pprj

Thank you. When you say PCA are you referring to a program from Porsche Club of American? Care to share more specifics?

pprj

Thank you.

pprj

I know. That is the case here. 500 miles on the set.

911seeker

pprj, I am going to be more direct... your car should NOT understeer significantly (i.e. enough to make you feel unsafe or ruin your driving experience) at 50 mph regardless of what tires (if in acceptable conditions), pressures (if within a minimally reasonable range) or "driving technique" you apply, provided minimally reasonable adherence conditions (i.e. road not icy or flooded). If it does, something is wrong. Check it. If it may be only your impression, so have someone else that has driving time on a 991.1 drive your car and confirm or reject if it does.

TheEngineer

The two day school at Barber is awesome. One topic they cover very clearly is the connection between your right foot and under/over steer.
I have only had scary understeer twice on the street an both times were due to cold weather + summer tires + too much pre-apex throttle.

Crester

After going thru this thread I also believe it's your driving style which is making you feel like you are understeering. You cannot drive the RWD Porsche 911 the same way you'd drive an all wheel drive Audi. The weight distribution is very different. Also in the AWD Audi, the front axle is helping to pull you through the corners. You don't have that in your RWD Porsche. With some all wheel drive cars you can just throw your car into a corner and thru brute force the drivetrain will pull you thru the corner. But your 911 won't do that for you.

I think what's happening is... you are probably going into corners very hot and then turning really hard which is probably overwhelming the front axle causing the car to slide forward instead of turning. Not only does your Porsche not have power going to the front axle... but it also is much less weight over the front axle to push the wheels down into the ground. Try changing your driving style and see how that helps.

I came from an AWD car and had to change how I drove to get the most out of the Porsche. Not only because the AWD system functioned differently than the AWD on my Porsche... but because I didn't have as much computers "helping me" push the car anymore.

K-A

Wow, that is nuts! I’d have an experienced 991.1 driver drive yours to see what they think, determining if something on your car is off. Also, as everyone is saying, adjust your driving style and learn the dynamics of a R/R car. It took me a minute to adapt (I still am) as mastering a 911 is like mastering a new language (which is what makes the experience so amazing). You shouldn’t have to brake through those turns at all, but if you do, do it before entering the turn. I find if you don’t know exactly what you’re doing, trail braking this rear setup can feel almost sloppy. While in a Cayman/Boxster, you can take a turn however you’d like and it’ll rotate like a compass. The Cayman is like “Beginner” level while the 911 is “Pro” level, thus when you truly drive it to its potential, there’s no reward like it.

chuck911

Right. PCA has three outstanding driver development programs. The instructors and everyone else in these programs are volunteers. Nevertheless, their caliber is high. In many cases I have seen the same people instructing PCA and working paid jobs instructing professionally run programs. Either way, the essential content is the same. My first choice for a program would be PCA. Or BMWCCA. But that depends somewhat on where you live. Some areas simply may not have the depth of talent to do it right. The same of course applies to the pro's. Whatever. Main point is that while the physics are so similar in every respect that you could learn a lot just watching the old (yet still supremely relevant) Going Faster video by Skip Barber, the reality is you NEED an experience instructor sitting beside you to really, uh, drive the point home.

Driver Skills is a course ideally run on a large runway or parking lot, with exercises marked off with cones. The exercises are designed to focus on braking, cornering and throttle steer, late apex line, looking ahead (proper use of eyes), and often with something like a mini-autocross at the end to tie it all together. Some of the better events will have a truck come out and wet a section so you get wet driving experience. Speeds at these events generally top out around 60-80. Moderate speed plus cones makes it a lot easier to freely push your car to the limit and beyond.

Autocross is a timed competitive event run on a course marked off with cones. The course is different each event and you generally only get three or four runs that count. Because of this autocross places a HUGE emphasis on mental preparation- studying the course, memorizing it, analyzing your performance after each run, studying the other drivers.

Driver Ed events are run on a track, with the emphasis being on technique not speed. Learn to perform all the basic skills- braking, late-apex line, throttle control- and you will go fast. DE is not racing. Passing is cooperative. Speeds vary by track but this is where you get going fast enough to put serious wear and tear on your brakes and tires.

