The bumpsteer isn't there at stock height or close to it. You really have to push it to see the problem though.
The parts to fix it are the toe arms in the rear and up front the steering rack spacers. Both mods are not allowed unless you are in ssm.

I thought the bumpsteer issue wasn't a problem till recently. I am just starting to push the limits.

 

Where does whiteline factor in?

Let's clarify things here a little.

Are we talking about a cross-brace that looks like an X? Anything of that sort is not legal in ST due to the triangulation.


Or:



Either of the above is what I think of when someone says 'X-Brace' or 'cross brace'.

Now, if it's a 'strut bar' which is what the rules are made for (in the S2000's case, only from the left shock tower to the right schock tower) it's fine. But a strut bar is not usually called an X-Brace or Cross-brace. If that's what you're thinking, then your terminology needs to be fixed.

That clear things up?

--kC

 

I would claim that this rule does apply to an X-Brace or cross brace. A "Strut Bar" that is mounted to the lower left and lower right suspension mounting points per the rules sounds like a cross brace to me.
The whiteline or a single wide transverse brace that attaches in the same location could be considered the same as a "strut bar". A strut bar typically uses two mounting bolts per side (one forward and one aft) just like an X-Brace. The theoretical single wide transvers brace would give you the same triangulation as an X-Brace while possibly meeting the rules.

I don't care to argue the case. I mainly wanted clarification on past rulings regarding this rule as I believe it has come up on other vehicles. This rule seems a bit vague to me.

I searched SCCA forums for posts regarding this rule in other classes but came up empty.
Thanks for the discussion.

 

I thought the only legal strut tower bars were ones that were not restricted in motion in more than one dimension (ie, if one side was disconnected they still have to be able to rotate around the other strut tower), like spherical joints would give you. This provides no triangulation at all.

I remember this discussion a while back when ST was STS... and everyone complaining that their existing STBs would not be legal.


(BTW, I found the old thread that discussed it and it was from 07... so I'm not sure if it has changed since.. I'm not a rules guru. It was started by TheNick on a local forum, so maybe he can chime in)

 

There are many things that could be considered 'cross braces'. A strut bar is a type cross brace. But it's called a strut bar. A swaybar is a type of cross brace, but it's called a swaybar... and they have to be transverse, with only one location of attachment on either side.

An X-brace, (something that looks like an X) is an "X-Brace". If it looks like an "X", it's not legal. It attaches in 4 different places.

Not hard. Really.

Specificially 2005 with the BMW M3 Convertable vs M3 Coupe.

Someone ran the crossbrace on their M3 coupe saying it was a standard part. It was a standard part, but only on the convertable to add chassis rigitdity. Ruled not a legal modification in ST. If he ran a convertable, it would have been allowed. But since the M3 Sedan didn't have the X-brace as a standard part...

http://sccaforums.com/forums/permalink/282...ShowThread.aspx

The result of that event was published in the June '05 Fastrack on pg F-132:
Hopefully this helps clear up the confusion.

--kC

 

Since when is a swaybar considered a brace?

There are many strut tower braces that have connection between two different bolts from side to side. Two top strut bolts.

Isn't STR closer to STX? I don't see this bmw comparison from 2005 being relevant. Did the rules change after 2005? We are talking about a whole new class.

The whiteline does not look like an x..

 

I'm curious if anyone has details of when bump steer becomes an issue on the early models. I'm not looking to drastically lower the car... I was originally thinking somewhere around a .25-.75" drop with spring rates close to what TheNick has posted.

 

(I was answering GEARHEAD's post/question that he remembered the protest, or "issue") .

The summation of the confusion of the "X-Brace" is as follows:
Note: Term used: "X-Brace".
Note: Another reference to "X-Brace".
More talk about X-Brace.

I posted pics showing the difference of what an "X-Brace" actually is... an X... and there's more talk about things being called X-brace being legal.

An "X-Brace" looks like an X, or sort-of looks like an X, and more importantly mounts in 4 separate points/locations.

Please stop calling a strut bar an X-Brace.

Whiteline makes a rather large number of chassis/suspension reinforcements for many makes and models (but only list 2 parts for the S2000 on their site).

For example:
http://www.whiteline.com.au/product_detail...t_number=KSB706

That's a whiteline "X-Brace" (Lower control arm brace) and it is *not* legal. Why? It attaches in more than 2 points, 4 separate locations to be exact. If you're talking/thinking about a part that is only connected at two points (a strut bar on most cars goes around the upper strut/shock tower and uses those 2-3-4 bolts circling the strut-tower hole, but that's considered 1 point)... that's legal, because that's still considered one "point". It's one left mount, and one right mount, and only goes left to right (transverse) and not to any other locations.

They don't make a 2-point "strut-bar" for the S2000 like they do for the WRX here: http://www.whiteline.com.au/product_detail..._number=KSB554)

Does that help clarify it even more?

Now, if Whiteline offered the following part for the S2000, I think that'd be legal: http://www.whiteline.com.au/product_detail...t_number=KSB716

The only other part for the S2000 by whiteline for the S2000 is a swaybar, and I hope you're not considering a swaybar an X-Brace.

4 separate points: bad.
2 separate points: good.

There are also strut tower bars that go back to the firewall as a 3rd point of attachment/reinforcement... those are also not legal.

We good here? If you want to consider the Whiteline lower control arm brace legal... go ahead and run it. I won't stop you. However, don't be surprised at the outcome if there's a protest.

--kC

 

You and me both. I just started researching this myself.

--kC

 

Jeez kC - in a good mood tonight? Or you just trying to get your fingers ready for the onslaught of internet bench racing on 9million forums now that Nats is over? You have more patience than I my good man


Re Bump Steer: like I said - I've had none such issues on my AP2. The best thing I can tell you and Matt is to just experiment - you might find that you have to run higher rates in the rear than an AP2 or you might need the SPC camber adjuster in the rear used to clock the hub a certain direction to lower the tie rod, or you might need nothing at all. Could be that you just need to run a decent chunk of static toe in as well.