Petevb

You may well have been able to use more rear wing with that setup. Porsche avoids giving us enough rope to hang ourselves, so if you add front downforce it's likely the rear wing wasn't adjustable enough to compensate.

The 4.0 did feel stiffer and Sebring is very bumpy, perhaps the track rewards a soft setup. I can't help much here- the 4.0 setup felt significantly better to me, but I obviously wasn't at Sebring.

It is true that soft is sticky- all else equal you'll get more mechanical grip over bumps with a soft setup. This may be why Porsche chose to raise the 991 RS ride height rather than stiffen the springs, as is normal practice on race cars with aero. Keeping the softer springs and letting the car sink into them is probably the quick way around the 'ring, not to mention more comfortable on the street.

Assuming you mean stiffer rear swaybar that'll give you a car that turns in better at low speed but doesn't oversteer at high speed. Pretty common way to deal with a car that has issues getting turned in (like a traditional 911). Works very well up to a point, but it's speed sensitive especially if not in moderation.

Then you've got triple adjustable shocks, brake bias, bump steer...

The nice thing about a factory Porsche package is that you know it works in nearly all situations and you won't exceed its limits. Compare this to other makes, the Viper ACR for example. When they added 1000 lbs of downforce to the '09 do you think they re-engineered the suspension to cope with the loads? Would you feel comfortable topping that thing out on the autobahn consistently? I wouldn't... I know for a fact that if you take previous gen Viper (before ABS) and jump on the brakes from about 100 mph intentionally trying to lock a wheel... Around 50/50 the front suspension rips off the car.

Porsche occasionally has issues with durability, as we all know, but the factory solutions are well engineered to keep you out of trouble relative to other makes.

TRAKCAR

Thanks Pete. As always.

Always felt Porsche knows better than some aftermarket stuff and trusted the stuff coming off a tried and tested CUP car.
I may go PFC calipers if they'll fit

Sebring is different and bumpier but I always figured the Ring is bumpy as well and if it works at Sebring or the Ring, its close enough to work almost everywhere if, like me you like a car moving its (porky) weight around. The comfy daily ride is just a bonus :-)

The 4.0 made inexplicable jumps both front and rear over bumps is couldn't deal with, just moved up half a car width. The first time I drove a 4.0 I asked "WTF was that?" The driver answered "it does that every lap" When I got mine, same thing and we never got it fixed messing with ride height or rake.

.1 GT3 we always ran in soft PASM, the .2 was in between, I left it stiff and both softer or styiffer didn't matter in the 4.0.

Probably pointless rambling. Even on my racecar I don't want adjustable shocks, I'm better (Not very good still) at driving around the problem than to try and explain the problem and or fix it with car setup.

Look forward playing with the 991 OEM rake and toe with adjustable swaybars and tire pressure is about as far as I can get. Camber is for tire life
Than we will see about a deeper splitter depending on how far we can angle the wing with gurney..

ScottKelly911

Pete, you seem very knowledgeable and you're right about what you're speaking of from a Theoretical standpoint. But practical use does not always give you the same outcome as what theory would tell you. Many factors, driving style being one, track or tire conditions etc. or also, it's possible that the stock front aero on the car is actually better balanced with the bigger wing. What has been reported by using the Crawford wing points to that as a very real possibility. It has been reported that the unsettling under high speed braking has gone away with the wing, that's a good thing. The snap oversteer has gone away, so while you're right that it may be inducing some understeer, it's also more predictable. But it sounds like the amount of oversteer that's been added is just enough to keep the car from unsettling, but not enough to feel like he's not getting enough turn-in. For 95% of HPDE drivers, slight understeer is easier to control and better suited to their driving style. Once you get to the Pro level, then yes a nervous car is usually a fast car because they're pushing the limits of the capabilities of the car, but they're also better suited to bringing the car back once the limits have been reached or pushed. Now, all that being said, what has been reported, I believe has been for Sebring, which isn't a super high speed track, it's bumpier and has quite a bit of slower turns. Take the same car to Road America on the other hand, and your concerns may become more valid as it's a much higher speed track and the front end might lighten up a bit and require some additional front aero such as canards.

Petevb

Just to be clear, I'm using theory to help explain why, but I've also tuned aero in practice. If theory doesn't explain practice you're simply doing the theory wrong.

Please re-read my second note, which I think covers most of what you've mentioned. Achieving slight aero understeer is exactly why you'll often aim for around 5% more rear downforce than weight bias, and it is generally faster for most drivers. I have no doubt the Crawford wing achieves this and could certainly achieve more. The point is that if you're getting to GT3 RS levels of downforce in the back without changing the front it's not a car you'll want to drive. Crawford will agree...

FastLaneTurbo

Since none of "Them" have the GT3 Crawford Wing on their GT3 America, have ever used it or have any experience with it, I'm sure "THEY" are "EXPERTS"
It's only the stupid GT3 owners like us who have been "dumb" enough to use them, reduce our lap times and given rave reviews. But what do "WE" know?

Nizer

You lost me.....

"Additionally, the Porsche 911 GT America will be permitted to use the DP specification Crawford rear wing instead of the category’s standard wing used on the majority of GTD cars at Daytona."

shapiroeric

Just like a Scud....

street

...and the marketing hype about lightweight.

Anybody see any difference between RS and Carrera doors other than the straps? At least the 7 .2 deleted map pockets and one radio speaker. (Does this car really weigh 100# more than a Carrera?!)

MarcusG

There is no doubt Porsche scrutinized every single detail of this car right down to the few oz. saved by going with the decals again.

It's the sum of the parts and anyone that thinks the performance between the 3 & the RS isn't that great is most likely correct but I don't doubt everything is there for a reason to shave whatever can be shaved off a 3.

I agree with the real world pics of that 21" rear wheel and the fender overlap looks a bit off or at the very least less attractive than the existing rear stance of the 3.

The one thing I want with my RS is the ride height slammed and looking like it means business. Just like a 997 RS. Aerodynamic downforce aside I'm still scratching my head.

Nizer

You mean like this? Prepare to spend. You'll need new uprights all around.

GT America prepped for IMSA GTD class (note Crawford wing).

Dan39

Can't we get it lowered about 10mm without changing any parts?

Given Pete's description of the downforce/ride height, sounds like it wouldn't be an issue below 300kph.

TRAKCAR

I prefer the 4x4 stance..

alaint101

My guess: worst case scenario

alaint101

You are correct.

And their numbers reflect our opinions, wants and desires accurately...

MarcusG

Thanks Nizer!

And yes. Doesn't that look fantastic!