# New Mexico Spitfire



## Kilomike (Sep 14, 2018)

Hello all,

I'm a new member, but have been lurking for a few months and have read countless threads. I'm in the process of starting my first conversion and need some input from those with more background than I. 

*Quick background:* I'm an engineer by school and trade and a machinist by hobby. I have a small machine shop in my garage and have friends with just about everything under the sun. I live in a hilly area and want to use the car for a 3 season daily driver. 

*The conversion:*
Car: 1976 Triumph Spitfire 1500 (running!) with 3.89:1 final drive
Motor: AC PM Netgain Hyper9 w/ AC-X1 SME controller from EV West (planned)
Batteries: ~12kwh, ~100v Gen 1 Leaf Modules (planned)
BMS: Orion BMS (very open to others)
Charge: Open to suggestions
Timeline: Driveable by 4/19, drive all summer, rebuild/modify/change/restore next winter.

*Questions:*
*Drivetrain: *My biggest question right now is whether or not to use the stock tranny. I really like the idea of direct drive and the advertised Hyper9 specs seem to suggest it would work (as well as several threads on here). Is this reasonable or should just run the stock tranny for the near future? For those that have done direct drive with the Hyper9, how is performance?

*BMS:* I'm leaning towards the Orion series simply because of proliferation and support. Is there something better out there for a 1st build? I'm pretty comfortable with most aspects of the conversion, but BMS is voodoo.

*Batteries:* The leaf cells seem very popular and there are good datasheets available online, but I'm still not clear on what sort of discharge I can expect. I'm thinking I'll limit my peak current draw to ~500-600A (for multiple reasons). Can a 4P28S (since they're 2P2S modules) handle 600A peak and ~200A cont.? I've considered building an 18650 pack, but the cost would be more than double.

I think that's enough to get started. Any and all feedback is GREATLY appreciated!

Kilomike


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## brian_ (Feb 7, 2017)

Kilomike said:


> *Drivetrain: *My biggest question right now is whether or not to use the stock tranny. I really like the idea of direct drive and the advertised Hyper9 specs seem to suggest it would work (as well as several threads on here). Is this reasonable or should just run the stock tranny for the near future?


Can you fit the HyPer 9 into the transmission tunnel, where the transmission is now, without structural modification? If you can, the gain of space in the original engine location for battery modules would be a significant advantage; however, if it doesn't fit there and has to be forward of the firewall then saving some weight would be the only benefit and you will be limited in torque to the wheels by not being able to use a lower gear.



Kilomike said:


> For those that have done direct drive with the Hyper9, how is performance?


At this time, I think you'll be lucky to find anyone who has even completed a HyPer 9 build, let alone one without a transmission and in a car of comparable size to the Spitfire for a useful comparison.


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## Kilomike (Sep 14, 2018)

From what I've read, I expect that the Hyper9 will fit about 9in back into the transmission tunnel. I haven't removed the old engine/tranny yet, so I can't say for sure. That said, I could easily modify the transmission tunnel if it was worth it. 

And I figured as much on the Hyper9 builds. I've seen that several are using them, but I haven't been able to find any actual numbers outside of some calculations.

Thanks for the quick response! Any suggestions on BMS or what I should be looking for?


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## brian_ (Feb 7, 2017)

Kilomike said:


> *The conversion:*
> Car: 1976 Triumph Spitfire 1500 (running!) with 3.89:1 final drive


Have you seen any of the Spitfire conversions in the DIY Electric Car Garage? The Garage has been non-functional for a while, but pages are available from the Wayback Machine. Here are a few:

E-Fire by Moltenmetal - build thread: E-Fire '75 Spitfire conversion: 1st build!
Thistle by Baratong - build thread: '79 Spitfire Conversion
69 Spitfire by Mike Gahan
If you're interested, there are more and I can extend this list.


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## brian_ (Feb 7, 2017)

Kilomike said:


> From what I've read, I expect that the Hyper9 will fit about 9in back into the transmission tunnel. I haven't removed the old engine/tranny yet, so I can't say for sure. That said, I could easily modify the transmission tunnel if it was worth it.


Getting the motor right out of the engine space would be nice, but all of the Spitfire builds that I've seen retain the transmission. The tunnel itself is one thing, but I would wonder about clearance between the frame rails. With the motor dimensions available, and the car in the garage, it should be easy to check.



Kilomike said:


> Any suggestions on BMS or what I should be looking for?


Not my area, but I'm sure you'll get suggestions, widely varying in approach.


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## Kilomike (Sep 14, 2018)

I've seen several of them, but I haven't been through the garage (it not working explains why I haven't found it!). I've read through Molten's thread twice as well several others that showed up when I searched "triumph" or "spitfire".

I've also looked on EVAlbum.com where there are ~12 spitfires. The common trend I've seen is LiFePO4 "brick" batteries and DC motors. I think this is mostly because they were done before AC was common and Lithium was put in production vehicles, but I could be missing something. 

Am I correct in thinking that AC is a better option today? Regen seems like a no-brainer and there's a reason all of the big OEMs use them in the production vehicles. 

I'm relatively new to all of this, so please correct me if I say anything dumb!


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## Kilomike (Sep 14, 2018)

Here's a pic of the car from back when I picked it up. Didn't trust driving it 100miles, so it got to ride on the trailer.


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## brian_ (Feb 7, 2017)

Kilomike said:


> I've seen several of them, but I haven't been through the garage (it not working explains why I haven't found it!). I've read through Molten's thread twice as well several others that showed up when I searched "triumph" or "spitfire".
> 
> I've also looked on EVAlbum.com where there are ~12 spitfires. The common trend I've seen is LiFePO4 "brick" batteries and DC motors. I think this is mostly because they were done before AC was common and Lithium was put in production vehicles, but I could be missing something.


