V1 Brian's City Goblin-06/Crate MotorTC #61

[Brian74]

Started on the aluminum work for my front wing today. Cut the lower brackets from a single piece of 1/4" 6061 T-channel. This stuff is very rigid and slightly challenging to cut. It will work well.

Had a vistor this morning; this genius wizard aerospace engineer came by. He looked over my frame and gave me some excellent pointers on increasing torsional rigidity. I will draw up some gussets and stiffeners and have my local shop bend & cut the tubing.

 

[Brian74]

Cut the forward Aluminum mount brackets and welded the forward supports. Good.Night...This front clip is not anywhere close to being square; the aft left bracket was welded crooked at the inside end; also explains why it doesnt want to fit right on the car... I'm not sure how they jig these things up when they are welding them, but its not being jigged in a manner that keeps it true. Its not even heat distortion; its just really bad jigging and attention to detail. I will laterally shim the wing mounts from the forward supports to get the brackets straight. The lower radiator mounts wont fit either where the mounting holes are cut, which makes zero sense because there is no possibility of heat distortion there either... I will either center cut the forward cross brace and weld in a suppport to establish the proper spacing, or move the brackets or just 3D print some offset bushings.

Just aggrivates me, because I am spending as much time jigging, measuring, determining and fixing bad fabrication as I am designing and I just want to get this car done without having to take extra time to fix bad fabrication.

 

[Brian74]

Hard to find time to get in the garage during the work week, so I figured I'd get myself set up with some CAD work to do in my off time during the weekdays.

I want to 3D print ram air intake ducts for both my cold air box and the intercooler radiator. I did a laser scan of both the left and right frame sections. I did the scans with minimal post processing in order to preserve as accurate geometry as possible.

Pulled the scans into my point cloud software and used the recognition software to pick up recognizable features and point references to convert to solids.

Sent that data into CAD as a solid/mesh overlay file and drew in the remaining solid features using the mesh as a reference.

These ducts are going to be a challenge to design because of the complexity of the frame curvature... Still trying to decide whether to go with a multi-planar sketch, or start with a solid and use subtractive methods.

 

[David]

Hard to find time to get in the garage during the work week, so I figured I'd get myself set up with some CAD work to do in my off time during the weekdays.

I want to 3D print ram air intake ducts for both my cold air box and the intercooler radiator. I did a laser scan of both the left and right frame sections. I did the scans with minimal post processing in order to preserve as accurate geometry as possible.

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Pulled the scans into my point cloud software and used the recognition software to pick up recognizable features and point references to convert to solids.

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Sent that data into CAD as a solid/mesh overlay file and drew in the remaining solid features using the mesh as a reference.

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These ducts are going to be a challenge to design because of the complexity of the frame curvature... Still trying to decide whether to go with a multi-planar sketch, or start with a solid and use subtractive methods.

Fucking love it, your going to make me buy a 3d scanner. Was thinking about the EINSTAR VEGA what are you using?

 

[Brian74]

Fucking love it, your going to make me buy a 3d scanner. Was thinking about the EINSTAR VEGA what are you using?

Einstar Einscan HX and Geomagic Essentials software

 

[Rauq]

I thought I had better pics of this somewhere but I've been running this for probably 3 years now. Printed in PETG and skinned in fiberglass. I dialed in my tubing axes and planes with a bunch of test prints, a scan would've been much easier

I unfortunately don't seem to have a great picture of it installed on the car, though.

 

[Brian74]

I thought I had better pics of this somewhere but I've been running this for probably 3 years now. Printed in PETG and skinned in fiberglass. I dialed in my tubing axes and planes with a bunch of test prints, a scan would've been much easier
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I unfortunately don't seem to have a great picture of it installed on the car, though.
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Did it seem to help? Looks similar to the direction I plan to go but haven't started on that side yet.

 

[Rauq]

I’ve been reasonably satisfied with my IATs despite running a twincharged setup. I added the duct at roughly the same time as the turbo, so I don’t have a true apples-to-apples baseline for comparison. The LSJ also doesn’t have a good way to measure temperatures between the supercharger and the intercooler, so a direct post-supercharger/pre-intercooler vs post-intercooler comparison isn’t really quantifiable.

That said, if I were to characterize the temperature rise from pre-supercharger to post-intercooler, and compare the temp rise before and after the duct and turbo install, the before was probably slightly greater than the after. That's probably a combination of the effectiveness of the duct, and greater ∆T at higher air temps.

