Another mini conversion

Have you made or bought a converted vehicle if so this is for you
andylaurence
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Postby andylaurence » Sat Nov 08, 2008 10:38 pm

That sounds brilliant. Love the Blue Peter CAD. I did something similar using a spare Mini 'box to see feasibility of a single motor over the top of the standard 'box. It's a fallback I'd rather not use. I think the possibilities with independant drive are too good to pass up, although something that works is preferable to something that doesn't. We'll see how it pans out. The Swift solution looks very neat and tidy and the Mini goes surprisingly well with an 8" motor. Rather subjective, I know!

If you're looking for a chain drive, I could recommend a Quaife unit for putting lots of power down in the best way possible. Actually, there's a cheap one on Ebay at the moment. The way they drive is invigorating and the traction is, quite obviously, astounding compared to an open differential. As a major plus point, Quaife offer a lifetime guarantee, even for competition use, and there's no clutches to wear out as it's all gear-based.

I see you're conscious of noise for your project, hence the belt driven approach. I'm sticking with chains as noise isn't a worry for me. Driving a Smart Roadster, noise is a familiar beast and the Mini is unlikely to become my daily driver. I just need to find the time to actually complete my project. I'm close to getting someone else to work on it just to actually get it moving. I've lost today after I've randomly developed a sore neck and upper back. I really needed to get the new manifold on my Golf too. That's my current competition car, until I'm all-electric.

I've not had much progress for a while but I'm documenting the process on the Mini's website. There's an RSS feed if you want to keep updated.

Cheers,
Andy
Image
Above figures include track days and the odd competition.

MalcolmB
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Postby MalcolmB » Sun Nov 09, 2008 7:14 pm

Yes, I'd really like to try the independent drive to the wheels (front or rear) as well. It's an elegant, minimalist solution which should be lightweight and fairly efficient with the right gearing. I don't think it's the best approach with these motors though. Do you have any particular motor in mind yourself yet?

Thanks for the link. I've been keeping an eye out for a second-hand Quaife diff for a while. They do a mini-specific one as well, which would save a bit of work and expense. Not sure whether I really need to go to the extent of a Quaife unit though. A twin cross pin diff from Minispares or the like would probably be strong enough for my needs.

I was looking at a Smart Roadster the other day, thinking it would make a good conversion candidate. No idea how suitable it would be mechanically though.

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qdos
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Postby qdos » Mon Nov 10, 2008 12:20 am

MalcolmB wrote:I was looking at a Smart Roadster the other day, thinking it would make a good conversion candidate. No idea how suitable it would be mechanically though.


Rather fiddly from what I know of Trevor Lees experience converting a For Two as the cars are pretty much fly by wire but should be possible Trevor's probably your man I really like the Roadster and if one came along at the right price I'd like to get one. AC were supposed to be starting up the production after Smart killed them off but nothing seems to have come of it

andylaurence
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Postby andylaurence » Tue Nov 11, 2008 6:15 pm

MalcolmB wrote:Yes, I'd really like to try the independent drive to the wheels (front or rear) as well. It's an elegant, minimalist solution which should be lightweight and fairly efficient with the right gearing. I don't think it's the best approach with these motors though. Do you have any particular motor in mind yourself yet?

Thanks for the link. I've been keeping an eye out for a second-hand Quaife diff for a while. They do a mini-specific one as well, which would save a bit of work and expense. Not sure whether I really need to go to the extent of a Quaife unit though. A twin cross pin diff from Minispares or the like would probably be strong enough for my needs.

I was looking at a Smart Roadster the other day, thinking it would make a good conversion candidate. No idea how suitable it would be mechanically though.


The Mini-specific version would help you connect up the driveshafts but you'll still need to get a sprocket on the diff and mount it somehow. You don't need a Quaife unit but they really are phenomenal. An open diff will lead to wheelspin, especially as you'll be pulling weight out the front by ditching the engine & 'box and adding weight at the rear end. I think the Quaife would be a worthwhile investment.

As for the Roadster, it's quite light (800kg) but there's no space in it whatsoever. The engine bay is tiny and the boot is non-existant. It would benefit from the extra weight up front when you fill the front boot with batteries, though as the front end is very light.

Cheers,
Andy
Image

Above figures include track days and the odd competition.

andylaurence
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Postby andylaurence » Tue Nov 11, 2008 6:25 pm

qdos wrote:
MalcolmB wrote:I was looking at a Smart Roadster the other day, thinking it would make a good conversion candidate. No idea how suitable it would be mechanically though.


Rather fiddly from what I know of Trevor Lees experience converting a For Two as the cars are pretty much fly by wire but should be possible Trevor's probably your man I really like the Roadster and if one came along at the right price I'd like to get one. AC were supposed to be starting up the production after Smart killed them off but nothing seems to have come of it


The Roadster is the best car I've ever had, both to drive and for economy. It doesn't seem to consume any fuel (see below). The fly-by-wire could make life difficult or very easy. I guess there's a handily placed robust TPS, for starters. Project Kimber was the idea to bring the Roadster back but was doomed to failure really, even though they got the AC name. The car has some pretty fatal flaws and nearly all of them revolve around leaks, so as an EV, I'd say it's not a good bet!

