Eric's Build

Follow progress of your fellow builders. Pictures encouraged!
ChrisS
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Re: Eric's Build

Post by ChrisS » 06 Sep 2018, 04:43

Looking good Eric. Casting your own parts is a bit above & beyond for me though ;)

I worry about those upper rear wishbones though. Specifically, how they are going to handle forces acting on the top of the upright.

Midlana1
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Re: Eric's Build

Post by Midlana1 » 06 Sep 2018, 09:25

I can't see enough of the upper rear suspension to comment, but it appears to be different than the plans. If so, be sure to check rear bump-steer to make sure it's not too crazy.

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Re: Eric's Build

Post by ChrisS » 06 Sep 2018, 09:39

I’ve got into trouble before for making observations that I honestly thought could be helpful, so I absolutely accept I could be talking utter bollocks :)

ShadowCat38
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Re: Eric's Build

Post by ShadowCat38 » 06 Sep 2018, 21:37

ChrisS wrote:Looking good Eric. Casting your own parts is a bit above & beyond for me though ;)

I worry about those upper rear wishbones though. Specifically, how they are going to handle forces acting on the top of the upright.
Midlana1 wrote:I can't see enough of the upper rear suspension to comment, but it appears to be different than the plans. If so, be sure to check rear bump-steer to make sure it's not too crazy.
I've run it through its travel, and I couldn't detect much bump steer, but I don't have all the bushings in place around the rod ends, yet, either, so there might be something that needs to get adjusted for.

The layout for the rear suspension is based on the book, only with the inside pivot points moved aft about 8 inches as a block. That makes things look strange with the upper wishbones, so I'm curious to see how they hold up as well. Technically, they should be fine. But since everything is at a significant rearward angle instead of somewhat centered over the axle, forces might play a bit rougher with this shape of triangle. The way this is designed, the lower wishbone seems to have to take most of the energy out of things, but sometimes paper and reality don't match.

Worst case, I get to cut it all off and start over. :lol:

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Re: Eric's Build

Post by ChrisS » 07 Sep 2018, 04:21

I hope my concerns are groundless - I've not done any calculations, just eyeballed it and jumped to a conclusion :) My old Applied Mathematics teacher would set me something like that as a test question I suspect ;) Hah, Mr Barton - not thought about him for 40 years.

ShadowCat38
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Re: Eric's Build

Post by ShadowCat38 » 14 Sep 2018, 07:10

My list of things to get done to become self-driving by December 31st:
  • Brakes - run lines and verify function
  • Electrical - adapt stock donor harness to accommodate the custom build, and mount controllers and protection
  • Cooling - Fabricate radiator mounts, power the fans, run the coolant lines
  • Fuel - buy or build the fuel cell, install the fuel pump, connect the fuel lines
  • Air - ...yeah, this is going to take some thought
Since I have so much to do to meet my goal, I've decided to start prepping the wire harnesses for the car while i'm waiting for the rest of my brake parts to arrive. I'm also very aware that this goal might be a bit overzealous. That's a lot of stuff to get done in essentially 3 months.

That said, brakes are very close to complete.

Cooling is going to be less complex (famous last words) in this build since I'm using rear-mounted radiators, mainly because I'm not making a run to the front of the car and back again. I'll still need to figure out how I want defoggers to work, and I have some ideas, but nothing that can't be added in later.

Fuel will be as easy or as hard as I want to make it for myself. I love Kurt's fuel tank design, but I'm a bit apprehensive about taking on something that potentially catastrophic myself. Buying a cell, while likely more expensive and less likely to take full advantage of the available space, could put my mind at ease a bit. Adding to that my TIG and stainless steel welding skills are largely unexplored and that's the primary source of my apprehension. I could do very well; I could also make a very large and expensive non-functional "piece of art." All that just means I'll probably save that for last.

