[PeterG]

I've been tinkering away on converting a low mileage Toyota IQ (2012, 16k on the clock, 1020kg after conversion) with a Hyper9 kit from EV West and a 30kw battery pack.

I've made some design decisions that are bound to raise a few eyebrows. The big one is to retain the CVT gearbox including the torque converter! The next is to keep the alternator, AC unit and power steering 😊 Do these design decisions work? “Hell yes!” the car goes like a cut cat (off public roads of course!), as it hasn’t been certified yet. The CVT keeps the Hyper9 in mid rpms while applying smooth, buttery power to the front wheels. That’s not to say that it's tame, if I pull on the hand break on a hit the throttle it will spin the front wheels or drag it’s arse along the tarmac 😊.

The big secret with retaining the CVT is to spoof as much of the original engine sensors as possible and to use the blended Torque and Speed setting in the X1 controller to apply smooth and controlled power and to idle the motor at about 900rpm when the car is stationary. This approach provides oil pressure for the CVT and powers the alternator so that the electric steering remains active. No need for a DC to DC converter! Also no need for extra micro controllers and custome software to make it work.

I don’t have the range and top speed info as the car needs to pass certification before I can take it on longer road trips. I’m keen to hear what the community thinks of my project and the design decisions I’ve made. Cheers Peter

 

[VintageVolts]

Nice! I like how every EV conversion is unique, this looks ideal for nipping around in the city

 

[Electric Land Cruiser]

Very interesting conversion. I'd be interested to see more about the mating to the CVT. Never seen that done before. I guess it makes sense and should work well. For all the faults of a CVT at least they are efficient. Running the alternator and "idling" the motor while stopped are two thing that are going to draw a bunch of gasps and guffaws from the usual crowd but it will be interesting to see how your range/efficiency and everything works out once you get it certified.

I rented a gas 5-speed version of that I think when I visited NZ. Perfect little car for blasting around all those twisty roads! I like the red color too.

 

[remy_martian]

Seriously? Range and efficiency affected by an alternator and idling a motor under no load other than a transmission pump? 🤦‍♂️

@OP: Nice & clean conversion. Everything seems done right and in proportion to the car. Did you buy or build that coolant bottle?

You'll hopefully be pushing 200 mile range by having had the design/build discipline of keeping the weight below a tonne.

-One of "the usual crowd"

 

[PeterG]

Very interesting conversion. I'd be interested to see more about the mating to the CVT. Never seen that done before. I guess it makes sense and should work well. For all the faults of a CVT at least they are efficient. Running the alternator and "idling" the motor while stopped are two thing that are going to draw a bunch of gasps and guffaws from the usual crowd but it will be interesting to see how your range/efficiency and everything works out once you get it certified.

I rented a gas 5-speed version of that I think when I visited NZ. Perfect little car for blasting around all those twisty roads! I like the red color too.

Thanks for the nice reply, here are some photos of the adapter plate and support frame required to mount the front right axle support bearing. Note that the cvt adapter plate is made up of to pieces bolted together with high tensile cap screws. Cheers

 

[PeterG]

Seriously? Range and efficiency affected by an alternator and idling a motor under no load other than a transmission pump? 🤦‍♂️

@OP: Nice & clean conversion. Everything seems done right and in proportion to the car. Did you buy or build that coolant bottle?

You'll hopefully be pushing 200 mile range by having had the design/build discipline of keeping the weight below a tonne.

-One of "the usual crowd"

Hi Remy, thanks for the reply, search for "Universal 1L Alloy Aluminium Engine Oil Catch Can Breather Tank Radiator Overflow Tank " on AliExpress, very inexpensive, but well made. The alternator in an IQ is tiny but puts out a huge current when required for the big ticket loads like headlamps and electric steering, to buy a reliable DC-DC convertor is just another cost, also the ac compressor is also driven of the Hyper9 rear motor shaft, there is not much room in an IQ so I had to integrate them both into the Hyper9 motor support mounting. I've just finished rechecking the weight distribution or the IQ after conversion and adding the tool kit and jack, I'm very pleased with the results. The curb weight is now 1050kg, up a little from 1020kg, it's ICE curb weight was 880kg with a terrible front to back ratio (60:40). Now the IQ has a front to back ratio of (51:49), much better . Cheers Peter P.S. sorry for the long reply.