Yes, the longer list of Spitfires in the Garage here shows a trend over time from lead-acid, to individual LiFePO4 prismatic cells, and just starting into salvaged production EV modules. Similarly, older builds are all DC, and some newer builds are AC induction (while DC builds continue); aftermarket AC PM motors had not appeared until this project, and I haven't seen any salvaged production EV motors or drive units yet.


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## brian_ (Feb 7, 2017)

Kilomike said:


> Here's a pic of the car from back when I picked it up. Didn't trust driving it 100miles, so it got to ride on the trailer.


You got a hardtop with it!


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## brian_ (Feb 7, 2017)

Rather than assembling a longer list of previous Spitfire projects, I'll attach my spreadsheet as a PDF file. I would just put it in this post as a table, but vBulletin (at least as implemented in this forum) doesn't do tables.

And in case anyone is wondering why I have this spreadsheet already lying around... what brought me to this forum is that we have a Triumph Spitfire with a dead engine. I have an extensive list of potential engines to swap in, but an EV conversion was another option. It may still happen, someday...


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## Kilomike (Sep 14, 2018)

Brian, Thank you so much for the guide to other spitfires! I'm very interested in Bottomfeeder's Sparkfire. It looks like the only one that's known to have went direct drive. I just found the thread and hope to get through it tonight. 

Thanks again for all of the guidance! Any other nuggets of insight?


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## brian_ (Feb 7, 2017)

Kilomike said:


> I'm very interested in Bottomfeeder's Sparkfire. It looks like the only one that's known to have went direct drive. I just found the thread and hope to get through it tonight.


Good catch - I had forgotten about that one that eventually eliminated the transmission. The story of his switch to "direct drive" was in a post in another build thread (_Planning a new ev from a triumph spitfire_ - post #16). It was a late change, and I don't think it appears in his build own thread at all.

_Sparkfire_ appears twice in my spreadsheet, to represent the initial and later versions.



Kilomike said:


> Any other nuggets of insight?


My conclusion was that the Spitfire is an antiquated and flawed but fun package. Everything in it can be improved, but if you go down that route you have built a new and different car, so why start with a Spitfire? For instance, by the time the suspension is fixed and structure is improved it might as well be a Miata... and just buying a Miata would be cheaper and easier. The optimal compromise _for me_ would be a powertrain replacement with as little effect on the rest of the car as possible, which means a transition between new stuff and old at either the input to the final drive, or the input to the transmission. What follows from that is that there is no point in trying to produce more torque than a well-prepared original Spit would have... not much more than 82 lb-ft into the stock transmission, or the corresponding stock non-U.S. input to final drive of 287 lbf-ft | 389 N-m @ 860 rpm shaft speed (first gear @ 3000 rpm engine speed). I also have little desire to do bodywork, so battery packaging into existing spaces would be a major issue and would lead to a moderate range... especially since I would refuse to stack cells in the nose or tail, to avoid ruining the vehicle dynamics.

But hey, that's just my thinking, and I haven't built it yet.


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## Kilomike (Sep 14, 2018)

Thanks for the link to the thread! I probably would have never found that!

As for you comments on the spitfire in general, I completely agree and I think you hit the nail on head about some of my concerns. I chose the spit because of the styling and availability. I paid $2500 for a running spitfire with a clean body. I worry about the rear suspension, but at the same time my only intent is to use this to turn heads and drive the 12 miles each way to work. I'm not looking for crazy performance and I don't ever plan to run autocross with it. I just want it to be fun to scoot around town in. This also lets me get away with an approx 10kwh pack, which at ~250wh/mi, should give me a 30-40mi range.

Going with the Hyper 9, I do worry about blowing up the final drive/tranny. I'm almost certain it would destroy the tranny if I let it loose. That's another reason why I'm leaning toward going straight to direct drive. It looks like the final drive should be able to handle the 1:1 ratio torque (173ft-lb advertised peak vs your stated 287ft-lb stock load). Using the tranny may actually be bad in that regard as it would also allow over-stressing of the final drive in lower gears. 

I did some more looking at the Hyper 9 specs and I think direct drive should work nicely. I sacrifice a little efficiency at low speed (<~20mph) but that seems to be the only significant detriment. 

Hyper 9 curves: http://www.go-ev.com/PDFs/HyPer_9_120V_Performance.pdf


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## brian_ (Feb 7, 2017)

Kilomike said:


> As for you comments on the spitfire in general, I completely agree and I think you hit the nail on head about some of my concerns. I chose the spit because of the styling and availability. I paid $2500 for a running spitfire with a clean body. I worry about the rear suspension, but at the same time my only intent is to use this to turn heads and drive the 12 miles each way to work. I'm not looking for crazy performance and I don't ever plan to run autocross with it. I just want it to be fun to scoot around town in. This also lets me get away with an approx 10kwh pack, which at ~250wh/mi, should give me a 30-40mi range.


That all seems reasonable to me. I would add that running an autocross (assuming you mean a pavement autoslalom, not a rallycross type thing!) is reasonable, too, since the "swing spring" design of the later Spitfire suspension calms down the swing-axle silliness. As long as you limit the torque to a reasonable level, pushing it around a course shouldn't be a problem for the car.

While searching to confirm that the 1976 would have the swing spring, I ran across an online discussion in which a Spitfire owner was proposing rear spring changes (to an earlier variant). A wise participant noted this:


> The thing about a Spitfire is by the time you're putting down enough power and have enough traction that the spring rate is a concern, you have much more important things to worry about, like the differential, u-joints and axles.


This goes well with my thinking, that keeping the power - and the tires - reasonable means that you don't really need to worry about a lot of other things, in both drivetrain and suspension.



