# Possible MGTF Sports conversion?



## madderscience (Jun 28, 2008)

Fast and short range should be no problem presuming you have the budget. Use a high voltage, low AH pack built with cylindrical lithium cells, something like 40ah, 300V. Such a pack should not weigh more than a couple hundred pounds. That will give about 40 miles range (driven normally) and lots of power available to the motor/controller. 

good luck.


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## FireCrow (Nov 11, 2011)

Where are you mate, because that little sweet MG looks like an interesting build to me! Although it will be a bit like building car from scratch (which makes it even more interesting! FG bonnet, wheel arches? That would be nice and keeping it as light as possible!


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## Midnight (Dec 12, 2011)

Mmm, FG bonnet etc I hadn't thought of that but yes would make perfect sense in keeping the weight down and I know someone who does them too!

I'm beginning to really warm up to this possible project.

What about costs? 

What realisticaly would the EV part come in at for a fast short range EV?

Any suggestions ( I have a lot of research to do!)

Just reading your blog Madderscience, great stuff!

Cheers


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## Guest (Dec 13, 2011)

If I can make an MG Midget a 30 mile vehicle with 100Ah HiPower and 120 volts then you should have no trouble doing what you want. You should have no trouble making a quick little car that can do 40 miles and keep the weight balance of stock. You can even make belly pans to help lower the center of gravity and add more cells to get more distance and keep the weight balance proper. Keep the weight behind the front wheels and in front of the rear wheels as much as possible and keep the weight as low as possible. 

Good luck with your build. Keep us in the loop with the progress and with photos. 

Pete


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## Midnight (Dec 12, 2011)

I'd love to weld a belly pan but the car already sits very low and with the speed bumps in the UK I suspect it would ground out.

I'm thinking about stacking the batteries where the current fuel tank sits behind the seats and some more in the front bay. Not sure at this stage if that would provide enough space.

I've contacted someone in the UK who has already converted an MGF so hopefully will get some ideas there.

I want the car to be fast so I'm also researching motor and battery options.

Any suggestions?


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## FireCrow (Nov 11, 2011)

Yes, in UK everything seems to be rather problematic to get... But I'm guessing Warp9 should be more than good for you?... So whereabouts are you? Just asking as I'd love to get involved in any sort of build before I start my own conversion  So what about rest of the car parts, because the only thing you mentioned so far is bodyshell....
Another thing, what sort of budget you're considering here, because most likely quite big chunk of it will be swallowed by batteries...


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## Midnight (Dec 12, 2011)

I can't get passed the battery placement issue with this possible project.

The only options I see are building a rack directly over the motor where the engine sat or cutting the floor pan below the seats. I'm concerned that given the depth of the batteries that such a pan may ground out and be too low.

I don't have much knowledge on batteries, can anyone direct me to which are the smallest lightess batteries for such a project (it doesn't seem luck there is much space availble with this car).

I thinking the conversion would run on a Warp9 with a Solitron controller.

Cheers


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## Duncan (Dec 8, 2008)

Hi Midnight

Fast and short range - that is what I am doing with a Lotus 7 type machine

I have bought Headway cells - 88 off 16Ah cells arranged 44 series and 2 parallel

This gives 44Kg - 4.6Kwhours - 3.8Kwhours to 80% - 14 miles range (at 250whrs/mile)

Headways are rated at 10C continuous (46Kw) and 20C burst (92Kw)

I bet you could fit two of my Headway packs in place of the old fuel tank!

The headway 16Ah cells are like giant D cells - 160mm long x 40mm diameter x 0.5kg

I got the Headways direct from China - 
Funny how everybody is worried about buying from China when it is American organizations that have ripped people off!

Pouch cells may be better again - but a lot more money


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## Midnight (Dec 12, 2011)

Thanks Duncan

Looks like I should be able to mount the battery racks above the motor/gearbox and some more in the front where the spare wheel sits.

The TF engine/gearbox sits on a removable rear sub frame see pic 

Where would you mount the battery rack? 

I'm thinking it could be fixed to the subframe on some fabricated mounts?

What do people think?


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## Duncan (Dec 8, 2008)

Hi Midnight

You have got a 60 liter petrol tank? - each of my Headways is 200cc (0.2L) - theoretically you could put 300 of them in place of the tank
60 / 0.2 = 300

In practice you can't get that many in there,
The Soliton can use 200v - 60 series x 4 parallel - 200v x 64Ah = 120Kg 240 cells??
and 12.8Kwhrs - at 80% - 10.24Kwhrs at 250 whrs/mile = 41 miles
Max power - 640amps x 200v = 128Kw continuous, 256Kw burst

Take the tank out and look at the space - you should be able to get a couple of hundred cells in there


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## Midnight (Dec 12, 2011)

Duncan

Thefuel tank is about 52 lts but its a strange shape and sits behind the seats (see pic)

I'm currently thinking that maybe the best aproach would be to fabricate a battery shelf above the rear subframe where the engine currently sits. This would give me enough space to mount sufficient power to run both track & road.

I'm sort of planning to start this conversion off by moddifying the rear subframe 1st. Mounting the motor and welding a battery rack directly to & above the subby. Can you forsee any problems with mounting the battery rack directly to the subby?

I'm new to EV so not fully up to speed with the methods used (been doing an intense amount of research!) and was wondering whether there are any advantages to not using the original gearbox for tranmission.

