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Thinking about electrifying the Weissach...

 
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jacobroufa  



Joined: 18 Nov 2016
Posts: 291
Location: Rockford, IL

PostPosted: Mon Aug 10, 2020 4:00 am    Post subject: Thinking about electrifying the Weissach... Reply with quote

I've been researching all this for awhile, and I'm very nearly ready to pull the trigger. The hardest thing for me has been to decide which car to convert, as I'm quite sentimental about all my vehicles for various reasons. It's been a toss up between this and our '63 Beetle sedan.

The Weissach I have tried to keep clean and original to the extent that I can. I used it on the track a few weeks ago, and discovered that world -- I think my 931 will become a track toy, and keep me in the transaxle internal combustion world quite nicely. I really have grown to enjoy these cars..

One of the things I'm struggling with is that because of that originality, and how much I enjoy that facet of this hobby -- maintaining that originality and collecting patina -- I wonder how much I'll miss of it.

Anyway, it all kinda lines up. The car is not worth much as any sort of investment. Folks been saying for years 924s will gain value and maybe the 931s but not the plain ole toofah... I doubt it's worth what I've got into it over the years, and so that seems (in my mind) to make it a worthy candidate. That's a big part of why I chose this over the Beetle; ultimately they're both pretty original but that one is actually worth something as an investment.

Writing all this out feels freeing. I've never been big into car modification. I really dig "OEM+" type upgrades, if anything. There's a big place for that in the automotive hobby writ large, but I think it's time to dip my toe in a bigger (and growing) pool...

--

Rough plan:

* Tesla Small Rear Drive Unit (peak power ~290 hp, peak torque ~240 ft. lbs.)
* OpenInverter.org replacement PCB
* Nissan Leaf battery pack and BMS

I want to keep the car stock looking as possible, and maybe even to the point where someone could return it back to stock if they wanted. I will come up with some way to mount the motor to points where the transmission currently sits, and likewise with battery system and all. In a perfect world I will also be able to keep the weight distribution even split.

I want my controls to be the same -- e.g. won't upgrade to power steering. Would like to set up a couple switches in a shifter coupler or bracket, for instance to push forward to engage Drive and rear to Reverse. It will still need a cooling loop, so calibrate a sender to interface with the stock coolant gauge displaying roughly the "correct/warm" value in the center of the gauge. Battery has a capacity, so again come up with an interface to the stock fuel gauge. Utilize the stock speedometer because cable driven so why not. Probably replace the tach with my take on a modern Porsche screen gauge unit where you can switch between some controls and info, if I can source a round screen...

Primarily I'm just concerned at the moment with getting this going; stripping out all the ICE gear, getting the motor, mocking up mounts..

I have one more DE day in the fall at which I want to drive this since the 931 is not quite ready, then I think I will begin.
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Paul  



Joined: 02 Nov 2002
Posts: 9452
Location: Southeast Wisconsin

PostPosted: Mon Aug 10, 2020 4:24 am    Post subject: Reply with quote

Something like this?

https://www.ebay.com/i/143436105904?chn=ps&norover=1&mkevt=1&mkrid=711-213727-13078-0&mkcid=2&itemid=143436105904&targetid=4580909046526137&device=c&mktype=&googleloc=&poi=&campaignid=395665104&mkgroupid=1236950791146267&rlsatarget=pla-4580909046526137&abcId=1129776&merchantid=51291&msclkid=bb877550e61016050eed2a60d49b39b7


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jacobroufa  



Joined: 18 Nov 2016
Posts: 291
Location: Rockford, IL

PostPosted: Mon Aug 10, 2020 4:52 am    Post subject: Reply with quote

Paul, no more like this:
https://www.ebay.com/itm/114255626892

The large drive unit like you posted has way more power potential than I am looking for, is also physically bigger and heavier, and the small drive units are also more efficient from what I understand.