Kilomike said:


> Going with the Hyper 9, I do worry about blowing up the final drive/tranny. I'm almost certain it would destroy the tranny if I let it loose. That's another reason why I'm leaning toward going straight to direct drive. It looks like the final drive should be able to handle the 1:1 ratio torque (173ft-lb advertised peak vs your stated 287ft-lb stock load). Using the tranny may actually be bad in that regard as it would also allow over-stressing of the final drive in lower gears.


You could program the controller to limit the current (and thus torque to the transmission and subsequently the final drive), which wouldn't take full advantage of the motor at low shaft speed, but wouldn't change high speed operation. Eliminating the transmission is an obvious solution, which wasn't so desirable with typical 9" DC motors but more feasible with the HyPer 9; however, it is effectively like driving in 4th gear all the time, while the final drive could withstand 3rd or even 2nd.



Kilomike said:


> I did some more looking at the Hyper 9 specs and I think direct drive should work nicely. I sacrifice a little efficiency at low speed (<~20mph) but that seems to be the only significant detriment.
> 
> Hyper 9 curves: http://www.go-ev.com/PDFs/HyPer_9_120V_Performance.pdf


Losing the lower gears means losing the resulting torque multiplication and the ability to keep the motor in a more efficient speed range... which as you say only matters significantly at lower speeds.

If you run higher voltage, you have the option of using the HyPer 9HV, which (if given enough voltage) can provide a broader range of speeds over which full power is available. On the other hand, given the stock tire diameter (22.8" and 914 rev/mile for a 155SR13), and a final drive ratio of 3.89:1, a mile per minute (60 mph) would be 3555 rpm... so maybe all of the area of power improvement would be at speeds you'll never drive anyway without a transmission or other reduction gear.

I think this is the core of the single-speed problem: with enough voltage a modern motor can work well over a wide range of speeds, but the range is likely to extend up to 8,000 to 12,000 rpm. That means one ratio is fine, but it should be a much greater ratio than a typical final drive contains; in fact, production EVs all use two reduction stages to get the desired overall ratio. There is one production EV motor which was designed to work with a ratio similar to the Spitfire's 3.89:1, and that's in the Chevrolet Spark EV. Unfortunately, that's not the most common EV motor, it might be difficult to run with a readily available inverter (and the stock inverter would require hacking), and it's large in diameter. A HyPer 9 is a more practical choice, even though its speed range doesn't match the available gearing well.

The other really effective fix to the motor/gearing mismatch is to add simple fixed reduction gear to the back of the motor, instead of the multi-speed transmission. This can make a relatively small motor effective, by matching its speed range to the operating speed range of the car. Unfortunately, that's not a trivial bit of hardware: the only one I'm aware of is the ev-TorqueBox, which is a bit of overkill and not cheap (US$3500).


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## Duncan (Dec 8, 2008)

Or you could throw the Hyper9 away and get a normal 9 inch forklift motor which will produce more than enough torque and rpms for a great machine at a fraction of the cost


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## Kilomike (Sep 14, 2018)

Brian,

I plan to keep the stock tires, so it sounds like I shouldn't have too much to worry about with the final drive/rear suspension for the near future. I've been concerned about needing to do a complete rear-suspension replacement, but it sounds like I should be ok. If not then I'll cross that bridge when I get to it. I plan to limit the peak current to somewhere in the 500-600A range, so I think my concerns about the final drive are mostly settled. 

As for the RPM range, that was the only reason why I even consider keeping the tranny. I figured I would only use 2nd and 4th or just leave it in 3rd. Realistically, in direct drive I'll probably not get past 4000rpm, which is really under-utilizing the Hyper 9 (and AC in general) capability. 



> Losing the lower gears means losing the resulting torque multiplication and the ability to keep the motor in a more efficient speed range... which as you say only matters significantly at lower speeds.


This has been my main concern, but looking again at the advertised curves for the motor, once I get to ~20mph I should be up around 87% efficient. I think that's good enough. 

I've considered the HV Hyper 9 as well, but I haven't really seen the benefit. since I only want an ~10kwh pack, and the leaf modules are ~60Ah 7.4V each so a 2P14S pack of modules will give me ~104V and 120Ah (~12kwh). I can go higher voltage, but it really just gives me a bigger pack that I don't necessarily need. I am probably going to up to ~120V though just because the only real cost difference to do so is the bare modules.

Real quick on the battery. This is where most my research has focused and it seems like the Leaf modules are both the easiest and most cost effective to work with. I can buy the bare modules for ~$150/kwh which seems to blow everything else out of the water, but I am worried about their peak draw capability. I heavily considered building a custom 18650 pack, but not wanting to use salvage cells puts just the cell cost north of $3k for a barely 10kwh pack. And that doesn't even consider the HUNDREDS of hours to actually build the pack! I haven't looked hard at other production EV packs, but from what I've seen the leaf modules are about the easiest to get and work with.

Lastly, back on trying to match RPM to gearing, I have considered building a custom fixed ratio tail for the motor. Something like 1.25:1 which would let me use a lot more of the Hyper 9 capability. That said, it doesn't do me a ton of benefit at low speed, so I don't think it's worth it. And I have no idea yet what it would cost, just in materials, for me to build such a tail. I've looked at the ev Torque-Box but I think it is both too big and too expensive for this project. Total EV conversion cost I expect to be $8-10k. An additional $3500 just doesn't seem worth it or necessary. 

Duncan,

Using a DC forklift motor is actually where I originally started on this project. I was inspired by the super cheap conversions on youtube. But I haven't had much luck finding a usable motor. Local craigslist and such are an empty desert. Ebay has some, but anything under $1k doesn't have any information with it and I'm pretty gun-shy being a first timer. Things like advancing timing and inspecting the coils for over-volting/current capability is just a little out of my wheelhouse. I considered using a Warp 9, but at $2k+ (not counting controller) we're back up in the price range of the Hyper 9 IS package (~$4150 including controller). Plus, I like having regen capability, reverse on a switch (with no extra hardware), and less maintenance than DC. And I can't discount the benefit of having a company I can call if I have to for technical support. 

