JCP911S

Shifted both 901 and 915 on track.

Shift speed is based on decision-making time, not shifter design.

It's your brain, not the gearbox that determines shift speed.

I double clutch on every downshift because it eliminates synch delay.

Speed on downshifts is not critical because 99% of the time, the car is under threshold braking, so managing the braking is the top priority, but a missed shift will lock up the rear tires, so on a cost-benefit basis, a no-risk downshift is preferable.

A stock 915 can be shifted faster than your hand can move if you do it properly, but as I said, just check the PDK box, and the computer will do it for you.

ProCoach

Agree 1,000%! Great post, but if you can't "check the PDK box," devote time and energy towards learning how to choreograph this as well as Leh and Brady. It's worth it and it CAN be done.

GTgears

Nuff said.

Though a Cup with a blipper comes pretty close to a PDK.

mark kibort

During a racing situation, or even DE, its very tough to feel the spring resistance. It's the reason that there are so many mis shift blown engines. Especially in the BMW where the synchros are so good that you can probably put the car in reverse at 140mph.
yep, slowing down is definitely a good way to approach things until you can shift without even thinking about it.

mark kibort

that's not true at all. its gear spacing, rev matching speed (engine inertia) , and throw and coupling characteristics and distances.
a great example of this is a Porsche 928 (one of the longest throws I in the business, maybe on par with the very old 911s) vs a BMW e36. night and day ability to go through the gears on downshifts as far as speed and ease.

JCP911S

Not sure what your point is. My point is simply that with practice, the driver can learn the behavior of the mechanical system, whatever its flaws or limitations, and make adjustments in action and timing to optimize the performance of the system.

ProCoach

+1,000,000!

This is why current pros like driving old cars.

Watching Leh in the 1999 GT winner, Jochen Mass or Brian Redman in older Prototype (908/910/917/956) or Patrick Long in the 1967 2-Liter GT winner is awesome, and PROVES that it is the driver that is usually the limiting factor negotiating less than optimal (read: older) equipment...

mark kibort

I agree....you can optimize to the equip, but its never going to be as fast . the point is that the shifter speed is NOT based on "decision speed" its based on mechanical limitations , as I mentioned. regardless of how "good" someone can drive it, its still much slower.

Peter brings up a couple of good videos. proof here , that you can optimize the system. However its much slower than the new stuff. speed is not the object either. as you say, working in the "system". optimal might be naturally slower anyway, which might match other mechanical components. too fast and thing can wear prematurally. fortunately, the old stuff is sell regulating in some cases due to long throws and loosly compliant couplings.

or


These cars are still much slower as far as shifts, vs the new stuff, and you know that was the point. you can drive to the limits of the equip, and that's fine, but you will never be as fast as the new stuff, and much of the old stuff isn't able to survive things you can do with the new stuff as well.

So Peter, those video are good examples of going through the gears as fast as possible, but those cars are no where as fast as modern tech, nor do they shift as well..... I should know.... I drive one of those pre-1980 designed gear boxes!
Look at Patrick long's run .. ahem.... 8:35, he boggles a shift, badly..... few times, less than optima..... etc etc... times not that fast... fast for the car, but the car is no where near what the new stuff is, and that's really not that old! . in other words, with a modern gearbox, it would be a lot faster and a lot cleaner.... Personally, I thinks its more real driving, and respect those that can drive the new stuff more than guys running the new or newest gear. in a newer car, he would never have those shift times nor any of those small errors.

winders

Like I said, the baulk ring transmissions cannot be shifted, up or down, as quickly as what Leh was doing in the original post.

But go ahead, JCP911S and Peter, disparage my skill some more.....

mark kibort

I don't get Peter and the others...they seem to take such pride, and ego boost, out of proving someone wrong, rather than understanding and adding value to the question or discussion.

As the video proved that I attached to my post, even Leh and P.Long have a hard time shifting as fast, or being as accurate as they could with the newer stuff. In fact I would bet that the top POC guys that run these older cars every weekend are better with the older stuff.

Do I need to post the Sebring/Laguna new style racer video to compare to Leh and P. Longs run at laguna to show a contrast??

Der ABT

I think you are all arguing the same basic concept and getting stuck on details....
yes you can **** a 915 fast when done right.....put a robot with the correct motion and I bet the gears can be changed at the same speed in a 996 vs a 915
pdk double clutch obvious no chance

But I also agree the new Trans with superior linkage makes it easier for a human to repetitvely done fast....but I still think the mechancs of it would be very similar if you take the human out of the equation....flame on haha

ProCoach

Fellows, this is what I said. Not disparaging anyone, just pointing out that I have seen and measured shift duration that's really, really good, period.

I said above that the old stuff WAS "less than optimal (readlder) equipment."

But I also said that IF a driver was sympathetic, knowledgeable about how these things go together and work, honed the timing of their hands and feet, that they shift PDQ...

CCA

O' the irony!

Dave in Chicago

Back to original question… I skip gears… always have… but, I do heal/toe all downshifts into turns.

YMMV

Dave in Chicago
'92 968 E-Stock, Midnight Blue

winders

Peter,

Look how slow Leh is shifting the RSR. He is being deliberate on both upshifts and downshifts. He is not shifting super fast because the 915 just doesn't like it. Sure, you can do fast upshifts but you will put a lot of wear on the synchros. If he chose to double de-clutch the downshifts, he could downshift faster, but there is no real point.

So, again, my original point is accurate and still stands. Or is the fact that I say you can't shift a 915 as fast as a more modern gearbox because I suck?