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NASCAR style door bars


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  • Technical Advisory Committee
Posted (edited)

I would put one just inside of the bend radius on both ends (just aft of bend at front, just forward of bend at rear), and 3rd in the middle between those 2 points.  The idea is to keep things from making it between the horizontal bars, so evenly spaced at as close to door skin as possible makes sense.

 

Alternatively, line up the rear one with drivers hip (which is probably really close to about where that rear bend is) and then even space up to the front one - this gives that extra protection where your most valuable item is in the car.

 

Alternative for center vertical post - offset from centered between FR/RR vertical tubes to line it up with approximate CG of vehicle, and extend another tube down from same node to use a jack point to get left side of car up.

Edited by NigelStu
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Yeah the cage on this car was pretty good, but it had X bars that were inside the door cards.  I’ve moved the bars out about 6” from that point. Only an inch or two off the door skin.

Ive started with exactly as you’ve said.  3 vertical bars on the straight section of the bars.  I just want to make sure I’m legal is all and I wasn’t missing something. 
 

It’s a FWD car, so jacking under the from down tube of the cage actually lifts both wheels.  Otherwise I’d do what you mentioned. 

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Our cage has 4 vertical bars with 3 horizontal sections.  One right at the bend, then the other 3 are evenly spaced.  Took a full on side hit from a mustang and all we had was a tire mark on the number panel and bent door skin.  Miata btw with maybe 4" of ground clearance so we sit pretty low.

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24 minutes ago, petawawarace said:

May add and extra diagonal on the one opening.  Or add some 1/8” plate for intrusion protection.  

B83FC2EE-89EA-4902-86B4-7391A5A7C113.jpeg

Looks solid. I would extend at least the middle one (maybe all) down to the door sill with spreader plates to really tie it to the car. Tech is fine with extra bars here even when they ‘add attachment points’ to the chassis.

 

Extend isn’t the right word... add another tube directly below the middle vertical tube down to the sill. 

Edited by enginerd
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  • Technical Advisory Committee

Looks good on the verticals.

 

Gussets/corner tabs at the main hoop / a-pillar are a good thing to add as well.  Helps make the cage more rigid and maintain driver cell shape.

 

And gussets/tabs for dash bar / main hoop cross bar while you are in there.

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1 minute ago, NigelStu said:

Looks good on the verticals.

 

Gussets/corner tabs at the main hoop / a-pillar are a good thing to add as well.  Helps make the cage more rigid and maintain driver cell shape.

 

And gussets/tabs for dash bar / main hoop cross bar while you are in there.

I may actually do the extra A pillar bar. But I want to get it down onto the ground and see how restrictive it is getting in and out.  

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I would add a horizontal third "sill" bar right at the rocker and just tie it into the bar at the firewall and main hoop as close to the floor as possible. Then you can put some vertical supports from the main door bars to it. That helps protect the integrity of the seat mounts as the factory rockers usually aren't that strong. The main frame rails are usually farther inboard. 

Edited by XelderX
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I welded my sill bar to the sill.

KIMG0641.jpg.69c67244449ab721f5b132bbf54c2efb.jpg

 

I also tied the seat structure into the cage. I added a second cross brace at the bottom of the hoop because i don't think the Civic floor pan has enough strength to resist a big side impact.

 

KIMG0649.jpg.2cd562157afb3defac144cecc45d1255.jpg

 

No penalty for attachment points between the front and rear hoops.

Edited by mender
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  • Technical Advisory Committee
Posted (edited)
15 hours ago, XelderX said:

I would add a horizontal third "sill" bar right at the rocker and just tie it into the bar at the firewall and main hoop as close to the floor as possible. Then you can put some vertical supports from the main door bars to it. That helps protect the integrity of the seat mounts as the factory rockers usually aren't that strong. The main frame rails are usually farther inboard. 

Here’s an example of what @XelderX described

 

 

5F7ED4A8-BC6F-4D82-9F51-4E2ACBEEF6B4.jpegEdit note: this one took some thought and planning to weld the door bars up. To get to the welds on the outside of the sill bar, everything was fitted and tacked together, then I removed the 2 lower bars to weld them up fully, then reinstall. Snaking them through the B-pillar, 1 on each side was tricky. But it was cool once finished! (And more importantly, strong and safe. ) 

 

70BCCCCA-7D46-44DE-90A1-0DC8866AEC9F.jpeg

Edited by mcoppola
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  • Technical Advisory Committee
Posted (edited)
17 minutes ago, TiredBirds said:

why you want them OUT as far as possible. wreck2.jpg.4683eb9dbac89b98599d8af04ffbd6e1.jpg

Great example of bowed nascar bars doing their job. Hope the driver was ok in that crash. I’ve seen @TiredBirds post this pic before. 
I’ve worked at an oem doing vehicle crash testing for the past 20+ years. There is no substitute for, or equivalent to “crush space.”

Edited by mcoppola
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15 minutes ago, mcoppola said:

Great example of bowed nascar bars doing their job. Hope the driver was ok in that crash. I’ve seen @TiredBirds post this pic before. 
I’ve worked at an oem doing vehicle crash testing for the past 20+ years. There is no substitute for, or equivalent to “crush space.”

Driver was a tad shaken but ok. Car not so much. That was at maybe 60mph. The cage has been removed and inspected. It is fine. Will be going into  the new car soon. 

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On 4/23/2021 at 4:50 PM, NigelStu said:

Alternative for center vertical post - offset from centered between FR/RR vertical tubes to line it up with approximate CG of vehicle, and extend another tube down from same node to use a jack point to get left side of car up.

 

Please don't.

 

9.4. NERF BARS OR EXO-SKELETON

9.4.1. Added structural elements that extend beyond the outline of the original body line are not allowed.

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15 minutes ago, takjak2 said:

 

Please don't.

 

9.4. NERF BARS OR EXO-SKELETON

9.4.1. Added structural elements that extend beyond the outline of the original body line are not allowed.

 

 

It's easy enough to facilitate a jacking point integrated into the cage structure that can be accessed easily without violating the rule. I also don't believe an extension of the cage that serves as a jacking point that also can't be seen past the body line when looking down vertically violates the rule. If we are getting that picky than any of the trucks that run would be in violation with bars going from the top of the main hoop diagonal to the frame in the bed area. 

 

I "think" I understand the internet of the rule, but it needs to be applied correctly to intentional exo-skeletons. It's a good rule, but incomplete or written poorly. 

 

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16 minutes ago, wvumtnbkr said:

Wait, What?

 

It's just a little post that sticks out the bottom of the car that you use as a jack point.

 

https://images.app.goo.gl/fHb6gZ4Eta6w1qMq7

That thing comes out the side?? Haven’t seen one of those... make it like this (or like this but tying to the cage):

image.jpeg.e18696dab9916681b59b37d0d2d1c281.jpeg
 

also, I agree that this kind of jacking post does not violate the exoskeleton rule. 

Edited by enginerd
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The kind that stick out sideways were common on Trans Am cars as the aero got in the way of vertical ones. They still remained inside the bodywork and an adapter was slid into them that stuck out for a jack. If you look closely at the sides of Trans Am cars there is a little hole in the bodywork above the rockers. That's where the adapter goes. 

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2 hours ago, enginerd said:

That thing comes out the side?? Haven’t seen one of those... make it like this (or like this but tying to the cage):

image.jpeg.e18696dab9916681b59b37d0d2d1c281.jpeg
 

also, I agree that this kind of jacking post does not violate the exoskeleton rule. 

Naw.  Exactly like what you show there. 

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