I'm open to going back to DC, but I simply haven't seen enough cost benefit to outweigh what AC offers. And the Hyper 9 seems to just be the best AC package on the market at the moment.


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## brian_ (Feb 7, 2017)

As with other modern motors, there are performance graphs for the HyPer 9 showing output over the full speed range of the motor, given various supply voltage limits.

For the same supplier's brushed DC equivalent (WarP 9 or another size), Netgain provides only those silly charts resulting from clamping a brake on a spinning motor, so there is only (questionable) data from free-spinning speed down to something near the torque peak. Is there any useful source of objective data for the torque (or power) output of a "forklift" motor over the speed range which is actually used in a car? Or do people just assume that the torque and current from stall to peak torque speed are constant at the peak values?


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## Duncan (Dec 8, 2008)

Hi Kilo

They take a bit of finding but there are lots of forklift motors out there for scrap metal prices - I have bought a total of four ranging from $100 to $200


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## Kilomike (Sep 14, 2018)

Brian,

What you state is all that I've been able to find as well. At best I've been able to dig up a stall torque. Nothing about max RPM, efficiency, etc.

Duncan,

How much of an issue is advancing timing and brush maintenance? What other concerns are there with going DC? Saving ~$2k is definitely enticing. It does seem that they are somewhat less efficient than SRIPM AC (~80-85% compared to ~94%). I'm open to the idea, but I'm gun-shy to minimal data and not having the technical background with them. 

Where do you find the motors at that price? 

Another reason why I've leaned toward the Hyper 9 is it is IP67 rated according to EVWest's page. But now that I look at literature on go-ev.com I'm not seeing any such claim. The only thing I've found is IP54 (limited dust intrusion). If it is in-fact IP67 then that will help a ton, because I am certainly concerned about moisture under the vehicle. It rains almost every day here from late June through late August. The more I look, the more I find wrong on EVWest's page for the Hyper 9. The motor curves they show do not match anything that I've found in other literature.

Kevin (Kilomike)


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## brian_ (Feb 7, 2017)

Kilomike said:


> Another reason why I've leaned toward the Hyper 9 is it is IP67 rated according to EVWest's page. But now that I look at literature on go-ev.com I'm not seeing any such claim. The only thing I've found is IP54 (limited dust intrusion). If it is in-fact IP67 then that will help a ton, because I am certainly concerned about moisture under the vehicle.


The HyPer 9 motor is made for Netgain by SME; Netgain is just the distributor (although EV West lists them as manufacturer). It is one of their "SRIPM" series. SME's web page for this product is a bit general, and I don't see any indication of the IP code rating, but you could ask them.



Kilomike said:


> The more I look, the more I find wrong on EVWest's page for the Hyper 9. The motor curves they show do not match anything that I've found in other literature.


The more links in the communication chain, the greater the errors...

The motor performance graph shown by EVWest appears to be from Netgain, but is for 64.5 volts RMS at the motor or 96 V DC supply, which doesn't match the EVWest package description (of 120 V); it doesn't even look quite like the 96 V grapsh published on Netgain's website. The shape suggests to me that it might be for the HV motor, but it's not labelled that way and Netgain only publishes 120 V and higher for the HV. SME does not publish details for the specific motor which they supply to Netgain.


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## brian_ (Feb 7, 2017)

Kilomike said:


> Brian,
> 
> What you state is all that I've been able to find as well. At best I've been able to dig up a stall torque. Nothing about max RPM, efficiency, etc.


Efficiency is one of the data items in the performance charts for Netgain's brushed DC motors, but only for the speed range of the test. They only publish data for 72 volts supply voltage, but here it is in what I find to be a more useful form... but it's the same data as their graphs so it still doesn't cover most of the working speed range of the motor.


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## MattsAwesomeStuff (Aug 10, 2017)

I love a build thread that multiple people are excited about!

Mike - Don't look at Ebay or craigslist. Look up every forklift repair place in your area. Show up in person and ask if they could keep an eye out for 9" DC motors on any lifts that they're scrapping and to give you a call.

Offer to pull the motor out yourself, with your own tools, if they'll let you, they might.

Depends on the shop, some might go through the effort of taking them out (if it's not removed it's worth 1% at the scrapyard as it'll get attributed to basic steel rather than copper/iron). They might have some available that they'll sell you for scrap price or slightly less.

Scrap prices are currently low, so, $100-200 is about a fair rate.

If the first place says no, ask another.

They're functionally bulletproof. Make sure it's not rusted all to hell or corroded inside, and has intact brushes (you can see them), maybe bring a spare car battery to see if they'll spin up.

Brush advancing is as simple as drilling 2-4 holes and rotating a plate a few ballpark degrees. It's not super precise.

Brushes last just about forever.

You'll give up regen. This is about a 5-10% difference in range, way less than everyone presumes.

And then boom, save $2000. Build your own controller from several of the plans available, boom, another $1000 saved probably.

Put the rest into beer and batteries.


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## Kilomike (Sep 14, 2018)

brian_ said:


> The motor performance graph shown by EVWest appears to be from Netgain, but is for 64.5 volts RMS at the motor or 96 V DC supply, which doesn't match the EVWest package description (of 120 V); it doesn't even look quite like the 96 V grapsh published on Netgain's website. The shape suggests to me that it might be for the HV motor, but it's not labelled that way and Netgain only publishes 120 V and higher for the HV. SME does not publish details for the specific motor which they supply to Netgain.


This is exactly what I'm referring to. I'm not sure where the graph came from, but it makes it seem like high efficiency isn't achieved until almost 3000RPM, whereas all other charts show it around 1200RPM. I can work with low efficiency up to 20mph, but no up to 50mph!

