Newbie 996 C4 versus C2 question
04-12-2014 | 12:58 AM
#18
Rocky Mountain High
Rennlist Member
Rennlist Member
Joined: Aug 2007
Posts: 17,769
Likes: 1,635
From: Colorado
The AWD system in the 996 wasn't designed for wet roads or winter conditions. It's a completely mechanical system using a viscous coupling to drive the front wheels. As previously mentioned, the system sends approximately 5% of the power to the front wheels all the time. It can send up to 40% of the power to the front wheels, but this only happens in certain circumstances. Specifically, this happens when the rear wheels are turning at a rate faster than the front wheels. This speed differential causes the dilitant fluid in the viscous coupling to heat up and become nearly solid, thereby engaging the clutches in the viscous coupling and driving the front wheels. Here's the kicker: if you're getting rear wheel spin due to slick road conditions, the PSM system will intervene and cut power to the rear wheels before the front wheels are ever engaged.
The 996 AWD system shines in track use and in very spirited driving. In these instances, the speed differential between front and rear allows you to engage the front wheels and power aggressively out of corners. This is what the system was designed to do.
Porsche's testing of the 996 C2 vs. the 996 C4S at the Nurburgring showed that the C4S was approximately 4 seconds faster. Many people feel that the wider tires, bigger brakes and improved suspension are more important than the AWD system in this test (the C2 shares engines with the C4S), and that a C2 with these upgrades would be faster due to the reduced weight. This may be true - I have no idea.
Some people don't like the added weight and complexity of the AWD system. Some people feel that it makes the car easier to drive at the limit because it tends to "push" a little more in corners due to the added weight up front.
Ultimately it's up to the buyer to decide what is most important for them. Either car can be very fast on the track - the driver is the biggest variable in my opinion. The vast majority of drivers will never approach the limits of their 996 on the street or the track.
Getting back to the original question: my opinion is that a C4 will not offer an advantage in wet conditions over an equally equipped C2 (especially one with PSM).
The 996 AWD system shines in track use and in very spirited driving. In these instances, the speed differential between front and rear allows you to engage the front wheels and power aggressively out of corners. This is what the system was designed to do.
Porsche's testing of the 996 C2 vs. the 996 C4S at the Nurburgring showed that the C4S was approximately 4 seconds faster. Many people feel that the wider tires, bigger brakes and improved suspension are more important than the AWD system in this test (the C2 shares engines with the C4S), and that a C2 with these upgrades would be faster due to the reduced weight. This may be true - I have no idea.
Some people don't like the added weight and complexity of the AWD system. Some people feel that it makes the car easier to drive at the limit because it tends to "push" a little more in corners due to the added weight up front.
Ultimately it's up to the buyer to decide what is most important for them. Either car can be very fast on the track - the driver is the biggest variable in my opinion. The vast majority of drivers will never approach the limits of their 996 on the street or the track.
Getting back to the original question: my opinion is that a C4 will not offer an advantage in wet conditions over an equally equipped C2 (especially one with PSM).
04-12-2014 | 07:36 AM
#20
Burning Brakes
Joined: Sep 2006
Posts: 1,142
Likes: 66
From: Florida
I like what Nick says. Great write up Dennis. Very...neutral. I disagree with your last bit tho. Ive had 70k miles on both a light C2 with coilovers and now 20k miles on a C4S in lots of rain and dry conditions. For my aggressive speeds the C4S is superior.
Last edited by Seeeu911; 04-12-2014 at 08:19 AM.