 

[Duncan]

If you get it certified in time then you will be welcome at out 1/8th mile drags in Gore on the 19th Feb

 

[PeterG]

Hi Duncan, thanks for the invite, maybe next year. Is is this an EV thing or is it all classes? Cheers Peter

 

[Duncan]

Hi Duncan, thanks for the invite, maybe next year. Is is this an EV thing or is it all classes? Cheers Peter

Its anything road legal - and some non road legal things - the cost of putting events on is going up - so I can't promise that we will have the event in 2024
I'm normally the fastest EV although I had the wrong tyres two years ago and a Porsche Hybrid V8 thing beat me by 6 hundreds of a second

 

[remy_martian]

Hey Peter,

If it's not a lot of trouble, would you mind pulling a tape to get the overall lxwxh measurements of that catch can when you get a chance? Within 5cm is close enough; don't need super accurate.

Might be a fun way to waste time in my welding class for a day or two 🤓

 

[PeterG]

Here you go, the full dimensions are available on AliExpress - https://www.aliexpress.com/item/33000305016.html

 

[remy_martian]

I can't even buy the screwon cap and its bung for that much 😂

 

[brian_]

... For all the faults of a CVT at least they are efficient. ...

Actually, they're not efficient, compared to conventional alternatives. Mechanical (traction drive) CVTs have lower efficiency than any gear transmission, and the torque converter added to the front of it to prevent engine stalling is - like any torque converter - lousy until it is bypassed by a lockup clutch.

The desirable efficiency of a complete powertrain including a mechanical CVT results from the CVT keeping the engine at a good speed for efficiency (hopefully more than making up for lower transmission efficiency), which is much less of a concern with an electric motor than it would be with an internal combustion engine.

 

[brian_]

I've just finished rechecking the weight distribution or the IQ after conversion and adding the tool kit and jack, I'm very pleased with the results. The curb weight is now 1050kg, up a little from 1020kg, it's ICE curb weight was 880kg with a terrible front to back ratio (60:40). Now the IQ has a front to back ratio of (51:49), much better .

For drive traction, that's not better. For handling, it's only better if the spring rates, damper settings, and stabilizer bar stiffnesses have been adjusted to match the change. For braking, it's only better if the brake balance has been changed.

Original:
front: 60% of 880 kg = 528 kg
rear: 40% of 880 kg = 352 kg

Converted:
front: 51% of 1050 kg = 536 kg
rear: 49% of 1050 kg = 514 kg

The change in front axle load is minimal, with the gain in mass being carried essentially only by the rear axle, so if the suspension were changed to match the results of the conversion the changes would logically be stiffer springing, damping, and stabilizer bar, plus larger-diameter brake disks and matching calipers (of the same piston area)... all at the rear.

Of course you could always think of the conversion as just carrying the car's maximum cargo load at all times (without ever actually carrying any cargo in the back or passenger in the rear seat), and consider the result acceptable because the stock vehicle handles acceptably (but probably not very well) when loaded loaded with cargo.

 

[Electric Land Cruiser]

Actually, they're not efficient, compared to conventional alternatives. Mechanical (traction drive) CVTs have lower efficiency than any gear transmission, and the torque converter added to the front of it to prevent engine stalling is - like any torque converter - lousy until it is bypassed by a lockup clutch.

The desirable efficiency of a complete powertrain including a mechanical CVT results from the CVT keeping the engine at a good speed for efficiency (hopefully more than making up for lower transmission efficiency), which is much less of a concern with an electric motor than it would be with an internal combustion engine.

Actually this is wrong, a belt driven CVT, which is what we have here, is 88% efficient and an automatic is 86% efficient.

SAE MOBILUS

 

[remy_martian]

Actually this is wrong, a belt driven CVT, which is what we have here, is 88% efficient and an automatic is 86% efficient.

SAE MOBILUS

Actually, @brian_ was absolutely correct.

From the paper you cited, the one that's $35 for most people to look at:

...and for the "geared transmission" @brian_ talked about being superior, from the paywalled paper you cited:

You can bs some of the people some of the time, but facts, if they can even be accessed, speak for themselves.

