PSM and Viscous Coupling Questions

[josserman]

Does PSM bypass the VC or is it limited by the VC? Example if the car is starting to oversteer will PSM be able to apply more teh 40% of the drive to the front wheels to correct the oversteer?

I've been driving around in my a4 w/ quattro all week in the snow here in New England and as every season I am more and more impressed with the quattro system. I know the 996 tt will run pretty well in snow with the right tires and wheels, but I can't imagine it will have the corrective capabilities that the audi does if it can't apply more the 40% force to the front wheels...or will it?

[Dus10R]

Does PSM bypass the VC or is it limited by the VC? Example if the car is starting to oversteer will PSM be able to apply more teh 40% of the drive to the front wheels to correct the oversteer?

I've been driving around in my a4 w/ quattro all week in the snow here in New England and as every season I am more and more impressed with the quattro system. I know the 996 tt will run pretty well in snow with the right tires and wheels, but I can't imagine it will have the corrective capabilities that the audi does if it can't apply more the 40% force to the front wheels...or will it?

PSM has not much to do with the VC. PSM applies a break at any one corner to help reign in oversteer and is meant for dry roads not snow. The owners manual even says to turn it off when driving in snow. However, it will work in snow at slower speeds and will help correct the car from getting too squirelly, but it's operation is pretty evasive and you feel it constantly trying to correct. I tell my wife to keep it on when she's driving it because it will help correct some tail out issues she's not prepped to correct on her own. But with the system turned off, you need to have very quick reactions to what the car is doing. If it starts to slide / oversteer you need to correct for it fast or it will get beyond correctional control and will spin. So no, it's not as confidence inspiring as the Audi quatro system in snow, but it's really not meant to be either.

[josserman]

Does PSM bypass the VC or is it limited by the VC? Example if the car is starting to oversteer will PSM be able to apply more teh 40% of the drive to the front wheels to correct the oversteer?

I've been driving around in my a4 w/ quattro all week in the snow here in New England and as every season I am more and more impressed with the quattro system. I know the 996 tt will run pretty well in snow with the right tires and wheels, but I can't imagine it will have the corrective capabilities that the audi does if it can't apply more the 40% force to the front wheels...or will it?

PSM has not much to do with the VC. PSM applies a break at any one corner to help reign in oversteer and is meant for dry roads not snow. The owners manual even says to turn it off when driving in snow. However, it will work in snow at slower speeds and will help correct the car from getting too squirelly, but it's operation is pretty evasive and you feel it constantly trying to correct. I tell my wife to keep it on when she's driving it because it will help correct some tail out issues she's not prepped to correct on her own. But with the system turned off, you need to have very quick reactions to what the car is doing. If it starts to slide / oversteer you need to correct for it fast or it will get beyond correctional control and will spin. So no, it's not as confidence inspiring as the Audi quatro system in snow, but it's really not meant to be either.

Great thank you! Sounds like I will have to just see for myself. Maybe I should consider a used STI as a replacement for the Audi.

Thanks,

Justin

[Dus10R]

Does PSM bypass the VC or is it limited by the VC? Example if the car is starting to oversteer will PSM be able to apply more teh 40% of the drive to the front wheels to correct the oversteer?

I've been driving around in my a4 w/ quattro all week in the snow here in New England and as every season I am more and more impressed with the quattro system. I know the 996 tt will run pretty well in snow with the right tires and wheels, but I can't imagine it will have the corrective capabilities that the audi does if it can't apply more the 40% force to the front wheels...or will it?

PSM has not much to do with the VC. PSM applies a break at any one corner to help reign in oversteer and is meant for dry roads not snow. The owners manual even says to turn it off when driving in snow. However, it will work in snow at slower speeds and will help correct the car from getting too squirelly, but it's operation is pretty evasive and you feel it constantly trying to correct. I tell my wife to keep it on when she's driving it because it will help correct some tail out issues she's not prepped to correct on her own. But with the system turned off, you need to have very quick reactions to what the car is doing. If it starts to slide / oversteer you need to correct for it fast or it will get beyond correctional control and will spin. So no, it's not as confidence inspiring as the Audi quatro system in snow, but it's really not meant to be either.

Great thank you! Sounds like I will have to just see for myself. Maybe I should consider a used STI as a replacement for the Audi.

Thanks,

Justin

Funny you mention the STi, I recently owned both a 2005 STi and a 2005 Evo VIII MR (bought both new). Long story short, the EVO was a better built car.

I'll give a run down...

STi: Cooler dash instruments, better stereo, more torque due to larger displacment, a hair better in snow.

Evo: Better Seats, Better Transmission, faster, better handling, more tuner friendly, more reliable (never in shop except for tune-ups; STi was in shop multiple times for squeaky struts, dash malfunctions, Exhaust rattles, leaky door seals) more solid built (STi rattled and squeaked like a John Deere tractor and water leaked in at car washes)

Compared to an Audi, they're both loud on the inside due to minimal sound deadening materials to save weight.

Both fun cars... but after selling them both I still miss my EVO. This is no joke, my Evo was more stable at 170mph than my Porsche TT (Evo makes more downforce) (STi won't due 170mph, limiter kicks in at 155mph.)

So if you drive in a lot of snow and that's your priority, then the STi is slightly better. The Evo does great in snow too but it's AWD system is more automatic whereas the STi lets you actually lock the torque split at 50/50. But when the roads dry out, the EVO is miles ahead.

Edited December 26, 2008 by Dus10R

[Loren]

Please keep your posts Porsche related - thanks.