I really appreciate the input! Now I'm itching to get started on the car, but I've got to finish renovating the garage first! 

I did just think of one other question on going direct drive. Will I need to allow for axial play between the motor and final drive? If I understand correctly, the TransWarp 9 has a slip-yoke spline for the U-Joint output to allow for some axial play. Will I need to devise something like this? I was hoping to just mount one of these below on the motor shaft and just hook directly to a custom length drive shaft. Allowing axial play will definitely be a challenge, but should be doable if needed. I'm just not sure if it's actually needed!

http://www.evwest.com/catalog/product_info.php?cPath=44&products_id=428


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## Kilomike (Sep 14, 2018)

Brian, 

I totally missed your second post! That's the first curve set I've seen for a DC motor. And yes, the range I really care about (<1000RPM) is completely skipped. That seems like a very important region to neglect, even for mounting up to a tranny. 

Matt,

Welcome to the thread! I'll do some looking and make some phone calls this week and let you guys know what I find. I still prefer to go Hyper 9 from a technical point of view, but that much potential savings is hard to pass up... 

I usually take the approach of using whatever is cutting-edge technology and somewhat reasonable price wise. Part of my desire for Hyper 9 is somewhat ego driven. Being able to quote high efficiency and point at leading technology is a big plus to me. That said, pointing at an old forklift motor and a homemade controller has it's own ego boost as well. OH THE DECISIONS!!! I'll have to do some serious thinking if I come across a deal on a good DC motor.

On advancing timing real quick. About how much is timing usually advanced? And I'm assuming you just change the rotational location of the commutator end plate? Lastly, by advancing the timing don't you lose the ability to use a reversing contactor for reverse? So therefore I'd need to keep the tranny?


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## brian_ (Feb 7, 2017)

Kilomike said:


> I did just think of one other question on going direct drive. Will I need to allow for axial play between the motor and final drive? If I understand correctly, the TransWarp 9 has a slip-yoke spline for the U-Joint output to allow for some axial play. Will I need to devise something like this? I was hoping to just mount one of these below on the motor shaft and just hook directly to a custom length drive shaft. Allowing axial play will definitely be a challenge, but should be doable if needed. I'm just not sure if it's actually needed!
> 
> http://www.evwest.com/catalog/product_info.php?cPath=44&products_id=428


There will be some movement of the final drive in its mounting bushings, so there needs to be either some axial freedom in a component of the shaft, or some longitudinal compliance in the motor mounts. Vehicles always handle this in the shaft (not by having the shaft shift the engine and transmission), and I wouldn't to depend on motor mount compliance, for the sake of the motor bearings.

EV West may be counting on that compliance, or assuming that there is a plunging or slipping section of the shaft. Allowing the transmission output yoke stub to plunge is common, and what the TransWarP motors are set up to do; however, in some propeller shafts there is a slip joint (splined and sliding section of the shaft), especially in the rear section of a two-piece shaft (which has a support bearing midway between the transmission and the axle). The most straightforward way to avoid problems would be to use a slipping section of shaft with that fixed yoke on the motor.


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## Kilomike (Sep 14, 2018)

A sliding spline drive shaft sounds like the ticket for sure. Axial loading the drive shaft is just going to wear out U-joints. Looking real quick online it looks like some Triumph drive shafts are the sliding-spline type. I'll have to see what mine has when I start pulling it apart. Worst case I think I'll just have to find a sliding spline drive shaft from a different vehicle that is the correct length. I still have no idea where the shaft of my motor is going to end up in the transmission tunnel.


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## brian_ (Feb 7, 2017)

Kilomike said:


> A sliding spline drive shaft sounds like the ticket for sure. Axial loading the drive shaft is just going to wear out U-joints.


I agree, but the rear suspension of a Spitfire carries all of the lateral load through the axle shaft U-joints... which seems to work.



Kilomike said:


> Looking real quick online it looks like some Triumph drive shafts are the sliding-spline type. I'll have to see what mine has when I start pulling it apart.


I didn't even notice if our Spitfire has a sliding section; if it does, the problem is solved. 



Kilomike said:


> Worst case I think I'll just have to find a sliding spline drive shaft from a different vehicle that is the correct length. I still have no idea where the shaft of my motor is going to end up in the transmission tunnel.


Or get one made up, with the appropriate yokes; it's a routine service from driveline specialty shops.


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## Kilomike (Sep 14, 2018)

I think everyone agrees that the axial load on the half-shafts is a bad idea though. Triumph got it to work in that application, but I wouldn't count on it elsewhere. 

I just tried crawling under the car, but I still can't tell what style driveshaft mine has. I'll just have to wait to find out I guess. And yes, when it comes that time I will find a drive-line shop and just have them provide one. Whether it's custom made or an off the shelf I really don't care. I just want it to be professionally done. Last thing I want is my DIY driveshaft vibrating like crazy or separating!


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## Baratong (Nov 29, 2012)

Hey, I haven't visited in a while and am happy to see another Spitfire conversion ongoing! 



I really love driving my '79 Spitfire. You've probably looked at my thread by now, but I started out planning on direct drive. After working through the numbers I decided it wouldn't have the performance that I wanted out of the build (I do like the jackrabbit starts off the line) so I switched to a Borg Warner T5 (1352-246). The gearing matched what I had spread sheeted as an ideal (for me) performance. 



During normal around town driving I usually start in 2nd gear and shift to 4th. It is nice however to have 1st for the fast starts, and overdrive for highway driving -- it has no problem doing 85mph. My spreadsheet of the overall performance predicts it would have a top speed of ~120 @ 4900 rpm in overdrive.


I'm looking forward to seeing your build progress...