 

[Brian74]

Well today was exciting. I checked the front clip for squareness and appears to be gtg. I decided to mount the lower aluminum rails to the front clip. I am a little shocked.... My mount holes on both sides came out lining up dead perfect; four 1/4" holes on each side with four 1/4" bolts in each hole, all drilled by hand...didn't need to oversize anything. THAT NEVER HAPPENS, lol...

I clamped everything up to get a good mockup of the front wing. I will get the fwd cowling at the precise height and then laser scan the lower portion and CAD draw up some front cowling brackets. Instead of hinges or dzus fasteners, I think I will go with locking quick release pins.

I am super happy with the looks of the wing. The end caps really set it off. I still need to add the 15 degree bend. I have the lower airfoils 3D printing; which is about an 8 hour print with a .8 nozzle.

 

[Brian74]

Trying to get the frint cowling mount figured out and its sorta kicking my ass... As it sits the cowling is not quite straight so may need to tweak the mounts. I cant go any further on the front spoiler until I get the cowling mounted. I took some measurements and will draw something up in CAD.

I did design and printed the ram air intake which turned out good. I will start designing the drivers side intercooler radiator ram air next.

 

[Brian74]

Pulled the front clip today and cut & welded in gussets and joint brackets for the cowling. I decided to just use pivot bolts, which will allow the cowling to swing forward without fully removing it. I may add in dzus fasteners later on the sides to increase stability of the cowling if needed. Still need to fit the cowling and mark & weld in the upper brackets. Once this is done I can fit & rivet the front spoiler/wing in place & call this task completed.

 

[Brian74]

This morning I started trying to fit the forward cowling mounts and noticed the cowling was very crooked and the forward cowling just would not line up without a fair amount of force. Probably wouldn't be very noticeable without the front spoiler, but with the spoiler it is very obvious because the spoiler butts up against the forward cowling and everything needs to be perfectly square.

Investigating further, I actually found that DF Goblin welded the rear cowling mounts off center; the pax side was 4 1/2" inboard of the A pillar tube and the driver side was 5" inboard. Not sure if it this was a one-off mistake or they jigged and welded all of the frames like this. Unfortunately, I originally used their mounts as a reference points to line up my own hood pin mounts, so my hood pin mounts are also now misaligned.

I re-clamped the cowling to the aft mounts using some shimming and with a few careful adjustments I was able to finally get the cowling positioned nice and square.

After some measurements, I found that my aft cowling pins need to be moved to the right by ~3/8". I decided to trim my old pin brackets and add an additional L bracket and flat plate, which will allow me to move the pins over to the right where I need them.

I will 3D print a mockup hood pin body that has a through hole, so I can center punch mark the new pin position. Then I can tack weld the new mounts in place and drill the new hood pin mounts.

Aggrivating as hell day, but suitable fix.

 

[Brian74]

Brought the hood bracket misalignment issue up to DF and they verified it and are willing to help remedy things on their end. I have always appreciated DF for their customer service and always being willing to try and help and correct issues.

Ground down one of my old mounts to prep for the new mount. I am on a 2nd iteration design on the hood pin mount tabs, trying to get the geometry perfect. I want to have the pins at an exact 90 degree angle, so any height adjustment on the pins doesn't affect lateral or longitudinal fit.

The hood cowling could be way off and nobody would probably ever notice... But once you mount a custom front wing that is designed to fit flush to the forward cowling lip, things need to be square.

I'll cut and weld up these new mounts and hopefully get this cowling squared away. Looking forward to finishing the front wing.

 

[Brian74]

Played with a few trial/error hood mount designs. The problem is designing a clampable mount that will stay put so I can index the hood pin mounting hole properly squared up.

Iteration 3 is a mount with wider brackets and a squared up bent tab that allows the mount to be clamped in place and moved to adjust the angle as needed.

I did the CAD design based on the popular 2 1/2" metal stock width which negated the need for extra cutting. Took less than an hour and an angle grinder/ die grinder to cut the parts.

I took a 1" stock piece and bent it ~30 degrees in the press to conform to the tube and added it in as a flush mounting point.

These mounts can now actually be clamped to the crosstube while I fit the hood. Once I get them right I will drill the holes fot the mount pins, and then weld them in.

With the XY plane of the hood centered up I can then focus on designing the fwd hood pivot mounts.

Progress.