Air... air. Technically, this is pretty easy. Just bolt the donor filter back up to the engine and go, but that seems like too much of a cop-out. Plus, it won't fit well when the panels are made. I don't want to repeat Kurt's collapsing plastic vacuum, but I also am not sure which way I want to go for air intake. Coming in the sides would be neat, as long as I don't aggressively collect road debris, or at least have some way to let that fall off the filter. I don't know how this is all going to wind up, yet, so as much as I don't know about how I'm going to do the fuel, the air intake is even more so. Usually, when I dive into things like this, pieces start lining up as I actually start working towards something, so this will certainly get better when it becomes a focus.

Electrical is where I'm in my element. I've seen lots of groans in other builds about working on this step, but I've been looking forward to this part. I've spent a few years running diagnostics on harnesses in construction equipment and RVs looking for problems in controllers, security systems, engine connectivity, gauge functionality, etc. Over the past several months during bits of spare time over lunch breaks or while travelling, I've been pouring over the donor FSM schematics and redrawing them to focus on physical layout as opposed to service functionality. This helps me find where wires are routed on the actual harness and add or remove connections as needed with confidence. The engine harness remained entirely unchanged. The harness connecting the drivetrain to the ECM and dashboard was mostly unchanged, just a few circuits modified to remove the unnecessary power steering pressure sensor and separate the A/C support for removal later (although, my brother is trying very hard to convince me to keep A/C...we'll see). Dash and Cabin harnesses have a lot more modification to them since a majority of that part of the car has no equivalent in this build. I'm two days into this, and that's what I start working on next, so I'll be able to get a picture up of the pile of wires left over when that's done.
wiring.jpg
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ChrisS
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Re: Eric's Build

Post by ChrisS » 14 Sep 2018, 11:33

If you retained the book space for the fuel tank, a Lotus Elise/Exige tank is a perfect fit.

Funny enough, I’m looking forward to the wiring too (if not finding space for it all). I guess we always go to what we know. Just short of 40 years of messing with wires means I never really appreciate why others are put off by them.

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Re: Eric's Build

Post by Midlana1 » 14 Sep 2018, 14:46

I'm an electrical engineer by training, so wiring isn't a big deal, but the amount of time it takes to do it well is not lost on me. Like mention somewhere in the book, adding big parts to the car does wonders for a positive mental attitude. When doing the electrical, you have to keep reminding yourself over and over that it's just time, and regardless of what you're working on, it's that much closer to getting done. But yeah, seeing the car look exactly the same for months as dozens of wires were cut and shrink-wrapped did kinda get to me.

ShadowCat38
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Re: Eric's Build

Post by ShadowCat38 » 04 Feb 2019, 13:21

I can't believe I haven't posted here since September.

Ugh. Well, first of all, I even didn't reach my goal of starting the car before the end of 2018, much less seeing it move around under its own power. To be honest, I haven't worked on it much over the last 4 months. If you recall about 18-24 months ago, I began wrapping up key bits of work so that I could relocated (for my job) to a new place 750 miles away. I was counting on that stability being present after all that went down then. Fast-forward to 4 months ago, and the same exact stuff is already happening again here as what happened before the shut-down in my previous location. With the stress and anxiety that came with uncertainty on the job front, I found it hard to focus on this project, much less dump any money into it. It has sucked.

In the next few weeks, maybe I'll try my hand in the aerospace engineering world since working on products for land-vehicles have just not gone my way. We'll see. At the very least, some things have taken place now that has drastically reduced the stress level I've had for this whole time, and I've finally been able to set my mind to something on the car again.