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## Kilomike (Sep 14, 2018)

Baratong,

Thanks for the input on direct-drive vs. tranny. I'm still torn. I'm not terribly concerned about performance, so I think Direct with the Hyper 9 will work. If i go that route then my backup plan is to make a small single speed "transmission" that will bolt onto the face of the motor. AC will allow 6-8k peak RPM, and going direct drive only lets me realistically use about 4k rpm. A ~1.25 ratio at the motor would be very helpful....

On your thread, I started reading it last week, but actually just finished tonight. I'm amazed by your BMS system. Your electronics skills are lightyears ahead of mine. That said, I'm leaning towards an Orion for the simplicity. In your experience, is this a good option? Or what else should I consider?

Also, on your batteries, what drove you to use LiFePO4 bricks? It looks like you started in 2014. Were there production lithiums available at the time or were the bricks the only real option? I'm planning to use Gen1 Leaf Modules because they're about $150/kwh and a lot more energy dense than LiFePO4. What are your thoughts on Li-Ion vs LiFePO4?

Kevin


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## Kilomike (Sep 14, 2018)

Well, no luck on finding a forklift motor locally. I looked around and could only find one shop that actually repaired/serviced forklifts within 2 hours of here. I talked to them for a few minutes over the phone, told them what I was looking for and why. They said that they hardly ever get any electric fork trucks in and it's once in a blue moon that it would actually be scrapped out. He couldn't even remember the last time they had an electric one in. He did say that they sometimes will have the smaller walk-behind style, but it's my understanding that the motor on those is a little too small. 

Anyways, I'll still keep my eye out for a good deal, but I'm just going to stick with the Hyper 9 plan. 

On another note, I'm about halfway done renovating my garage, so I'm getting closer to actually starting on the Spit!

Kevin


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## Moltenmetal (Mar 20, 2014)

Consider me subscribed!

My E-Fire was a lovely beast- unfortunately it was destroyed back in July by an inattentive driver changing lanes in a big pick-up truck.

A few cautions with your plan:

1) Use production EV batteries from a wrecker- Volt, Leaf etc. Give up on the LFP bricks because they are handy but way, way too expensive and regrettably not getting sufficiently cheaper.

2) Use a BMS. Minimally necessary safety equipment. 'nuff said on that.

3) Throw away the Triumph transmission- it's not up to the job. 

4) I vote for keeping a tranny so you have speed/torque options. It improves the fun factor of driving by a lot, in return for very little efficiency loss and extra weight. I used a Toyota W50 in mine but you can use any number of options. Making a transitional driveshaft is comparatively easy if you have a lathe and a welder, but a driveline shop can do it for you too for not too much money.

5) The weak spot is the differential and the half shaft u-joints. The suspension transmits thrust when cornering through the U joints into the bearings of the diff. Go with greasable ones and then you do need to grease them. Changing them properly requires removal of the whole axle assembly which involves disconnecting the brake lines- messy but you get good at it rather quickly. Drill a drain hole in the diff casing so you can change its oil.

DC will not give you regen braking so that will mean you'll be relying on the original brakes- front discs, rear drums. That's OK as long as you know that the car's acceleration performance will not be matched by its braking performance...and no "free" power brakes either. You're going to have to step on them hard to lock them up.

Do a good job with the transmission mounting plate and hub or else you'll burn up transmission input shafts and bearings. Tolerance is about 5 thousands of an inch, not more. I pushed the "easy" button and bought a plate and hub from CanEV- motor installation took at most an hour all in and installation precision was perfect.

Depending on what my insurance company finally offers me (it took 3 months just to get an insufficient first offer from them), I may be looking for a new clean Spitfire. Anybody in the US who sees a nice clean one- no rust, needing minor body work and paint is OK- with a blown engine, say an Arizona/New Mexico/California car, I might be interested- send me a PM if you come across a real beauty. Not yet, and not at all for certain- I may be stranded without enough money to make re-doing an E-Fire Mark 2 a worthwhile effort.


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## Kilomike (Sep 14, 2018)

Molten,

Thanks for all of the feedback. I absolutely agree with 1, 2, and 3. For the batteries I'm planning to use Gen 1 modules from a Leaf. That may change to Gen 2s depending on price when I go to buy. BMS if a definite (planning to use an Orion BMS since I'm rather ignorant on the topic). And I'm certain that the Hyper 9 would destroy the tranny and probably the final drive if I left the Tranny.

On the talk of the tranny, I'm still torn about using one or not. RPM wise, direct drive works out very well (~3400 rpm at 60 mph). Being an SRIPM motor, the Hyper 9 has near full torque at ~0 rpm all the way up to ~3600 rpm. Correct me if I'm wrong, but I believe that DC motors don't get full torque until ~100 rpm (can't remember where I read/heard that). If that's true, then I can see needing a tranny to get off the line with a DC motor (or pure inductance AC), but maybe not with the Hyper 9. 

A 2 speed transmission seems like it would be ideal, but I'm not willing to pay $3-5k for a powerglide (or similar). I've kicked around the idea of building my own ~1.25:1 single speed transmission and pushing the motor RPMs up into the 6000 rpm range at highway speeds. If I go that route then I'll definitely have to do forced air or liquid cooling on the motor though, as it's continuous rating is only 3300 rpm. 

It all really depends on what performance is going to be like and what I think I need (which I have no idea...). The car currently has the week 1500cc motor in (with problems), and I'm not very good on stick and it still seems to scoot about with plenty of pep (when the carb actually feeds fuel ). 

On making a custom drive shaft or adapter plates. I have a full size mill and lathe as well as welders, grinders, etc. I think I can make just about anything I need, although I'll probably pay to have a proper drive shaft made. I'm really excited to get started. Just have to finish renovating the garage first! Almost done wiring, next up is insulation....

P.S. I didn't mean to put the angry face on the subject line...


