# Tesla large drive unit in Ford Expedition



## DrGee (Aug 22, 2018)

Here's a motor mount question. 
Can I put a Tesla LDU with the required custom half shafts, in the engine bay of a 4WD Ford Expedition? I would remove the ICE, transmission, prop shaft, rear differential and half shafts. 
This would make it a 2.6 ton FWD SUV. Is this feasible? It would certainly be easier than fitting the LDU in the rear and cutting the rear subframe to mount it.


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## brian_ (Feb 7, 2017)

It might be feasible, although the space between the frame rails would need to be measured and compared to the drive unit width, and it probably won't be enough.

On the other hand, a front wheel drive Expedition doesn't seem like a desirable vehicle to me, and it is not at all clear how a useful amount of battery (100 kWh?) would be installed in it.

There is also a potential concern with overheating the motor, since it will be working harder than it would in any Tesla.


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## hallkbrdz (Jan 2, 2018)

FWD doesn't work well for heavy vehicles, especially starting from a stop uphill where everything is working against you. If the units will fit, I would look for a dual motor setup with the largest battery you can find. Expedition's are fairly wide, so you may be able to place the battery pack as-is underneath although you will give up some ground clearance.


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## DrGee (Aug 22, 2018)

Thanks guys, 
The front wheel drive question was my biggest concern. Cutting metal and welding is not within my current skillset. Perhaps I'll have to contract that bit out to a professional and have them put the LDU in the rear.
I've owned several Navigators/Expeditions and we have a Navigator now. I've taken measurements and I'm happy with the available space for batteries between the rails (two 60kwh packs from Chevy Bolt Pro's).


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## brian_ (Feb 7, 2017)

hallkbrdz said:


> Expedition's are fairly wide, so you may be able to place the battery pack as-is underneath although you will give up some ground clearance.


You can hope that, but reality is different. Any EV battery pack - especially one from a Tesla - is wider than the frame rail spacing of something like an Expedition, so the whole pack won't fit between the frame rails (even if there were not multiple crossmembers and other components in the way. Repackaging the pack would result in a much taller pack, and still a big problem to fit in. Hanging a complete pack entirely under the frame would be fine if you only drive on perfectly flat surfaces, but in the real world there wouldn't be functional ground clearance left.

There are reasons that all of the serious proposals for new electric pickup trucks use a completely different structure from any existing vehicle.


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## brian_ (Feb 7, 2017)

DrGee said:


> Cutting metal and welding is not within my current skillset. Perhaps I'll have to contract that bit out to a professional and have them put the LDU in the rear.


Since the Expedition already has independent rear suspension that's a possibility, but dimensions would still need to be checked and the fabrication work would be substantial.


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## brian_ (Feb 7, 2017)

DrGee said:


> I've taken measurements and I'm happy with the available space for batteries between the rails (two 60kwh packs from Chevy Bolt Pro's).


What's a "Pro" version of a Chevrolet Bolt?


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## DrGee (Aug 22, 2018)

Oops!.. My miskate.. By Chevy Bolt pro, I actually meant Nissan Leaf Plus.


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## DrGee (Aug 22, 2018)

brian_ said:


> You can hope that, but reality is different. Any EV battery pack - especially one from a Tesla - is wider than the frame rail spacing of something like an Expedition, so the whole pack won't fit between the frame rails (even if there were not multiple crossmembers and other components in the way. Repackaging the pack would result in a much taller pack, and still a big problem to fit in. Hanging a complete pack entirely under the frame would be fine if you only drive on perfectly flat surfaces, but in the real world there wouldn't be functional ground clearance left.
> 
> There are reasons that all of the serious proposals for new electric pickup trucks use a completely different structure from any existing vehicle.


My plan was to build a battery box about 36 inches wide. The Expeditions' "ladder" is about 40 inches at the narrowest. There is space for a box 6 feet long and 11 inches deep. There are two cross-members that the box would sit on, but I'd have to add another to take the weight of the box.


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## DrGee (Aug 22, 2018)

brian_ said:


> Since the Expedition already has independent rear suspension that's a possibility, but dimensions would still need to be checked and the fabrication work would be substantial.


The fabrication is my main issue Brian. I wish I could build it as a FWD, like all those minivans (Chrysler and Dodge etc). They don't weigh 2.5 tons though...