Cheers,
Andy
Image

Above figures include track days and the odd competition.

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qdos
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Postby qdos » Tue Nov 11, 2008 11:07 pm

hmm I had noticed the 44 mpg image on your signature, canot say that is particularly impressive particularly these days my mum's C1 gets about 55mpg on average and my Zest can get over 60mpg but I have to say I do love the looks of the Smart Roadster I happened to drive past one this evening and I would very much like to get one.

So what leaks ? By the way I've had 4 open top cars and a Lotus so I'm well used to leaks LOL

andylaurence
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Postby andylaurence » Thu Nov 13, 2008 6:27 pm

qdos wrote:hmm I had noticed the 44 mpg image on your signature, canot say that is particularly impressive particularly these days my mum's C1 gets about 55mpg on average and my Zest can get over 60mpg but I have to say I do love the looks of the Smart Roadster I happened to drive past one this evening and I would very much like to get one.

So what leaks ? By the way I've had 4 open top cars and a Lotus so I'm well used to leaks LOL


You're right, it's not good MPG. The difference between my Roadster and your mum's C1 is the driver. That 44mpg is achieved, despite driving spiritedly most of the time and also includes competing in an AutoSolo and a road rally. I like to enjoy my driving but I like to do so whilst consuming the least amount of fuel. I spent a lot of time driving diesels but I prefer the smaller petrol engine solution I have now!

Cheers,
Andy
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Above figures include track days and the odd competition.

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qdos
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Postby qdos » Fri Nov 14, 2008 10:43 am

andylaurence wrote:I like to enjoy my driving but I like to do so whilst consuming the least amount of fuel.


Ah good to see someone else out there with the same enjoyment of motoring The more I think about it the more I think I ought to have got a Smart Roadster. My G27 is just parked up and goes nowhere but it's a superb car and having built it I'm loathed to be without it. It just adds to the collection of toys I seldom play with. With petrol the way it is though I'm still determined to do something equally as fun with electric though.

MalcolmB
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Postby MalcolmB » Tue Jan 06, 2009 3:57 pm

Just a quick update. I'm making slow progress here, but I've managed to sort out one problem that was nagging at me.

I'd originally wanted to mount the motors face to face across the subframe, with each motor driving a drive shaft independently via toothed belts. Problem was the motors were too long and would have intruded into the wings. It finally dawned on me that if I removed the fan I could shorten each motor by about 40 mm. Even better, this would give me a straight section of shaft on which to mount the pulley, rather than having to machine pulleys specially to fit the existing taper. Two birds with one stone - magic! I planned to use small blower fans to duct cooling air into the commutator ends of the motors anyway, so the loss of the internal fan isn't a problem.

Thanks to a friend (cheers Ian!) both motor drive end plates have now been cut back by 40 mm and the shafts machined to give a 25mm dia straight section. The shaft is still the original length, but I plan to shorten that by the same amount soon. The small pulley in the photo needs to be be bored out to 38mm and it'll then be fixed to the shaft using a Trantorque keyless bushing.

Image

I'm planning to order a pair of 90 tooth alloy sprockets to drive the inboard ends of the drive shafts. As you can see from my latest CAD* study the motors now fit (just) across the subframe. All I have to do now is make up some hinged support frames to allow belt tensioning and make some bearing supports for the drive shafts and pulleys...

(*CAD = Cardboard-Aided Design)
Image

MalcolmB
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Postby MalcolmB » Tue Jan 13, 2009 1:37 pm

I'm hoping someone can help me with a little advice on setting up a tachometer to monitor the speed of my motors.

It may seem a bit premature to want to do this before I've even started putting everything together, but I want to check the timing of my motors first, before I set about advancing them to cope with higher voltage. I think they're neutrally timed at the moment, so they should demand roughly the same current and run at the same speed whether I wire them to run clockwise or anticlockwise.

To check this I was hoping to use the existing rev counter from my mini. This is an electronic rev counter with a positive and a negative terminal (12V supply), plus a third terminal that is normally connected to the negative, primary side of the ignition coil.

I'm hoping to drive the rev counter using a pair of small magnets fixed to the shaft of one of the motors at 180 degrees. These will trigger a reed switch mounted close to the shaft.

My question is how do I connect the reed switch to the rev counter. I know one side of the reed switch goes straight to the "coil" terminal, and I think that the other side goes to the negative terminal on the meter, but do I need any additional components to mimic the signal that the meter would get from an induction coil?

I've read elsewhere that some rev counters may need a signal of more than 12V in order to operate correctly, since they normally see higher voltage spikes from the coil. Any advice or pointers to more information would be appreciated.


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