Is this design legal?

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Doc Bro

New member
Is this cage design legal? Let's assume that the plate is less than 144sq in. The question is ; Is plating the top of the box and incorporating the RSM (rear shock mount) legal?








BMWE46013.jpg
 
Sure it is. The only question is is it necessary. Typically the shock mount of a stock coilover car is pretty strong to begin with. Now if you were in a class that allowed you to convert from a noncoilover to coilover, where the chassis was probably not strong enough to begin with, then I would see the need. I do this on Mod class BMW E30's all the time for customers. Don't get me wrong, its a good idea if money and or weight are no issue. If I were building a weight challenged car though i would pass.
Chris
 
SCCA yes... not so sure on NASA though. IIRC theres a rule in there about tubes meeting at one point.

I personally like a "better fitting" pad than just building a box and welding it in. E30's have an oddball shape on each side, but a box makes for an aweful lot of space where nothing's tying into the chassis. Just my opinion ;)
 
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Does it become grey when you REPLACE the upper strut mount with a mounting pad? Greg's is surely 100% legal - but he has the stock upper strut mouting in place. Knowing that Rob is building an ITR E36, this rear upper shock tower area is a known weak point.

It begs the question: Can you cut out the stock upper shock tower and replace it with a pad?

Not sayin' either way, just sayin'.
 
You can't cut out the upper mount and replace it w/pad. Even if it rips out ala E36's, you'd still have to repair it to factory specs THEN attach the pad to it.

Like tGA, I'm assuming that the factory sheet metal is still under there.
 
Speed Raycer said:
SCCA yes... not so sure on NASA though. IIRC theres a rule in there about tubes meeting at one point.
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The NASA rules that may affect this, as how we designed the NX (from the 2008 CCR):
- Incorporate rear strut tower bar +1 (includes a horizontal bar between bars that functions as and replaces a rear strut tower bar...
- One or more bars that are welded to the chassis (directly or with a plate) anywhere farther than 6” from the end of a tube where it terminates at a plate +2
​
I'm not sure what that second one means...I always took the +1 for the "rear strut bar"; no charge in SCCA...

GA
 
Not saying what is legal and what isn't legal....but it looks to me like Greg's original strut tower pad is only 1/2 there.
 
Andy Bettencourt said:
Does it become grey when you REPLACE the upper strut mount with a mounting pad? Greg's is surely 100% legal - but he has the stock upper strut mouting in place. Knowing that Rob is building an ITR E36, this rear upper shock tower area is a known weak point.

It begs the question: Can you cut out the stock upper shock tower and replace it with a pad?

Not sayin' either way, just sayin'.
Click to expand...

Doc building a ITR car? Oh Goodie more competition.:D WTG!
I would think that any modification or reinforcement to the factory shock mount is illegal.:018: Therefore if you build around it, maintaining the 120 sq in rule, it would be legal.
 
Daryl said:
...it looks to me like Greg's original strut tower pad is only 1/2 there.
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It's not; it's under there. We just welded the plates on top of the existing rear strut "tower" sheet metal (and that can be verified by looking inside the wheel well.)

When we did that it was such a revelation (well, at least in Club Racing) that we carried with us - and were asked to produce twice to tech inspectors - the cardboard templates of those plates to ensure they were below the maximum plate area (144 sq-in?) We actually had one tech inspector break out a ruler and calculate the area... ;)

The other eye opener was the "rear rollcage lateral strengthening structure". Even my buddy Dick Patullo all but accused me of cheating, until he read the rule and thought about it... ;) In hindsight, the same results could have been obtained by putting it between the rear rear leg tubes, and it would have resulted in a lot less "in your face"...

GA
 
What about the front strut mount area? During post race tech I've noticed that some have been chopped off and replaced by welding on a camber type plate thus allowing much more adjustability. Is that legal?
 
robits325is said:
What about the front strut mount area? During post race tech I've noticed that some have been chopped off and replaced by welding on a camber type plate thus allowing much more adjustability. Is that legal?
Click to expand...

Sure. Some modification to the top of the tower may be necessary to fit the allowed camber plates. I have seen some VW photos that really pushed the limit but I think it is all legal.
As to Greg’s strut bar, what was cutting edge with regard to attachment points 5 years ago is now pretty commonplace.
 
Andy Bettencourt said:
Does it become grey when you REPLACE the upper strut mount with a mounting pad? Greg's is surely 100% legal - but he has the stock upper strut mouting in place. Knowing that Rob is building an ITR E36, this rear upper shock tower area is a known weak point.

It begs the question: Can you cut out the stock upper shock tower and replace it with a pad?

Not sayin' either way, just sayin'.
Click to expand...


I thought that was an illegal modification when I saw it. The reason I ask is because I'm trying to be SCCA and BMWCCA legal. That mod is totally legal in BMW club, but iffy in SCCA. Andy picked up on what I was trying to ask, without biasing the responses. Thanks

R
 
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