I've also thought about a motor from a Nissan Leaf (such as https://www.ebay.com/itm/233548354360 ), as they can push ~150 hp and have more torque than power. They can be found for way less cost than a Tesla motor also.. Not much more power than e.g. a tuned 931 but instant torque from zero and all the benefits of an EV would make it a riot of a car nonetheless.
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jacobroufa  



Joined: 18 Nov 2016
Posts: 291
Location: Rockford, IL

PostPosted: Mon Aug 10, 2020 4:54 am    Post subject: Reply with quote

Not to mention that you can get a motor with an aftermarket controller already installed and all the controls you need -- just bring your own battery -- for roughly the same cost as the ebay link you posted.

https://hsrmotors.com/products/driveunits/large/base
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Paul  



Joined: 02 Nov 2002
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PostPosted: Mon Aug 10, 2020 4:57 am    Post subject: Reply with quote

Looks like a challenging conversion. Custom powertrain mounting points, custom drive shafts, fitting the batteries in the front, etc.
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2066
Location: MI

PostPosted: Mon Aug 10, 2020 5:21 am    Post subject: Reply with quote

You ever drive one of these electric cars?
I haven't, but I'd be wanting a test drive in one of them to see if I even like it before committing to something like this..

Maybe you could find another 924/44 to "save" by doing this conversion on it instead of tearing up a pretty nice one?

Also sounds pretty expensive..
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jacobroufa  



Joined: 18 Nov 2016
Posts: 291
Location: Rockford, IL

PostPosted: Mon Aug 10, 2020 6:01 am    Post subject: Reply with quote

Paul, I'm hoping it'll be something of a challenge!

Eddie, actually no... I feel silly now haha... I mean, nobody has ever asked me this... the idea in my head has been there for years now and I've kept it mostly between me myself and I. Just fantasized about it as shops like EVWest have popularized the idea of a conversion.

Thanks for asking though, I needed that. I will plan to drive a few soon, including the Model S and Nissan Leaf from which I'm thinking about taking the powerplants. I have had an idea of what it'll be like, but man you are right. Seat time counts for a lot.. All that said though, a conversion will drive a lot differently than a stock car that the EV motor comes from.

I have also thought about "saving" another 924 (don't really care for 944, I dig the narrow body style) or 924s. There's always a few around, but that adds to my vehicle count and project cost which I'm trying to keep reasonable. An extra $2-3k depending on condition (I'm including cost of refurbing also, which is all up to date on my car) plus the time to spend to fix the components that stay on the car like brakes and suspension which inevitably has to be done..

I'm probably going to be getting rid of one of my vehicles as it stands already (anyone interested in a 1971 VW Type 2 Westfalia?) just so I can do this project, so that has made it hard to accept the idea of getting another. Don't really have the space. If I did, it would be a different story, but I'm a few years away still from building a nice big garage and trying to prioritize a bit.
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safe  



Joined: 18 Mar 2017
Posts: 176
Location: Sweden

PostPosted: Mon Aug 10, 2020 6:28 pm    Post subject: Reply with quote

Some advice....
You probably won't be able to use any of the stock mounts.

Don't be shy with the grinder, just cut away the entire rear floor, fabricate a new subframe to hold the electric drive train and suspension.

If your not comfortable with doing and pulling this off, by a Tesla instead.

There is a guy on youtube that does a lot of Tesla retrofit stuff. Its not that straight forward, its incredibly complicated. You can't take stuff and make it work easily, Tesla isn't the esiest company to work with either, you can't buy stuff from them unless you have a Tesla.
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jacobroufa  



Joined: 18 Nov 2016
Posts: 291
Location: Rockford, IL

PostPosted: Mon Aug 10, 2020 11:12 pm    Post subject: Reply with quote

safe wrote:
Don't be shy with the grinder, just cut away the entire rear floor, fabricate a new subframe to hold the electric drive train and suspension.


I've thought about this, yeah. We'll see what happens, but this is definitely a line of modification I have reckoned may happen... I appreciate you bringing it up! I've made my peace with it, though I'll surely try without, curse and shout, and then say "well what did safe tell you?" and it'll be clear that I need to start cutting.

safe wrote:
Tesla retrofit stuff... not that straight forward, its incredibly complicated. You can't take stuff and make it work easily...


