Front Suspension Fit, Video Update #2

Video Update:

For those of you who prefer to read I’ll be covering:

  1. The challenge of trying to save money on parts
  2. Distractions from the project
  3. Front suspension fit considerations

1) Parts:

I’m still working on the initial phase of getting the Model S running without error codes before moving parts to the Vanagon.

It feels a bit slow, but progress is being made. I’m expecting a used steering rack from a wrecked Land Rover Evoque to arrive soon. DHL got it earlier this week in the UK and it’s headed to Oregon. If it all works out then the $700 plus time invested will pay off. I’m hopeful that the Land Rover aluminum housing will work with the Tesla electronics parts, if not then that was just a learning experience and I may need to buy a new one after all. 

I’m hoping to find a set of stock 19″ wheels with Michelin tires for a good price. I hear the Michelins have lower rolling resistance and I’m going to need every little bit to get near my target of 200 mile range. Lowell Simmons has helped a lot trying to get a set that I found online in his part of the country, but as of today the seller seems to have disappeared. Buying new parts may cost quite a bit more, but at least the suppliers are reliable. The adventure continues.

Do you have a friend at a Tesla approved body shop? I’m looking for damaged parts that they may be throwing away. I expect to modify these parts on the final conversion and so it seems a waste to buy them new when all I need is to make the electronic systems happy. Parts I no longer need are marked with an *. These are the parts that I think may be helpful:

  • Active louvers, all three. Wiring harness parts for them as well
  • * Left AC condenser and fan. It just needs to hold refrigerant pressure
  • * Left hose, pressure sensor and fan controller for above
  • Coolant radiator
  • Left headlight
  • Left side marker light would be cool too, but not that important

I’m also looking for these parts in good working condition. If you know of anyone parting out a Model S please let me know. I’ve posted pictures of some of these below. (edit: I’ve ordered all these parts new from Tesla)

  • * Left Steering knuckle
  • * Front Air Strut
  • * Lower control arms
  • * Brake line, Height sensor, Wheel speed sensor

If you have any leads on any of these parts, please let me know with a message here.

2) Other Distractions

As much as I’d like to spend all my time on this project, I’ve been working on some other good projects as well.

I designed the Zilla motor controller years ago and I’ve been working on experimental code allowing it to use a wide range of accelerator pedal inputs.

I’ve also been assisting Hai-Yue Han as he works on the Tri Zilla project. It’s all back-burner stuff since we don’t know if it has a business case, but the Tri Zilla has the potential to be a 1000 HP AC drive which is plenty of fun in itself. Initially we plan to run it in the Honda Insight with a GM EV-1 motor as a proof of concept, but someday we may put it in the Stretchla for higher power testing.

3) Front Suspension Layout

Several times I started on this update, and each time I’d feel I’d done so little on the project that soon I’d be measuring the front suspension since that’s as one of the difficult parts.

I intend to use the Tesla suspension and brakes for a number of reasons. I love the adjustable ride height and smooth ride of air suspension, especially on washboard dirt roads. The rated axle weight capacity is 808 lbs (367kg) higher on the Model S. The ventilated brakes and Brembo four piston calipers are huge, and the ABS system is required in order to safely allow regenerative braking.

The front suspension is a challenge since I am trying to optimize ground clearance and reduce aerodynamic drag all while avoiding raising the front seats.  The front seats happen to be located directly over the front suspension on a Vanagon. I’ve been measuring every which way, and when I didn’t like the outcome I’d measure more and more accurately but it’s still a tight fit.

The Tesla front suspension looks like it was designed for excellent handling, light weight and a great ride but it was never intended to fit under the front seats in a VW van. The Tesla seats feel wonderful, but are also about 10mm taller from the mounting rails to the seating position than the VW seats. These things add up.

There are a couple of critical interference points in this mashup. The Tesla tires are almost 4″ larger diameter than the Vanagon tires and that puts an absolute limit on how low the VW body can sit since the top of the larger tire will rub inside the wheel well. The wheel well can’t be raised since it has a seat above it. But the more restrictive limit is that the height of the Tesla Suspension from the bottom of the lower control arm at the pivot (I’m assuming that I’ll make a new subframe) to the lowest clear area for the seat rail. This distance is about 665 mm. Ideally I wish it were closer to 610 mm and the extra 55 mm will have to extend under the car. This will reduce ground clearance while increasing aerodynamic drag. The alternative would mean making suspension pieces to some custom design which seems like a huge project in itself.

In this case I think I’ll accept the compromises and make it fit as best I can. I expect it will increase the frontal area of the van and therefore the air drag by about 5%. I can live with that even if it means I’ll have to perform some minor aerodynamic miracle to reach my range targets. I have friends from the OSU Solar Car Team with Aerodynamic modelling software and it looks like that optimization is going to be more important than ever. We’ll have to see what we can do to improve the efficiency. But most of that can wait until the Stretchla is up and running. I love the fact that the Model S displays energy use in Watt hours per mile, that will make it easy to quickly evaluate the effect of any modifications.

Thanks for following along, knowing that you enjoy hearing about it makes this blog worthwhile. Thanks to Nikki at Transport Evolved, it was fun to be on your show and I love your idea that we could all be wearing “i void warranties” shirts. Extra thanks to those of you who have contributed time and funds to help obtain the needed parts!

Frugal, or just plain cheap?

What will it cost to do this anyway?

Do I hunt for a better deal, or make progress faster? That is often the question with a project like this one.

