Front Sway Bar?

[Mrmaddbrad]

Originally Posted by stephen wilson

I believe the GT3 bar is stiffer than stock (even at the softest setting), which will increase Understeer.

That is if you're already Understeering... But it could potentially just reduce oversteer, and body roll as they are designed to do...

[stephen wilson]

Originally Posted by Mrmaddbrad

That is if you're already Understeering... But it could potentially just reduce oversteer, and body roll as they are designed to do...

No, a stiffer front bar will increase understeer. The only unusual case where it MAY not, is on a high CG, front-heavy car, with poor camber control ( like a 60's muscle car ). In which case the reduced roll (and reduced positive camber), adds more to the front grip than the increased weight transfer (from the larger bar) removes . A Boxster certainly doesn't fit into this catagory.

There are plenty of books that explain the affects of weight transfer in detail.

[Brad Roberts]

Ira emailed me the GT3 bar versus the stock bar info. I'll post it up shortly.

I will tell you running the short drop links with the GT3 bar, decreases the effectiveness of the bar in corner. As you input more steering wheel, it UNLOADS the outside tire in the corner

He was at our shop late last week test fitting some new parts I don't have to ask for permission


B

[Stroked & Blown]

Brad,
That chart is great, thanks for posting.
A couple questions:
- Do you have a common comparison for the H&R rear bar?
- Can a Cayman front bar be fitted to a 986?

[Brad Roberts]

The CaymanS bar will not fit

I have personal "butt" experience with the H&R rear bar, but I do not have numbers in comparison for it. I do know it is stiffer on full soft than the Tarett rear on full stiff. I have taken them out of several of our race cars. Just too stiff for some of the open diff cars.

My biggest issue right now is the rear drop links everyone sells for the rear bars. They are too short. Take a look under a Cayman Interseries car and notice the rear "pry bar" they have going on. The rear links are way way to short for those cars. Everyone sells a replacement heim based drop link for STOCK replacement. Stock replacement is GREAT for STOCK shocks/springs at euro or USA ride height, but when you lower the car, the upper link mounting point goes UP in the chassis!!! and in turn it points the rear bar into the SKY!!

B

[Kroggers]

Originally Posted by Brad Roberts

I have personal "butt" experience with the H&R rear bar, but I do not have numbers in comparison for it. I do know it is stiffer on full soft than the Tarett rear on full stiff. I have taken them out of several of our race cars. Just too stiff for some of the open diff cars.

How about on a Boxster S with a lsd?

[jaykay]

Thanks for the chart! What short drop links??? Stock ones?

Originally Posted by Brad Roberts

Ira emailed me the GT3 bar versus the stock bar info. I'll post it up shortly.

I will tell you running the short drop links with the GT3 bar, decreases the effectiveness of the bar in corner. As you input more steering wheel, it UNLOADS the outside tire in the corner

He was at our shop late last week test fitting some new parts I don't have to ask for permission


B

[Brad Roberts]

The stock ones won't work either.. all the aftermarket links are based on these!!

Run the LSD with one link removed and zip tied up to the toe link (they move at the same rate) and test the car without the rear bar. LSD's inherently induce understeer that has to be dialed out. I leave the nut on the floating drop link and run the car for a session with the bar disconnected, then quickly reconnect it for the next session for side by side comparison.


The rear links being sold are a compromise.


B

[Kroggers]

Originally Posted by Brad Roberts

The stock ones won't work either.. all the aftermarket links are based on these!!

Run the LSD with one link removed and zip tied up to the toe link (they move at the same rate) and test the car without the rear bar. LSD's inherently induce understeer that has to be dialed out. I leave the nut on the floating drop link and run the car for a session with the bar disconnected, then quickly reconnect it for the next session for side by side comparison.


The rear links being sold are a compromise.


B

Interesting, so you recommend actually downgrading the rear if the car has an LSD?