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## hallkbrdz (Jan 2, 2018)

I was going to say, I don't see the pack height being an issue on a truck based platform, at least in most of the US. Build a frame around the pack, add a lift kit, and you can maintain the clearance.


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## brian_ (Feb 7, 2017)

DrGee said:


> I wish I could build it as a FWD, like all those minivans (Chrysler and Dodge etc). They don't weigh 2.5 tons though...


But they do, nearly. "Mini"vans are all over 4,000 pounds empty, although not as heavy as an Expedition.

Front wheel drive works; I just don't see the logic of buying an "SUV" with only two driven wheels, or a vehicle which gets rear-heavy when only moderately loaded that only drives the front wheels. I have a Toyota Sienna (FWD minivan), but I wouldn't go to great effort to build an electric one.

Two decades ago when Ford and GM built electric pickup trucks, they took different approaches, for the same reason:

Ford replaced the stock rear suspension in the Ranger Electric with a de Dion setup so they could put the motor at the back and leave the space between the frame rails clear for a huge battery pack;
GM used the complete drive unit of the EV-1 car to make the electric S-10 front wheel drive, leaving the space between the frame rails clear for a huge battery pack.
It seems to me that you are faced with a similar problem, and similar options.


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## brian_ (Feb 7, 2017)

hallkbrdz said:


> I was going to say, I don't see the pack height being an issue on a truck based platform, at least in most of the US. Build a frame around the pack, add a lift kit, and you can maintain the clearance.


Sure, if you are going to entirely custom-build a frame, modify the body to work with that frame, and use a drive configuration which does not require a shaft down the middle, a large battery pack can be incorporated.


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## mayes8229 (Dec 8, 2020)

brian_ said:


> You can hope that, but reality is different. Any EV battery pack - especially one from a Tesla - is wider than the frame rail spacing of something like an Expedition, so the whole pack won't fit between the frame rails (even if there were not multiple crossmembers and other components in the way. Repackaging the pack would result in a much taller pack, and still a big problem to fit in. Hanging a complete pack entirely under the frame would be fine if you only drive on perfectly flat surfaces, but in the real world there wouldn't be functional ground clearance left.
> 
> There are reasons that all of the serious proposals for new electric pickup trucks use a completely different structure from any existing vehicle.


Not only is a Model S pack much wider than the frame rails under an Expedition, it's nearly as wide as the Expedition itself! The track width of a Model S is only 1 or 1.5" narrower than the track width of an Expedition. It's a VERY wide car.




brian_ said:


> Sure, if you are going to entirely custom-build a frame, modify the body to work with that frame, and use a drive configuration which does not require a shaft down the middle, a large battery pack can be incorporated.


In my K5 Blazer the transfer case, transmission crossmember, and exhaust all hang well below the bottom of the frame rails, so the "useable" ground clearance is about 6" below the frame. Most 4WD trucks are the same way. You could have a pack that's significantly taller than the height of the frame rails without really sacrificing much ground clearance. It wouldn't be very attractive to have a pack 6" below the frame all around the vehicle, but it wouldn't necessarily detract that much from the utility.


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## DrGee (Aug 22, 2018)

brian_ said:


> But they do, nearly. "Mini"vans are all over 4,000 pounds empty, although not as heavy as an Expedition.
> 
> Front wheel drive works; I just don't see the logic of buying an "SUV" with only two driven wheels, or a vehicle which gets rear-heavy when only moderately loaded that only drives the front wheels. I have a Toyota Sienna (FWD minivan), but I wouldn't go to great effort to build an electric one.
> 
> ...


I like the "SUV" in quotes, Brian. You're right. Most of these cars are really not SUVs. They are just big cars. I used to detest the idea of a 2WD "SUV". I've become more accepting of the design as a conversion, because of the cost and complexity of a 4x4 or AWD configuration. In fact, I'm "feeling" the GM S-10 design right now...


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## DrGee (Aug 22, 2018)

mayes8229 said:


> Not only is a Model S pack much wider than the frame rails under an Expedition, it's nearly as wide as the Expedition itself! The track width of a Model S is only 1 or 1.5" narrower than the track width of an Expedition. It's a VERY wide car.
> 
> 
> 
> ...


That's a valid point. In the Expedition/Navigator, the cross-members hang lower than the frame and they still leave 9 inches of ground clearance. Those trucks really ride high. Most models have a running board- I always use the running board to "climb" into the vehicle.


