tigerspill

Hi,
Having just bought a 2009 997.2 C4S PDK the only word I can use to describe is ia AWSOME! Absolutely fabulous car.

BUT I have a number of questions that I have been posting on here and many have been good enough to tolerate and answer my questions.

But I have another.
I don't really understand how the AWD works. Things like is it permanent 4WD? What percentage front/back? Is that fives? Is it electronic or mechanical? Differentials etc.?
I just want to understand some basics to maybe start to think how it behaves in different road conditions - dry, wet, icy or snow. In particular how it helps in poor conditions.

Thanks

9114Scab

May I make a recommendation, read as much as you can from the periodicals at Barnes and Noble, such as Total 911, GT Porsche, 911 and Porsche world. They have had a ton of articles over the last 3 months about how the 4wd system has evolved and how it works, in detail.(Also, Excellence is very good).

As far as books are concerned, go to Amazon.com and purchase the book written by Peter Morgan and some other guy. It is a pretty in-depth book about the 997, 2004-2012. That is a great reference also.

I'm not that strong on the mechanics in detail. (sorry) lol

Linnm

check on Ebay for a C4 brochure. Read it.

Canyonrs4

here is a link to a discussion here a few years back: https://rennlist.com/forums/997-foru...wd-system.html

91469972

Really?

JayRace

Here's some good reading that will tell you everything you want to know about your C4S:

http://www.topspeed.com/cars/porsche...s-ar59586.html

paddyh

Excellent overview of the 997.2

tigerspill

Thanks
Nice read.

Edgy01

The 997.2 AWD system is a significant improvement over the dated viscous clutch arrangement that Porsche went to years ago when they were having a lot of technical issues with the 959-like system found in the 964 Porsches of 1990. The 997.1 system is similar to that found in the Volkswagen Vanagon Synchro. Temperature differences are sensed within a tube filled with silicon. As electronics have matured, Porsche moved back to a sophisticated computer-governed system that provides a significant technological leap over the 997.1 system. It is the same system as found in all turbos from that period, and earlier.

stronbl

The TopSpeed article is a good source. Much of the PTM description is verbatim from Porsche's Technical Service Information brochures. If you want more details than in the TopSpeed article, do a search on internet for Product Information Porsche 911 Turbo and look for the 2006 997 version. This is essentially the same system in Carrera 4 & 4S and updated from 996 AWD and used in 997. Minor adjustments in 997-2 but they did not materially change functionality. 991 AWD systems had a major change in the clutch and electronics such that driver and road inputs are realized faster and more precisely. But the 997 AWD system is still an excellent system and maintain Porsches rear wheel traction bias until inputs require a change in front wheel torque.

alexb76

While 997.2 AWD is definitely an improvement over 997.1, it impacts the steering feel a lot more than 997.1 AWD... not sure why that is, but it's significant and immediately noticeable if you drive the two back-to-back.

Ryan M Hartman

Buy this technical information book from Suncoast. It's a fabulous resource to understand how everything in your P-car works...

http://www.suncoastparts.com/product//PNA91102109.html

9114Scab

[QUOTE="Ryan M Hartman;11472551"]Buy this technical information book from Suncoast. It's a fabulous resource to understand how everything in your P-car works... http://www.suncoastparts.com/product//PNA91102109.html[/QUOTE

Thanks for that info Ryan, I didn't have that manual, I just ordered it .

StormRune

BTW, I have that Technic Book and while it is around 175 pages of great information, it does not discuss how the AWD system works... but pretty much everything else. It DOES have a fantastic section on the PDK though, including several pages discussing the shifting strategies for various modes and conditions. It is a good buy... just wanted you to know the AWD part is not there.

mk85911

The descriptions of the Porsche all wheel drive systems are long on generalities but short on specifics. When I was researching the build options for my prospective Cayenne purchase I was able to determine that if I purchased the diesel version the standard torque split was 60% rear, 40% front, but there was no mention of torque to the front during normal driving for the non diesel models. I have owned Audi Quattro's for many years and I like having substantial power to the front all the time; I didn't want power to the front AFTER slippage developed. Quattro was very good when driving in heavy rain at highway speeds, and it was also nice in that with proper throttle the front wheel "pull" gave even a large, front heavy sedan a rather neutral feel thru tight corners. As it turned out, we got the gasoline Cayenne with what appears to be the same system offered in the 997, and, based upon subjective "feel", I don't think there is much torque directed to the front during normal driving, including turns. I expect that the mapping is different for a 997 than a Cayenne because of the different dynamics. The literature suggests torque delivery to the front based upon steering angle and speed, but it is vague.