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991 C2S Suspension Overview

 
Old 08-11-2014, 05:44 PM
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Elephant Bart
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Default 991 C2S Suspension Overview

For your enjoyment, we've put together a suspension overview for the 2014 991 C2S. We've compared and contrasted the suspension to 997 and here's what we found.

http://www.elephantracing.com/tool-b...n-overview.htm




For GT3 comparison, check out our 991 GT3 suspension overview we've posted few months ago.

http://www.elephantracing.com/tool-b...n-overview.htm


Enjoy.
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Old 08-11-2014, 07:56 PM
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chuck911
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Awesome post! For 40 years I've been telling people that however much different a 911 may look on the outside, the real changes are inside. Unfortunately almost nobody bothers to look. But this is really where its at. Not heated steering wheels, ventilated seats, and especially not backup cameras. Engineering!

Compared to earlier cars, the 991 is so incredibly more robust! Like you pointed out the upper strut mount being for the first time cast aluminum instead of formed sheet metal. There's dozens of little improvements like that- bushings designed with metal sleeves to reduce squish while retaining vibration damping, redesigned wheel carrier and subframe, etc- each one taking its own little bite out of slop, improving precise handling.

Bore bolt heads! Hollow anti-roll bars! The lengths these guys go to reduce weight!

And that's just the front suspension! The rear, with its subframe now directly mounted (like previous GT3's) is even more impressive.

This reminds me of the great post you did a while back, almost identical except focused on bushings. This one seems to cover more details.

In my view people in general spend far too much time talking about appearance and accessories like backup cameras- none of which has anything to do with the 991 being the worlds best drivers car. For that, what you have posted here is where its at.

Here's a great big Thank You for helping shift that balance back where it belongs!
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Old 08-11-2014, 08:38 PM
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Larry Cable
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very cool Bart thanks, now a trivia question, where on the Nordschleife is your homepage background images taken from? I cant place it!
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Old 08-11-2014, 08:42 PM
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Chuck, I truly appreciate your kind words! Thank you.

The 911 is a spectacular car, inside and out. But like you said, it's the inner workings that make the car what it is.

Looking under the 991 is like looking at results of a science experiment that started 50 years ago. The 991 really is the culmination of 50 years of refinement. Each generation of the 911 introduces, removes or improves on something and it's absolutely amazing to see the changes made from one generation to another. The evolution of the front control arms, transition between torsion bars and coil springs. Trailing arms to multi-link suspension, even the rubber compound used in the bushings is completely amazing. Total geek heaven.

The German engineers have really outdone themselves here, again. The 991 is a very capable car. A rare example of a street machine that is equally appropriate on the track.
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Old 08-12-2014, 12:03 AM
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Great info! So stock camber around -1.3 fr / -2.0 rear, adjustable to -1.8 fr / -2.6 rear. With a typical suspension setup, adding negative camber is desirable on the track to make the outside tire sit flatter on the track surface while loaded in cornering. But with PDCC, is there any benefit to adding negative camber over stock settings? Presumably, by limiting body roll, PDCC keeps the outside tire's contact patch maximized on the track surface. Certainly people have been reporting fairly even tire wear across the tread surface with PDCC cars. So would adding negative camber simply wear out the inboard tread surfaces quicker from straight-line running?
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Old 08-12-2014, 12:14 AM
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ipse dixit
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Great info.

Appreciate the work and taking the time to share.
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Old 08-12-2014, 02:41 AM
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Which transmission is in your example?
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Old 08-18-2014, 02:07 PM
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the car sports a PDK transmission.
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Old 08-18-2014, 02:17 PM
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Originally Posted by paradocs98 View Post
Great info! So stock camber around -1.3 fr / -2.0 rear, adjustable to -1.8 fr / -2.6 rear. With a typical suspension setup, adding negative camber is desirable on the track to make the outside tire sit flatter on the track surface while loaded in cornering. But with PDCC, is there any benefit to adding negative camber over stock settings? Presumably, by limiting body roll, PDCC keeps the outside tire's contact patch maximized on the track surface. Certainly people have been reporting fairly even tire wear across the tread surface with PDCC cars. So would adding negative camber simply wear out the inboard tread surfaces quicker from straight-line running?
I'm not sure if I know answer to that question yet. The PDCC controls the roll of the car. However, roll can also be controlled by adding heavier sway bars and spring rates. 996 and 997 track cars with heavy springs and sway bars do tend to run 3+ degrees in the rear despite having very little body roll.

I think the question is what is the dynamic camber gain of the 991. For that we'll have to crunch more data and maybe some "research" at the track
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Old 08-18-2014, 02:30 PM
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Originally Posted by Elephant Bart View Post
For your enjoyment, we've put together a suspension overview for the 2014 991 C2S. We've compared and contrasted the suspension to 997 and here's what we found.

Enjoy.
Bart, thanks, its posts like this that really add a lot of value to forums like this.
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Old 08-18-2014, 02:47 PM
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Absolutely fascinating!!! Thanks for sharing this!
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Old 08-19-2014, 12:35 AM
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thanks so much! very informative!
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Old 08-19-2014, 09:25 AM
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Super video, so informative, thank you.
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Old 08-19-2014, 11:06 AM
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Please report back on dynamic camber change once you've had a chance to measure it. Also, would love to hear your thoughts on the rear ride height adjustment and any advantages to be gained there. It seems to be on the highest setting and I'm not sure the cg moment gain will be more beneficial than than the other issues with rake change like brake bias and aero. But a free lunch is always nice if there's something to be gained! I asked a tech about this and got a blank stare in return. Not sure they're aware of the reason this was incorporated into the design.
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