[Electric Land Cruiser]

I was going to link that one... thanks for catching it first.

This is the thread for the build: 300ZX Electric Conversion
The rear suspension is from the S platform, presumably the S13, so if the Leaf unit fits in this 300ZX it will also fit in the subframe (but perhaps requiring body modification) of the same-generation 240SX (for example), and a subframe from any of these models could also work for a Leaf drive unit in another vehicle.

Like most suspensions, the shock extends well above the top of the subframe, and mounts to the vehicle structure rather than the subframe. That's certainly a feature to consider in the potential use of any subframe in any vehicle. Fortunately, it's just a shock-mounted spring, not a MacPherson strut, so it doesn't serve a lateral locating function and takes only vertical force.

you can do it with many car's rear subframe. I'm guessing it would even fit in a Miata's subframe. The point is not to use a 300ZX subframe on a Miata lol.

Most Tesla drive units place the motor(s) behind the axle line, not ahead of it like the Leaf unit - that will certainly affect fit and required subframe modifications. The rear unit of the Model 3 and Model Y is the notable exception, with the motor ahead of the axle line.

Obviously it depends on how it's done and most does not mean all.

 

[Tremelune]

Welding up shock mounts to the frame or subframe seems straightforward as long as the angle is reasonably close to stock and there is no interference through travel. Probably involves cutting into a trunk, but that seems like a given for the rear-subframe approach.

Doesn't the Tesla inverter bolt off, or does that let the fluid out? It wouldn't be hard to rig up some wires for a "remote" inverter.

 

[remy_martian]

It's not as straight forward as you'd think to remote the LDU inverter.

 

[brian_]

Welding up shock mounts to the frame or subframe seems straightforward as long as the angle is reasonably close to stock and there is no interference through travel. Probably involves cutting into a trunk, but that seems like a given for the rear-subframe approach.

It should be straightforward, unless the placement of something (such as vehicle structure) makes it not straightforward.

Doesn't the Tesla inverter bolt off, or does that let the fluid out? It wouldn't be hard to rig up some wires for a "remote" inverter.

The Tesla large drive unit uses cables between the inverter and motor anyway, so I agree that longer ones shouldn't be a problem. Fluids are probably a bigger issue, but it's obviously possible (although not necessarily easy) since it has been done many times.

 

[remy_martian]

The LDU does not use cables between motor and inverter.

It's a contorted internal 3 phase bus bar connection with two of the phases having current sensors integrated with the busbars.

Each phase leg of the inverter has its own coolant inlet and outlet from the gearcase.

It has been done a few times (I know of maybe four), yes, but it is far from a trivial endeavor.

 

[UglyCarFan]

E30 has another spacious trailing arm setup...Track width is 56" (though I think I really want the hub face to hub face measurement):

Tremelune: Are you thinking of a specific vehicle, or is your post about general applications? I agree in principal with your comments, and have thought along the same lines. Saw a guy last year throwing Subaru rear units under all sort of odd vehicles, but they were pretty narrow. I bought a Ford 9" rear end several years ago for a project in order to get better brakes, and a beefier rear axle, but it turned out to not be a positraction unit as advertised when it arrived. I sent it back. Since then, I've looked into various suspension upgrades, and have come to the conclusion that it is probably easier to just swap something in like you are referring to. Add in the EV conversion issue, and it might make sense.

Last summer I measured a 5 series BMW rear that was within 3/8" of inside tire to inside tire dimension of that same car, which happens to be a Unibody. I'm not confident about hacking up something like that, and I don't weld. Looking at various specifications, I've noticed that published track widths don't tell the whole story, and are only a guideline. It appears different specs are used, such as center of wheel, back of disc mounting surface, etc. A tape measure seems to be the right tool for the job.

I'd like to see some projects where a Leaf unit, or small Tesla motor is used with a rear end swap like this. Very interesting.

 

[Tremelune]

"Track width" does seem to be an ambiguous term, and the real measurement we would want (to avoid wheel offsets) would be hub face to hub face.

Many of the cars I've thought about converting are old RWD cars with solid axles, and this decision comes up every time...Right now, I'm thinking mostly about a 1951 Studebaker Champion, which is body-on-frame.

