Luke's 2001 NB MX-5

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necrogt4
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Luke's 2001 NB MX-5

Post by necrogt4 »

So I started collecting parts a couple of years ago while saving for a house so things we're pretty slow going. I've bought the house and have a lot of time at home these days so things are moving along much much quicker.

The first few posts will be a bit of a catch up, here's the short and curly of the project so far...
  • Vehicle: 2001 NB MX-5 (LSD, 6-speed manual, 1090KG wet).
  • Motor: Netgain HyPer 9 120v.
  • Gearbox: Retained standard 6-speed with a 4.1kg aluminium flywheel and Exedy cushion button ~400nm clutch.
  • Batteries: 115V @200A 120x 3.7V 50A CATL NCM cells ~200Wh/Kg (maybe, I've also considered Tesla modules and LG Chem pouch cells. Currently testing a batch of the CATL cells).
  • BMS: Batrium (not yet purchased).
  • Charger: TC 6.6kw (not yet purchased).
  • DC/DC Converter: Undecided, the TC charger has DC out but very very low current. Not enough to run much but I'm not sure of load yet either.
  • Cooling: Custom designed (by me) chill plates for battery packs.
The aim of the project is to come in at spot on 1,000kg. Which with the help of lighter seats, brakes, flywheel, wheels, less cooling etc should be achievable. Weight is a consideration with each and every change. I've actually weighed every single item that's come out and that's going in to have a fairly accurate measure of final weight.

Along with the standard EV components I've also replaced all of the wear components: polyurethane bushings, tie rod ends, steering ball joints, bearings, sway bar ends links, sway bars (at some point soon), tyres once running and brakes (willwood calipers, discs, brake lines all round). While the power increase won't be substantial from the ICE powerplant, sharpening up the handling to go along with the smooth power delivery should make for a much more enjoyable drive. This conversion is about efficiency and fun rather than outright power. Better use of what power you have in all circumstances.

A couple of photos of just after I purchased the car:
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And another just before I moved, none of the ICE hardware in the chassis.
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Last edited by necrogt4 on Fri, 04 Sep 2020, 10:41, edited 2 times in total.
necrogt4
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Re: Luke's 2001 NB MX-5

Post by necrogt4 »

As I was saving for a house and the HyPer 9 motor I decided to get busy with convenience electronics and teach myself how to use Arduino. I'm not a fan of manually holding power window buttons down, it's a thing. So now I don't have to...

A couple of four relay boards 12V -> 5V signals into the Arduino with 5V -> 12V signals out of the Arduino. Powered by a USB charger. I also have two hall effect current sensors (one for each power window motor).

The power window switches in the MX-5 are super simple and run the full current from the battery, through the switch and into the motor. So the Arduino is spliced into these wires and holds the circuit open via relays until a present time is reached (fail safe), the button is pressed again or the current sensor detects a current spike (i.e. the window has reached top/bottom).

My old workbench (now retired, I'll post a workbench build later):
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The big mess of wires and circuits that make it all work:
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And a video of it all working, it looks boring and that's the point. It just works like any other car does and nothing else, exactly how you'd expect an OEM feature.
https://drive.google.com/file/d/1ANTsEA ... sp=sharing
necrogt4
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Re: Luke's 2001 NB MX-5

Post by necrogt4 »

I also mentioned lighter seats, there's two reasons for this.
  • I'm too tall for the standard seats
  • These seats are half the weight and look twice as good (IMO).
Image
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brendon_m
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Re: Luke's 2001 NB MX-5

Post by brendon_m »

I assume the custom battery boxes are going underneath where the fuel tank was? Any going in the boot or under the bonnet?
necrogt4
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Re: Luke's 2001 NB MX-5

Post by necrogt4 »

There will be a large battery box in the engine bay that sits behind the front axle that holds 80 cells and another smaller box in the fuel tank cavity that will hold a further 40 cells, the charger, contactor, fuses and DC/DC converter.

The fuel tank cavity (see below) is pretty small. One of the reasons I'm not looking at Tesla modules anymore is I would have had to cut an opening into this cavity which would have meant a chassis rigidity test (~$2k).

There will be no batteries going into the boot. Except maybe the 12v replacement battery (made from the same cells, or LTO possibly) in the original location behind the drivers side rear wheel in the space between the chassis rail and body. Which to be honest seems like a terrible place for a battery. I'll try to squeeze this into the fuel tank cavity if I can. Anything behind the rear wheels makes a noticeable negative impact to handling (even groceries!) so I've taken the spare wheel and jack out.

This is the front of the cavity can be seen here, it's normally covered with a few panels that adds a bit of extra strength and carpet.
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Behind, that cutout on the left is where the fuel tank filler neck used to go. Perfect to run the charge cables from the original fuel tank inlet.
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Underneath:
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CZal
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Re: Luke's 2001 NB MX-5

Post by CZal »

Nice looking car Luke!
necrogt4
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Re: Luke's 2001 NB MX-5

Post by necrogt4 »

CZal wrote: Wed, 09 Sep 2020, 18:01 Nice looking car Luke!
Thanks! It'll look even better once it's moving under it's own electricity...
necrogt4
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Re: Luke's 2001 NB MX-5

Post by necrogt4 »

I decided to get serious about tools and workspace a bit over a year ago now and upgraded from my Ikea kitchen bench to a set of cheap Ebay shelves and some Bunnings supplies. I wanted something standing height that would have everything I needed within arms length.

So from this:
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To:
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A blank canvas for tool hanging:
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And more recently the addition of a workshop vice and 4x 27 litre drawers. Now my only wish is that it was all bigger 😅
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All up I think it's cost about $450 (no way I could buy an off the shelf bench for that much) which includes:
  • $85 for the bench
  • $27 for the particle board top
  • $29 Pegboard
  • $16 Pegboard backing support
  • ~$30 Paint and fixings
  • ~$30 Pegboard pegs and zip ties
  • $40 for a surge protected 8 outlet powerboard with individual switches
  • $64 for an adjustable monitor arm 20kg capacity
  • $30 castor wheels with locks
  • $20 3000 Lumen florescent light
  • $15 Shelf railings (C channel aluminium bars) + screws
  • $48 4x 27lt Sistema tubs for shelves
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