You may think that money is not an issue for someone who can afford to buy a Tesla, but we all have our limits and this project has been one to push my comfort zone. I suppose that that’s part of what makes it all interesting as well. I find it rather amusing to watch my initial resistance and then my justifications for spending funds along the way. Much of my life I’ve been concerned with money and here I’m strangely driven toward a large optional expenditure. It’s not like I’m concerned about making rent or food budget here, I’m very fortunate in that way these days, but this does involve what I would call considerable sums from what most people would suggest I’d do better to save for retirement.

It all started with getting the Tesla base vehicle. Six months ago when I started this project my budget seemed simple. I’ll buy a totaled Model S for $18K or so (seems about right for a luxury wreck), throw in a few grand to get the essentials running and then it will take much labor but very little cash to merge it with the stretched Vanagon body. Not pocket change, but not bad at all for such a cool EV. Ah grasshopper, you have so much to learn. After losing a couple auctions with my low bidding limit I reconsidered my budget. Had I not justified $30K for a battery pack on the conversion project this replaced? And is not $10K a perfectly reasonable amount for a powerful drivetrain? What about the value of a huge panoramic sunroof? That practically essential tech package? Don’t I need a test bed for high power AC drives in order to further my business? That retirement fund isn’t earning much anyway and besides this is going to be fun! I’ll sell a few vehicles to help with the cash flow and free up some work space as well. Within a few weeks I had talked myself into a $40K bid limit. Not that I’d need that much, no, I’m sure I’ll get one for $30K. Did I mention how I used to teach “Creative Justification 101”? I waited and watched some more. A number of less than ideal auctions went by with issues, no air suspension, the smaller 60 kWh battery, $50K selling prices, those were not for me. After over three months of auction watching my car showed up. The damage was not too bad, it had almost every feature I wanted, lacking only the dual onboard chargers, and best of all the passenger air bags were all intact so the interior was perfect. Very nice! Not only that, the pre bid value closed at only $12,300. It’s not uncommon for the final bid amount to be twice the pre bid, but not often much more than that. I thought long and hard about my bid limits for this car the night before the auction deciding I would go as high as $38,200 but not to my $40K hard limit. If I didn’t get it for that then I’d accept it was “not meant to be”, thereby giving my guardian angels a vote.  Either I have a lesson to learn about expecting a good deal, or my guardian angels have a great sense of humor because the other bidders stopped at $38K and I won it for $38,100. As I watched it bid to $38K I knew I had to mentally let go, and even when I “won” it, I had to wait for the insurance to approve the sale since they had a $40K reserve, but I held tight and still won it. In the end auction fees, broker fees and shipping brought it to $42K.

$42K for a totaled car. What-Had-I-Done!? Prior to this, my most expensive car was a new Prius for about half that, and this one was a severe wreck. I just had to laugh. It started as a nervous laugh but now that the car has been here almost a month I can really laugh about how nutty it seems. Oh well, I reserve the right to do nutty things when I can, I guess it reminds me I’m alive. I’m grateful to have this freedom. The Stretch project in 1998 felt similar. Back then the front half was also the most expensive car I had bought by a factor of two and I promptly cut it up. It feels a bit like I’m trying to cut up my mental blocks. But this is not the end of those.

I think I got over the cost of the donor car. I’m still working on adjusting to the cost of luxury car parts. The steering rack mounting ears were broken in the accident. This is not uncommon in a wreck so you just replace the rack. I’m well accustomed to old Volkswagen prices and I normally pause a bit before I spend a few hundred dollars on a steering rack, but $3066.60 for one? This pause it taking longer.

Now I have a choice, do I buy a new rack or try for some alternative fix? Buying new is quick but costly. Alternatives take more time, carry more risk of lost time and money but can have hidden benefits. As a child I wanted a new go-cart, it was there in the Sears catalog and it would have been so cool! But buying a new go-cart was not an option in my family and so I had plenty of time to ponder alternatives. Eventually I built a much more creative go cart for almost no money and learned how to build things along the way. I’m not vouching for its safety, but I survived and gained valuable skills. I would have preferred the easy path of a new go-cart at the time, but the financial limitations forced me toward an education that my friends from wealthy families missed.

Back to the steering rack. If the Tesla were a few years older I might buy one from a wrecking yard for under $1000, but as of today I have not found a single Model S being sold for parts. A friend suggested having it welded so I took it apart. Now this part was fun, I’d never taken apart a modern EPS rack. If you are as curious as I am about these you can read about them here: It’s the high end Paraxial Servo Unit on page 8 and 9. I didn’t find this document until I had it apart, so I had the joy of discovering the fine brushless motor and belt, the integrated torque sensor and even how to put a few errant balls back in the recirculating ball gear before reading about them. With it apart I was able to take the housing to the finest aluminum welder in the region. He said there was a good chance he could weld it up, but complications such as the proximity of precision surfaces and my desire to run it on a heavy vehicle had me agreeing with him to look into other fixes first and only consider welding as last resort. The rack is made by ZF Lenksystems and with help from friends and Google we’ve found the cast housing may be the same as the one on a 2012 right hand drive Land Rover Evoque. There seem to be more of those in the scrap yards than there are Teslas. There’s one on eBay in the UK for $327, I’m awaiting more details from the seller to see if the housing is the same so I could swap it. Maybe this will work, but I’m warming up my justifications in case it doesn’t.

The steering rack is just the most expensive part. My list of parts to get it rolling comes to $8000.61 and I’m sure I’m missing some things. Many of the smaller parts are clearly worth buying but the air strut at about $1800 has me looking for alternatives as well. Eventually I’ll either find a workaround or get tired of looking for alternatives and just spend the money. I don’t want to wait too long to order parts since I hear Tesla parts sometimes have long lead times.

I wanted to write this post to let you know that I’m still working on it, even if it feels like nothing is happening on the outside. It may take some time to adjust my comfort zone, but with some minor delays the Stretchla will make progress.