Here's the update to my list:
  • Brakes - Fronts are installed, rears are mostly routed. I need to finish up a couple of brackets, and possibly buy some more hard line.
  • Electrical - Done
  • Cooling - Still the same: Fabricate radiator mounts, power the fans, run the lines
  • Fuel - buy and modify a fuel cell, install the pump, run the lines
  • Air - still needs thought
  • *new* Transmission - Turns out, I need to be able to shift gears. This has been a fun challenge
  • *new* Throttle - I think I was grouping this in with fuel, but it really is completely different Pedal is made and installed, I just need to measure out a cable and order it.
Brakes:
Brake Stuff.jpg
clevises.jpg
Front Brakes in.jpg

Steering:
I know this isn't on the list, but it is really just getting the real parts in now and installing them. The adapter was something I had to make. The only ones I could find to buy were from a guy on another forum, and that offer ended 3-4 years ago. Since I needed some good precision with this part, I tried a new (to me) method called "lost PLA casting." I modeled the back of the stock steering wheel that should mate up to the controls that I have on the steering shaft, then 3-D printed the adapter with some runners. Then, I buried the entire printout in Plaster-of-Paris. Once it set up, I heated it up in the forge to melt/burn out the plastic, then slowly cook the remaining moisture out of the plaster. After that, it is ready for molten aluminum to be poured in. It took a couple of tries to get this right, because plaster likes to get brittle or explode when the moisture is baked out if it gets too hot too fast. But I did get a good run, and bolted it up to the steering shaft after some cleanup.
Steering Adapter.jpg
Throttle:
Similar to above, I modeled the part, 3-D printed it, but used sand casting instead of lost PLA. It came out nicely, and is ready for a cable.
Throttle Pedal 1.jpg
Throttle Pedal 2.jpg

Mazda, it all their wisdom, went against convention when they created the G5M transverse transmission used with Ford's 2.0L Zetec in the Escort ZX2 model. Rather than use a couple of levers to push and pull the x and y position of the shifting mechanisms with cables, they used a single "shaft" that could be rotated +10º to -10º degrees, and pushed in or pulled out of the transmission 0.5 inches when aligned with one of the three rotating positions. This shaft was attached to the shifter in the car by a connecting rod, and parallel to a reference connecting rod also attached to a hard point on the transmission. I think this allowed the shifter in the car to move slightly with the torque and vibration of the engine to prevent popping out of gear during a lot of engine movement.

In any case, this "shaft" is located on the aft of the transmission. While that isn't a problem if you are behind the transmission during operation, it is a significant challenge when you're in front of it. I've seen some custom builds done by others that can make use of a connecting rod with this type of operation behind the driver, but it looked too easy to get completely wrong. Plus, having a connecting rod that needed to rotate that far back behind me means a long run of moving parts that could cause issues with other systems, such as fuel, coolant, exhaust, and possibly the ability to withstand drivetrain movement within the mounts without popping out of gear.

The setup needed to be converted to cables. Since I didn't have anything to attach the cables to to make this work, I needed to create my own adapter carriage. Thus, this was designed:

It is just as complicated as it looks, but it is small and should hold up nicely to the stresses involved with shifting, as well as the challenges of reliable operation in an engine bay exposed to some elements of road travel. The plus side is it lets me use a modified version of Kurt's homemade shifter design. Since the connecting rod forced the transmission to shift opposite of the movement of the shifter, if I wanted to retain the same shift layout that is typical, I needed to reverse the "y" direction of the shifting mechanism from Kurt's design. I'm extending the shaft further down below the rotating block and attaching the "y" cable onto the lower side of the hinge point. To do this, I needed to remove more of the box tube, and use a thicker material to make up for the loss of rigidity.

I'm playing with recording video of the work, now, as well. I might start putting together a YouTube channel if I can keep the workload of that task under control (...distractions :roll: ). It might prove to be too much to take on without sacrificing significantly in other areas. This custom shifter project will be the first one I record, and I'll edit it together properly when the shifter is complete.

Here's what I have modelled up to build:
Shift Adapter.JPG
Shift Adapter 2.JPG
Shifter 1.JPG
Shifter 2.JPG
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ShadowCat38
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Re: Eric's Build

Post by ShadowCat38 » 04 Feb 2019, 13:28

The 10-attachment limit got me. Here's the parts of that shifter design that I've built so far...
transmission bracket 1.jpg
transmission bracket 2.jpg
Shifter Base.jpg
Small Bits.jpg

More parts are in the mail.
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