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Discussion Starter · #1 ·
Hi I'm Terry from Pittsburgh PA and I created Exotruck a couple years ago. It's popularity took off, I recently lost my job due to Covid19 and now I am build Exotruck chassis's. It's a Subaru base kit, but I'm hoping to add an Electric option. As of today, the EV West 818 conversion kit is what I'm looking at, but hoping to learn how to put something together myself. I also don't know if the AC-50 motor will live up to Exotruck performance expectations. However, I need to keep cost in mind. The kits meant to be an easy to drive errand mobile.
The EVexo prototype will be powder coated Electric Pink and test driven by my wife

 

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I wouldn't have guessed it, but "Exotruck" seems to be a unique name - a Google search for just that comes up with only relevant forum discussions and the right Instagram page. :) To anyone else wondering what the original Exotruck is all about, I suggest that search and some reading... there's lots of good stuff to be found.

You're probably already doing this, but you might want to talk to people who have built kits (with engines or as EVs) about what they want to find in a kit. For instance, not having to design huge numbers of details themselves and having usable documentation will probably both be high on the list. Buying just a frame with a promise that Subaru bits will fit would be a daunting prospect for most potential builders.

As for the EV aspect... I realize that this vehicle started with the desire to use a Subaru Forester, but there's not much reason to use any of a gas-engine car's powertrain in a vehicle built from the beginning as an EV. I suggest seriously considering using only the Subaru suspension in the EV version, rather than using the Subaru transaxle and driveline.

I don't know what your performance expectations are for the EVexo, but if they are anything like the performance of the Subaru-powered Exotruck the AC-50 would be very disappointing.

So welcome to DIY Electric Car... and please consider starting threads in the appropriate sections for design discussions and the build.
 

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I'd second Brian's advice... AC-50 is not a bad piece of kit but there are far more powerful motors around.
A Hyper-9 might be a little better. But I see you've got 450whp - the Hyper9 only does ~88kw.

For much better power you could use a pair of Leaf motors - one front and one rear. With the stock inverter (only requiring a VCU) they max out at ~110hp apiece - but that's a good 110hp and will pull very hard.

If you want the best performance, grab a pair of Tesla drive units. The small ones push 300hp apiece, that should be enough to make anyone happy (I don't want to know what 2 of those would look like in a ~2500lb kart). LSD kits are available, $1400 per or so.

Or a single large Tesla unit with a special gear set so that it can split front/rear (4.5:1 ratio to run to the diffs, might want 3:1 or even 2:1 for top speed).

You've got choices.
 

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Discussion Starter · #4 ·
The electric builds not meant for performance, just an acceptable level of zoom for around town. I'm pretty much settled on a Hyper9 with 7 Tesla packs for 168v. The same AC50 adapter will fit the Hyper9. This kit should also get me 120 or so mile range and is around my 20k budget.

My performance model is still my flex fuel version. It's actually halfway through a motor build to get me almost 700hp
 

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Discussion Starter · #7 ·
Frames coming along. No buyers, real disheartening since I have almost everything I had left into this. I'm still so back and forth on power train. As is I can use a hyper9 strapped to the stock transmission. But I really want to use model S drive units. I'd love to do a 057 kit but I can't justify $8,000 for a used drive unit and control box, plus shipping. I also really like the EVcontrols unit. But sadly without sales of frames, I don't have anything left to invest in Exotruck EV R&D.

I can either invest what's left towards fitting a Hyper9, or buy a Tesla drive unit and build the chassis to accept that. But then I have a used unit that's a "paper weight" according to 057

121475
 

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I'd love to do a 057 kit but I can't justify $8,000 for a used drive unit and control box, plus shipping.
I assume that stock used drive units and DIY replacement controller boards would be substantially cheaper than any commercially available aftermarket controller solution with drive unit; the DIY solution seems to exist for both Tesla Model S and Leaf motors.

While the Leaf was traditionally limited to 80 kW in stock form, that was always a programmed limit in the controller to protect the battery. With the 40 kWh battery the motor power limit was increased to 110 kW, and with the (recent and still presumably rare) Leaf+ 62 kWh battery the motor power limit is now 150 kW... perhaps with no change to the motor itself. The right Leaf units would be very quick in stock form if you can handle the system management issues, and any Leaf unit with a DIY controller and the right version of Leaf inverter (the early ones likely can't handle double the power of their intended application) would be practical to build and very quick.

