2015 RCR #3

Questions and answers about CMC and NASA rules

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Al Fernandez
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2015 RCR #3

Postby Al Fernandez » Sat Sep 26, 2015 1:20 pm

Rear weld in strut tower brace
---1) Dustin Mozader, Rocky Mountain Region #45, Supercharged111@gmail.com/719-648-0594
---2) Rule reference:
7.6 Chassis Strengthening
7.6.1 The frame or subframe shall be stock for the body used. The front and rear subframes may be tied together (front to rear only) with subframe connectors. The subframe connectors may be bolted or welded to the unmodified subframes, but may not be welded or bolted to the floor along the length of the subframe connector. The subframe connectors may not pass through the floor or intrude into the inside of the car. OEM seat mount points may be altered or reinforced. The reinforcement may tie into the subframe connectors or the cage but may not span across the floor from driver to passenger side.
7.6.2 One bolt in stay rod may be fitted between the upper front strut towers and between each strut tower and the firewall. The minimum distance between the center of any of the stay rod’s bolting points to the edge of the base plate for the roll cage’s 7th/8th points is 18 inches.
7.6.3 A lower chassis front suspension brace (G-load brace) may be fitted. It must bolt on only using a maximum of four existing OEM factory holes or mounting bolts and no cutting, welding or other modifications may be made to the structure of the car to install this brace.
7.6.4 A front steering brace may be fitted. It must bolt on only using a maximum of four existing OEM factory holes and no cutting, welding or other modifications may be made to the structure of the car to install this brace.
---3) Recommended Revised Wording:
7.6.5 A bolt in brace or weld in tube may be fitted between the rear shock towers. It must connect at no more than 2 points.

---4) Reasoning for change MUST include at least 1 of the following:
---------->a) Will decrease series cost because…
---------->b) Will increase driver safety because…
---------->c) Will promote series growth because...
---------->d) Will improve competition because…
---------->e) Will provide more clarity because... Plenty of cars have a piece of roll bar tubing connecting the shock towers already under pretty relaxed interpretation of the roll cage rules. Adding this wording would eliminate doubt that this is ok.
Al Fernandez
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MHISSTC
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Postby MHISSTC » Tue Sep 29, 2015 8:21 am

Dustin, it's already black and white. You can't do it.

:wink:

Now that busting your chops is out of the way...

Other than those items specifically mentioned in the rules like the G-load brace, strut tower brace, and subframe connectors, there are to be no other items whose sole purpose is chassis reinforcement. I don't think this RCR is needed to provide additional clarity. I think it is more about specifically adding a structural reinforcing item that was not previously allowed.

Chassis reinforcement is a byproduct of good cage design. If you have a well designed and constructed cage, you've likely already placed your cage mounting points at or near the rear shock towers and have already incorporated such a bar in your cage. And as part of your cage, this bar is completely legal. If, however, the cage builder didn't really think it through and didn't incorporate such a feature in your cage, too bad for you. Adding another bar, strictly for chassis reinforcement, when you could have had it incorporated into a cage of better design, isn't a good excuse to subsequently add this bar now. Any such add-on outside of the cage design isn't legal and shouldn't be allowed after the fact. If you have one installed, it needs to be removed.

By adding just the working you suggest, I think you are opening the proverbial "can of worms" because what you propose will need additional clarification. If I bolt it in, where are the bolts to be located? How many bolts can I use? If I weld it in, what size base plate am I required to use, or am I limited to? Is it to attached to the top of the shock towers, the side of the shock towers, or can I also attach it to the top and side, or can I attach it to the side and the floor between the towers? Will that count as 2 points, or is that 4? Can I tie this bar into my cage? What if I have such a bar currently built in the structure of my cage? Will my cage be grandfathered in, which will require an additional statement in the rules to specifically say so, or will I have to modify my existing cage?

And if you're attempting to add this wording now to cover the sins of poor rule enforcement in the past, that's the wrong reason to make any rule change request. Try better rule enforcement of what we already have.

