'71 Super Beetle Autocross Build

For road racing, autocrossing, or just taking that curve in style. Oh yea, and stopping!
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ChadH
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Re: '71 Super Beetle Autocross Build

Postby ChadH » Wed Nov 09, 2016 9:19 pm

I received my 1302 camber plates from Silver Project today. Being that they are out of Poland, I was a little skeptical of what I'd find in box.. Shipping only took 1-1/2 weeks, and the parts look as nice as could be expected. The plates are heavy, have nice looking welds and thick powder coat. My fears are abated. For a buck twenty-five (and $37 shipping, I couldn't expect more). Heck, they have plates for a MK7 GTI for $160. I might grab a pair for it too (everything else for this car is $400 ++)

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FJCamper
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Re: '71 Super Beetle Autocross Build

Postby FJCamper » Thu Nov 10, 2016 3:18 pm

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Here's our set in our 1973 Super with 1974 struts. We're been very happy with them.

Be advised you can now adjust camber from both the top and bottom (!) the difference being if you adjust from the bottom, you move scrub axis more.

FJC
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ChadH
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Re: '71 Super Beetle Autocross Build

Postby ChadH » Fri Nov 11, 2016 12:21 pm

Be advised you can now adjust camber from both the top and bottom (!) the difference being if you adjust from the bottom, you move scrub axis more.
FJC
Yes - I figured that out :wink: I'm going to have more ways to adjust this car (and ways to f' up handling) than I know what to do with. With the limited track time I'll be able to get, I'm guessing it will take at least a year of races to get it all reasonably sorted... but I guess that's half the fun.

I think I might have mentioned it already, but I have a neighbor up the street with a fancy water jet in his garage. He makes custom brackets and other cuts for people as a business. I want to CAD up some top plates (similar to what you have) and maybe a few other brackets -n- bits and see what he wants to cut them for me.
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ChadH
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Re: '71 Super Beetle Autocross Build

Postby ChadH » Sat Nov 12, 2016 8:05 pm

I brought home cage tube today. 40' of 1.5"x0.095" and 30' of 1"x0.095. It's just ERW, and I know DOM is better stuff, but I'm not likely to crash into a barrier rail at 129mph. I'm anxious to get started, but need to take the time to do a little more cleanup on the inside before I dive in. I want to clean up the rest of the glue, cut out the factory seat rails, e-brake mount, and heater cable tubes first. I have some generic rust barrier chassis paint I'd like to lay down on the pan first. I'm also thinking about patching some sheet metal over the heater channel vent holes too, since it seems like they would be a weak point. All the white stuff is 2k dust that I need to clean up too.

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Marc
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Re: '71 Super Beetle Autocross Build

Postby Marc » Sat Nov 12, 2016 9:02 pm

When I first started circle-tracking, all that was required was 1¼" .095" wall (with a 2" gusset at all main welds, which were buzz-box back then). It was only after they increased the maximum displacement/vehicle weight that it was deemed necessary to step up to larger/thicker tubing (worst-case scenario envisioned was being on your side in a 1600 lb car and getting drilled in the roof by a 2500 lb car at speed).

So long as the design is good you should be plenty safe with 1½" .095" in the main cage, I survived more rollovers than I care to remember with 1¼" and never had to repair more than sheetmetal damage.

We determined that 1½" .083" was stiffer at about the same weight per foot as 1¼ .095", but would bend/crease easier if impacted from the side...it would typically be used in "optional" bars, like the diagonal "Petty bar" from the center of the crossbar in the main hoop to the RF corner, where stiffness at minimal weight was desired and there was little chance of ever being exposed to a side load.
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ChadH
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Re: '71 Super Beetle Autocross Build

Postby ChadH » Sun Nov 13, 2016 2:13 am

90% of the reason for my cage is to stiffen the chassis. Getting drilled by a big car is pretty unlikely since it's autocross, but not totally impossible. There are other cars on the track at the same time. Even though efforts are made for safe spacing, some cars can can get off course or lost, and encroach onto the wrong part of the track. I have seen a few cars, with sticky tires, get up on two wheels too, so tipping over isn't impossible either. I'm going to follow SCCA requirements for a road race cage , even though It's not required for solo, since thres a lot of good information and guidance contained within. Between the cage and harness, I should be better off in an accident than a non-airbag car with just 3-point setbelt.
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FJCamper
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Re: '71 Super Beetle Autocross Build

Postby FJCamper » Sun Nov 13, 2016 12:23 pm

Chad,

Build the cage with bolt-on (i.e. removable) cage-to-suspension links.

You'll have the best of both worlds.

FJC
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ChadH
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Re: '71 Super Beetle Autocross Build

Postby ChadH » Mon Nov 14, 2016 11:10 am

Chad,

Build the cage with bolt-on (i.e. removable) cage-to-suspension links.

You'll have the best of both worlds.

FJC
You all talked me into it. I agree it will make building the cage easier. If I do it right, I might still be able to pull the body off the pan if needed. This is why I bought the 1" tube, since 1.5" is probably overkill for bracing some of the suspension ties.

I think building with both left and right threaded bungs will make fabrication pretty easy. I'm assuming metal to metal hiem joints are what I need, since there shouldn't be much movement when installed, and they have higher bearing capacity. Let me know if I'm wrong on this.