 

[brian_]

... Looking at various specifications, I've noticed that published track widths don't tell the whole story, and are only a guideline. It appears different specs are used, such as center of wheel, back of disc mounting surface, etc.

"Track width" does seem to be an ambiguous term, and the real measurement we would want (to avoid wheel offsets) would be hub face to hub face.

"Track width" is not ambiguous: it is the lateral distance between tire centres on the same axle. Hub face is also clear, but is not the same thing: it is the track width plus the wheel offset on each side.

Some amateurs and incompetent professionals may measure hub face width and report that as track width, causing confusion.

Wheel offset is not bad. There is an ideal wheel offset for each hub design, and to fit required components within the wheel volume essentially all modern vehicles are designed to work with moderate (15 mm to 50 mm) positive (hub face outboard of wheel centre plane) offset.

The same vehicle is sometimes available with wheels of different offsets, resulting in different track widths even with identical hub face spacing. Too much change in track width by this method results in poor suspension and steering geometry, and inappropriate bearing loads. This is especially important with steering axles (not the usual swap situation considered in this forum), and with independent suspension.

Due to the suspension, steering, and bearing issues, the important dimension really is the intended track width, but hub face width is what can be readily measured when there are no wheels mounted, and the offset required to result in that track width must be known to select the correct wheels.

 

[UglyCarFan]

"Track width" is not ambiguous: it is the lateral distance between tire centres on the same axle. Hub face is also clear, but is not the same thing: it is the track width plus the wheel offset on each side.

Some amateurs and incompetent professionals may measure hub face width and report that as track width, causing confusion.

Wheel offset is not bad. There is an ideal wheel offset for each hub design, and to fit required components within the wheel volume essentially all modern vehicles are designed to work with moderate (15 mm to 50 mm) positive (hub face outboard of wheel centre plane) offset.

The same vehicle is sometimes available with wheels of different offsets, resulting in different track widths even with identical hub face spacing. Too much change in track width by this method results in poor suspension and steering geometry, and inappropriate bearing loads. This is especially important with steering axles (not the usual swap situation considered in this forum), and with independent suspension.

Due to the suspension, steering, and bearing issues, the important dimension really is the intended track width, but hub face width is what can be readily measured when there are no wheels mounted, and the offset required to result in that track width must be known to select the correct wheels.

Brian: Thanks for that explanation. I did have a pretty good handle on offset, but had the wrong terminology.

 

[UglyCarFan]

"Track width" does seem to be an ambiguous term, and the real measurement we would want (to avoid wheel offsets) would be hub face to hub face.

Many of the cars I've thought about converting are old RWD cars with solid axles, and this decision comes up every time...Right now, I'm thinking mostly about a 1951 Studebaker Champion, which is body-on-frame.

Tremelune: I really like the old Studebakers. My favorite steel one is the GT Hawks, from around 1962-1965, if I'm recalling properly. My favorite is the Avanti, '63, '64. Of course, they are fiberglass. Big fan of the 50's trucks too.

Have you ever been to the Studebaker museum in Indiana? If not, you should go. It is very interesting, and well done.

 

[UglyCarFan]

Tremelune: I really like the old Studebakers. My favorite steel one is the GT Hawks, from around 1962-1965, if I'm recalling properly. My favorite is the Avanti, '63, '64. Of course, they are fiberglass. Big fan of the 50's trucks too.

Have you ever been to the Studebaker museum in Indiana? If not, you should go. It is very interesting, and well done.

Tremelune and others:

I'd like to learn more about these various suspension options, and how well they work with options like the Leaf motors, and the Tesla small motor. There are so many old rwd vehicles that could benefit from an upgrade, without having to go crazy on power. Personally, I don't know how to quantify what you could do with either of those options, trying to use OEM parts, and keeping it reliable and simple.

I don't think I've seen any posts about how reliable a Tesla small motor is, or comments about how you would repair the inverter if it fried. With Toyotas, Lexus, Nissan, Volt, etc there are plenty of options, but does that apply to Tesla?

I've seen posts where people talk about horsepower factors, sizing batteries, etc, but still have no way to judge what the overall experience would be like "in the real world" where most people rarely use much of the power that a typical ICE motor can provide. Is there a rule of thumb to determine if a Leaf (for example) could adequately power a Camaro, or a '51 Stude? I'm too old to be interested in little cars, so I'm much more interested in things I can actually get in and drive, load up some tools for a project, or just go cruising.