Why you would aggressively belittle @brian_'s expertise and then cite a source behind a paywall that does not support your stated position is beyond me. I knew better, so I looked.

 

[PeterG]

Hi guys, thanks for the comments. I think I need to clarify a few things, firstly I love the IQ with an ICE engine or an electric motor (better as an EV, more grunt , for it's size it has good safety features, this one being very low mileage (16,000k) I don't need to worry about age/mileage related issues that plague other EV builders.
I'm not keen on manual gearboxes, they seem like a step backwards, I haven't owned a manual for many decades so I'm not going back there. I took a gamble using a CVT in the EV conversion, but no problems so far, I think I can feel the torque converter locking up at about 60kph, I'll need to examine the CANBUS codes to find out what's really going on. Sufficient to say that the CVT works seamlessly, shift the transmission into drive and go for it, shift the IQ into reverse and it works just as will (no reverse switch needed).
Members seem to be obsessed with the efficiency of a CVT verses a Manual gearbox, in most use cases this the correct approach but not mine, within reason I don't really care about the efficiency or range of the IQ, I have a 30kw battery pack with a range of approximately 200k but it will never leave the city, 40k would be about the max for one day. Charging is from solar so power cost isn't an issue. I've installed a standard J1772 charge port so I can use public charging stations or charge at home, the onboard charger is only 2kw (got it free, may upgrade it later) so public charging is a bit pointless. Cheers guys
Update: The IQ passed it's pre-certification warrant today the certification inspection is on March 10th. Wish me luck

 

[PeterG]

Hi Guys, just working on the next version of the IQ software, here's a snapshot of the start screen. This is part of testing the IPS screen resolution (1024x600) and the HDMI switching system, there are three HDMI sources, I'm using an M5AtomDisplay to bring up the start screen (3 seconds from ignition on) followed by speed, RPM and kilowatts in digital form, once the PI has booted and is ready to take over it will force the HDMI to switch over and display PI based information. I haven't started programming the PI yet, I have a feeling that the M5AtomDisplay may be able to do the heavy lifting on it's own. I'm using two isolated M5Atom canbus modules to retrieve data from the car's canbus and the ZEVA BMS/HYPER9 canbus. The three M5Atom modules will communicate over a small Grove network. Cheers Peter

 

[PeterG]

For drive traction, that's not better. For handling, it's only better if the spring rates, damper settings, and stabilizer bar stiffnesses have been adjusted to match the change. For braking, it's only better if the brake balance has been changed.

Original:
front: 60% of 880 kg = 528 kg
rear: 40% of 880 kg = 352 kg

Converted:
front: 51% of 1050 kg = 536 kg
rear: 49% of 1050 kg = 514 kg

The change in front axle load is minimal, with the gain in mass being carried essentially only by the rear axle, so if the suspension were changed to match the results of the conversion the changes would logically be stiffer springing, damping, and stabilizer bar, plus larger-diameter brake disks and matching calipers (of the same piston area)... all at the rear.

Of course you could always think of the conversion as just carrying the car's maximum cargo load at all times (without ever actually carrying any cargo in the back or passenger in the rear seat), and consider the result acceptable because the stock vehicle handles acceptably (but probably not very well) when loaded loaded with cargo.

Hi Brian, I neglected to mention that I've fitted Firestone airbags in the rear (specified for the IQ) to assist in releveling the IQ back to the original unladen height (about 15mm), I wasn't happy when the car felt and looked like it had two big fat bastards in the back, the airbags tightened things up nicely at about 18PSI, the WOF inspector said that the IQ's braking was spot on, perfectly balanced. This model IQ is only a two seater, the space in the back was intended for cargo. Well, I have 250kgs (162kg NET after removing the ICE junk) of cargo/batteries in the back, installed very low down and centered forward of the rear axle, the car is level and drives and handles better than when it was ICE powered, in fact it has almost no side roll when cornering or any other bad habits! Thanks again for your comments, I really appreciate your feedback cheers Peter

 

[brian_]

... I took a gamble using a CVT in the EV conversion, but no problems so far, I think I can feel the torque converter locking up at about 60kph, I'll need to examine the CANBUS codes to find out what's really going on.

It should be locking up at a much lower speed than that.