S2's Build Thread
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Scott
Lifetime Supporter
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.
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.
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.
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.
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.
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.
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.
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.
Excellent job. Looks much better. Even if you were going with no interior, this looks much better.
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
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
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.
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.
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.
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
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.
Scott
Lifetime Supporter
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).
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).
Scott
Lifetime Supporter
I’ve been through a bunch of iterations on the cooling system. At this point, I not using any of the heating or cooling parts supplied by Superlite nor the LS7 mechanical pump. During the process the following diagram has been through multiple iterations and hopefully this is the final, final, final version — LOL.
As I’ve previously mentioned, the single best resource that I’ve found on automotive cooling systems is this article on 4x4 Pirates. While it doesn’t mention remote electric pumps or mid-engine cars, its content is directly applicable.
My current plan is to not run a thermostat, but I have ensured that there is space to add one if needed. The LS7’s mechanical pump places the thermostat on the inlet side of the engine for reasons covered in the aforementioned article. While placing it on either side would work, fitment works better for me on the inlet side.
The one feature that I’m going add that isn’t covered in the article is a coolant swirl pot. Apparently these are very common in race cars to separate air bubbles. The Raver SL-C has one and the following excerpt is from Engineer to Win:
Diagram from Engineer to Win
Do I need one? No, but I needed to merge the two -12 lines from the engine into the the 1-1/2” tube that runs sown the left side pod and the swirl pot serves that purpose. In addition, continual de-aeration can only help things considering that 2% air in the system results in 8% less heat transfer, but 4% air results in 38% less!
The swirl pot is made from 2-3/4” aluminum tube and I decided to dome the top to promote air bubbles escaping… plus it looks cool;-) I purchased a 4” half sphere and while I was pondering how in hell I was going to clamp it so that I could cut the tip off, Abe tack welded it to a scrap 4” tube which made it easy to cut on a horizontal band saw. Once the cut was cleaned up, I needed to mark the exact center. To accomplish this, I put some layout dye on the middle, stood it on end against a vertical surface, measured the OD on a digital height gauge, divided that number by two, reset the gauge to that number, and rotated the cap while marking it with the foot. Given that all of the lines intersected, I knew that I had the center — or as close as possible given that the OD wasn’t perfect.
I used a hole saw to cut the bottom and the arbor created a hole in the middle. Rather than fill the hole, I decided to enlarge it and add a bung for a drain. I ground the back side of the weld bungs until they were flush with the inside surface. I’m still waiting for a couple of parts, but it’s almost ready for Abe to weld together.
As I’ve previously mentioned, the single best resource that I’ve found on automotive cooling systems is this article on 4x4 Pirates. While it doesn’t mention remote electric pumps or mid-engine cars, its content is directly applicable.
My current plan is to not run a thermostat, but I have ensured that there is space to add one if needed. The LS7’s mechanical pump places the thermostat on the inlet side of the engine for reasons covered in the aforementioned article. While placing it on either side would work, fitment works better for me on the inlet side.
The one feature that I’m going add that isn’t covered in the article is a coolant swirl pot. Apparently these are very common in race cars to separate air bubbles. The Raver SL-C has one and the following excerpt is from Engineer to Win:
Diagram from Engineer to Win
Do I need one? No, but I needed to merge the two -12 lines from the engine into the the 1-1/2” tube that runs sown the left side pod and the swirl pot serves that purpose. In addition, continual de-aeration can only help things considering that 2% air in the system results in 8% less heat transfer, but 4% air results in 38% less!
The swirl pot is made from 2-3/4” aluminum tube and I decided to dome the top to promote air bubbles escaping… plus it looks cool;-) I purchased a 4” half sphere and while I was pondering how in hell I was going to clamp it so that I could cut the tip off, Abe tack welded it to a scrap 4” tube which made it easy to cut on a horizontal band saw. Once the cut was cleaned up, I needed to mark the exact center. To accomplish this, I put some layout dye on the middle, stood it on end against a vertical surface, measured the OD on a digital height gauge, divided that number by two, reset the gauge to that number, and rotated the cap while marking it with the foot. Given that all of the lines intersected, I knew that I had the center — or as close as possible given that the OD wasn’t perfect.
I used a hole saw to cut the bottom and the arbor created a hole in the middle. Rather than fill the hole, I decided to enlarge it and add a bung for a drain. I ground the back side of the weld bungs until they were flush with the inside surface. I’m still waiting for a couple of parts, but it’s almost ready for Abe to weld together.
Last edited:
Johan
Supporter
Scott, the cooling system diagram lookes fine, I have the exact same setup. They differ only that I integrated the overflow tank into the expansion tank with a welded wall in between.
The only thing is that the overflow tank should be vented to athmospheric pressure, eighter with an open line or a zero pressure lid so the fluid, if any, could be draw back to the expansion tank when engine cools.
Scott
Lifetime Supporter
I was asked how I cut the clean holes on the tangent of the swirl pot. While I do have access to Abe’s tube notcher, this was simple because the holes were drilled at 90 degrees. I used a bi-metal hole saw that I purchased at Home Depot (sharp tools make clean cuts). I dropped a scrap piece of tube into a vice on the mill so that when I dropped the quill it would just miss the end of the tube. This allowed me to see where the saw would plunge and to move the Y-axis until it looked like I had everything lined up perfectly (i.e. the outer edge of the cut was just inside of the ID of the tube at the middle point). I then slid the tube under the hole saw, put some oil on it and cut away… nope, I was off a little so I tweaked the Y-axis and did another test cut…. bingo, it was spot on.
In went the real piece, I aligned the x-axis so that the middle of the saw was aligned with the sharpie mark (see on first hole above) and the hole came out perfect. I moved the X-axis and drilled the second hole. The inside was cleaned up with a deburring tool similar to the one shown below and the outside was cleaned up with the tube sander/polisher discussed in a previous post.
