Front Sway Bar?

[Brad Roberts]

We will need more info!! what tire/size?? what spring/shock combo?

We run a LOT of Boxsters with SCCA. 99% of them are running the GT3 bar for more adjustment to conditions/driver.



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[Mrmaddbrad]

Running typical 17" Boxster tire set up... And stock springs.... Plan on buying some adjustable Koni Shocks.

Still. If everyone else is running GT3 Sway Bars, then thats probably the way to go....

I did say i was building a C-Stock Boxster. Therefore implying stock rim size/width and stock springs.

[stephen wilson]

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

[Brad Roberts]

I'm not familiar with C-stock rules Most of our cars are in prepared classes BSP/FP/XP

That being said.. stick with the stock bars and buy some BoxsterS bars (MO30) I typically carry with me 3-4 rear bars and just swap them out until I have a stock shocked car balanced the way I want it. The rear takes 10min to swap out.. the front takes a little longer.

Bars I go to the track with (and AutoX)

Tarrett
MO30
Stock

I believe you can backdate/update in C-stock?



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[Boxster44]

Originally Posted by stephen wilson

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

for what it's worth.... I have an old sheet from Ira at Tarett and it shows the front GT3 bar at softest - is 50% stiffer than stock S bar.

kj

[stephen wilson]

I was looking for that information today! I knew I had seen a list comparing the stiffness of the various roll bars that are available.

[thstone]

Originally Posted by Boxster44

for what it's worth.... I have an old sheet from Ira at Tarett and it shows the front GT3 bar at softest - is 50% stiffer than stock S bar.

kj

Any chance you could scan it and share with us?

[Boxster44]

Originally Posted by thstone

Any chance you could scan it and share with us?

I would normally, but it's from a known source and Ira created it. I really don't want to step on toes and duplicate without permission.

However, I'm pretty sure Ira would be okay to give out to people who ask.... he's really very generous that way. It's called "Boxster Sway Bar Stiffness Ratings"

... sorry if it's inconvenient.

kj

[Kroggers]

So if the GT3 bars are a recommended upgrade, where is a good place to get them from - direct from Porsche or e-bay or?

[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


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[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?

[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


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