A very compact drive unit which runs at 150 kW stock is the one in the Chevrolet Bolt; however, there is probably zero aftermarket or DIY support for this unit. Yabert used one in stock form in his Westfalia project - keeping everything connected to it as necessary to work in stock form - and it appears to work very well. Two of them would be wild, and even one (in the rear, 2WD) would be an enjoyable drive.
 

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Discussion Starter · #9 ·
I've often considered a Hyper 9 strapped to stock Subaru manual transmission (current chassis configuration). The only "off the shelf" couple I can find is through EVwest for the 818.

I was so excited about going Tesla earlier, then I realized how I'd have to redesign the entire chassis to fit unknown suspension and wheel components. 68" or whatever the track is on a Tesla S is simply too wide
 

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I was so excited about going Tesla earlier, then I realized how I'd have to redesign the entire chassis to fit unknown suspension and wheel components. 68" or whatever the track is on a Tesla S is simply too wide
Yes, the Tesla Model S has too much track for the Tesla subframes and suspension to be usable in a compact vehicle; all suspension and wheel/tire components are oversized for this application. The usual solution is to use just the drive unit, with a different suspension and subframe. Since the ExoTruck is designed for Subaru suspension, a practical solution would be to use the ExoTruck tube frame and Subaru suspension as-is, with custom tubular subframes at each end to "connect the dots" between Subaru suspension mounts, Tesla motor mounts, and the ExoTruck frame... although it is likely that there will be some conflicts between suspension components and the Tesla drive units. A Leaf (or Bolt, or any other compact production EV) drive unit would probably be an easier fit.
 

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Discussion Starter · #11 ·
Getting back into this. Been thinking a lot of just bolting the hyper9 right to the rear 4.11:1 differential. Subaru uses the R160 and R180 differentials and ratios from 3.545 to 4.444. If I read right, the rpm range should work well with that 4:1 gearing. And I'd also save all the weight and torque loss of the transmission. With motor in back and batteries up front I can also get good weight distribution and optimal cooling for batteries.

Only problem I have now is money 🤪
 

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We had a saying in our business development and product planning team: "sunk funds are irrelevant to decisions about the future"

It's just pipe. Sell the Hyper9 (they're $5,000 now) stuff off, stop making bad decisions you can't afford to make, get the product to where it sells itself.

If I already wasn't heavily invested, I'd help you out. It's a good idea, but you're panicking vs sitting down, and cutting up and welding pipe for the right drive unit.

It's not Model S...too wide. Attaching a motor to a beam axle or direct driving a rear end will be shit -- EVs have spoiled consumer expectations on acceleration. Think about a Model 3/Y cradle, maybe...
 

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Discussion Starter · #13 ·
I've sold a couple gas powered Exotrucks but I'm really trying to get into the EV game. The trucks highlights are the open air feel and the utility of having the bed. I could easily fit a Tesla motor but then I'm into big bucks for custom axles, need enough batteries to get 400v which are heavy. The motor is the easy part, suspension, steering, battery boxes, wiring is where the works at. The Subaru stuff is what I know, easy to fab for. The rear differential is IRS so a motor could mount to the pinion flange and I just support the other end on bushings. Nothing really moves, just some rubber for nvh. Complete I'm probably around 1600-1800 pounds depending on batteries. Got a chassis nearly complete.

Couple Subaru powered finished trucks.

Wheel Tire Land vehicle Vehicle Automotive tire
 

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... I could easily fit a Tesla motor but then I'm into big bucks for custom axles, need enough batteries to get 400v which are heavy.
The voltage doesn't determine the battery weight - that's just a matter of configuration and availability of suitably configured modules (if not building a battery from individual cells). For instance, most plug-in hybrids run the same voltage as battery-electric vehicles (typically 360 V nominal), with only 8 to 16 kWh of capacity. But yes, availability of suitably configured modules is always a challenge for any operating voltage, capacity, or target vehicle.
 

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The Subaru stuff is what I know, easy to fab for. The rear differential is IRS so a motor could mount to the pinion flange and I just support the other end on bushings. Nothing really moves, just some rubber for nvh.
I think you need to either rigidly support the motor to the final drive case with the motor and pinion shafts precisely aligned, or couple the motor's shaft to the pinion shaft with a coupling that allows some angular compliance - it can even be one of those rubber doughnut things (a "giubo" flex disk).
 
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