Yeah, I'm aware of the complications regarding Tesla's claimed intellectual property and their lack of sharing and openness about repair parts and such. Have also watched a lot of folks' conversions on YouTube, and read an incredible amount about it over the last decade. This is part of why I have settled on the openinverter.org controller boards -- they are open source and if I need to modify some bit of code, I have that option. Hardware support for it also exists via the creators. There are other controllers available which are not open, and would leave me with even fewer options for support.. Read up on that inverter project and you'll see that it is not reliant on Tesla for any part but the motor (which exists for sale aftermarket on eBay and elsewhere) and has a thriving community of folks who have built EVs with it. It'll be a mix of different parts from various electric cars as well as off the shelf also, not just Tesla. I'm not afraid of some electronic bits and programming.

I also don't really care to buy a Tesla. If I wanted one, I would have another car payment, but I don't. I like my German classic cars. I daily drive a 924 as long as weather permits because I love the driving dynamics of the car..

There's no way I'm going to get through a project like this with ease, I'm pretty well aware. But being an enthusiast who likes 40+yr old cars, nothing is easy in that world anyway... And what constitutes easy or straight forward, anyhow?
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Golten951  



Joined: 14 Jan 2017
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Location: Edwards CA

PostPosted: Sat Sep 12, 2020 7:48 am    Post subject: Tesla Parts Reply with quote

Give Autobahn Parts in El Cajon CA a call. They are parting out a lot of Tesla. Talk to Henry. 619 444 2290 They could help with some of the parts sourcing.
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jacobroufa  



Joined: 18 Nov 2016
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PostPosted: Fri Sep 18, 2020 6:27 am    Post subject: Re: Tesla Parts Reply with quote

Golten951 wrote:
Give Autobahn Parts in El Cajon CA a call. They are parting out a lot of Tesla. Talk to Henry. 619 444 2290 They could help with some of the parts sourcing.


Thanks for the referral, I'll check it out!
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Adie  



Joined: 11 Aug 2004
Posts: 73
Location: Toronto

PostPosted: Fri Oct 16, 2020 1:17 am    Post subject: Reply with quote

If you want a file to build a cross member to fit a LDU into the back of a 924/944 I have one. I blew up my car so I’m going to put it in a 986 now. But it fits the 944 incredibly well
https://photos.app.goo.gl/2teBo7KMP7czARpW6

https://photos.app.goo.gl/Ey9z5Wdx5qGe1t2a7

https://photos.app.goo.gl/maUcZzVQujiYXpgw9

I think you get the idea.
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Adie  



Joined: 11 Aug 2004
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PostPosted: Fri Oct 16, 2020 11:09 am    Post subject: Reply with quote

I also have an arduino that controls momentary buttons to select D N R like the Roadster, obviously you cannot put it in park as there is no pawl like on the roadster but you could easily use a solenoid to activate the handbrake cable
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jacobroufa  



Joined: 18 Nov 2016
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PostPosted: Fri Oct 23, 2020 2:04 pm    Post subject: Reply with quote

Adie, thanks! That's pretty cool, I would probably try to do something similar with the Arduino. I have thought about the LDU but honestly I want to be a bit more moderate for my first swap, hence looking at the rear SDU or Leaf motor.

--

Honestly though this is getting vetoed from the higher-ups. I need to focus on other things like proper storage for the vehicles. I hate to have to post this. We've talked about building a garage but that's 3 years out at least. I can put up a carport next year, but she's put her foot down about an EV swap before a proper garage goes up.. Currently have a mid-century 2-car (17' x 18') which is not bad, but with 7 cars something's gotta give. Good point made that the money I'd spend on a swap is probably equivalent to a down payment on a loan for a really nice garage.. grumble grumble.

Research will continue in earnest for sure, and I may start to build some smaller things such as that control mechanism that I can hide away in a box. I've been building small electronics a lot lately -- working on some guitar pedals and the like -- so I can keep updating with that sort of thing as I do more there..
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