Ian Hooper's RX7 Conversion

Post by **zeva** » Sat, 07 Apr 2012, 18:56

Hi all,

Well now that I actually have some progress to report, I've decided it's time to introduce my new EV conversion project - a 2000 model Mazda RX7 Type RS. It's a very exciting project for me - basically I'm finally getting to build my "dream car"!

In brief: Dual Impulse 9 motors, a Zilla 2K controller, and a 25kWh pack of Headway batteries. 0-100 in around 3.5s (if my BOE calculations are correct).

http://zeva.com.au/Projects/RX7/

Comments or constructive criticism most welcome!

Post by **woody** » Sat, 07 Apr 2012, 19:10

Great car choice - looks fantastic.

Post by **ohmboy** » Sun, 08 Apr 2012, 02:18

Should be one awsome EV.
Look forward to following it's progress.

Post by **BigMouse** » Sun, 08 Apr 2012, 02:48

Very cool! My first conversion was a DC RX7 (though mine was the previous model). Looks like a great start. The headways are becoming pretty popular.

Website · Post by **htial** » Sun, 08 Apr 2012, 02:59

I've considered the same car... ...Also an R33 Skyline... ...But I must get my mechanic skills up before I even think of trying a conversion...

I'm going to be following you closely... ...And I can't tell from your plates if you're in Vic/Melbourne or not... ...Because I'd love to put up my hand and come and help if you ever need it...

Website · Post by **Simon** » Sun, 08 Apr 2012, 07:41

Nice car Ian!
Looking at your website I was surprised how much weight you lost on the rear axle! 133kg seems like a lot for fuel tank, exhaust and spare wheel?

Post by **zeva** » Sun, 08 Apr 2012, 08:37

htial: I'm actually in Perth, but the car came through a NSW compliance workshop on its way to me from Japan, so was first licensed in NSW. I'm just going to relicense it in WA once it's converted.

Simon: Yeah I was pleased with the amount of weight that came out, lots of allowance for the electrics. The engine in the RX7 is significantly behind the front wheels so that would have contributed to the rear axle weight reduction - and also that the 60L fuel tank plus muffler are both behind the rear axle. Was quite impressed with how accurate the reputed 50:50 weight balance was when I first weighed it!

Post by **Nevilleh** » Sun, 08 Apr 2012, 13:15

I'll be interested to see how you manage to fit 25 units of electricity's worth of batteries under that sleek skin!

Website · Post by **htial** » Sun, 08 Apr 2012, 16:47

Oh well... ...If I'm ever over in Perth I'll let you know and come and put in a hard days work...

Post by **photomac** » Sun, 08 Apr 2012, 17:19

Ian - you'll probably have people queuing for copies

and it is a great blog!

Post by **jonescg** » Sun, 08 Apr 2012, 21:07

Ahh Ian! Not headways! Nooooo!

Oh well, they're better than thunderskys at least. You couldn't source enough A123 cells for the job?

Another DC conversion... It's a testament to their reliability eh?

Post by **EV2Go** » Tue, 10 Apr 2012, 04:17

I briefly thought about that conversion (250v 11in instead of twin 9's) but 20k for a donor was more than I was willing to pay. Look forward to the results.

Post by **gholm** » Thu, 12 Apr 2012, 03:27

Damn, Ian, this one will be sweeeeet!
Always liked the car, my business partner buys himself one the other day which got me thinking of the what-ifs in EV terms, and now you've well and truly pulled the trigger!

Twin 9inch too! Soo much torque. Top speed might be limited, but I don't suspect that's supposed to be the fun part.

Got my chair, filled my popcorn and will definitely be keeping an eye on this project.

Post by **Thalass** » Wed, 30 May 2012, 04:09

That is going to be one amazing car!

Post by **zeva** » Wed, 27 Jun 2012, 00:01

Despite a plethora of other distractions getting in the way of my RX7 conversion, there has been some progress happening

I've posted an update to the blog - basically details of the motor cradle fabrication. A couple of the pics from the blog below too.

http://zeva.com.au/Projects/RX7/?section=drivetrain

I'll hopefully also write up the progress on the battery boxes later today. I was planning to write up complete portions of the conversion as I finish them, but might instead do incremental updates (so they will come more regularly from now on!)

Test fitting the two motors and coupler in their cradle

Test fitting complete motor cradle in the engine bay

Post by **zeva** » Tue, 17 Jul 2012, 01:46

I've just posted another update to the blog, mostly starting about halfway down the Battery page (http://zeva.com.au/Projects/RX7/?section=batteryPacks) plus a bit of new content in Drivetrain too. I also started the Auxiliaries section (for vacuum pump, heating, 12V battery etc). In summary:

- EV Works did the motor coupler for me.. so it's almost time to get the motors in the car.
- I'm about halfway through assembling the Headway cell arrays
- I did the A/C compressor bracket and attachment to the motor frame
- Vacuum pump is installed and plumbed up
- Built a little 12V 20Ah lithium battery to replace the big, heavy lead acid aux battery.