If you notice a progression, that is not by accident. Having instructed hundreds over years I can say without a doubt the absolute best approach is to do at least one Driver Skills, then autocross for a year or so, then progress to the track. If ever. Do the first two, you will be head and shoulders above almost anyone at the track.

TimboCarrera

Hope this doesn't confuse things further but here it goes. I also previous to my current 991.2 c2 had a sweet 991.1 c2 cpo with old tires. I experienced everything you have stated here. However in every situation and temperature the bad handling went away if I warmed the tires thoroughly. Thoroughly meaning you could smell the tires melting. When the tires were really hot these problems disappeared, even in cold temps. I have not experienced any of these habits in the 991.2 c2. I also had a chipped audi avant and if I drive the 991.2 through a curve like I did the Audi I get the power cut and rear end hop. Driving a c4s like an Audi through a curve and it seems not to care. I think you would love a 991.2 c4s, however I believe you will become a better driver mastering your current ride. We are all blessed to be driving any 911. They are all special and beautiful.

chuck911

Right. Its all about weight transfer. Tires deliver traction based primarily on how much force is pushing them down onto the road. With a 911, engine behind the rear axle, that explains why so many people say they allow you to get on the throttle a lot earlier than other cars. And you can. Without risking a spin. But you still have to wait for the car to be pointing in the right direction! Otherwise, a lot of that power is wasted pushing the fronts along in understeer. Or worse. Because the newer cars with things like PTV and PSM trying to make sense of your mixed inputs (Does he want to turn? Or accelerate? Because we can't do both!) errs on the side of caution (duh) and brakes the inside rear. Which is why we see all these guys complaining about rear brake pad wear. (Its the driver! Not the car!) So the correct approach is brake first, turn in as you come off the brakes, feather in only enough throttle to balance the car through the turn, then just as you come through the apex begin to roll on some throttle.

Actually, since you went to Barber then you know what's in the Going Faster video, which is even more advanced (and risky, and scary) the notorious trail braking, which if I remember correctly he refers to as the only really new development in driving technique in something like 50 years. Which that video was made decades ago. And nothing new since! So its not like any of this is rocket science. Yet people just aren't taught it. Go figure.

K-A

I feel like understeer comes down to adjustable dynamics almost if not more than it does inherent engineering, as experiences seem to wildly vary when it comes to understeer. For example, when MT reviewed the .2 base, they said it understeered more than the .1.

chuck911

Its the driver. Not the car.

Yes all the standard ideas will work and will affect handling to some degree. Tire pressure, camber, wider tires and wheels, springs and anti-roll bars, spoilers and wings, all these things matter. Except for when they don't. Which is the instant you push gas or brake. Because all these things together, they might add up to 10% or maybe even 20% more traction. But throttle and brake, not even full-on they transfer the weight of the car to the tune of well over 1,000 lbs, probably more like 2,000 lbs, which affects traction a whole lot more. Way more. Not even close more.

Want proof? Porsche has gone to great lengths to tame the oversteer inherent in their rear-engine design. Yet even with all their best efforts and sending the car out the door biased towards understeer people still manage to spin the darn things. Which, if you look it up, is called oversteer. Which, read the thread "track day spinout" https://rennlist.com/forums/991/1037...questions.html can happen even with a 4!

Despite the understeer bias the cars are still close enough to neutral that while one driver complains about understeer another driver is spinning out in oversteer.

They should make a refrigerator magnet, or stencil on rear view mirror or maybe a T-shirt with Bart Simpson writing a 100 times: Its the driver. Not the car.

Quadcammer

Lol what? you driving around in reverse?

StormRune

One thing I haven't seen mentioned is the 1/32" toe-in I see on the front wheels (positive being toe-in). This converts to close to 0 degrees 5 minutes, which is which is near the middle of the Porsche recommended range of 0 minutes to 10 minutes. Porsche is known to prefer understeer on its street cars. Toe-in increases understeer and is often used for street alignments since understeer is considered safer. You'll probably see some improvement if you drop the front toe down to zero; the bottom end of the recommend range. As a side effect you'll get slightly better front tire life too

http://winhpde.com/car-setup/track-alignment/

StormRune

Here's another interesting reference I forgot to mention: http://www.morpca.org/drivers-educat...eer-oversteer/