daleadbull wrote:First off, I don't want to come off like I'm arguing cus you're obviously more experienced than I am. This is more of a discussion anyway, what forums are meant for.
Agreed. It's always a worry that the wrong emotion will be conveyed in a forum, and I think I may be particularly bad at avoiding that problem. This is intended entirely as logical discourse, and I am glad that you feel the same.
I am however talking about the tire friction with the ground. In full-time AWD vehicles, the torque is split among all four wheels right? So wouldn't it be fair to assume the car needs to overcome more static friction in order to get moving.
If my understanding of static friction is correct, it is not in play unless you want to break traction.
Are you talking about rolling resistance?
http://en.wikipedia.org/wiki/Rolling_resistance
You've got 4 wheels worth of rolling resistance no matter how many of them are used for propulsion. The un-driven tires still have the same amount of RR.
In 2WD, all the power is going to 2 wheels thus less torque being needed to overcome that static friction but the threshold is lower too so easier to break traction by transmitting too much torque to the wheels and spinning the tires.
I totally agree with that, but I don't see how it's relevant to no-gas launching. You won't be breaking traction and spinning them either way.
Also, in the case of hard launches. You said: "LESS slipping with AWD since you aren't worried about breaking traction". I don't think that's quite right in practice. If you simply side-step or dump the clutch at high rpms in a AWD car you are more likely to bog because unless your car is an absolute monster or your tires are bald, you won't spin the tires and the drivetrain will end up taking up the slack. This is why a lot of people don't like launching their AWD cars even though technically they are the best at launching because you need to "abuse" the clutch to do it.
No doubt, a harder launch with less slipping is more abusive. I originally wrote that post with an added piece but decided to remove it:
LESS slipping with AWD since you aren't worried about breaking traction (OTOH you might choose more slipping because you're worried about breaking the car).
Just wondering, have you owned any AWD cars?
No, and I don't claim to know personally about the hard launches that can only be done with AWD; on that subject I know what has been posted to Standardshift. Shadow has posted about how he would rev it up to redline, pop the clutch, and make use of all 4 tires, abusing the car horribly but getting one hell of a launch. See the last paragraph in this post for one example:
http://www.standardshift.com/forum/view ... 00#p354900