No pictures, but I got the interior cleaned up a bit before starting. I left the seat rails in, though, since it's really difficult to cut out the welds and remove them cleanly.

I have another race next weekend, then with Thanksgiving, I might not actually get to cut and bend tube for awhile. There's just not enough time on the weekends. :(
Ol'fogasaurus
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Re: '71 Super Beetle Autocross Build

Postby Ol'fogasaurus » Mon Nov 14, 2016 11:33 am

Chad, on my buggy build I am just finding out how important to pan stiffness those seat tracks add to it. I was able to get my pan halves w/o the seat mounts because I wanted the seats to be mounted lower in the pan (CG purposes) which causes the seat to have to be mounted farther to the rear for leg room than stock seating is. With the new seats mounts bolted in place then I get into the buggy to check seat spacing the pan will "tin can" a bit; I can both feel it and hear it. The flat areas starting at the rear seat floor well are not now supported by the seat track which acts as a stiffening flange. Something you wouldn't normally think about. Go figure!

I'm a bit confused about the right and left hand thread bit or that is at least that is what I got out of it. Please correct me if I am wrong. Right and left hand threads seem to be used when self tightening fasteners are in the want (lug nuts are that way on some vehicles to stop the lug nuts from backing off on one side of the car). Turnbuckles and tie-rods yes, is that what you are doing... preloading the cage or make it easier to remove the suspension attachments? If so I think I would gusset the stubs and flanges (if any) for a just-in-case added structure.

Interesting build to follow.

Lee
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ChadH
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Re: '71 Super Beetle Autocross Build

Postby ChadH » Mon Nov 14, 2016 1:35 pm

I didn't think about "tin-can" effect. I don't think leaving the factory tracks in is a big deal - they don't weigh much, and I don't think they'll conflict with new seat mounting. I expect the whole car will be one loud and rattly
tin can, regardless, since I'll have solid engine mounts, and have gutted all interior insulation and panel damping. At least I'll only need to put up with it for a few minutes at a time.

I guess what I was getting at with the suspension ties and cross supports is to put a left hand thread on one end, and right hand on the other end of each rod - like a tie rod. It would make them easier to install and adjust to length. Not really to pre-load anything, but just to make sure everything is tight.

Sorry - I spend more time thinking and posting thought on this build than I do actually working on it ;)
Ol'fogasaurus
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Re: '71 Super Beetle Autocross Build

Postby Ol'fogasaurus » Mon Nov 14, 2016 1:55 pm

I didn't think about "tin-can" effect. I don't think leaving the factory tracks in is a big deal - they don't weigh much, and I don't think they'll conflict with new seat mounting. I expect the whole car will be one loud and rattly
tin can, regardless, since I'll have solid engine mounts, and have gutted all interior insulation and panel damping. At least I'll only need to put up with it for a few minutes at a time.

I guess what I was getting at with the suspension ties and cross supports is to put a left hand thread on one end, and right hand on the other end of each rod - like a tie rod. It would make them easier to install and adjust to length. Not really to pre-load anything, but just to make sure everything is tight.

Sorry - I spend more time thinking and posting thought on this build than I do actually working on it ;)
Yeah, I understand the thinking and posting time but also the thoughts I get back.

The "pre-load bit" was the same as your "make sure everything was in tight". I think it is a good idea especially to get the loose "smudges" of gap out. You give things a bit of room and they try to take more don't they?
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ChadH
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Re: '71 Super Beetle Autocross Build

Postby ChadH » Fri Nov 25, 2016 7:35 pm

Bending Tubes ..Or why I'm glad it's a long weekend and I bought extra steel.

Front hoop v1.0
Close - but no cigar. My bender starts the actual bend about an inch from where I though it would. The result was the hoop was a bit too wide near the door window frame.

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Rear hoop final version
Got it first time, right where I want it. I'm getting the hang of it!

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Front hoop v2.0
..Or maybe not. The width is good and bends are better..but it's about 2" too short and the rearward bend to follow the window angle is too low I'll try again tomorrow. At least I'm getting my exercise!

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ChadH
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Re: '71 Super Beetle Autocross Build

Postby ChadH » Sun Dec 18, 2016 12:30 pm

Kind of quiet in here. Time to post progress from the last few weeks.

I did get a third hoop bent that fits much better. Floor plates done, main hoops and a few bars welded in. I have today to get a little more done.

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ChadH
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Re: '71 Super Beetle Autocross Build

Postby ChadH » Tue Dec 20, 2016 12:28 am

More from yesterday.

I finished the "X" on the top of the cage. No pictures though.

For the tie into the torsion tube, I went ahead and cut out some sheet metal for better access. I'll add another tube from this area that I'll connect up to the rear hoop, about halfway up to get some triangulation. I'll need to patch up the sheet metal when I'm done.

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I found a good online fish mouth calculator that's pretty flexible in generating templates. It worked really well in generating a template to match up the 1.5" tube to the torsion tube. I was able to get it right after just one test fit. http://cq.cx/tubejoin.pl

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Both sides are welded too - no pictures.
Ol'fogasaurus
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Re: '71 Super Beetle Autocross Build

Postby Ol'fogasaurus » Tue Dec 20, 2016 1:08 am

In the last picture, I like the way you are marking the tubes very much. Sure saves time inthe long run (pun not intended).

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