Reply To: The Classification System is open for the 2017 Autocross Season

#9946
Jeff Roberts
Keymaster

Hi Paul –
The team did our research prior to this change and we discussed it at length at our annual meeting and all of us agreed that this modification is significant enough that it should be charged points.

Facts
– The E9x M3 is equpped with front centering pins from the factory that prevent any camber adjustment while in place.
– It is widely known that these pins are removed to increase negative camber beyond the factory setting.
– If the pins are no longer there, they have been removed.

Our classification system assumes any change you make is done so to yield the maximum benefit.

Some examples:
– install wider wheels, assume you run wider tires
– install adjustable shocks and/or springs, assume you corner weight and dial in your suspesion
– change the ECU tune, assume the change yielded a benefit
– install camber plates, assume you changed camber
– remove centering pin, assume you changed camber

How much of a change you make (or don’t make) by removing the centering pin is not for our judgement. I have camber plates and could align my car to the factory setting, but I can also align it to maximize negative camber which I know is a worth-while change for autocross. I’m charged 5 points for having them because the system assumes I will use them to my benefit.

There have been two threads on the FB group, unfortunately deleted, discussing this very topic. From there I learned a few things about the E9x.

E9x factory alignment specs here:
http://www.m3post.com/forums/showthread.php?t=192175

That’s -1.10 degrees with a max diff between the two sides of +/- .2 degrees. In the deleted thread I mentioned we saw an E92 post-pin removal alignment sheet with -1.65 degrees. When compared to factory setting this is about -.5 degrees of increased negative front camber. That’s a significant change.

I was unable to locate the alignment section for the E90 M3 specifially, but I do have it for the E92 – Reference

The first page, right at the top aside the large triangle with exclamation point reads:

The centering pin may only be driven or twisted out if the camber
is outside the specified tolerance after toe adjustment.

With the pin in place, no front camber adjustment is possible on any BMW equipped with the pin from the factory. We can only assume if someone removed it, that they did so to change the camber as set from the factory.

Our policy is consistent with the 2017 Street Category Rules where Section 13.8 B reads:

Both the front and rear suspension may be adjusted through their designed range of adjustment by use of factory adjustment arrangements or by taking advantage of inherent manufacturing tolerances. This encompasses both alignment and ride height parameters if such adjustments are provided by the standard components and specified by the factory as normal methods of adjustment. However, no suspension part may be modified for the purpose of adjustment unless such modification is specifically authorized by the factory shop manual.

SCCA also recognizes the potential benefit of alignment changes and addresses them specifically in their rules.

Hope that helps! Please don’t delete as we lost a whole bunch of good dialog from the FB group and others will benefit from seeing this.