What alternatives are there ie direct drive and would they provide any performance advantages (I must research this LOL).

Thanks for any advice.


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## dtbaker (Jan 5, 2008)

Midnight said:


> Where would you mount the battery rack?



doesn't have to be in one chunk of course... looks like you have things apart, but what I did was to install the things that would be in pre-determined positions like the motor first, then move around blocks of weights under the 'bonnet' and in the rear area where the fuel tank was until I had balance close to where I wanted it, just stacking the other misc components like controller in approximate positions.

you might consider 1/4" polypro sheets for battery boxes, which are easy to fabricate, non-conductive, and you can bolt right thru them into floorpans or subframe as available. It is easy to heat-weld the edges, or bolt into a steel or aluminum 'frame'. The 1/4" is pretty stiff (about like plywood), but needs support or cross-bracing over long spans.


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## dtbaker (Jan 5, 2008)

Midnight said:


> Duncan
> 
> Thefuel tank is about 52 lts but its a strange shape and sits behind the seats (see pic)


WOW.... it would make me nervous to have a gas tank right behind the seats! depending on what's behind that.... firewall I am guessing, you might consider adding a thin cover with some insulation for supporting the seats and cut thru towards the back to open up that space to mount contactors, fuses, dc-dc and things like that on the back of it.... then make 'saddle boxes' on either side of the motor for batteries. Do take into consideration that the motor gets pretty warm under continuous load and you don't want to mount anything too close where it may get baked.



Midnight said:


> I'm sort of planning to start this conversion off by moddifying the rear subframe 1st. Mounting the motor and welding a battery rack directly to & above the subby. Can you forsee any problems with mounting the battery rack directly to the subby?


that thin high-tensile sheet metal is pretty tricky to weld. you might want to consider adding weld-nuts to minimize welding, or drill and use high-strength jacknuts or thru bolts.



Midnight said:


> any advantages to not using the original gearbox for tranmission.


depends on the power you plan to run thru it. If max torque with your planned motor/controller isn't too much more than stock engine, I'd say stick with OEM.



Midnight said:


> What alternatives are there ie direct drive and would they provide any performance advantages


you'll find that you'll sacrifice either accell from stop, or limit top end without at least a couple gears. Especially with DC motors that you really don't want to run up much over 5000 or 6000 rpm


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## dtbaker (Jan 5, 2008)

Midnight said:


> Duncan
> 
> Thefuel tank is about 52 lts but its a strange shape and sits behind the seats (see pic)



how come this picture show a RED body, and the earlier one in front of the garage is black? are we talking about the same car?


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## Midnight (Dec 12, 2011)

dtbaker said:


> how come this picture show a RED body, and the earlier one in front of the garage is black? are we talking about the same car?


No different car to demonstrate where the fuel tank is.

Thanks for all the tips.


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## Duncan (Dec 8, 2008)

Hi Midnight

Battery position - you want to keep them low! low C of G is a really good idea

Gearbox
I am not using one - I was going to use an old ford 4 speed - then I calculated that I would be able to break traction in top gear - now I have put the motor where the gearbox would have gone

Gearing - what do you mean by a "fast" car
My thoughts
Speed limit here 100Kph
The sort of track I could use ~ max out at about 90mph (144Kph)

I am using a fork lift 11 inch motor - 
4000rpm probably OK - 110 Kph
5000rpm - marginal - 137 Kph

a 9 inch motor would be 40Kg lighter, good for 6000rpm (165 Kph) and probably still spin the wheels 
BUT my 11 inch cost me $100 - a good 9 inch (new) would be over $3000

I am aiming on being fast like a Lotus 7 - not fast like a Ferrari


Get your motor position sorted out and build lots of cardboard battery boxes while you sort out the best place for them


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## Midnight (Dec 12, 2011)

Duncan, I love the sound of an EV Lotus7, fantastic track machine!

Your build design sound interesting and it would of course be cool to save some money on the motor. 

Do you have a blog/thread on the build, maybe I could get some ideas.

Can I ask how you have gone about setting up your drive shafts using direct drive from the motor? I like the idea of ditching the gear box but I do want the MG to be a usable weekend road car as well. 

I love the cardboard box suggestion that should give me something to work with. Having given it some thought though I think I'm limited to stacking the batteries above the motor where the engine sat and also some in the bonnet at the front. 

I am concerned though that the batteries may be affected by the heat of the motor sitting directly above them. The MG has an engine bay fan which might provide some cooling.

Can I ask when mounting the motor to the subframe do you guys fit torque bushes. Is vibration an issue with these EV motors?

Regarding speed I'm more concerned about acceleration that top speed. I would be happy to top out at 80/90mph as long as the 0-60 was good. Again I'd be happy with a 0-60 of under 6 seconds. I'm sure this should be achievable.

Oh gwad, I'm lusting after a Lotus 7 now!


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## Jozzer (Mar 29, 2009)

Come down to Brighton and try my MX-5, will give you an idea what's possible..

Steve


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## Midnight (Dec 12, 2011)

Jozzer said:


> Come down to Brighton and try my MX-5, will give you an idea what's possible..
> 
> Steve


Hey, Steve thanks for replying to my email yesterday.

I'll definately pop down sometime after Crimbo just need to get that out of the way 1st!


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