There are a couple of dozen new pics on the blog, but here's a selection:

Motor coupler from EV Works

Unpacking lots of Headway cells

Test fitting one cell array in the rear battery box

Vacuum pump installation

Test-fitting the A/C compressor bracket

Assembly of a 12V aux lithium battery in progress

Post by **woody** » Tue, 17 Jul 2012, 17:09

"By law, all cars in Australia need a source of heat for the purpose of demisting the front windscreen." - I think you are mistaken:

ADR15 applies from 1971 (for passenger cars, later for others) and doesn't mention a heater.

Cooling air con should be able to demist the windscreen by virtue of the fact that aircon dries the air.

It's my understanding that a few cars have passed engineering using just A/C for demisting, you should check with your engineer if he will allow it.

The ADR specifically mentions 1500rpm in neutral which may be a problem.

Travel (12V) hair dryer may be a solution?

Post by **zeva** » Tue, 17 Jul 2012, 23:10

According to NCOP14 it's in ADR 16.42: "The removal of the engine will necessitate the provision of an alternative source of heat for demisting air (or, perhaps, alternative demisting arrangements). A performance comparable to the original demisting system must be maintained"

Interesting that A/C might be an acceptable alternative, that would certainly be easy. I also wonder if a couple of cheap eBay car heaters sitting on the dash would be sufficient.

Here in Perth it rarely gets cold enough to really need a heater in the car, but being able to demist is useful sometimes I suppose...

Post by **zeva** » Mon, 13 Aug 2012, 08:14

Some more progress to report on the RX7 - feels like it's getting pretty close to being drivable now! (But still plenty of work to do...) Here are quick links to the new parts of the blog on my website for full details:

OIl Circulation for Tailshaft Bushing

Front battery box

All of the new Electrical section

And a few pictorial highlights:

Gears to circulate oil in gearbox section

Completed motor assembly before installation

The motors are in, the drivetrain is complete!

Rear battery box and power wiring complete

Post by **PlanB** » Mon, 13 Aug 2012, 21:38

Hi Ian. I note your RX7 supplier has a 2001 model listed for $19k. Is that typical for a Mazda rotary of that vintage imported from Japan? Also I just wanted to say beautiful workmanship & excellent documentation on your blog. Would sure be nice to get you over to the AC side of the force. Do you get many people arriving on your doorstep clutching parts, car & cheque book? If not, can I be the first?

Post by **zeva** » Tue, 14 Aug 2012, 00:13

Mine was actually somewhat more expensive than $19K due to being a Type RS, a higher auction grade (4.5), and lower K's. But $19K for a Type RB seems OK. It's probably pretty cheap because it's right up near the 100,000km mark, which if often considered "engine rebuild time" for rotaries - not that we'd care much!

There are a lot of cheap RX7s available in Australia but from what I've seen the *majority* have accident history, and/or are in rough condition. In Japan, any accident history must be declared at time of sale (auction grade R) which greatly reduces their value - the Japanese are a bit superstitious about cars which have been in accidents. So Australian car dealers snap them up cheap to sell in our market - where they don't have to tell you about any accident history, and you have to actually get the cars inspected to find out. That's the main reason I ended up importing, rather than just trying to get something cheap.

I try not to take sides in the AC / DC wars

I think it's fair to say AC is better but DC is cheaper. I had originally hoped to go AC for the RX7 but just couldn't find anything which could remotely compete bang-for-buck with a Z2K controller + 2x 9" DC motors.

It's such a huge job doing a whole conversion, especially one-offs, I fear I would go mad doing it for a living! I'm more interested in trying to help others do their own conversions, through information/documentation, providing widgets like the EVMS/FGD - and occasionally getting my hands dirty to help with some tricky jobs. I'd certainly make an exception for anyone interested to try breaking some records though. In these early years of the "EV renaissance", projects which push the boundaries are worth their weight in gold - both for advancing the state of the art, and raising awareness.

Post by **jonescg** » Tue, 14 Aug 2012, 00:59

I too thought about doing the CRX conversion on a budget, but then I thought, as an ambassador to the EV movement, I really ought to put the best ingredients into the car rather than a compromise. It's a tough call though - spending >$50,000 on a conversion. I rest easier knowing that the $2500 car I bought to convert will get a second lease on life, and should be good for at least another 10 years. I also feel good that the same motor and controller from the race bike will go into the car

Hey Ian, did you get along to the UWA open day? I was stuck in the undercroft manning a stall at Plant Biology, but got to have a quick look around between the showers.

Post by **woody** » Tue, 14 Aug 2012, 02:16

Ian - your conversion pages are a great read and a great inspiration. I have enjoyed reading about your work since I found your MX5 halfway through! Keep it up

Post by **PlanB** » Tue, 14 Aug 2012, 19:44

Apart from the not insignificant technical challenges, I find a lot of psychological hurdles in the EV home built genre. Like if I bought a $20k glider would I really have the balls to start dismantling something that works OK for something that might not? Conversely it's crazy to blow ~$40k on a bucket of bolts.
Re the AC/DC debate I figure with the cost of batteries & decent glider the motor/controller cost is not all that great. I take your point about DC being way cheaper Ian but $9k for a Eurodrive/wavesculptor seems in proportion to $30k-$40k worth of car/batteries.

Post by **Johny** » Tue, 14 Aug 2012, 19:52

PlanB wrote:.... I find a lot of psychological hurdles in the EV home built genre..

Amen.