PDCC and the Track
#31
When the 991.1 was introduced (early 2012), Porsche's literature described it as providing something like 13 seconds faster time around the Nurgbergring than the previous model when equipped with Sport PASM (shorter stiffer springs (+additional 20mm lower than PASM) and stiffer roll bar, and PDCC, in an S (which also had the mode sensitive, stiffening" engined mounts). They attributed about half of the gain to the SPASM and half to the PDCC.
As I understand it, the SPASM option gives mode sensitive damper rebound rates and the faster/sharper response makes the car feel like it "rides harder" at hight rates. The PDCC varies roll stiffness by mode and speed and keeps the car "flatter" - the principle advantage for track times being that it keeps the tire contact patch at its maximum.
Thirteen seconds is a lot of time, but over a very long run at high momentum speeds at the "Ring. I don't know how that would transfer to a more typical track (e.g., 2-3 miles), but damper rebound rate, center of gravity and contact patch are important variables around any track -other things being equal.
As I understand it, the SPASM option gives mode sensitive damper rebound rates and the faster/sharper response makes the car feel like it "rides harder" at hight rates. The PDCC varies roll stiffness by mode and speed and keeps the car "flatter" - the principle advantage for track times being that it keeps the tire contact patch at its maximum.
Thirteen seconds is a lot of time, but over a very long run at high momentum speeds at the "Ring. I don't know how that would transfer to a more typical track (e.g., 2-3 miles), but damper rebound rate, center of gravity and contact patch are important variables around any track -other things being equal.
997.1 8:05
997.2 7:50
991.1 7:44
991.2 7:34
I don't know which options were on each car.
#33
I had PDCC on both of my 991S's and liked it a lot (first one had PDCC/PASM, second one had PDCC/SPASM). Kept the car very flat during cornering and the ride on the highway was very comfortable. Others have posted that it was a bit artificial feeling but I never minded it. As a matter a fact I sought out PDCC equipped cars and have also ordered my incoming 2018 911 GTS with PDCC.
#34
#35
It never bothered me - I always knew mine was so equipped - but when they started adding the button, it was easy for those who didn't read their owners manual to assume that it was an on or off button.
#36
Heartfelt thank you to the folks who posted (esp. the video). It's refreshing to actually get assistance with a question on RL. I'm happy this thread didn't become about what percentage the PDCC option will depreciate over my ownership of the car .
#37
Couple questions about PDCC.
One: Does anyone know if the cars that Porsche uses for the sport driving school at Barber are equipped with PDCC?
Two: For those who track their cars, what's the verdict on PDCC?
Three: General comments about PDCC are welcomed too.
Thanks.
Tim in Nashville
One: Does anyone know if the cars that Porsche uses for the sport driving school at Barber are equipped with PDCC?
Two: For those who track their cars, what's the verdict on PDCC?
Three: General comments about PDCC are welcomed too.
Thanks.
Tim in Nashville
Two: Can't tell you sorry. I plan to track my own car eventually but life and kids keep getting in the way for now.
Three: I got PDCC and SPASM on my C2S and I love the roll control on back roads and hard corners.
#40
General comment on PDCC, some of the usual guys know this but a lot do not, its main function is not so much to make the car corner flatter when cornering hard as to make the car drive a lot smoother when its not. Another misconception is that cornering flatter means cornering harder. It does not. I'm not going to explain this since every single info source on car handling clearly states that if you want to stick better (understeer or oversteer less) you DECREASE, not increase, roll stiffness.
The real reason a car with greater roll stiffness goes faster is not because it sticks better, but because it transfers weight so much faster. Essentially what happens is that in a car with a lot of roll stiffness when you turn the wheel the resulting force of weight transfer loads the outside wheels exerting maximum turning traction really fast. A car with a lot of body roll wastes a lot of time rolling instead of turning. Tenths of a second add up fast on a track.
So with PDCC two very beneficial things are going on at once. It is faster because it transfers weight faster like a car with a stiff anti-roll bar. And it is faster because it does this with an anti-roll bar that actually has LESS roll stiffness, allowing it to stick like a car with a lot of body roll.
The real reason a car with greater roll stiffness goes faster is not because it sticks better, but because it transfers weight so much faster. Essentially what happens is that in a car with a lot of roll stiffness when you turn the wheel the resulting force of weight transfer loads the outside wheels exerting maximum turning traction really fast. A car with a lot of body roll wastes a lot of time rolling instead of turning. Tenths of a second add up fast on a track.
So with PDCC two very beneficial things are going on at once. It is faster because it transfers weight faster like a car with a stiff anti-roll bar. And it is faster because it does this with an anti-roll bar that actually has LESS roll stiffness, allowing it to stick like a car with a lot of body roll.
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d-- (04-12-2023)
#41
But, but, but, Chuck, all marketing focus groups conclude that the more super-stiff a car’s suspension is, the more of a sports car it is...
LOL. All kidding aside, post #2(?) with which I completely agree
LOL. All kidding aside, post #2(?) with which I completely agree
#42
Yeah, and this is the kind of over-generalizing that people love to attack, but I remember reading somewhere that Porsche tends to make cars with softer (and more) suspension travel than most other cars in its competitive class. I've heard this attributed to everything from they tested on the Nurburgring way back before it was the standard, back when it had those drainage (or whatever it was) things that would get the cars airborne (you've all seen the poster), to Porsche wanting their cars to be able to handle German winters with snow. Whatever. The fact is a lot of the same things one would do to make a suspension fast on the track, where traction is high and odd bumps and dips tend to be engineered out, can actually make it slower (and less controllable) on everyday public roads, where traction is all over the map and odd dips and bumps are the norm.
So, in other words, however much faster a PDCC equipped car is on the track, it is probably at an even bigger advantage out in the real world.
So, in other words, however much faster a PDCC equipped car is on the track, it is probably at an even bigger advantage out in the real world.
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d-- (04-12-2023)
#43
The fact is a lot of the same things one would do to make a suspension fast on the track, where traction is high and odd bumps and dips tend to be engineered out, can actually make it slower (and less controllable) on everyday public roads, where traction is all over the map and odd dips and bumps are the norm.
So, in other words, however much faster a PDCC equipped car is on the track, it is probably at an even bigger advantage out in the real world.
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d-- (04-12-2023)