S2's Build Thread

This “disposable male genitalia” approach is endorsed by the #MeToo Movement.

Ohhhh - that's just messed up....:oops:
 

Scott

Lifetime Supporter
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ALL PICTURES AND ACTIVITIES SHOWN AND DISCUSSED IN THIS POST THAT TRANSPIRED OUTSIDE THE BOUNDS OF MY HOUSE OCCURRED BEFORE I SELF QUARANTINED. Well “self” is a euphemism for my my wife and mother demanding that, given my underlying health conditions, I not leave the house. I’m going stir crazy, but the last thing that I need is those two opening a can of whoop ass because they thought I sneaked to Abe’s shop to have some welding done!

The front hoop is constructed from a single piece of 1.5” DOM with a flat top and constant radius bends on the sides. While this is easy to manufacture, it doesn’t closely follow the body which has a non-constant radius. If the interior isn’t finished, the hoop is noticeable, but not overpowering. However, when the interior is finished and the hoop is covered, the A-pillars overpower the interior. They’re not in keeping with the organic dash, tub, roof liner or door cards. In addition, the optional A-pillar covers don’t cover the hoop and require an extra 1/4” or so of fiberglass to be added.

Nice interiors are expensive and there’s a price point where it makes sense to modify the front hoop to reduce the size of the A-pillars. I’m not sure what that number is, but I’m aware of one SL-C with a $45k interior with massive A-pillars. That car should have had a modified front hoop. The picture below shows how large the gap is between is between the front hoop and the body.

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There’s two ways to shrink the A-pillars; (1) cut the front hoop off of the cage an fabricate a new one or (2) stretch the existing hoop. Note that it’s my understanding that Superlite has changed the way they manufacture the front hoop which makes it narrower. This would increase the need for the mod as well make the stretching approach infeasible.

In any event, I decided to stretch the hoop with a hydraulic jack. We started about one third of the way from the top of the hoop and worked our way down. Non-marring vice grips were clamped to the hoop to prevent the jack from slipping off. As the bottom of hoop expands the tub the mounting plates lift off of the chassis and and the outer edges pitch upward. At some point the outer edges of the mounting plates began to collide with the body. So I removed the body and trimmed the mounting plates with a cutoff wheel. I didn’t cut them off because they were useful to keep the jack from slipping off. The body was replaced, and additional stretching was done.

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Once the right amount of stretch was achieved, the body was removed and the mounting plates were cut off with a portable band saw as close as possible above the weld. The bottom of the cut tubes were then trued up and made parallel to the chassis with a sanding wheel.

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A new bottom plate was fabricated from 1/4” steel. There are two ways to fill the gap between the bottom of the hoop and the mounting plate: (1) machine a slug with a shoulder that slides into the hoop or (2) fabricate a pedestal for the hoop to sit on. Apparently it’s a common practice when fabricating cages inside of a car (i.e., one in which the roof can‘t be removed) to construct the cage shorter than needed so that the top joints can be welded in the car and the entire structure subsequently raised on pedestals. The pedestals seemed the easiest option, so that’s the direction I took.

I fabricated two rectangular pedestals from 3/16” steel. No matter how I oriented the pedestals, the rear outer bolt holes on both sides were covered by the pedestal. Most builders could just relocate those holes, but I have removable side-impact bars which have tubes in the foot box that are welded to backing plates for the hoop, floor plates and the upper suspension mounting points. So, relocating those holes was a non-starter. The issue was solved by welding nuts, which will be located inside of the pedestals, to the top of mounting plates.

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Ratchet straps were used to tweak the location of the hoop and then everything was tack welded. With all of the changes to nose structure, suspension mounting points, etc. I want to realign the suspension and body again before doing the final weld. The hoop isn’t as tight as I want, but it’s a huge improvement.

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I had cut the dash to fit the old hoop and the white arrow indicates how much the bottom of the hoop moved. Previously the fit was tight and now I have a lot of filling to do.

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I want to see pics of the in process jacking action!
Way too late for me but a good piece of info for persons not there yet. More importantly (to me) is the amount of left hand corner vision that is blocked by the covered A pillar. To help mitigate I left mine uncovered, which also provides a bit of a grab point for egress.
 

Joel K

Supporter
Great work Scott. I have the side impact bars as well and was trying to figure out how to widen the front hoop and leave the mounting holes in place. Thanks for leading the way!
 
Beautiful work Scott, I was planning on cutting off the front roll hoop and fabricating a new one using a large tube roller. Amen, on needing the roll cage to match the A pillars more closely, are you aware of any other SLC builds that have this same modification? I think you are the first!
 

