yea he said "its not good"

thanks for the explaination frank. but i swear i could feel the fronts come on, when hard accelerating out of corners but rear's aren't breaking traction?

 

Don't forget when coming out of corners/bends there will be a difference in rotational speed from the front to rear so you are probably feeling the low driving dynamics of the system.
If the front dif was permanently fixed to the rear diff the car would try to hop around corners/bends much like a welded/fixed transverse differential in a grass tracker.
Its got to help having the Porsche 4 wheel drive system, thats why they fitted it. I just dont think its a good 4 wheel drive system for some not all road/driving conditions.
I for one have no intention of removing mine.I like the system more than I dislike it.
Frank

 

hmmm... never driven a grass tracker lol, but when i used to track the gtr, the system would send as much as 50/50 and that's exactly how I'd decribe taking hair pin corners "hopping" - front fighting the rear, just get the pitch right, then light up all fours and power out. violent, crude, and fun.

that said, haven't tracked the P car and prefer not to try this cornering technique on public roads. haven't decided how much i like/dislike the P AWD system, instead of feeling like the rear's squat put, pushing the car out of a corner, as if there's an invisible force tugging from front corner of the car. but imagine if i were to go all out, it would feel more so like a RWD. Think i read somewhere max torque to front is 15%?

not planning on removing mine either. as long as it stays a street car.

 

I bought mine because it was AWD. Having had my winter experience with it, I promptly removed it, and will likely never re-install it, and will likely by an RS6 for a fun winter car....

 

There is just one other thought I have on this but I cant prove it either way.Its just a theory at the moment
Here goes though, somebody else might have the info I need.

There is one way Porsche might be giving the front some permanent torque without the need for wheel spin.

Still assuming the Rear Diff and front prop spin at the same rate, if the front diff final drive ratio was just a little higher. ie the front wheels went round just a fraction slower than the rears then there would be a very small speed difference between the prop shaft going into the Front VC and the output of the VC to the front diff. ( same as a rear wheel spin) This would permanently give some thrust to the front wheels. Not a lot , but the faster you drive the larger the difference in VC input versus output hence even more torque to the front. This is because its a ratio.
ie 1:1 2:4 3:6 and so on. more input speed give even more output speed.
It cant be to much speed difference as the VC would overheat.
So I am trying to find the final drive ratio for the Rear Diff and also the front diff?
As you have mentioned feeling the front wheels pulling, it would certainly explain why that is.

PSM ABS must be programmed to except the difference??

I would be quite happy to find out that indeed a small amount of torque went to the front without the rear wheel spinning. It would make the idea more acceptable knowing there was some torque at the front and the whole 4X4 bit wasn't a complete waste of time.
Lets see what the diff ratios are.
Frank

 

Just Checked the Tech manual
Manual Car Rear 3.44:1 front 3.44:1
Tiptronic Rear 2.889:1 front 2.883:1 ( not enough difference)
So bang goes that theory.
I would have been well happy to proven that theory. Ah well.
Frank.


I wonder if they have geared the front prop output shaft form the gearbox internals to rotate a bit faster instead? Thats something I dont supose we can prove either way.
Also doing it that way would mean both the front and rear wheels would turn at the same speed and PSM/ABS would be happy. You would still get torque to the front wheels. Sounds more plausable.

Frank.

 

that was a good read!


The 4 wheel drive sounds pointless then!

 

Isn't the GT2 often referred to as the "Widow Maker"? I haven't driven a GT2, or own a TT (still looking), is a RWD TT difficult to control?

 

There are so many posts on this forum saying how they have converted to full RWD and said the car is better. So you might be right.
I'm just not brave enough to try it out
(You hear so many stories about the GT2 being a handfull I dont want my turbo to be like that.)

 

Well imagine going sideways, in a rear weighted car, at speed...what do you think is gonna happen? Fine line between super fun and super crashed...

 

While I don't road race or even DE my car, I went RWD for the summer with intention of going back for the winter. I have been RWD for over a year and have no idea where my front dif is, nor do I care!!!

 

I live in an area that gets a ton of snow every winter and plan to drive mine all year. I have a friend that has a 2007 turbo and swears by it in the winter. Granted we run dedicated snow tires, but I guess I'll find out next winter and report back. I know I have read articles in the past on the 996 turbo as a year round car and most of what I read was really positive. This is the first I have heard that the car is miserable in the snow. Were you running true snow tires? or AS?

 

The 997 has a TOTALLY different AWD system, that's way better. No, I didn't have snow tires, but the front tires weren't even spinning so what was the point? That's why I converted.

 

Well that makes me feel better. If the system is tied in any way to the traction control, then that would explain why the front would not spin. My BMW 335XI is the same with AS tires - terrible in the snow. I can only assume that the AWD system had to be improved over my 1991 C4 which is great in the snow with snow tires.

 

couldn't imagine driving this car in the snow, even with awd.