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## Duncan (Dec 8, 2008)

Re - Getting off the line with a DC motor

https://www.youtube.com/watch?v=LUpyAY2sFWw

You do lose some initial torque if you advance the brushes - I think I lose about 20%


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## EVSpitfire (Feb 28, 2014)

hi Kilomike.
I have over the years gone through this process and collected all the parts for my Spitfire build. Struggling to find the time to get started, life, business etc. but business sold now, so should be soon!
FYI, the powerglide i also looked at and purchased, but decided to use on an alternate project, as the size is rather prohibitive. i also looked at W58 5 speed but felt was over kill... in the end for what it's worth. i decided on a UQM 100kw 300nm motor with direct drive. I've made and sold a dozen kits to fit a Subaru diff direct into the spitfire chassis. I've opted for a LSDV (viscose) 4.44:1 diff. the numbers suggest a 6.7 sec 0-100klm. hope to put a build site up once i get started.


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## Kilomike (Sep 14, 2018)

Duncan,

I assume that's with a transmission and in first or second? Either way, impressive! I am hoping to avoid that though. Prefer to not break the wheels loose... It would be cool to be able to for showing off, but nowhere near a design goal.

EVSpitfire,

Sounds like you'll have quite the setup! A quick search on that motor shows some impressive specs. 221 lb-ft of peak torque, 80 HP continuous. Far better than the 173 lb-ft peak and ~50hp continuous of the Hyper 9. Alas, the cost and voltage is prohibitive for me though. Looks like ~$6500 and 300+VDC compared to the Hyper 9's ~$4200 and ~100VDC. I don't need a huge battery pack,so getting that kind of voltage would be tough for me. Either way I can't wait to see how yours works out! Your 0-100kmh should be impressive!

I am very interested in your subaru diff swap! That ratio would be perfect for what I'm wanting and word on the street seems to be that they can actually handle the instant torque of electric. Is it a direct sub for the diff, or do you also have to make major suspension mods? Any info you can share or point me to would be great. I'm already betting 50/50 that my diff will implode in the first year.

I can't wait to see your build thread/site!


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## Duncan (Dec 8, 2008)

Kilomike said:


> Duncan,
> 
> I assume that's with a transmission and in first or second? Either way, impressive! I am hoping to avoid that though. Prefer to not break the wheels loose... It would be cool to be able to for showing off, but nowhere near a design goal.


Nope - direct drive to a Hitachi forklift motor - no gearbox 

And - this may be relevant - through a Subaru LSD


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## Kilomike (Sep 14, 2018)

WOW!! I didn't expect that could be a direct drive. Do you know what kind of torque it puts out at low rpm? I wonder how much more it is than the Hyper 9. 

And how difficult was the subaru diff swap? Rough math suggests the triumph diff **should** be able to handle the torque of the Hyper 9, but I don't have that much confidence.

Kevin


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## Duncan (Dec 8, 2008)

Hi Kilomike

I started with a Subaru diff - complete Subaru back end - and front end as well!

But EVSpitfire is talking about putting a Subaru diff in a Spitfire - which sounds to me like a very god idea!

Don't know how much torque - I have bought some nice new sticky rear tyres "Nitto" - they say "recommended not for highway use" on the sidewalls - and the damn thing still breaks them lose - but a lot more controllably

I am feeding my Hitachi with 1200 amps and 340 volts - and I did kill my first one at the Drags last march - but I got another for $150 (and a "spare" for $200)


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## Kilomike (Sep 14, 2018)

> I am feeding my Hitachi with 1200 amps and 340 volts


That has to be ridiculous amount of torque!!!! I'm planning for 100-120 volts and ~700A peak. I'm doubting mine would break the tires loose if I go direct drive...

Where are you finding such motors for so cheap? I tried the 'local' forklift place (closest one is 2 hours away) with no luck. Said they almost never work on electrics anymore. I see motors that look like they could work on ebay for ~$1k (maybe $600ish), but I don't know enough about them to confidently buy. I'm also not thrilled with the idea of a reversing contactor for reverse (assuming I go direct drive).


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## Duncan (Dec 8, 2008)

Hi Kevin

You need to find where the forklifts go - there will be electric forklifts at places that do food or soft goods
Anything that would be spoiled by some exhaust soot

Find out who repairs them - and then visit - email and telephone are no good
You need to talk to the oily rags who do the work - they are the ones who will have stored up some motors "just in case" - you will require beer or folding money - or both to prize them loose

It took me quite a while to find our local elephants graveyard!

A decent motor is about 100 kg - and is an awkward heavy object that is normally only worth scrap metal value - $200 

Which is why e-bay is no use

I'm at the bottom of South Island - our nearby "big City" is about 50,000 people - I'm sure that there will be a lot more where you are


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## piotrsko (Dec 9, 2007)

Los alamos is probably too small for forklift rebuilders, but Phoenix isnt. 
Raymond does electric , as does hyster, perhaps toyota, so you need independent rebuilders of those. Typically anywhere there is an amazon or walmart distribution center. 
Brown & mills is a motor rebuilding shop chain.


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## Moltenmetal (Mar 20, 2014)

Note that Duncan has a lot more voltage than you're planning, so he can push a lot more current through his motor.

I'll let the DC drive guys inspire you with how to do what you're planning and wish you good luck.

Note that the Subaru diff may improve reliability and may help with a more favourable final drive ratio for a direct drive- basically equivalent to driving my E-Fire in 4th gear. I can tell you that with my HPEVS AC50, the car would be an embarrassment to drive if it was always locked in 4th gear. DC motors do have more low end torque, which drops off as you go to higher speeds. They also need brush maintenance, and numerous people here have had motors pack up on them and need major re-work or replacement. Some manage to get them to last fairly well- sometimes on their 2nd attempt though.


