I get the racing thing pretty much completely---just don't get how this would affect the oversteering component though. Then again that's why NASCAR uses the 4 link rear suspension with Panhard bars.

Not too many of us driving 10/10ths in a van or anything else on the street.

 

Actually , Cup cars use a truck arm , not as 4 bar.It's a derivative from the old truck swingarm suspension.

 

What is 10/10ths?

And how the heck can a van have oversteer? Aside from snow or ice or a near emergency…?

 

10/10ths means at the edge , on the limit. Only racers drive 10/10ths.
You don't drive like that on the street.

I can slide any vehicle on dry pavement, that is oversteer.
Again , you don't drive like that on the street.

 

I've never heard of that: 10/10ths but I get it now.

And I know what oversteer is, and I can drive like that too, but how does that apply to talking about oversteer on a full-size van in regards to adding a swaybar to the rear?

 

I find most E-Series have significant body roll and understeer---at least the way I try flat footing it through some freeway entry/exit ramps.

Fishtailing is also a big handling issue with E-Series, many times caused by worn suspension springs, bushings or shocks. Of course tires contribute to this as well but I'm assuming (hoping) we're all running LT type and properly inflated too.

 

This may sound odd but....run more air in the rear tires than the front ....it will help prevent oversteer.

 

A rear bar will loosen up the rear when driving hard in the turns. Between picking up the inside rear tire and changing the cross-weight in turns , it will add oversteer.