'71 Super Beetle Autocross Build

[Jadewombat]

Here's a place that carries metal working tools and a punch and flare set if you don't have one yet. They give a 5% discount to people on the H.A.M.B. or MetalMeet forums.

http://www.daggertools.com/

[ChadH]

I have some basic HF hammers an dollys, but It's the user more than the tools with those

I could definitely have some fun with the punch and flair tools, I'l need to peruse the site some more and look for more goodies. Thanks for the link.

[ChadH]

Weekend progress:

Spent all day Saturday with skim coat, sandpaper, and another application of 2K. The hood isn't 100% perfect, but it's as good as I can get it (without going insane.)



I removed all of the remaining front suspension and steering gear. All the ball joints and tie rod ends are still tight. There's play in the steering box - hopefully that will adjust out OK. Just ordered new bushings, camber kit, and tie rod end boots.

Since the car will be in the air for awhile, I made a "peg-leg" so I can move it around. I just welded this directly to the crash plate. I was going to remove it anyway, since it's just added weight, and doesn't appear to do much structurally.

[Piledriver]

now you have a good pic for "worlds slowest AX car"

Looking good, kudos, I hate bodywork with a passion.
(thus my username)

[ChadH]

now you have a good pic for "worlds slowest AX car"

Looking good, kudos, I hate bodywork with a passion.
(thus my username)

Hmm, I wonder if it would be derivable using a cutting brake.

I really hate bodywork too. I might take a break next weekend and clean up / paint the suspension bits so it doesn't get so tedious.

[Marc]

...There's play in the steering box - hopefully that will adjust out OK...

There's one easily-accessible adjustment (roller-to-worm play) which can be done with the box in the car. If you overtighten that the steering will resist self-centering coming out of a turn, and it can cause abnormal wear/damage too. Put the wheel 90° off-center in either direction, loosen the locknut & screw by ~one turn and then run the screw back in until you feel the roller contact the worm; tighten the locknut and check the play at the rim of the steering wheel with it 90° in both directions, it should be ~9/16" or less. If it's looser in one direction, repeat the adjustment with the wheel turned 90° that way and check again. DO NOT try to take out all of the play past the 90° point, it'll end up too tight.

If there's still too much slop it's probably due to worm spindle endplay. Rock the input shaft back & forth while observing the spindle, if you can see it move axially it needs adjustment. At this point the box has to come out for work. There's about 4 pages in the orange Bentley manual covering the procedure, which requires some special tools and selective-thickness shims...let's hope you don't need to go there. New boxes aren't available, only rebuilts, and they're rather spendy (money you'd probably rather put towards converting to R&P)

Note that `71-`73½ Supers use the same steering box as the 73½-`74s, but just have a different drop arm - so if you go shopping for a used box any year will do, look for one with minimal worm spindle play.

[ChadH]

I have the whole box out of the car now. Based on decent condition of the other suspension parts, I'm guessing it's not excessively worn, just out out adjustment. I need to clean all the crud off of it before I get to the adjustment.

Good to know I should only adjust it at +/- 90 degrees. It sounds like I'll need it back in the car for the final adjustment, but I should be able to get it close and check if it's toast.

I also ordered a new bushing for the idler arm. The stock bushing still feels pretty good, but I figured I might as well freshen it up while it's out.

[ChadH]

And while I'm logged in, another 12-months down-the-road kinda question..windows.

Per SCCA, I'll need to run both front and back windows. I'd like to forgo all the side glass, but I'm thinking the rear window will act like a big air-brake. Adding rear side windows "seems" like it would make it worse.

I really don't want to run windows in the doors, in fact, I already s**t canned the regulators. So, which is better, with or without rear side window glass? Also, would window rain deflectors on the doors provide any real benefit.

Or..Maybe at autocross speeds, it isn't that important

[Marc]

...Maybe at autocross speeds, it isn't that important

Quite possibly...but let's discuss some options anyway should you run out of bigger issues to address and decide to play with this.

On circle-track cars with rear windows they typically rework the front of the B-pillar into a gentle curve, and sometimes add a strip of aluminum (thin stuff, so it'll collapse without wounding the driver if he bangs into it) that goes inwards a couple of inches at a ~30° angle - they say it doesn't take a lot to make a significant difference in the amount of air entering the car.

I wonder if fitting rear side glass (or Lexan/Plexiglas panels) that was open at the rear, like stock pop-outs, would be effective at preventing air from entering while still letting pressure escape?

I'm assuming that they won't let you run a Lexan rear window with air-bleed slots in it; if that's legal it would be a simple option.

