the new pdk is likely a better shifter than most drivers on any track

 

I don't know, I don't know what you consider a unicorn.

 

987 (.2) Unicorn options: PASM, sport chrono+, (PDK, LSD), lightweight everything else: base manual seats, cheap headlights, base stereo, etc.

It's called a unicorn because they don't exist on the used market.

 

On top of that sport seats in a Boxster till you get to a Spyder but that is sitting at 10 to 20 grand more that 10 BoxsterS.

 

KJ and PF got it, when you drop to first, you are often traction limited, so cannot get max acceleration. I thought the pdk in our cayman would be used a lot for 2-1 shifts, but it turns out that almost never happens . The more common advantage is the quick 2-3 and back down in faster elements.

Also, the pdk is not seamless on the 2-1 shift, it will jerk and upset the car if you command it(paddle or stick). If you let the car shift itself, it is much smoother, it sometimes makes the down shift under hard braking(ideal) and sometimes only after you are picking up the throttle, where it feels like an old style auto trans, kind of slushy and indirect.

Launch control only really works for pro solo. It does that pretty well.
Having competed in both, I think it is close to a wash given the weight penalty. 50-70lbs is a lot of weight to carry. I am keeping at for pro solo launching, and for track work, but it is not without its limitations.

 

I did about 20 autox days in my (new to me) '11 Cayman S PDK this year, competing locally and regionally. I've never done a Nationals event. I experimented with full auto vs full manual mode, auto mode with paddle shifts, launch control starts vs normal, and PSM on/off etc. All done with SC in sport+, didn't test any other modes.

My results mostly echo the statements by XPC5 above. The sites used for a couple of local clubs almost guarantee one or two sharp hairpin turns (narrow airport runway w/ turnaround) and I found the best option was PDK in auto mode and manually select the 2-1 downshift while braking into the hairpin for exactly the reason above: sometimes PDK-auto shifts after corner exit, not during braking. You have to hit it at the right time to avoid the upset. I found shifting a bit early actually worked better even though it's a harder shift because I could complete the shift while still braking straight into the corner rather than have it shifting while trail-braking. There's a bit of time for things to settle before turning in.

The quick 2-3 and 3-2 combo also came into play a few times and I agree that there's a nice advantage there. Doesn't come into play much on the sites I frequent, but sweet when it does.

LC worked well for a couple events, mostly not an advantage on a typical autox start.

One thing to mention as well. I have not been a left-foot foot braker much (only in ice racing) and haven't yet acquired the sensitivity to do so naturally in this car. I'm training myself and hope to be able to do so skillfully next year. I think that PDK could make it easier to employ left-foot braking.

 

Speaking of launches, has anyone found launch control to do anything more than leave 200' of stripes? I've gone back through my video and it sure seems like my launches are just as fast (and a lot easier on tires) if I roll onto the gas from idle instead.

 

I was bot thinking of LC but how does that effect tire temps? Does it help on the first run but over heat the tires on runs 2,3, or 4?

 

If there is not good traction it seems to spend too much time in wheelspin or traction control cutting throttle. You can try the mini launch, where you do not push the gas pedal into the kick down range. It will only rev up to around 3k, and will launch with a lot less wheelspin.

It does not have much effect on tire temp, the cornering forces and power oversteer are much harder on the tires.

 

With good traction and long enough straight section it does launch a bit harder. Overall acceleration (according to my data acq) is marginally better. BUT: I had more occasions where it hurt than when it helped. What I found worked best in most starts was simply move same foot from brake to gas and floor the accelerator. I'll try to dig up some data logs if I can with LC on/off, but the effect was not huge. Puts on a nice show for the bystanders though.

A full or "mini" LC start in less than perfect conditions would trigger the behaviour XPC5 describes. Wheelspin followed by massive modulation of throttle to correct and what feels like an eternity until full acceleration resumes. In back to back starts using LC and the technique above, the simple "mash the go pedal" was consistently better. Solid, spin-free acceleration (presumably) at or near the traction limit without noticeable intervention. I don't really understand why in LC mode the system would be intervening so much more aggressively.

In general, I'm glad I have the PDK, and I think it offers some small advantages, but it would not be a deal breaker for me. I think PASM could be more valuable for autox (ie, PASM + manual > non-PASM + PDK).

 

PDK wil make you a faster driver. I am autox-ing my 4S.

The instant shifts can definitely give you the edge, especially if you are fighting for 100s of a sec.

On tight courses it will shift into 1st but you have to be prepared because the car will launch ahead since you have full power available...

In certain course designs you can even use launch control, the fastest way to start...

If you are shifting into 3rd in certain course designs, again you have the advantage, especially in the downshift since you can do it in the turn and not before, without upseting the balance of the car...

Now add all the above together = faster times...

My previous car was a 997 6 speed which i autox-ed too...

 

i am not sure if our cars react correctly with left foot braking... A friend PCA member codrove my car and he was driving at the time a tricked out Autox 07 GT3... One of the fastest drivers around and definitely a master of let foot braking... With my PDK, even with the PSM off as soon as he would touch the brake at the same time with gas input, the car would cut off power and mess up the run...

You can try it on your car but i doubt that you will have different results...

 

Bear in mind, though, you're giving up slight bits of speed in every turn and transition from that extra 80lbs of steel and solenoids. The instant shifting isn't "free", there is a tradeoff.

 

I've only driven a VW DSG, never a PDK. As a die-hard 3 pedal guy, I was fully expecting to hate it, but ended up quite impressed. Thing shifted lightning fast, and really didn't detract from the driving fun at all. I did run into a few issues though. A few questions about PDK and if it has the same concerns.

How is the launch timing? I drove a regular autocross, so it didn't matter, but there was a small delay between releasing the brake and getting action. I imagine it would be tough for Pro Solo. Is the PDK more instant?

How often does the 'box try and outthink you? The DSG car had a "kickdown switch" at full throttle (kind of like a 2-stage camera shutter button) that if activated would downshift whether you asked for it or not. I could learn to modify my throttle input to overcome that, but I'd much prefer it to hold a gear until I tell it otherwise.

In the same line, will the PDK let you bonk off the rev limiter if you want? The DSG would upshift at redline, again without asking / driver demand. In some rare situations the unexpected thrust change could break the delicate balancing act going on mid corner.

 

For Pro Solo launches, the PDK launch control works well. It does a very consistent, repeatable release that is similar to a manual clutch launch. You just release the brake at about the time you would have released the clutch.

In manual mode, "If" you can stay out of the kickdown switch threshold, the gearbox will let you run right to the rev limiter and stay there. The "If" is key, years of training to mat the throttle pedal makes it extremely difficult for me to stay out of the kickdown threshold when the adrenaline is running. It is also not a physical switch which would have been easy to disable, it is a spring based clicker, that allows you to to go to more than 85% pedal position. So now I get unwanted upshifts to 3rd sometimes, which causes some delay when it has to go back to 2nd. The PDK needs a 100% manual mode, and adjustable LC rpm to be perfect.