Joel K

Supporter
Beautiful work Scott, I was planning on cutting off the front roll hoop and fabricating a new one using a large tube roller. Amen, on needing the roll cage to match the A pillars more closely, are you aware of any other SLC builds that have this same modification? I think you are the first!
Mason, Johan did this mod as well. You can see a few photos on post #72.

 

Scott

Lifetime Supporter
I think pnut was the first to do it. He cut the hoop off. Bob stretched his hoop and machined slugs. I think I'm the first to do pedestals. The biggest issue was figuring out how to resolve the rear outer bolts which couldn't be moved due to the removable side impact bars which have a permeant cage in the foot box.
 

Scott

Lifetime Supporter
I want to see pics of the in process jacking action! Way too late for me but a good piece of info for persons not there yet.
Mesa, we stretched the hoop almost a year ago. I didn't take any pictures because I was thinking that it might not work and I'd wind up cutting the hoop off;-) Next time I have the cage off I'll mock things up and take some pictures.

More importantly (to me) is the amount of left hand corner vision that is blocked by the covered A pillar..
I will have better left-hand-corner vision with a modified hoop and covered pillar so long as: (1) you don't consider the space between the spider and hoop as useable and (2) time is taken to get the cover tight to the hoop.

To help mitigate I left mine uncovered, which also provides a bit of a grab point for egress.
I have been considering 3D printing a recessed finger grip that would be open to the windshield and bolted to the hoop for exactly this purpose. I don't think it would be visible from the outside. That said, I've watched Allan and pnut ingress/egress the car and they do it pretty easily without using the hoop. To my recollection they both use a similar technique. Pnut uses the top of the seat rather than the hoop. I can't try it because I haven't bolted mine to the floor yet. I actually took a video of pnut which I promised I wouldn't post... if anyone wants to see it, send me $$$ via PayPal LOL

I do think there should be a SL-C ingress/egress video thread -- slick and funny videos welcome.
 
Actually the small gap between the A post and the hoop is vision useful. Every little bit helps when you can't see what you need to. I just moved my left side mirror up one inch. Although it was in the perfect place to see directly under the wing and over the quarter, when turning into a left hand corner the mirror blocked the view of the corner apex.

I'm going to ramp the egress video challenge to "11".
Lets see - Stuck in your car videos....
Priceless, they would be.
 

Scott

Lifetime Supporter
Actually the small gap between the A post and the hoop is vision useful.
If you're peering through that gap, you might lose ~ 3/8" sliver of "total" visibility because there's a small gap between the hoop and the body (not enough to look through from the driving position) and the cover has thickness. However, you're not contending with big view - bar - very narrow view. The upper corner of the radius moves up which increases the vertical view because you can't see through space between the top and upper corner of the hoop and the body from the driving position.

IMO the mod improves driveability.
 
Great Scott!
I am in total agreement that the mod will provide the best vision. My comment regarded the A post cover on a stock roll hoop. It blocks vision, if you leave it off that little sliver of gap (at least in my seating position) provides marginal but usable additional vision.
 

Scott

Lifetime Supporter
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My son is interested in cars, but for the most part he’s memorized the specs on all of the exotics. He’s somewhat interested in the SL-C project, but I’ve been careful to not push it on him. One of the good things to come out of sheltering at home is that we’ve had an opportunity to spend some quality time in the garage — what’s better than that?

The battery in my 1993 BMW 850 CSi was dead and my charger couldn’t revive it, so I figured I’d teach my son how to swap the battery. In the end, I learned that the car has two huge batteries in the trunk. To get to the second one, we had to remove the CD changer (the black box above the wrenches). It was the first CAN Bus car and it had two ECUs, one for each cylinder bank — apparently one wasn’t powerful enough to manage 12 cylinders. I guess to power all of the new-fangled electronics it needed two batteries. It’s kinda cool because the car is passing through three generations — James Richard bought it, James Scott is enjoying it and James Connor is being groomed for it LOL

Last week we also went over thread pitches, tapping and drill press basics. He then drilled some holes in scrap, used clecos to keep everything aligned and then riveted them together. Connor thought the clecos and rivet gun were cool. Next week we’re going over milling machine basics — fixturing, edge finding, facing, making slots, using the DRO, etc.

So being stuck at the house isn’t all bad!
 
Scott,

Took my son to a kart race at 4. He was mesmerized. Ran his first race the weekend after turning 5. He’s now 20. Builds and drives his Sprint car, helps with my projects, has built 2 turbocharged Evoras, is studying Mechanical Engineering with an emphasis on aerodynamics and heads up the FSAE team.

Start them young. Give them a little more responsibility than you think they can handle. Let them make mistakes (as long as they don’t involve too much blood or money).
 
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