The kind of cars I raced were all short-track, mostly under half-mile, so maximum speed was seldom more than 75 MPH or so. We weren't required to run anything but the windshield; ONE guy built a Scirocco that was fully-enclosed and I doubt that it was worth the trouble. Biggest issue he faced was satisfying the promoters at every track that the door windows would stay in place yet be easily removable by safety workers - ended up using wingnut Dzus fasteners with larger-than-normal "wings" and release-direction arrow stickers at each one to make them happy. Must've been stifling on a hot day in a front-motor car.

[ChadH]

I like the pop-out rear window idea. If I did lexan side windows, I could tack on some brackets to have them permanently "popped", and maybe some Dzus fasteners to easily remove them. I think rear-side glass would help the car aesthetically too.

SCCA Prepared rules allow up to 500 sq-in of vents in fenders and hoods. It would probably be a stretch of the intent to drill a bunch of 4" holes in a lexan rear window though. I could email SCCA for clarification.

More brain storming... Maybe lexan door windows, but rather than a solid window, do something like a 6" tall slot along the whole length of the window. This would let in some air and let me hear the flagger and course workers if needed, but block some of the air that wants to enter the cabin. The whole piece could still be removable with Dzus.

[Jadewombat]

I wouldn't drill the rear window as it would disrupt the airflow off the back of the car. Probably not too much, but you don't want to be breathing exhaust fumes either if it creates a draw of air into the backseat area. Rear side windows, yeah, probably. I gutted the hell out of my doors, but I was also running side lexan windows in the doors with regulators because I was driving to and from events and rallycrossing requires the windows to be up all the way.

You could drill the rear apron too. (Ignore the decklid standoffs)

[Ol'fogasaurus]

Jadewombat is most likely very correct! When the air flow, as it comes off the top of the roof, wants to curl under in a roll which creates either a dead area or more likely continue the roll, which most likely will be a mix of exhaust/engine fumes, and get sucked into the pass cabin ; not be a pleasant thing at all.

If you have ever driven an open car or a roadster you would be aware of the way the wind swirls over the windshield and around the sides of it. Your hair get blown forward which is why I don't have much any more! Also, having to wash the windshield inside and out because of all the dirt and dust the swirling wind brings in several times a day when off-road or on trips is a big pain in the no-speak-about.

It also wouldn't surprise me if the opening rear side windows, when opened up, might act kind of like "wing windows" work on a roadster and move the air flows action towards the rear of the car.

For what it is worth.

Lee

[ChadH]

Weekend progress:

Took a break from bodywork to clean up some of the steering components:

Pressed out the old idler arm bushing.


I had one tough tie rod end. The rest came out pretty easy. This one required a few days with heat and PB Blaster, but it finally loosened up. I ran a tap to clean up the tie rod threads, and cleaned up the ball joints.


I started to clean up the steering box, and found oil leaking out of the large seal. Knowing that a new box is pricey, I decided to take it apart so I can re-build it with grease. Here's the lovely scene from the inside - oil/water mayonnaise. Everything is cleaning up nicely though. All the bearings and wear surfaces look fine.


I hit all the parts with black hammertone, and replaced the tie rod end boots. Still need to press in the new idler bushing and clean up the steering box housing.

[4agedub]

adewombat is most likely very correct! When the air flow, as it comes off the top of the roof, wants to curl under in a roll which creates either a dead area or more likely continue the roll, which most likely will be a mix of exhaust/engine fumes, and get sucked into the pass cabin ; not be a pleasant thing at all.

Bit of a thread hijack here. Here is my crude aero test on the rear window. First video was without a tab above the rear window and 2nd video to simulate the remelle type roof spoiler.


https://www.youtube.com/watch?v=zwrpjA-XAZQ


https://www.youtube.com/watch?v=IvEWZG_LBhQ

On the first video you will see the air sticking to the body towards the engine bay. On the 2nd video a vortex is generated and the air below the tab actually goes up. We did see an increase in top speed with the tab installed. I'm not sure how this will effect engine cooling though...

[ChadH]

4agedub:, This is good stuff. I've seen the roof spoilers, but wasn't sure if they really did much (other than racecar aesthetics.) I thought about installing one, but it would be one of the last things to worry about on my build.

Do they do anything to reduce the aerodynamic lift on the roof?

I'm not extremely worried about airflow with regard to engine cooling. Autocross races are usually around 50-60 seconds, with anywhere between a 5 and 20 minute cool down time (depending on the number of cars on the grid, and if It's a 2-driver car.)

I would almost consider running no fan or tin for cooling (drag-racer style), but I don't think I want to push it that far.