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Discussion Starter #1
Been working on this project for many years. And should start with thanks to Moltenmetal Baratong and EVmetro for their inspiration.

I've had this car since 1989, and always loved the car, hated the motor/ gear box. So the journey started.



I've opted for a Direct drive UQM PP100, with 108 CAM 72 Calb batteries, Zeva BMS-EVMS3.

Really got serious this last few months, once i worked out my motor mounts and battery positions.
 

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Discussion Starter #3 (Edited)
Preparation work, was to upgrade the diff. I've had my fair share of failed diffs and uni joint replacements.

So, I went a tested road that I've now made a few kits for and sold around the world, after making improvements too.
The R160 diff from the Subaru WRX. I was able to go 4.44:1 ratio with a VLSD version. Due to the CV not being suitable for the swing spring, I've also converted to a GT6 rear end which has the lower wishbone.

Some pic's of my build which took way too many years...
 

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Discussion Starter #6 (Edited)
The kit i refer to, is the three main brackets to bolt in a R160 Diff to a Spitfire & GT6 to replace the existing diff with no modification to the vehicle (or very minor). It is not a turn key with all components. I continue to sell these as i remember how hard it was to get these components when i started my conversion. The idea came from some guys in NZ who were building kit cars i think in the 80's. I eventually tracked them down and they were not interested in making any. BUT, were happy to provide me with details and they'll buy a set. Since the first batch of 7 which were snapped up through various forums. I installed mine, and was a bit disappointed. So i tweaked the dimensions, strengthened the front support and a few other changes.

The parts fit directly to R160 Diffs. For GT6 you can use the Subaru diff. For Spitfire (swing spring & original spring set up) you need the diff from a Datsun 510. Reason being is the Datsun R160 diff have bolt in stub axles. They are still available in USA. but bit hard to get. Recent customer from Texas ended up going to the Rally race club where he could buy a rebuilt diff with LSD.
What is needed but i don't supply is adapters from diff stub axles to half shaft flanges. but i do have drawings from a guy who purchased an early kit which i can not guarantee.

What i supply is
Rear Back plate
Front support plate
Spring plate

I do supply plugs for Rear back plate, Breather for Rear back plate.
And list of fastenings recommended, and part number for rear bushes from Rimmer Bros'.

Also see pics below
An old pic of the first R160 kit design with Datsun 510, R160-Diff along side the original Triumph diff
The datsun 510 stub axles with the bolt IN flange.
Adapter plates (for Datsun 510) required to match the original diff-width and half shaft flanges. Flanges can vary from old design spring set up with short shafts and long Swing spring half shafts..
 

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Discussion Starter #7 (Edited)
For those with a GT6 Rotoflex rear suspension.

My build was a bit more complicated, as i managed to obtain some very rare Half shafts from a Rover 100 (short side only) out of the UK,. and machining the GT6 uprights to fit the MGF Rear axle bearing the New (rover) Half shafts fit directly into the the Subaru WRX CV stub axle.

However, there are a few other alternatives, firstly you could do same as for the Swing spring with Datsun 510 diff,

OR .. The best solution I've seen and assisted with ... (but i have not done this myself) is machine the Subaru CV cup off. and weld on a blank to machine a new flange that matches width and Flange to the original diff width & Rotoflex half shafts flange, and/or upgrade with Canely Classic CV conversion (same spec).
See below pics for the process to modify stub axles.
 

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Impressive work!

The tubular compression member you installed between the two front suspension towers is a very good and very NECESSARY addition- my battery box served the same purpose essentially. You do need something to keep those towers from tilting inward toward one another over time as the torsional stiffness of the frame isn't sufficient to handle this load on its own.

I gave up when I saw how hard it was going to be to convert the rear of a Spitfire to something durable. I just bought a TR6, with no intention to convert it, then of course its transmission croaked and I decided enough was enough, and converted it. Nice, solid rear suspension and differential on that car- but of course the car itself is a LOT heavier too. Not nearly as zippy as the Spitfire was, but good enough for me for sure! After my crash, having a little more metal around me when I drive is comforting.
 

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For Spitfire (swing spring & original spring set up) you need the diff from a Datsun 510. Reason being is the Datsun R160 diff have bolt in stub axles. They are still available in USA. but bit hard to get. Recent customer from Texas ended up going to the Rally race club where he could buy a rebuilt diff with LSD.
This is an important factor. The guy I know who builds 510's (lots of them) in British Columbia says that the 510 community has switched to the Subaru version due to the lack of R160's.
 

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.. The best solution I've seen and assisted with ... (but i have not done this myself) is machine the Subaru CV cup off. and weld on a blank to machine a new flange that matches width and Flange to the original diff width & Rotoflex half shafts flange...
This is essentially what Yabert did to adapt his Bolt drive unit's outputs to his Volkswagen axles.
 

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Motor in Tranny tunnel...
The UQM PP 100 is apparently 286 mm in diameter, and is sitting above the frame rails (as any motor would, since the rails are at the bottom of the tunnel). What, if anything, did you need to do to the tunnel to allow the motor to fit?

I assume that the motor can only be installed and removed via the engine compartment, after removing the battery pack.
 

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Due to the CV not being suitable for the swing spring, I've also converted to a GT6 rear end which has the lower wishbone.
The swing-axle system doesn't have a lower wishbone... so how are the wishbone to frame mounts done? Are they welded on, or bolted in?
The longitudinal locating rods of the swing-axle and Rotoflex suspensions sit at different angles and anchor to the car at different locations; how did you address the difference in this conversion?
 