 

[remy_martian]

All depends on what you mean by "adequately".

"Cruising" is usually a bunch of bald guys or stoners going down a road at 30mph 😂

 

[Duncan]

All depends on what you mean by "adequately".

"Cruising" is usually a bunch of bald guys or stoners going down a road at 30mph 😂
View attachment 135451

We used to close the center of town off for an annual cruise - two years we were joined by a steam traction engine - so the speeds were not as high as 30 mph

 

[UglyCarFan]

All depends on what you mean by "adequately".

"Cruising" is usually a bunch of bald guys or stoners going down a road at 30mph 😂
View attachment 135451

Remy: Well, I might be getting old, but I'm not bald, and have never been a stoner. Even when I was young, and had very fast cars and motorcycles, I just never saw the appeal of doing burn-outs, or screaming down the road...stop light to stop light. I did spend a year in the Army in Monterey, riding my KZ-900 up and down Highway 1 as fast as I could.

I'm really serious about this "adequate" thing. Don't know how to quantify it. I look at some of the cars I have (ugly ones) and can do a rough comparison of the available power from a V8, but since I don't run them at their "optimum" level, I don't know how much of the available power I'm really using. That means I cannot decide if, for example, a Tesla small motor would be enough to replace the V8 in a pony car. Most of the cars I own weigh in at about 3200# in stock form. I doubt the factory specs would include a full tank of gas in those calculations.

I can certainly see why a lot of people go for smaller, lighter cars. Of course, smaller means less room for batteries, but that situation might improve as battery chemistries improve. But I'm not interested in the little cars any more. I like the pony cars, and big old lead sleds with hoods and trunks a mile long. Right now, I don't own any vehicles in that latter category.

I find myself going back to the idea of a GS450h a lot. But I'm worried about that oil pump issue. Been keeping an eye on Damiens projects regarding those.

 

[Electric Land Cruiser]

Tremelune and others:

I'd like to learn more about these various suspension options, and how well they work with options like the Leaf motors, and the Tesla small motor. There are so many old rwd vehicles that could benefit from an upgrade, without having to go crazy on power. Personally, I don't know how to quantify what you could do with either of those options, trying to use OEM parts, and keeping it reliable and simple.

I don't think I've seen any posts about how reliable a Tesla small motor is, or comments about how you would repair the inverter if it fried. With Toyotas, Lexus, Nissan, Volt, etc there are plenty of options, but does that apply to Tesla?

I've seen posts where people talk about horsepower factors, sizing batteries, etc, but still have no way to judge what the overall experience would be like "in the real world" where most people rarely use much of the power that a typical ICE motor can provide. Is there a rule of thumb to determine if a Leaf (for example) could adequately power a Camaro, or a '51 Stude? I'm too old to be interested in little cars, so I'm much more interested in things I can actually get in and drive, load up some tools for a project, or just go cruising.

Just about all of the pony cars had hairdresser versions with anemic slant-6 engines or other boat anchors. You absolutely could put an undersized electric motor into a big car and cruise around. My truck weighs 5300lbs and my 80kw LEAF motor accelerates it the same as the stock 212hp gas engine.

 

[remy_martian]

The Bolt EV weighs a couple hundred pounds more than a 60's/70's muscle car and has plenty of fun city and highway scoot at 150kW.

That said, it starts to fall off after about 70-75mph (that's why you need more horsepower), but who cares?

I'd say it's pretty much similar to the 350cu. in. 1970 Chevelle auto trans I used to drive.

So, a fun driver is ~40Watts/lb.

 

[Duncan]

The Bolt EV weighs a couple hundred pounds more than a 60's/70's muscle car and has plenty of fun city and highway scoot at 150kW.

That said, it starts to fall off after about 70-75mph (that's why you need more horsepower), but who cares?

I'd say it's pretty much similar to the 350cu. in. 1970 Chevelle auto trans I used to drive.

So, a fun driver is ~40Watts/lb.

When I put my device on the road I had 500 amps and 144 volts - 72 kW - at 820 kg - 1800 lbs - that was ... 40 Watts per pound !!!
And it was a very fun drive at that - would just fly up the steepest hills

 

[remy_martian]

To clarify, the 40W is a minimum, but more is not necessarily better. More will give you top speed, but more torque than tires can hold is useless and loses stoplight races (the stoplights being offroad, of course).

