CarManDSL

Photos taken at a June track event shows what PDCC and SPASM can do for body lean. These taken of our Advance/Instructor group shows remarkable composure of my 991S as compared to a 996 GT3, 997 GT3 RS, 997 Turbo S and 2 F458's.

It looks like I'm on a slow relaxed lap but in fact flat out chasing down those 458's that disappear on the straights!

Larry Cable

would love to see like cars +/- PDCC lap times ...

Grunty

The Ferraris are all swoopy compared to the Porsches.

John's 991

Still not clear how much lack of lean improves time. Ok, it looks good in the pics but is there materially less weight on the outside tires, so the inside can grip more?

Nice car btw

CarManDSL

Yes. The lack of lean allows the car to maximize contact patch size on inside and outside tires without excessive camber settings. Evens weight to all corners to better use that larger contact patch and therefore better grip. All this while not requiring larger sway bars and compromised ride quality. With 22,000 km on odo, the tire wear has been absolutely even across fronts and rear.

Porsche's Nurburgring record time of 7:37.9 in the 991S had SPASM and PDCC on P-Zero's. 39th fastest time in a production car. Besting a '09 GT3 time of 7:40.0 on Sport Cups.

https://nurburgringlaptimes.com/lap-times-top-100/

I think that says it all.

And thank you!

paradocs98

Nice photo demonstration. I'm also finding that it keeps tire wear remarkably even while using the stock camber settings. All is great until PDCC faults at speed on the track, though. Not fun when it happens--car kicks out of Sport Plus and you go from full assault mode to Toyota Camry mode while driving near the limit.

CarManDSL

Ouch! I have not experienced any PDCC faults.
Provide more details, please.

eg991

Pics show an amazing contrast, and your car looks awesome, car man!

Larry Cable

is it just perspective, or are you about 1/3-1/2 car width further "out" than everyone else - curious about your line relative to the other cars...?

GreenLantern

Awesome. This is useful visual data!

Thanks for sharing!

CarManDSL

Like you would know!


Yes I am. This is a 180 degree 2nd gear corner and I am taking the fastest line, slower in but faster out. The others are taking more of a protective racing line. I am on the same line as the blue Turbo S, but the zoomed shot on myself does throw the comparison out a bit.

I can exit faster and usually gain ground to other equal cars that take the racing line.

This is corner 2 at Mission Raceway Park, an hour east of Vancouver, BC.

todd92

PDCC creates ubdersteer, if that's what you're after. I doubt it improves lap times.

CarManDSL

Read what I wrote in posting #5.

Worked for Porsche at Nurburgring, can't see why it wouldn't be beneficial for improving lap times for anyone else.

GreenLantern

Besides, nothing wrong with a little ubersteer.

chuck911

Lack of lean or body roll is not in itself what improves time. What improves time is the reduction in the amount of time it takes to maximize weight transfer in turns. Reduced body roll is merely a side effect. Camber, tire wear, all the rest, ditto. Its the weight transfer speed that really matters.

In maximum cornering, on a skid-pad say or a very long curve, centrifugal forces acting on the car cause weight transfer from the inside tires to the outside. Think of all the photo's you've seen of cars hard cornering with the outside tires squished and rolled while the inside tires are barely making contact. Doesn't matter if its a F1 car cornering flat as a pancake, or a sedan that rolls like a boat, or for that matter a boat trailer. All the weight transfers off the inside to the outside.

Now since tire grip increases the more weight it has pressing it down onto the road, then the faster we can get weight transferred from the inside to the outside the faster we can get to maximum cornering. And there's your lap time savings.

Understanding this also helps one understand why cars like the GT3, RS, Cup, have bushings that are reinforced to reduce squish, or even altogether eliminated in favor of monoballs. http://www.elephantracing.com/tool-b...Comparison.htm Every single rubber suspension bushing represents a point that must be compressed first before weight can be fully transferred to the tires.

Body roll, bushing squish, tread squirm, all the rest, add up to time spent loading the suspension just getting the car ready to corner hard. Its not a lot of time. But added together and multiplied by the number of times it happens per lap, there's your time savings.