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Discussion Starter #13 (Edited)
The UQM PP 100 is apparently 286 mm in diameter, and is sitting above the frame rails (as any motor would, since the rails are at the bottom of the tunnel). What, if anything, did you need to do to the tunnel to allow the motor to fit?

I assume that the motor can only be installed and removed via the engine compartment, after removing the battery pack.
Here is a pic of the rear mount pos' you can see how it drops in between the rails. They are coming in at the rear which makes it tight. I did apply a bit of heat to the lip on the chassis rails and helped it with a hammer... as you might be able to see in the second pic'. The brackets are just tack welded for now... in these pics...

I have new tail shaft, but not installed yet. I 'know i will need to fold over the lip near the diff aswell, as the diff offset output-flange makes it close to the chassis causing slight interference. Has been dealt with by many in same way!. BUT the line between motor and diff looks good. I have the motor with a very slight tilt lower at the rear. this helps with alignment. I do have an issue with coolant inlet on the motor. It does touch the tunnel hood. I plan to cut a hole for clearance and fibreglass bulge. Is about 1 oclock in the tunnel, so no problems even for RHD.
Motor removal. I designed the brackets so that I can slide the motor forward and removed from engine bay. Thought about removal from inside cabin and decided not to go there. So, to remove motor is going to require battery box, and inverter removal first.
 

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Discussion Starter #14
The swing-axle system doesn't have a lower wishbone... so how are the wishbone to frame mounts done? Are they welded on, or bolted in?
The longitudinal locating rods of the swing-axle and Rotoflex suspensions sit at different angles and anchor to the car at different locations; how did you address the difference in this conversion?
You are right. but relatively easily solved. See pic's you can purchase lower wish bone bracket and trailing arm bracket as shown in the respective pic's. The trailing arm support bracket in the cabin even has the holes already in the spitfire tub, just need to pop out the rubber grommets.
they are not welded in yet. checking everything is right...

You can purchase all these straight from Rimmer Bos' catelogue.
 

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I noticed that the extra torque of my electric drive put a lot of stress on those lower arm brackets mounted to the body tub, and I had to weld in quite a bit of reinforcing steel to transfer the thrust to the new steel of my re-made floorpans so they would be stiff enough. I stuck my hand behind the driver's seat while driving one day and literally felt the thing buckling forward when I floored it, flexing back again when I let my foot off the accelerator.

The whole replacement of the rear diff and drive system is a major piece of work and I am really hoping you will be pleased permanently with the result. It's beyond my tolerance for cost and my abilities I'm afraid, just to maintain the appeal of Michelotti's beautiful body styling relative to the still sexy but much boxier appearance of the TR6. But man, that TR6 is noticeably heavier...and higher off the ground!
 

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I noticed that the extra torque of my electric drive put a lot of stress on those lower arm brackets mounted to the body tub, and I had to weld in quite a bit of reinforcing steel to transfer the thrust to the new steel of my re-made floorpans so they would be stiff enough. I stuck my hand behind the driver's seat while driving one day and literally felt the thing buckling forward when I floored it, flexing back again when I let my foot off the accelerator.
I think this is an excellent argument for limiting the motor current to correspond to a torque into the final drive no greater than than the stock engine would produce when multiplied by the lowest transmission ratio. Shock loads can similarly be handled by limiting the rate of rise of current, if that's available as a configuration parameter.

The whole replacement of the rear diff and drive system is a major piece of work and I am really hoping you will be pleased permanently with the result.
I don't know how much the GT6 Rotoflex-style conversion will help the issue of handling forces. The fore-aft forces are still carried through the trailing arm, and the drive torque is still carried through the differential case.
 

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See pic's you can purchase lower wish bone bracket and trailing arm bracket as shown in the respective pic's. The trailing arm support bracket in the cabin even has the holes already in the spitfire tub, just need to pop out the rubber grommets.
they are not welded in yet. checking everything is right...

You can purchase all these straight from Rimmer Bos' catelogue.
So, the lateral arm brackets are welded on - thanks. :)

From catalog illustrations, it looks like the stock GT6 trailing arm mounts to a frame bracket, not the body - maybe that's only some years. Adding another Spitfire-style bracket in the required location looks like an adaptation to make the GT6 bits work in a Spitfire.

Triumph trivia: a friend of mine just got a GT6, and I have discovered that in the last part of the last year (1973) of GT6 production, the GT6 switched to the same swing-spring swing axle as used by the Spitfire Mk IV/1500.
 

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Discussion Starter #18
I noticed that the extra torque of my electric drive put a lot of stress on those lower arm brackets mounted to the body tub, and I had to weld in quite a bit of reinforcing steel to transfer the thrust to the new steel of my re-made floorpans so they would be stiff enough. I stuck my hand behind the driver's seat while driving one day and literally felt the thing buckling forward when I floored it, flexing back again when I let my foot off the accelerator.
That makes sense the next weakest link in the chain, i had not considered that... thanks... do you have any pic's of what you did? i assume bracing under body?
 

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What I did wouldn't be applicable to you. I stiffened the joint between the radius arm pocket and the rear of the floor pan, and added thickness locally to the floor pan to give it some additional stiffness. Note that my floor pans were home-made from 14 gauge steel, so the factory floor pans will need LOTS of reinforcement in my opinion...
 

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Discussion Starter #20
Welded / bolted in all the major components, test fitted Bonnet, now Ready for strip down to powder coat all battery boxes and engine mounts.

20200716_113347_resized.jpg 20200716_113420_resized.jpg
 
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