Starting to research vintage Mazda conversion. Help appreciated.

[HuffnPuff]

A few months ago I purchased a 1969 Mazda 1500. Fairly rare car, but I like the look of it. My plan is to get it registered on its current petrol engine to ensure it is running to a suitable level and then begin the (expected to be) long process to convert to electric. I’m wondering about motors and range etc, but haven’t done any calcs yet. I love the look of the classic car and understand that due to its lack of bells and whistles should be easier to convert. It’s like this:

I understand direct drive is a little more efficient but I think I’d like to keep the gearbox to keep it a little more original in terms of the drive experience and perhaps give it performance equivalent to a modern hatchback. It will be a town car so won’t need a lot of range (initially at least).

Apparently it is around 1070kg from the factory with a 4spd 1500cc motor.

The main questions would be:
1. What sort of motor specs would I be looking at to get reasonable performance? (Or can you point me to a good resource so I can do the work myself)
2. Aside from no having an engine that need to idle is it possible to drive using a similar technique to an IVE manual car ‘if you want’?

[jonescg]

That looks to be in very good condition! Well done.

Aim for >200 Nm of torque for most of the operating speed.
Aim for enough speed to hit 135 km/h or so. This might be 8000 rpm on the motor.

Would you be seeking to retain the gearbox? I assume you will if it's a rear wheel drive.

[brendon_m]

If you keep the gearbox you can drive it like a normal manual car but you will probably end up just putting it in one gear and leaving it there and driving the car like an auto. With the instant torque of electric motors and the normally wide rpm range you don't really need multiple gears (depending on the size motor etc) but keeping the gearbox is an easy way to get the optimum gear ratio between the motor and wheels without way over sizing the motor for direct drive to the diff or trying to get a custom single speed reduction gearbox.

What sort of budget do you have in mind? Because that might help determine what sort of motor you want /get.

[HuffnPuff]

Thanks. I’d like it to be a low(ish) budget conversion, but don’t want it to be cheap and nasty. The pic isn’t mine, just on off the net. It is in pretty good condition, but the wiring loom is shot, melted wires around the ignition switch and I suspect brittle insulation elsewhere. Otherwise it is in pretty good shape.

Yes, it’s rear wheel drive and I’d like to retain the gearbox/clutch for nostalgia.

In addition I’m no stranger to mechanical work and have dabbled with electrical, including a couple of e-bicycles at present. I’m not an expert in any of these fields, but keen to learn and will have a go. I’d hope to do a lot of a conversion myself. Also hoping to have a running e-car by the time my 14yo gets a licence.

[Richo]

Aim for >200 Nm of torque for most of the operating speed.

60-70s Mazda with 1.5L.
I'd think 200Nm is too much.
You'd bust the box on the first trip.

More like 130-150Nm with the box.
If the gearbox was gone then 350-400Nm.

[jonescg]

200 Nm is my go-to level for a single speed reduction (total reduction of 1:7 or thereabouts). Assuming the motor can spin to 8000 rpm.
I'm thinking about what's a good torque level for 4th gear, so if you have a bigger reduction ratio you can get away with a bit less torque.

[Richo]

A 6-3/4" DC motor would work but be on the low performance side.
An 8"-9" DC motor would be as good or better than original.
You "could" think about getting around without the box with a 9" motor and would probably be the cheapest option.

There is some noob around here that if he got off his arse a hybrid AC motor + controller would be cheaper again...
Doh that's me



Sometimes I see those Fisker Karma motors on flebay.
150kW

[Richo]

single speed reduction (total reduction of 1:7 or thereabouts).

Normal diffs are like 3.8-4.1 : 1.
Where does the rest of the reduction come from?

Hopefully not the 50 year old box that only did 115Nm when new.

[jonescg]

I'm just going on a generic ~1500 kg car like a Leaf with a top speed of 140 km/h and 0-100 km/h time of 10 seconds. I believe the first generation Leaf had 80 kW and 250 Nm?

[Richo]

I’m wondering about motors and range etc, but haven’t done any calcs yet.

http://www.evmotors.com.au/products/appguide.html
https://www.evworks.com.au/netgain-impu ... le-for-veh
https://www.evworks.com.au/zeva-mc600sp ... controller

Pack size ~190Wh/km (including 80% DOD)
Most of the DC system are 120-144V.
So 190 x (range) km / 144 = Ah of battery

2. Aside from no having an engine that need to idle is it possible to drive using a similar technique to an IVE manual car ‘if you want’?

Yes it will drive the same.
The issues are if you go clutchless it may not easily change gears as the electric motors freely spin and take a while to match RPM.
The upside is there is more torque from standstill so you could just leave it in 2nd or 3rd if you can't be f'd.

[HuffnPuff]

I’m wondering about motors and range etc, but haven’t done any calcs yet.

http://www.evmotors.com.au/products/appguide.html
https://www.evworks.com.au/netgain-impu ... le-for-veh
https://www.evworks.com.au/zeva-mc600sp ... controller

Pack size ~190Wh/km (including 80% DOD)
Most of the DC system are 120-144V.
So 190 x (range) km / 144 = Ah of battery

2. Aside from no having an engine that need to idle is it possible to drive using a similar technique to an IVE manual car ‘if you want’?