Low rolling resistance tires, for example, spin to easily from a standing start and can be outright dangerous pulling out in traffic. Dragsters lose races if they wheelspin.

Why?

Because there are two kinds of friction. Static friction, what we call "grip", then as soon as a tire breaks loose, the amount of friction available drops dramatically.

This is why your ABS stops the wheel (relative to the pavement speed under the car) - it resets the slipped friction level back to the higher static value.

 

[UglyCarFan]

These are all helpful comments.

The Bolt EV weighs a couple hundred pounds more than a 60's/70's muscle car and has plenty of fun city and highway scoot at 150kW.

That said, it starts to fall off after about 70-75mph (that's why you need more horsepower), but who cares?

I'd say it's pretty much similar to the 350cu. in. 1970 Chevelle auto trans I used to drive.

So, a fun driver is ~40Watts/lb.

Remy/Duncan/Electric Land Cruiser: thanks for those comments. They help to frame some thoughts. I've got enough BMW modules sitting here on the shelf to reach that level, assuming a conversion weight around 3500# all in. Those modules are pretty heavy for their capacity, so I've been thinking more along the lines of using them in a project where the whole I3 battery would fit in the vehicle as is, with a 2011 Leaf setup. Heating and cooling that battery might be an issue, although it would be strictly for around town errands, no hills, range not a big deal.

I've been reading up on the Open Inverter forums to get a handle on the latest with the small Tesla (front) motor, and the gs450h for a pony car. Both of those are available to me right now, within driving distance. I watch Damiens videos for updates, and it appears that parts are starting to become available again, and various people are working out bugs. The gs450h would by far be the easiest, and it is actually smaller than my existing automatic. So the decision is which project to do. I don't have time to tackle 2. The Leaf project would be more work than the pony car, and in the end, would be worth squat. But fun, and usable, and I have most of the stuff now. The pony car, especially with a GS450h, would look stock except when you lift the hood. Lots of room in that engine compartment for batteries and inverters. The pony car would not be driven in winter.

A quick comment on the Tesla sdu...putting it in a rear IRS cradle would allow me to do that work outside the pony car, test it, and make minimal changes to the car. It would weigh more than the existing live axle, but would actually match or exceed the original V8 power. It would get rid of the drum brakes, but likely extend up into the trunk area. I like what I read this past week about splitting the inverter off that unit, and mounting it separately.

Fun stuff!

 

[Electric Land Cruiser]

These are all helpful comments.


Remy/Duncan/Electric Land Cruiser: thanks for those comments. They help to frame some thoughts. I've got enough BMW modules sitting here on the shelf to reach that level, assuming a conversion weight around 3500# all in. Those modules are pretty heavy for their capacity, so I've been thinking more along the lines of using them in a project where the whole I3 battery would fit in the vehicle as is, with a 2011 Leaf setup. Heating and cooling that battery might be an issue, although it would be strictly for around town errands, no hills, range not a big deal.

I've been reading up on the Open Inverter forums to get a handle on the latest with the small Tesla (front) motor, and the gs450h for a pony car. Both of those are available to me right now, within driving distance. I watch Damiens videos for updates, and it appears that parts are starting to become available again, and various people are working out bugs. The gs450h would by far be the easiest, and it is actually smaller than my existing automatic. So the decision is which project to do. I don't have time to tackle 2. The Leaf project would be more work than the pony car, and in the end, would be worth squat. But fun, and usable, and I have most of the stuff now. The pony car, especially with a GS450h, would look stock except when you lift the hood. Lots of room in that engine compartment for batteries and inverters. The pony car would not be driven in winter.

A quick comment on the Tesla sdu...putting it in a rear IRS cradle would allow me to do that work outside the pony car, test it, and make minimal changes to the car. It would weigh more than the existing live axle, but would actually match or exceed the original V8 power. It would get rid of the drum brakes, but likely extend up into the trunk area. I like what I read this past week about splitting the inverter off that unit, and mounting it separately.

Fun stuff!

This is like the coolest car ever if you want some inspiration: The Story of Kevin Erickson’s 1972 Plymouth “Electrolite”, a Tesla Swap Done Right