Rear Sway bar only upgrade?

[Topless]

Originally Posted by bbiela

Opinions, please.

I recently got a set of M030 sway bars for my 986S. A local shop recommended installing only the rear and see how that affected the handling of the car before deciding to install the front. The car is a DD and used for AX and DE's. Should I install just the rear or should I install both?

Thanks for your thoughts.

This is what I did on my 986. It reduces understeer a bit and allows the car to rotate more easily without getting too slap-happy. Depending on the exact tire sizes and compounds you run it may be the right move. I ran mostly 225/245 NT-01 and balance was good.

[maytag]

Originally Posted by Topless

This is what I did on my 986. It reduces understeer a bit and allows the car to rotate more easily without getting too slap-happy. Depending on the exact tire sizes and compounds you run it may be the right move. I ran mostly 225/245 NT-01 and balance was good.

Can you help me to understand this concept, please? (I'm still a little green on some of this)

I think I understand how upgrading the rear bar can reduce understeer. no problem there.
But I'm not following how it helps the car to rotate. Maybe I'm calling rotation something DIFFERENT from what rotation really IS?
When I enter a corner, there's a moment where the weight transfers in the rear and it helps turn the car. Occasionally there's a small slide associated, but it's usually just the weight moving to the outside. I think I'm typically (maybe always?) still trail-braking as this occurs, and so the weight goes especially to the outside-front tire, which then hooks /bites / turns.

It seems like the "looser" the rear is, the easier that weight transfers? It seems like stiffening the rear bar would decrease the roll, decreasing the weight that gets transferred, decreasing the rotation. It seems almost like it would oversteer a little more easily.

So, am I thinking of "rotation" incorrectly? or am I misunderstanding the dynamics of how it happens?

[bbiela]

Originally Posted by maytag

Can you help me to understand this concept, please? (I'm still a little green on some of this)

I think I understand how upgrading the rear bar can reduce understeer. no problem there.
But I'm not following how it helps the car to rotate. Maybe I'm calling rotation something DIFFERENT from what rotation really IS?
When I enter a corner, there's a moment where the weight transfers in the rear and it helps turn the car. Occasionally there's a small slide associated, but it's usually just the weight moving to the outside. I think I'm typically (maybe always?) still trail-braking as this occurs, and so the weight goes especially to the outside-front tire, which then hooks /bites / turns.

It seems like the "looser" the rear is, the easier that weight transfers? It seems like stiffening the rear bar would decrease the roll, decreasing the weight that gets transferred, decreasing the rotation. It seems almost like it would oversteer a little more easily.

So, am I thinking of "rotation" incorrectly? or am I misunderstanding the dynamics of how it happens?

I'm with you on this and the reason for my post. My understanding is a stiffer sway bar will cause that end of the car to be flatter and to lose grip sooner, hence allowing it to rotate better. My concern was that the car would then be tail happy. Correct me if my understanding is incorrect

I'm going to install it this weekend, I have a DE next weekend and can let you know.

[bbiela]

Originally Posted by maytag

Can you help me to understand this concept, please? (I'm still a little green on some of this)

I think I understand how upgrading the rear bar can reduce understeer. no problem there.
But I'm not following how it helps the car to rotate. Maybe I'm calling rotation something DIFFERENT from what rotation really IS?
When I enter a corner, there's a moment where the weight transfers in the rear and it helps turn the car. Occasionally there's a small slide associated, but it's usually just the weight moving to the outside. I think I'm typically (maybe always?) still trail-braking as this occurs, and so the weight goes especially to the outside-front tire, which then hooks /bites / turns.

It seems like the "looser" the rear is, the easier that weight transfers? It seems like stiffening the rear bar would decrease the roll, decreasing the weight that gets transferred, decreasing the rotation. It seems almost like it would oversteer a little more easily.

So, am I thinking of "rotation" incorrectly? or am I misunderstanding the dynamics of how it happens?

I'm with you on this and the reason for my post. My understanding is a stiffer sway bar will cause that end of the car to be flatter and to lose grip sooner, hence allowing it to rotate better. My concern was that the car would then be tail happy. Correct me if my understanding is incorrect

I'm going to install it this weekend, I have a DE next weekend and can let you know.

[maytag]

Originally Posted by bbiela

....My understanding is a stiffer sway bar will cause that end of the car to be flatter and to lose grip sooner, hence allowing it to rotate better.

See, if that's what "rotation" is, then I'm calling rotation the wrong thing. You're talking about oversteer, which can be useful in a higher HP car (you can "square-off" a corner that way) but seems counter-productive on a momentum car like the Boxster.

There are some great resources here, with some really knowledgeable guys.... hopefully they'll chime-in on this and set me straight, haha.