Changes in the Door Bar Rules??

[Knestis]

I've heard rumors that there has been (or will be?) a change that requires "2 door bars" on both sides (again, ??) of IT cars. Or maybe new IT cars??

(That's a lot of question marks, huh?)

I don't remember seeing anything in recent FasTracks but my 'memberer is suspect recently - from old age and overwork, methinks. Anyway, has anyone seen anything like this, is it spillover from Spec Miata changes, or what?

The issue is that the triangulated structure we had in Pablo's doors...



...might very fairly be considered to have a cross-sectional area of only one tube diameter, at the center of the main X. We're getting started on the new cage this weekend obviously don't want any surprises.

Have I just not been paying attention?

K

[Greg Amy]

Proposed, effective 2007. Require two side tubes both sides, allow NASCAR bars both sides including door gutting. See September 2005 Fastrack, page F-209. - GA

[Speed Raycer]

Kirk,

I've been wondering the same thing since most of the pass side bars I've done have been X's. Depending on the way its worded, X's could be "illegal" if it requires 2 bars from the main hoop to the front downbar.

Time for a clarification letter eh?

[Knestis]

Thanks, Greg. I don't know how I missed that. I swear that I looked! I don't think there's any need for "clarification" - it's clear that, if this is approved by the CRB, X door bars will be illegal.

K

[Bill Miller]

Originally posted by Knestis@Sep 21 2005, 11:24 PM
Thanks, Greg. I don't know how I missed that. I swear that I looked! I don't think there's any need for "clarification" - it's clear that, if this is approved by the CRB, X door bars will be illegal.

K

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Kirk,

I would agree that a traditional X bar, where you have one continuous bar, with 2 'cut' bars, would probably not meet the letter of the rule. However you could certainly make a 'siamesed' X, and use some of those neato gussets that Pablo has. Not sure what the difference in structural integrity would be.

As an alternative, you could run a traditional X, and put the second side tube down along the rocker

[joeg]

GUYS--MY next race is after October 1, 2005. Can I put my additional sidebars in now? (is the new rule officially adopted yet?); can I put the extra bar on one side now only (protruding into and gutting the door) and wait until the end of 2006 to do the other side?

They are not X-bars, so leave me out of that debate (which seems real silly as those X-bars are just fine.)

Regards.

[dickita15]

Originally posted by joeg@Sep 22 2005, 07:34 AM
GUYS--MY next race is after October 1, 2005. Can I put my additional sidebars in now? (is the new rule officially adopted yet?); can I put the extra bar on one side now only (protruding into and gutting the door) and wait until the end of 2006 to do the other side?

They are not X-bars, so leave me out of that debate (which seems real silly as those X-bars are just fine.)

Regards.

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You can certainly add extra bars now. you can not gut the right side door yet. the only two changes that are pending if I have it right are to require 2 bars (optional now), and allowing that gutting of the right door.

[dickita15]

Originally posted by Knestis@Sep 21 2005, 09:08 PM

...might very fairly be considered to have a cross-sectional area of only one tube diameter, at the center of the main X.

It would seem to me that the x would be legal. we have had no trouble with cage diagnals and horzontal bars intersecting in the same manner. I can however see how some ispector somewhere would make a different call.

It would seem as though the debate could be cleared up in the proposed gcr wording. was this a ITAC or RRB generated issue.

[Greg Amy]

Originally posted by Knestis@Sep 21 2005, 11:24 PM
...if this is approved by the CRB, X door bars will be illegal.

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I don't think so. The rule, paraphrased, is "...two sides tubes connecting the front and rear hoops across both doors is manadatory." There's nothing in there about requiring them to be horizontal (how would you enforce that anyway) nor anything describing that they cannot intersect (no specifics using the word "continuous" as in GCR 18.1.7.A. Further, any reputable mechanical engineer will attest that a properly welded parts are considered contiguous.

I think you're OK here with the welded X-bars. However, it never hurts to get a clarification. - GA

[Knestis]

This is going to confuse people - who assume that we will argue whatever suits our individual purposes, with whatever ammo we have available (see the 300ZX in ITS thread) - but I'm going to continue to argue that our triangulated X would be illegal if "two bars" are required. We would be wrong.

A cage builder on the East coast has made it common practice to leave the traditional parallel rear supports (from the main hoop) out of his designs, instead using ONLY an X. I've long argued that this approach does NOT meet either the letter or engineering aguments behind the requirement. Over some portion of that span downward to the rear end of the car, there is functionally only one tube there. The minimum cross-sectional area of the rear portion of the cage structure is just slightly over pi times one-half of the tubing diameter squared - or approximately "not very damned much."

To my mind, the same applies here.

Bill has actually hit upon exactly what we are going to do. The new cage is going to rock.