This could have been done almost as easily using a drill press and a drill press vice. I would orient the vice so that the fixed jaw was closest to column, clamp a piece of scrap and eyeball alignment the same way as described above. Since you can’t tweak the X-axis on a drill press, I’d cheat the fixed jaw a little closer to the column so that shims could be used to tweak the position. I keep scraps of every thickness in a box to use as shims when mocking or machining parts. If you don’t have a cache, just order a bunch of small pieces of various thicknesses from McMaster. I’d then clamp the vice to the table, do a test cut, and shim as needed. The only trick would be to not rotating the tube when drilling the second hole.
Scott
Lifetime Supporter
Some of the SL-C builders who are tracking their cars were blowing out their rear bearings. The stock C4 bearings and 27-spline stub axles are OK for street use, but they are not suitable for a SL-C on racing slicks (forum discussion here). While Superlite offers a racing upgrade for the suspension it’s not suitable for the street. In mid 2019 Superlite began shipping cars with new uprights, C5/C6 bearings and 30-spline stub axles. In addition to being more robust, the new hubs have integral reluctors which are an improvement over the reluctor rings that I had previously installed on the CV joints. Specifically, everything is enclosed and there is no need to fabricate custom sensor brackets which might get knocked out of alignment.
Fortunately, Superlite offers an upgrade path for existing cars like mine. The upgrade comes with the following; two uprights, two spacers, six stainless steel dowel pins and two stub axles. Unlike the previous generation uprights which were handed, the new uprights and spacers are symmetrical and can be used on either side. I wasn’t sure what the two 7/16”-14 holes where at the top of the uprights so I called Superlite. Apparently the new upright is the same as the one used on the GT-R which uses cross bolts for the top billet piece. So what might have been four different upright parts, is one. In addition, the use of a spacer allows a thinner piece of aluminum to be used for the upright which reduces material costs and machining time. This was a smart change.
The pictures below compare the older right rear upright (on left, part# SLC-RR-UR-01R) to the new upright (on right, part# SL-RR-UR-02RL).
Right rear uprights as viewed from inside the chassis; old on left, new on right. The front of the car is to the left.
Right rear uprights as viewed from the wheel; old on left, new on right. The front of the car is to the right. Note that the new upright has the spacer mounted using dowels in the three smaller holes.
Right rear uprights as viewed from the front edge; old on left, new on right. The 1/2” thick spacer is mounted to the new upright which makes the new assemble ~0.2 thicker than the old version. I had drilled and tapped holes for the parking brake bracket when this picture was taken.
Superlite forgot to send me the dowels, so I ordered some from McMaster (part# 90145A541). The first step is to insert the dowels into the uprights (light taps are all that’s needed). As mentioned above, the uprights are symmetrical so you need to insert the dowels into the side that faces the hub/tire. Once that’s done, the uprights are handed. The spacer can then be placed over the dowels and lightly tapped until it’s flush with the upright.
Another benefit to the new version is that it’s easier to drill and tap holes for the parking brake brackets. As can be seen in the pictures above, there is significantly less pocketing in that area than the old version and the middle web is ~0.91” (~23 mm) thick which easily accommodates M10 screws. I used the DRO on the mill to drill the holes, but I used layout dye and a micrometer to prevent another D’oh. Measure five times, drill and tap once. Following the 2x thread diameter rule of thumb for aluminum I drilled the holes 25 mm deep and used a M10-1.5 bottoming tap.
Fortunately, Superlite offers an upgrade path for existing cars like mine. The upgrade comes with the following; two uprights, two spacers, six stainless steel dowel pins and two stub axles. Unlike the previous generation uprights which were handed, the new uprights and spacers are symmetrical and can be used on either side. I wasn’t sure what the two 7/16”-14 holes where at the top of the uprights so I called Superlite. Apparently the new upright is the same as the one used on the GT-R which uses cross bolts for the top billet piece. So what might have been four different upright parts, is one. In addition, the use of a spacer allows a thinner piece of aluminum to be used for the upright which reduces material costs and machining time. This was a smart change.
The pictures below compare the older right rear upright (on left, part# SLC-RR-UR-01R) to the new upright (on right, part# SL-RR-UR-02RL).
Right rear uprights as viewed from inside the chassis; old on left, new on right. The front of the car is to the left.
Right rear uprights as viewed from the wheel; old on left, new on right. The front of the car is to the right. Note that the new upright has the spacer mounted using dowels in the three smaller holes.
Right rear uprights as viewed from the front edge; old on left, new on right. The 1/2” thick spacer is mounted to the new upright which makes the new assemble ~0.2 thicker than the old version. I had drilled and tapped holes for the parking brake bracket when this picture was taken.
Superlite forgot to send me the dowels, so I ordered some from McMaster (part# 90145A541). The first step is to insert the dowels into the uprights (light taps are all that’s needed). As mentioned above, the uprights are symmetrical so you need to insert the dowels into the side that faces the hub/tire. Once that’s done, the uprights are handed. The spacer can then be placed over the dowels and lightly tapped until it’s flush with the upright.
Another benefit to the new version is that it’s easier to drill and tap holes for the parking brake brackets. As can be seen in the pictures above, there is significantly less pocketing in that area than the old version and the middle web is ~0.91” (~23 mm) thick which easily accommodates M10 screws. I used the DRO on the mill to drill the holes, but I used layout dye and a micrometer to prevent another D’oh. Measure five times, drill and tap once. Following the 2x thread diameter rule of thumb for aluminum I drilled the holes 25 mm deep and used a M10-1.5 bottoming tap.