Yes it will drive the same.
The issues are if you go clutchless it may not easily change gears as the electric motors freely spin and take a while to match RPM.
The upside is there is more torque from standstill so you could just leave it in 2nd or 3rd if you can't be f'd.

Thanks. Will check out those links.
I think I’d leave the clutch there. Yes, it’s extra stuff an electric car doesn’t need, but it’s pet of the old car experience. I like the idea of being able to just start and stop without it though, especially for in traffic.

[T1 Terry]

I had the "high performance" 1500 SS model of this vintage as one of my first cars. Couldn't keep clutches in it if I drove it hard, the gearbox was never a problem though. You could get away with a brass button or ceramic clutch to handle the torque of the electric motor, but the original driving experience isn't there when using these clutch materials, the clutch take up is savage.

T1 Terry

[jonescg]

And the clutch in a conversion is largely to make upshifting, and in particular, downshifting a bit smoother.

[T1 Terry]

And the clutch in a conversion is largely to make upshifting, and in particular, downshifting a bit smoother.

Understand that part, but if the clutch wouldn't hold the torque of the mighty 1500cc twin carb ICE engine, it sure wouldn't couple up a high torque electric motor. The grip the brass button clutch achieves is by sort of welding the brass to the cast iron flywheel, so clutch release requires actually breaking that weld. Slipping the clutch just doesn't happen and if tried the shudders are savage enough to twist off a tailshaft. I've never actually driven a vehicle with a ceramic clutch so I can't say from personal experience just how they feel, but I've been told it is almost instant take up, certainly not the nice smooth launch off the lights when taking mum shopping or the kids to school

T1 Terry

[jonescg]

"Digital clutches" as @MDK described his MX5's race clutch.

[HuffnPuff]

I had the "high performance" 1500 SS model of this vintage as one of my first cars. Couldn't keep clutches in it if I drove it hard, the gearbox was never a problem though. You could get away with a brass button or ceramic clutch to handle the torque of the electric motor, but the original driving experience isn't there when using these clutch materials, the clutch take up is savage.

T1 Terry

That’s good to know, I guess the standard clutch would be ok for a while and then upgrade as necessary to a more heavy duty clutch.

As for motors, the links above have been useful, but is AC not a better system because it is easier to get regen happening, Of course along with a premium price?

[T1 Terry]

"Digital clutches" as @MDK described his MX5's race clutch.

Do you have a link Chris? I can see rpm matching between gearbox input shaft/motor speed to the required gear ratio much like the manual gear select in the electric buses, but how would you go about programming that into a gear select position switch, wouldn't you need the whole shift to be controlled by the same system to ensure the time was right?
A converter-less auto would be a better option with a manual shift upgrade to the auto, or just a very low stall point torque converter to make it fully auto shift with ultra smooth take off.

T1 Terry

[jonescg]

Matt's MX5 was an ICE car, but a race clutch with heaps of grab and virtually no slip is pretty standard fare.

In the case of the Prelude I put a race-y clutch in. Not the most grippy, but most of the way there. Again - purely for changing gears, as it will take off in third or fourth just fine.

[4Springs]

As for motors, the links above have been useful, but is AC not a better system because it is easier to get regen happening, Of course along with a premium price?

If you want regen you want AC.
Do you want regen though? Depends on your roads and driving style. If you have lots of hills then you want regen. If you mainly drive on the flat, but love to drive flat-out, then you want regen.
Drive around like you normally do, and take note of when you use the brake. If you hardly ever use the brake (including the engine brake) then you'll hardly ever use regen, so it would be a waste of money getting an AC motor just for the regen.

Regen will give you back (perhaps) a third of the energy of the vehicle's motion. So it is more efficient to accelerate-coast than to accelerate-accelerate-regen. Efficiency is not everyone's goal though of course!

In our case we have a DC conversion (without regen) and an Outlander hybrid (with regen). We live in the country, so we have relatively long stretches of road, with few hills. We don't stop much - there are zero stop lights and two T junctions on the way to work. If I drive the Outlander I normally turn off the regen so I can coast easily.

[HuffnPuff]

If you mainly drive on the flat, but love to drive flat-out, then you want regen... Efficiency is not everyone's goal though of course!

I guess id fall into the ‘enthusiastic’ driver category, especially if the EV torque is as addictive as everyone says. I’d also be mostly driving in suburban traffic with a few hills and plenty of stop start.

Assuming the energy is cheap and the range is in excess of my daily needs I’m sure efficiency won’t be priority one!

[T1 Terry]

The regen in my PHEV Prius was rather expensive a few mths back. It appears the battery reached max capacity on the long run down the hill into Adelaide some where in the 90km/h section and I coped a "flash for cash" before I realised it had run away and slowed it up with the foot brake. $450 something and the last of my points, bugga. The problem with the Prius is it only regens to the traction pack and that is only 6Ah I think, ( 1.6kWh) I need to set up something to dump back into the 40Ah pack so it can store all the regen.
You need enough capacity in the battery to be able to accept the regen, great thing when it's working and very useful when doing the rally driver thing on the windy roads.

T1 Terry

[Richo]

..is AC not a better system because it is easier to get regen happening, Of course along with a premium price?

DC motor + controller $4,300
AC motor + controller $6,600

AC is superior in pretty much every way except price...