K

[Bill Miller]

Originally posted by Knestis@Sep 22 2005, 12:13 PM
Bill has actually hit upon exactly what we are going to do. The new cage is going to rock.

K

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So, which is it, siamese, or 2nd tube along the rocker?? Inquiring minds want to know!

It's all about thinking outside the box!

[Knestis]

We're going to run one bar from the floor at the rear hoop, up to a center point in the door hole, then down to the forward upright. This one will have a twin running from shoulder height, down to the center of the door, then up to dash height in the front. They will meet at the apex of the X and be welded together along 3-4", then plated and gusseted.

The front downtube will be about 4" farther into the dash, which will allow our "WRC" diagonals to the top of the A-pillar to run straight and be farther from the driver's left hand. The main hoop will be about 3" farther back, to tie the structure together closer to where the rear beam bolts up, and we're going to be more assertive about the 100" plate rule, running two tubes from the front downtube to the firewall, right behind the strut turrets.

Finally, we're doing away with the fiddly little gussets, using full-diameter tube triangulation, a la typical touring/rally car current practice.

I still think that the crushable structure afforded by full doors is a valuable thing - moreso than NASCAR door bars.

K

[ddewhurst]

***- but I'm going to continue to argue that our triangulated X would be illegal if "two bars" are required.***

SURPRISE, we agree current "X".

***We would be wrong.***

NAW......


Now just to add fule to the fire. Read the Production car rules & explain how they can fab a 3 tube door bar "X" with no horizontal & be legal.

Bill, I saw John's 2nd gen car parked at the Runoffs for sale with no price. Was he there ?

[Bill Miller]

David,

Yep, he was there. I believe he was crewing for one of the guys running a Porsche GT3 Cup car in GT2. That car is a steal, I think he's only aksing $6500 for it, and that's w/ a fresh motor and a MazdaComp trans (albeit missing 1st gear). Would need some race shocks, but other than that, it's a hell of a start to an EP car. Hell, the rolling chassis is worth what he's asking for everything.

[lateapex911]

Originally posted by Bill Miller@Sep 26 2005, 12:03 PM
David,

Yep, he was there. I believe he was crewing for one of the guys running a Porsche GT3 Cup car in GT2. That car is a steal, I think he's only aksing $6500 for it, and that's w/ a fresh motor and a MazdaComp trans (albeit missing 1st gear). Would need some race shocks, but other than that, it's a hell of a start to an EP car. Hell, the rolling chassis is worth what he's asking for everything.

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Further info, he is there crewing for Mike Piera, who is in a Porsche Cup car. (veeeeery cool car, BTW) ...from the inside it sounds so refined on the track! (My car sounds like a$$, LOL).

Mike is a guy who went to the Solo II Nationals for the first time, and WON in a '73 Porsche 911S Targa (!) when it was not the car to have. Smart and methodical, Mike has won his share, and then some, of races this year. We'll see how it shakes out when everybody bolts in their "A game" engines, but I pick him as a dark horse, and would not be at all surpised if he popped the champaigne.

Johns car needed a bit more than dampers. I'm not saying that the $ asked wasn't a fair price, but there is a HUGE shopping list and it's not cheap stuff. He has already parted out all the good stuff, and is just trying to wrap it up.

[Tyson]

whats the point of nascar bars on the passenger side for an IT car?

[lateapex911]

Originally posted by Tyson@Sep 26 2005, 07:12 PM
whats the point of nascar bars on the passenger side for an IT car?

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It's a guess, but I bet HQ wants more beef in the cars. A Touring driver was killed and the conclusion, from what i hear, was that better right side protection would have helped. It's great deal...as defined, NASCAR door bars are just about anything,,and you get to gut the door. I think it would be foolish not to take the offer.

It's a real cake and eat it too deal, YOU decide what the best door bar configuration is, as long as it meets the definition, and you get to take off a chunk of weight!

[Tyson]

yeah, im not talking the weight benefit. just why would the CRB allow this change since they have a history of only changing things on the basis of safety or factual error.


i suppose the only difference is that it changes the load path on a straight T bone more directly to the vertical bars (pushing instead of pulling the welds) but that doesnt mean anything to make a safer cage for the driver on the other side of the car. thats why im asking...

[Knestis]

It's off to get the cage installed by Competition Cages in Hillsborough, NC...



Look for our doorbar treatment to be a natural - and legal - extension of what we learned from the one in the pic above. That vertical element right next to the driver's left hand, by the way, resolved all of the load of our roll's impact above the A pillar strictly in compression.

There is NO evidence of deformation in the cage structure...

K

[Bill Miller]

Kirk,

I think I just came up w/ a name for the new car. Ugly Duckling!!!