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Alternative Fuels For all those conversations about LPG, Electric, Hydrogen. Anything but petrol and diesel...

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  #11  
Old 13th January 2017, 11:47 AM
MikkiJayne MikkiJayne is offline
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The 2.8 FWD 5-speed with velour interior barely tips the scales at 1500Kg Its a passenger heavier than our TT!

Why do most conversions hook the motor up to the original gearbox (as WD did)? I would have thought direct drive to the diffs would make more sense, like the Leaf unit appears to do. With a motor having max torque from 0 rpm it seems like a gearbox is pointless.

Doing direct drive, you could easily put two motors in place of the gearbox, one driving the rear diff and one driving the front (use a rear diff flipped over). Then, all the power control and batteries go under the bonnet to keep the weight balance right. A pair of 150hp motors would push it along nicely
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  #12  
Old 13th January 2017, 01:24 PM
MikkiJayne MikkiJayne is offline
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Interestingly, the Leaf has a single reduction gear of 7.9377. The motor has a top speed of 10,390 rpm, so with the D2's tyres that would give a top speed of 100mph which is probably adequate

I still think you'd need two of them to have acceptable performance in a D2 though, since 11 seconds to 60 is a bit embarrassing for a car like that. It'd be relatively simple to fit in the front, but a little tricker to put in the back unless you decouple the controller hardware on top from the drive system. You could probably just extend the cables and put that in the boot though. The subframe may need a chunk of work to fit the drive in it too, since it looks quite wide.



If you could use an aftermarket controller with it then it'd be relatively simple to tie both drives together, electrically.

Two of these are a little heavier than the 5HP24, but the fuel tank goes as does the propshaft and rear diff so I reckon that's about even, leaving a good 250Kg left for batteries. The Leaf battery is 300Kg, so thats not far off.

Range would be a bit pants - probably only 50-60 miles. It'd be a good commuting car though
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  #13  
Old 13th January 2017, 02:14 PM
MikkiJayne MikkiJayne is offline
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And now I have this stuck in my head, so you lot can too

https://www.youtube.com/watch?v=MK1g5dMYR3s
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  #14  
Old 13th January 2017, 02:14 PM
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Goran Goran is offline
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Some great ideas there Mikki, keep em coming

Yes unfortunately the Leaf and Tesla motors need a single speed reduction gearbox, in order to attain motorway speeds. Interestingly both are roughly 8:1
There are exotic motors out there that have the torque at low rpm and high rpm capability that don't need a reduction gearbox at all, but I don't think they have made it into any cars yet.

Before I found out that Leaf and Tesla need 8:1 reduction gear, I thought about just using the D2 rear diff for front and back wheels and splining a motor directly into it. After all it is a bit like a reduction gearbox. If a more torquey motor can be found it could do alright with a 4.111:1 reduction?

Definitely two motors all the way. I don't know how it would work electronically though, do they need to be run from one controller so that traction can be controlled between front and back axles.

Great idea about space under the fuel tank, maybe a whole Leaf unit could fit under there if tilted at an angle?

Wow the Leaf unit is quite heavy with the trans included, that's around 80kg. With the control module its probably over 100kg?

Yeah! I'd rather have a D2 with 60 miles range than a Leaf!

Last edited by Goran; 13th January 2017 at 02:16 PM.
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Old 13th January 2017, 02:39 PM
MikkiJayne MikkiJayne is offline
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The WD car used a two-motors-in-one-housing unit to get the most power it could (link here), but even that only had 120hp peak, so the Leaf motor is quite impressive. The power curve for their motor looks just like a 40V S8's torque curve, but the torque for the motor looks like a steam engine

AC-35x2 Torque Curves

68Kg for that, so 80 for the Leaf including the reduction gear isn't bad. I reckon it would work with a 4:111 reduction based on the graph. Its just like being in 4th all the time which would be fine since you're not going for top speed. Using the 3.7 final drive from the 4.2 A8 would probably be better actually since you'd make better use of the torque spread up to 3000rpm - 64mph, vs 58mph with 4:111.

Koenigsegg can do 0-248mph with no gears using a torque converter and an MGU on the crankshaft! https://www.youtube.com/watch?v=glf_k4qGBAA. They're effectively in 7th gear all the time!

Controlling two motors with aftermarket controllers appears to be simple - one controller for each motor, both being fed the same speed signal input. Thats what the WD car did, albeit both motors were built in to the same casing. It would be interesting to see if the control device talks can-bus, then you could still run the ESP You'd need it with all that torque.
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Last edited by MikkiJayne; 13th January 2017 at 02:41 PM.
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  #16  
Old 18th January 2017, 09:59 PM
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Oh yes I saw that, amazing what they can do with just a torque converter, pure genius!
Good point I forgot that ESP is an independent system using the brakes.
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Old 19th January 2017, 05:41 PM
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Curtis Instruments or Zapi will do a controller (or matched pair) that will do your job.
The use a fly-by-wire input and simple voltage input for direction control.
Would be a lot easier to use a stand alone black box from these guys rather than trying to bodge a Nissan Leaf controller

A lot of 3-wheel electric forklifts use a single motor controller with dual motor outputs (one for each drive wheel on the front of the truck). They use a steer angle input to vary the motor speed (and even reverse drive) in tight turns. We wouldn't need that input but if you were getting creative you could use it as a form of traction control.
If the rear wheels were spinning you could theoretically cut output to the rear motor while maintaining the required power to the front axle (or vice versa) restoring it when the abs sensor inputs match

I can put a call in to either of those suppliers if needed
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Old 19th January 2017, 08:43 PM
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Default Crowd funding experience anyone?

Hi,

Does anyone know about this "Crowd Funding" lark? (Or have teenage kids who seem to know everything about the online world but not everything about reality...).

I think you can set up a profile that will allow folks to pledge but nothing gets taken until a set amount is raised. This gives us the chance to "put our money where our mouths are" but have some assurance that nothing will be frittered away on a project that just will not "fly".

Personally I wouldn't want to own any part of our own "Iron Man" car: just a blast (crawl??) in her would be worth my 50!

Thoughts?

Robert
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  #19  
Old 20th January 2017, 11:49 AM
tintin tintin is offline
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Quote:
Originally Posted by MikkiJayne View Post
Interestingly, the Leaf has a single reduction gear of 7.9377. The motor has a top speed of 10,390 rpm, so with the D2's tyres that would give a top speed of 100mph which is probably adequate

I still think you'd need two of them to have acceptable performance in a D2 though, since 11 seconds to 60 is a bit embarrassing for a car like that. It'd be relatively simple to fit in the front, but a little tricker to put in the back unless you decouple the controller hardware on top from the drive system. You could probably just extend the cables and put that in the boot though. The subframe may need a chunk of work to fit the drive in it too, since it looks quite wide.



If you could use an aftermarket controller with it then it'd be relatively simple to tie both drives together, electrically.

Two of these are a little heavier than the 5HP24, but the fuel tank goes as does the propshaft and rear diff so I reckon that's about even, leaving a good 250Kg left for batteries. The Leaf battery is 300Kg, so thats not far off.

Range would be a bit pants - probably only 50-60 miles. It'd be a good commuting car though
That Leaf motor looks a bit bigger than the Tesla ones, I'll see if I can find some pictures.
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  #20  
Old 24th January 2017, 10:34 AM
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Only because it is a part of the transmission. Its actually quite small, unfortunately I am not sure that it can be used on its own outside the housing which is part of the transmission casting.

Of course I would take a Tesla motor any day, much more powerful and no permanent magnets. They are not so easy to come by especially not for 1300 inc controller and transmission.
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