panels above the wheels.

0Q991

They are covered up in the mules, as are the ends of the wing and the wing uprights.

I'm fairly sure the model is accurate.

Petevb

I think you're being mislead. Those PSC2s in your link were developed as aftermarket tires for fitment to many possible vehicles to insure they can sell them to a wide market- they are listed as "example fitments".
When you look at the OEM fitment Pilot Sport Cup N spec that was specifically developed for 997, you get much lower load ratings:
997.2 GT3 F: 87 R:102
997.2 RS F: 89 R:101
At least according to Tire Rack. Where the PSC2s for the 918 and GT3 RS look OEM developed for those specific models, as is normally the case.
The original 1966 911 had a drag coefficient of around .38 to .39, and that's including its skinny little tires. A modern normal 991 is quoted as .27-.29 for the normal model depending on test. Airflow now remains attached over the back, and not only has downward slope on the tail been reduced by about 10 degrees, from 28 to 18, but with the standard spoiler the angle of the airflow is actually reduced further to something less than 12 degrees.
So the visual cues have largely been maintained, but the lift from the sloping tail has virtually, though not entirely, been eliminated through evolutionary design addressing this area.

The biggest aero drawback I see for the 911 is the underbody- the motor is right where you'd really like to put a diffuser/ tunnels.

Nizer

Agree with everything you said, hence my comment that the basic shape had been "massaged" over the years. But you're addressing reducing lift while my comment was directed at generating downforce and while related they're not the same.