However, if this bar NEEDS to be added because there is a demonstrated weakness in the chassis of any car, and we are trying to increase the structural integrity of the chassis in order to increase the longevity of the chassis in this series, I'm TOTALLY FOR adding such a bar.

SUMMARY:

A well designed and constructed cage may already incorporate such a bar legally. Adding wording to include a bar installed strictly for additional chassis reinforcement is not needed. But if the purpose of this bar is to correct a well known and documented structural issue that will increase the longevity of a particular chassis is this series, let's add it.
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BryanL
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Postby BryanL » Wed Sep 30, 2015 5:44 am

I agree with MHISSTC. There is no need to make this legal just because some cars already have the illegal item on there car. Though I would like a little more info. on the relaxed roll cage rules or maybe a picture of what we are talking about. I'll take a closer look at my cage this weekend.

Supercharged111
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Postby Supercharged111 » Wed Sep 30, 2015 7:41 am

If it's not allowed and we don't want to allow it, then I don't want to see it in ANY cars next year.
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D. Francis
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Postby D. Francis » Wed Sep 30, 2015 8:48 am

2015 CMC Rules wrote:4.1 Safety Requirements
All cars and drivers must conform to NASA's Club Codes and Regulations (CCR).


NASA CCR wrote:15.6.17 Additional Reinforcement
Any number of additional reinforcing bars are permitted within the structure of the cage provided that they are installed strictly for safety and do not violate CCR Section #15.6.2 Intent. This rule does not permit reinforcements in classes with spec cages.


Dustin, is this your question? CMC does NOT have a spec cage.

NASA CCR wrote:15.6.11 Rear Braces
The main hoop should have two (2) braces extending to the rear. The braces shall be attached as near as possible to the top of the main hoop, and no more than six (6) inches below the top. The braces should not contain any bends*. There must be at least 30 degrees between the plane of the main hoop and the plane of the rear braces. The main hoop rear braces may consist of an “X” pattern design. The main hoop braces may be mounted at the rear shock mounts or suspension pickup points (providing that the braces remain in compliance with all other sections of the CCR). They may go through any rear bulkhead(s) provided the bulkhead(s) is sealed around the cage braces. *There may be certain exceptions allowed for cars that cannot possible meet this “no bend” requirement. One exception is listed [Ref:(15.6.11.A)]. Other exceptions may be made if all of the required bars meet the specifications for a vehicle in the next heavier weight classification and the alternative design is submitted to the NASA National Office for special allowance.


And I think I've seen an X inside the traditional rear down bars.

There may be an argument that having ONLY a horizontal bar, without the X bracing (i.e. a rectangle formed by main hoop/rear down bars/top of shock mounts) is to add stiffening, maybe poorly, without adding to safety but that looks like it's covered by 15.6.17.

Do you have any pictures or cars you know of? Not asking you to throw anybody under the bus, but a picture often helps.

PS-I added that bar in last month (j/k, I couldn't resist)
David Francis
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Supercharged111
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Postby Supercharged111 » Wed Sep 30, 2015 1:29 pm

No pics, but there is a car running a welded bar between the rear shock towers. Since it had been OK'd with Al, I felt no reason to address it at the track but now that the rule change season is here we either add it to the rules to allow it or tell the guy to cut the bar off his car for next year. I don't have an issue with allowing it as I don't see it making the car go any faster so it's not something I'll even spend time or money on, i.e. no skin off of my teeth but if it's not in the rules it either needs to be or needs to be removed.
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D. Francis
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Postby D. Francis » Thu Oct 01, 2015 7:49 am

Supercharged111 wrote:No pics, but there is a car running a welded bar between the rear shock towers.
If welded to the cage/rear down bars it's likely legal. If welded to the car and outside the cage, likely not legal, given the way i read what i posted.
David Francis

#39 CMC Camaro

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