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## brian_ (Feb 7, 2017)

DrGee said:


> In the Expedition/Navigator, the cross-members hang lower than the frame and they still leave 9 inches of ground clearance. Those trucks really ride high.


Right, some of the crossmembers are low... but putting a pack below those crossmembers is obviously not feasible, and if you try to put it above them you have two problems:

the crossmembers have substantial height so the pack must be interrupted or indented for each crossmember; and,
if the battery pack is not interrupted for each crossmember it can only be installed from above, after removing the body.
In the Ranger EV, Ford used modified crossmembers which arched up above the battery pack, above the level of the frame rails.


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## mayes8229 (Dec 8, 2020)

brian_ said:


> Right, some of the crossmembers are low... but putting a pack below those crossmembers is obviously not feasible, and if you try to put it above them you have two problems:
> 
> the crossmembers have substantial height so the pack must be interrupted or indented for each crossmember; and,
> if the battery pack is not interrupted for each crossmember it can only be installed from above, after removing the body.
> In the Ranger EV, Ford used modified crossmembers which arched up above the battery pack, above the level of the frame rails.


True, unless the crossmember is bolted in from below like many trans crossmembers are. In the aforementioned Blazer I have one riveted crossmember just in front of the rear axle that hugs the floor of the body and the bolted-in trans crossmember. There are no others between the engine and rear axle (granted that my wheelbase is about 17" shorter than an expedition and other similar trucks).

I haven't seen many low crossmembers (except trans) in the area of interest on 4WD/RWD trucks unless they have a 2-piece driveshaft because the crossmember would be in the way of the driveshaft.


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## brian_ (Feb 7, 2017)

DrGee said:


> Oops!.. My miskate.. By Chevy Bolt pro, I actually meant Nissan Leaf Plus.


Thanks. 

There is one version of the original Bolt, at 60 kWh. For 2022, the next-generation Bolt gets 66 kWh, and the 2021 model of the first generation already has this higher-capacity battery.

In the current generation of Nissan Leaf, the base version has a 40 kWh battery using the same style of modules as the original, and the Leaf Plus gets a deeper battery pack with differently-configured modules (using the same cells) for 62.5 kWh. I was surprised to see that the builders of the _Toyota 4Runner 4x4 Race truck Leaf conversion_ have already found a 62.5 kWh pack in salvage, but it was apparently damaged in manufacturing, rather than already salvaged from a vehicle.


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## brian_ (Feb 7, 2017)

DrGee, what year is this Expedition? I would like to try to find a frame illustration, and that's pointless if looking at the wrong generation.


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## DrGee (Aug 22, 2018)

I took measurements from my 2015 Navigator. I intend to use a 2007-2014 Expedition as a donor. I think they have the same frame & chassis as the 2015- 2019 model.


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## brian_ (Feb 7, 2017)

DrGee said:


> I took measurements from my 2015 Navigator. I intend to use a 2007-2014 Expedition as a donor. I think they have the same frame & chassis as the 2015- 2019 model.


Thanks 
2007 to 2017 model years are the third-generation Expedition; there was a 2015 refresh that presumably wouldn't change the frame (although it tweaked the rear suspension). 2018 starts the fourth-generation, and a shift from the T1 platform (shared with the 2009-2014 F-150) to T3 (shared with the 2015-up F-150); the platform update will likely change frame details.

So there isn't a single 2015-2019 Expedition model, and 2007-2017 should all be similar.

Unfortunately, the Ford Body Builder Advisory Service doesn't cover the Expedition, presumably assuming that no one will mount alternate bodies or modifications to it. The closest I see is the F-150, which is presumably - but not necessarily - identical only to the back of the cab. The Expedition is shorter (in wheelbase) and has a completely different rear suspension (and thus rear frame section), but should match in the front.








The width between the frame rails at the widest point, which is only extends for a small fraction of the wheelbase, appears to be that 40" mentioned earlier, but that's the widest, not the narrowest.

Unfortunately the crossembers of the Expedition are not described by this documentation.


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## DrGee (Aug 22, 2018)

I'll have to get dirty and go under the car again... I'll post measurements as soon as I can. 😊


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## Electric Land Cruiser (Dec 30, 2020)

If you want to do an EV conversion and you can't weld, you're gonna have a bad time.









Luckily welding is pretty easy to pick up!


