(2011) Stock Class Question

[jrushbmw]

The stock class says to have an oem differential but can i switch it to a different final drive ratio or do i have to use the one that came on my car? the new one would still be oem? Also are their any rules about rtabs, fcabs, and transmission and motor mounts?

Thank you for your help,
James

[mcoupemindy]

The stock class says to have an oem differential but can i switch it to a different final drive ratio or do i have to use the one that came on my car? the new one would still be oem? Also are their any rules about rtabs, fcabs, and transmission and motor mounts?

Thank you for your help,
James

James,

These are great questions - some of which are already defined in our rules.

We will soon be releasing a survey and there is a section for class change requests. I highly suggest you put these comments there for consideration during our annual meeting.

The intention of the showroom category is to permit all non performance enhancing items or accessories. If we get into performance modifiers, you bump to tuner. Although not defined, I would agree that the engine and trans mounts dont affect low speed performance. Suspension bushings would change the handling characteristics and would entail a bump to tuner.

Again, please include this on the survey so we can get a defined answer for you.

Thanks!

[woodym3]

The intent of the rules would have a change in rear-end ratio take you out of the showroom category. We call it "showroom" to avoid confusion with the SCCA's very liberal "stock". It does become a grey area sometimes. For instance I think the OE E30 325i has a 3.73:1 ratio but the E30 325i convertible with automatic transmission has a 4:10.

[bobesser]

My personal interpretation:
for Showroom, the differential must be stock. If you want to be anal, if the *specific* car did not come with it, it isn't stock. One step down from anal: If the desired differential was an available option on that *specific* car, you could use it. in the above example, if you have an e30 325i convertible, you could use the 4:10, but, not if you have a hard top.

On fcabs/rcabs, falls under "Other suspension" and for showroom, they must be stock.

On the engine/trans mounts, I would argue that they do enhance performance since they limit engine motion and assist in putting more power to the ground - helpful in launching and pulling out of slow corners. As such, I would think they would be a tuner mod.

The showroom restrictions have saved me an enormous amount of time and money as I would have modded a lot by now otherwise.

Bob

[Zchild]

+1; that has always been the my understanding as well. I changed the ratio on my differential from 3:07 to 3:46 and that changed the class which I participate in during auto-cross events. I also have a few more mods as well. Just my two and a half cents worth...

[mcoupemindy]

James,

The survey was released today. Please take a moment to complete with your classing observations.

Best,

Jonathan