 

[Brian74]

Finished grinding the old brackets off and removed all evidence of their previous existance. I cleaned up the new brackets, lined them up, and clamped them at 12 degrees fwd low to match the hood cowling angle. Marked the pins and drilled the pin mount holes. Got the hood back on and it fits nice and square now up front. I will start working on the fwd hood pivot mounts next. I think I will also need to add in some sort of side stabilizer mounts to the hood cowling for support; not yet sure how I will skin that cat.

 

[Desert Sasqwatch]

Brian, you may want to add button latches to the sides of the hood for stability. I added these to my hood and it is very rigid in its location when the top and sides are latched.

 

[Brian74]

Brian, you may want to add button latches to the sides of the hood for stability. I added these to my hood and it is very rigid in its location when the top and sides are latched.
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I was hoping you would chime in. That looks like a viable solutuon. I just wish those button latches weren't so **** expensive, lol. They sure are proud of them.

 

[Brian74]

Ok... Progress!

I spent my evenings after work this week finding the best method of approach to get this cowling squared up. It is much harder than it seems when you dont have good solid reference points. I ended up deciding to tackle the front mounts first, as they are the most critical for being square for my front wing to line up. That ended up being the ticket.

I designed the front brackets for the cowling by basically cutting and eyeing out what I thought would work. I wanted to be able to pivot the hood forward. I decided to use bronze bushings at the hinge joint to prevent wear and rubbing. I bought slightly over-lengh bushings and then compressed them into chamfered holes. I welded up some clampable mounts and mocked them up. I figured if the height was off, I'd just re-cut and weld new mounts. These actually fit and worked perfectly first time go. I bolted them in and then found it was now WAY easier to get the aft pins aligned.

I should have never drilled my new aft pin mounts. I ended up removing them and welding the previous holes I drilled up. I then reinstalled them and ensured they were laterally square. I installed the cowling using my new front mount. With the cowling in place I used 3D printed jigs to mark the new spots for the pins. The punch marks were much better centered on the mounts this time. I drilled & tapped the new holes and reinstalled.

My cowling is now mounted solidly and square. Front height is perfect with zero interference. Words cannot explain the satisfaction I feel seeing this **** cowling FINALLY mounted squarely on the car. This was kicking my ass for two weeks. Its crazy some of the stuff that seems difficult is seamless, and what seems simple turns into a 2 week project.

Its finally time to move on to the front wing, which I have been looking way forward to. The design is already done and entire process planned; just a lot of precision bending/ drilling / countersinking / riveting left on the wing.

Due to my aft front wing supports, it looks like the cooling hose bend off the fwd tubes may be a bit too sharp. I think I am going to run 16AN cooling hose through the tubes, this way I can put elbows at the end and make it fit perfectly. I already dont like the design nor the idea of pulling a narrow tolerance rubber hose through the frame rails to begin with. I read up on past forum stuff and it appears that 16AN hose has already been done without any mentioned issues. Oh so much more fun... Looking for custom fluid fittings online...

 

[Brian74]

Not much done today.... I wanted to start working on the front spoiler but the lower radiator cooling line fit was bothering me. I am severely baffled why DF didnt just go with 1 3/4 OD DOM tubing on the lower frame tube; which would have added strength and an inner diameter that would have negated that entire ridiculous hose pulling process, as well as offered numerous hose options.

I decided to go with 16AN hose. I ground away some of the inside fwd tubing to allow more bend. I am hoping I can fit a 60 degree fitting and a 16AN to 1 1/4" adaptor and remain flush enough with the radiator return outlet.

Went to a local speed shop and bought a 2' sample of 16AN hose for mockup and measured/ took pics of their fittings.

Got home and test fitted the hose and looks like I should be able to make it fit as planned.

Ordered the hose and fittings.

 

[Brian74]

So, my original fog lamps were on these custom ball bearing arms I designed that were electromechanically actuated outward from behind the cowling when the fog lamps were turned on. This concealed them nicely behind the cowling when they were off, and was a really neat custom touch.

The problem now is with the new front spoiler, it completely blocks the fog lamps now at the height and location they were at.

Dammit... Time to do some brainstorming.

With the way I have repositioned the cowling on my new forward mounts, I have found that there is a perfectly sized pocket down low below the spoiler inside the cowling where I can relocate the lights, with mounts that attach to my rear spoiler support gussets. I designed and welded up some mounts and relocated the fog lights there. I did a fair amount of angle checking to get everything flush. So much better now because they are lower, still well out of view, and I've removed some complexity. It ended up working out very well. The lights also sit just high enough above the rails that they are protected from speed bumps and curbs.

With all that over with, its time to start riveting the front spoiler together.