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## DrGee (Aug 22, 2018)

Yeah, 
It looks like I'll have to learn. Otherwise I'll be paying someone for what I don't know.


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## DrGee (Aug 22, 2018)

These are the measurements I took under a 2015 Lincoln Navigator L. The diagram is from a 2007 Expedition.


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## remy_martian (Feb 4, 2019)

Not sure how long that LDU is going to last in a vehicle that heavy.


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## DrGee (Aug 22, 2018)

remy_martian said:


> Not sure how long that LDU is going to last in a vehicle that heavy.


Hi Remy-
Someone else raised this point too. I still don't fully understand it though. The complete conversion will have all the ICE bits removed as well as the spare wheel and middle seat in the second row. I estimate the weight should be 5700 lbs with one Nissan Leaf Plus battery pack or 6600 lbs with two packs. The old (2012) Tesla Model S Performance weighed 4647 lbs. With 5 adults on the way to the airport with a 55lb suitcase each, the total weight would be 5692 lbs - about 5700. The Expedition's 5.4L Triton does 310 hp & 365 ft-lbs torque. The 2012 Performance motor does 416hp with 443 ft-lbs torque. It beats the 5.4L Triton hands down. In my proposed conversion, it would be hauling about the same weight if I use the single battery pack from the Nissan Leaf Plus. Will the Performance motor overheat as a regular daily driver?


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## remy_martian (Feb 4, 2019)

I wasn't too concerned about overheating, actually. More on the component wear side, bearings and gear faces, as the running HP is going to be a lot higher pushing that brick through the air. You can fix that by adding a rear drive unit to the truck, lol.

Weight is a factor for rolling resistance, which may be equivalent to the P85, but at highway speeds...


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## brian_ (Feb 7, 2017)

DrGee said:


> The complete conversion will have all the ICE bits removed as well as the spare wheel and middle seat in the second row. I estimate the weight should be 5700 lbs with one Nissan Leaf Plus battery pack or 6600 lbs with two packs. The old (2012) Tesla Model S Performance weighed 4647 lbs. With 5 adults on the way to the airport with a 55lb suitcase each, the total weight would be 5692 lbs - about 5700.


So the empty converted Expedition will weigh as much as a loaded Model S, but have much more aerodynamic drag. That's assuming the converted vehicle weight estimate is correct - most estimates miss a lot of minor components which add up.



DrGee said:


> The Expedition's 5.4L Triton does 310 hp & 365 ft-lbs torque. The 2012 Performance motor does 416hp with 443 ft-lbs torque. It beats the 5.4L Triton hands down.


The power ratings don't matter because those for the Tesla cannot be sustained. The Triton 5.4 can pump out 310 horsepower for hours; the Tesla can produce 416 horsepower for seconds. It's not clear how much of the Tesla's thermal limitation is in the battery, how much is in the inverter, and how much is in the motor, but in competition this drive unit has proven to be unable to sustain full power. Of course you don't need full power, but that's all the specs are comparing.



DrGee said:


> Will the Performance motor overheat as a regular daily driver?


Perhaps.


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## brian_ (Feb 7, 2017)

DrGee said:


> These are the measurements I took under a 2015 Lincoln Navigator L. The diagram is from a 2007 Expedition.


Excellent! 

For those who might not be sure what they're looking at, the left or far end is the front, and is the same as an F-150. The rear end is very different from the pickup, because it designed to work with the Expedition's independent rear suspension. The rear suspension components are essentially all on the outboard sides of the frame, leaving the final drive (differential) between the frame rails and axle half-shafts going through the holes in the frame.

The crossmember annotated as "May remove this..." is the transmission support. It won't be needed for the transmission, and seems to me like a good candidate for replacement if the narrowing space forward of it would actually be used for battery.

The crossmember right in the middle is a "through-rail" design - meaning that it goes right through the main frame rails on each side - to add torsional stiffness to the structure. It also supports the intermediate bearing of the driveshaft, which of course won't be used in the conversion. A fixed replacement as high as possible might be better than a removable replacement underneath, as this will be where ground clearance is most critical for high-centreing... but of course maybe that means you want structure under the battery there.

The tubular crossmember annotated "Remove this..." is also through-rail. The rail shape where is goes through suggests that while this member supports the front of the final drive (taking the reaction to drive torque), it is structurally much more important than just that.


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## DrGee (Aug 22, 2018)

Great stuff Brian,
Really useful!

Greg


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