Recent door bars

Ironically, neither are rally cars...

E36 4 door Chumpcar.


Kern Racing BMW M3 GTS-2 road race car

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Grant Hughes

Okay, okay, here's some GD STI door bars we did a while back...



My personal favorite design is still the sill plus one... Not as photogenic though...


Well, since we're here, this was my first bent V car.


That was first cage we did for a customer. Crazy since we today started on number 10.

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Grant Hughes

When I have my cage done, I think I'm going to go with the same design that's in that STI. Side impact is definitely my biggest concern...I'd also like to gut the doors, switch to fixed Lexan windows, and put that Impaxx foam inside the doors. It's expensive stuff, but it's hugely beneficial...especially since side impacts seem to be one of the most dangerous aspects of gravel/woods rally.

Love looking at raw cage pics! Random thought/question I'm having maybe you could answer Grant. Waiting on my car to come home with a cage and am thinking about paint. Plan on getting the whole car done next winter but until then, what would be a good option to keep the cage from rusting up? Just rattle a coat on it for the time being?

Have also been wondering what thoughts on interior color and what not. I know I know, don't worry about that crap just get on stage..... I've got a shop that'll do the work for materials in trade for some vinyl on the car, plus I've kicked them some business already. So, it'll be pretty cheap. Why not? I'm planning on painting the exterior flat green(drab) and the interior either black or white. Cars already white. Thoughts? Insight?

Here is the red car from Grant's post with white interior. It didn't really stay white long. If I was more intelligent I would have gone silver so it wouldn't look so dirty.

Nothing smells better than the inside of a well used rally car... Fuel, oil, sweat and dirt...
I've still not finished painting interior of merkur...

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Grant Hughes

I like the bent V door bars that bend out like the ones on the GTS-2 M3, that's what I've been doing on GC 2-door cars at work.

Speaking of door bars...







Ouch! It actually broke the door bars forward of the gusset, bent the tubes joining the X bars to the sill bar, pushed everything way across but thankfully the new car designs have about 6" between the cage and side of the seat.

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Ryan Huber
VA3AWD

Grant do you have any more pictures of the GD cage? debating where to attach the main hoop; either on the lower tier, upper tier, or i've seen people do a half and half looks like it could be easier to weld than just on the lower tier.

As far as interior color, I like white. Makes seeing stuff in the car much nicer, especially at night. Also white shows cracks and damage much easier.

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phlat65
As far as interior color, I like white. Makes seeing stuff in the car much nicer, especially at night. Also white shows cracks and damage much easier.

And white is cooler; less of a radiant heat source when the floor panels get heated from the exhaust or engine. I painted one car flat black on the inside to reduce night glare, but man, did it ever radiate heat off of the floor boards over the exhaust....

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czwalga
Grant do you have any more pictures of the GD cage? debating where to attach the main hoop; either on the lower tier, upper tier, or i've seen people do a half and half looks like it could be easier to weld than just on the lower tier.

We do the same feet as on the GC. In fact, we even used the same feet that I have cut out on a CNC plasma in bulk. Just now used the final set from the last run I had done. Which is nice cause now I can have a run of BMW ones done at the same time next.



There's an album on my facebook to the full GD cage, just none with any close shots of the cage feet, but we basically do what is commonly called a plinth box or some weird word. I don't think I can link to it though...

I like the look of the bowed out door bars, though not totally convinced on their applicability. I suppose they are an intermediate for side protection between a straight X and full Nascar bars. I've always felt like they might give a little more room but something about them pushing out on the main hoop and half lateral vs. pulling feels weird to me.

I like a sill bar plus single cross design. Think about what is being protected (occupants) and a full X doesn't add much while making it much more difficult to get in and out of the car.

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Grant Hughes

If you don't mind my commenting on this (again), understand that a straight bar is only as good as the weld strength at the ends, the tube tensile strength, and the points to which it is anchored. The idea that the straight side bar will be held straight in tension is a fallacy; the half lateral with the A-pillar brace will stay fairly steady but the main hoop's vertical section will just simply bend forward under the tension (if a weld does not break). You have around 40" to 45" typically of free vertical tube in the main hoop vertical, and the tension will simply pull this forward. It only takes 1" to 1.5" of bending there to allow the side bar to move in 6" at the center.

The X brace is theoretically a bit better in that it could help to triangulate the lower part of the main hoop and resist some of the forward bowing of the main hoop vertical at the side bar attach point under the impact tension on the side bars. BUT that only works if the X's center point stays at its original location during the impact. With no locating device at the X's center, that is problematic; the single point where the X tubes converge is just too 'noodly'. If you looks at the Aussie cars, you will see a vertical tube coming up from the sill bar to the X center point; the purpose of that short vertical tube it to try to firmly locate the center of the X and keep it from moving; it helps but does that in a so-so fashion only as it can bend inward.

The bars you show at the start of the thread get all around that, by make the whole side bar/sill bar assembly act more like a solid plane of material. It will act far better to keep the vertical part of the main hoop from bending (as much). And the spacing that it gives you is an even bigger advantage; the caage can bend/give a LOT more and it will stay off your body. That is the number one function of the cage: keeping bad, hard stuff away from the occupants.

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starion887
If you don't mind my commenting on this (again), understand that a straight bar is only as good as the weld strength at the ends, the tube tensile strength, and the points to which it is anchored. The idea that the straight side bar will be held straight in tension is a fallacy; the half lateral with the A-pillar brace will stay fairly steady but the main hoop's vertical section will just simply bend forward under the tension (if a weld does not break). You have around 40" to 45" typically of free vertical tube in the main hoop vertical, and the tension will simply pull this forward. It only takes 1" to 1.5" of bending there to allow the side bar to move in 6" at the center.

What do you think of adding a mid-rear stay (And forward mid-stay to strut tower) like in this diagram?

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One. Class -- 2WD

www.quantumrallysport.com

http://www.facebook.com/home.php?#/pages/Quantum-Rally-Sport/281129179600?ref=nf

Door bars on my MKII Syncro build, obviously not gusseted yet:



Josh, any tips for half-lateral to front strut bars on the MKII? Haven't seen any close up photos, but the more I look at it, the more it seems like they could be a huge pain to weld.



Edited 1 time(s). Last edit at 11/26/2013 02:24PM by ronerickson.