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## Duncan (Dec 8, 2008)

Hi Molten

The extra voltage helps the rpm - not so much the current

At one stage I had my controller set to 1000 amps but a 130v battery

It still took off like a scalded rat - but it was speed limited - as in full throttle gave me 100 kph - just 

It only takes a few volts to get 1000 amps at zero rpm but the back EMF rapidly rises and at about 3500 rpm the 130v could only push 200 amps through the motor


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## Kilomike (Sep 14, 2018)

I really appreciate all the feed back. I'll look around again for a forklift rebuild shop. Los Alamos definitely does not have a forklift shop, and from what I've heard Santa Fe doesn't either. I talked on the phone to the only one I could find online, which is down in Albuquerque. I'll look around again though. Phoenix is 8 hours away....

I still hesitate to go DC though as I sort of fancy the idea of direct drive. DC, and the limitation of advancing brushes and such, concerns me. I mean, there's a reason that all of the OEMs use some kind of AC correct?

Molten, I can definitely agree with your assessment of Direct Drive with the AC50. But I think the Hyper 9 will be in a better position to handle it. The Peak torque is 44% higher and power is ~90kw (~120hp) at the same rpm point as the AC50's peak power (~71hp at ~3500 rpm). As long as I can take off at a stoplight at a rate similar to normal driving of an ICE, then I'll be happy. From there I'm confident I can get the speeds I'll need for my drive to and from work. 

Technical question: I know back EMF is a big issue for DC, is it for AC though? I'm not an electrical engineer, but my understanding of how the motors work would suggest that it isn't as much of an issue since the field is in constant flux instead of discrete steps field-to-field of DC.

Wife and I are going on a mini vacation, so I may be off for a few days. Again, thank all of you for the input and awesome discussion.


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## brian_ (Feb 7, 2017)

Kilomike said:


> DC, and the limitation of advancing brushes and such, concerns me. I mean, there's a reason that all of the OEMs use some kind of AC correct?


Yes, even forklift trucks use AC now. Of course, the priorities of a manufacturer and of a DIY builder may not be the same.


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## EVSpitfire (Feb 28, 2014)

Hi Kilo
See attached first-version of adapter plates with diff (I've modified them slightly from this) Rear plate, Top Spring plate, and forward plate, which all pick up existing Spitfire mounting locations.
The big thing is whether you decide to stay with the existing swing spring setup. If so, you must use the Datsun 510 diff which is exactly the same casing as Subaru diff, (not sure of ratio options) however the difference is the Datsun510 has bolt in stub axles which are required for the lateral load from the swing spring half shaft design. Adapter flanges required can bolt straight onto existing half shafts. The subaru/forester diffs use CV splined shafts held in with snap ring and can not take any lateral load.

Alternatively, in summary... I've gone to the trouble of converting over to the Triumph GT6 Rotoflex with lower wishbone. With other mod's such as MGF bearing, ford fiesta shafts, which then uses the sub'y CV stub-axles. more info available as a starting point for those interested. http://sideways-technologies.co.uk/...iots-guide-to-cv-conversion-on-rotoflex-cars/ and other sites... http://www.teglerizer.com/triumphstuff/spit6whiteyFI/spit6whiteyFI_CV-axles.html 

I should have my motor back in a week with adater finished for direct drive & park-brake... I'll use that to launch me into starting my own page and will go into a lot more detail.
steve


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## EVSpitfire (Feb 28, 2014)

I realized there was no pic of the back plate in last post.

Also see pic of someoneelse's install with rotoflex red Subaru diff.
Also some pic's of the Datsun510 diff stub axle with adaptor plates to go straight onto spitfire half shafts.


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## brian_ (Feb 7, 2017)

EVSpitfire said:


> See attached first-version of adapter plates with diff (I've modified them slightly from this) Rear plate, Top Spring plate, and forward plate, which all pick up existing Spitfire mounting locations.


Good work. 



EVSpitfire said:


> The big thing is whether you decide to stay with the existing swing spring setup. If so, you must use the Datsun 510 diff which is exactly the same casing as Subaru diff, (not sure of ratio options) however the difference is the Datsun510 has bolt in stub axles which are required for the lateral load from the swing spring half shaft design. Adapter flanges required can bolt straight onto existing half shafts. The subaru/forester diffs use CV splined shafts held in with snap ring and can not take any lateral load.


I know a guy who is an almost obsessive 510 enthusiast, who has built many of them, with friends. As I recall he said a while ago that they now use Subaru diffs, because the Datsun hardware is now rare. That will vary by location, of course.


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## EVSpitfire (Feb 28, 2014)

Hi All
For the record. I don't take credit for the original adator plate design and concept! that was actually done by some guys in NZ making kit cars. I hunted them down, and they were not interested in making more, but happy to pass on the info. I now have a third batch in production (10 sets) available to keep them available to people like us. PM me if anyone interested.


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## Kilomike (Sep 14, 2018)

EVSpitfire,

That is some invaluable information about the diff for sure. At least for this first pass I'm going to try to use the stock final drive. I would like a 4.11 or higher ratio offered by some R180 configurations, but I think I need to stay as simple as I can on my build. If I blow up the stock diff then I will definitely be coming back to these posts, but hopefully I can save some time and money in this first year!

On the hardware, do you have design files you'd be willing to share? I'm a design engineer and hobby machinist. Would love to have them just in case, and if people in the US are interested I could go about getting a small production run made. 


In other news, I'm closer to getting the garage ready for the Spitfire! Wiring and plumbing is done. Should be insulating this weekend and putting up walls soon after. With any luck I'll be ready to start disassembling the Spitfire in November! Now the question of when to start ordering hardware comes to mind....


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## piotrsko (Dec 9, 2007)

Fwiw: the stock pinto 4 banger differential held up suprisingly long with the built 302 pushing it. It died due to lack of lube one hot night in Yuma.


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