[dhymers]

It has been over a year since I finished my Toyota pickup conversion and used it as a 90% daily driver. I got itchy to do something else, something faster and lower

I'll admit I have a soft spot for old Toyota's. (and rwd cars that weigh under 2klbs)

The plan:

Fix rust
Swap in an 8.8 posi rear from a Ford ranger with hopefully 3.08 and maybe migrate to 2.73.
Direct drive AC or BLDC motor - I am keeping my eye on UQM 135s, 150s or even a 220.
Tesla, Volt or Soul batteries about 35-40kw of.

Does anyone have any idea if anyone is working on breaking Tesla motors from their gear/IRS sub setup to be put into in-line mount applications ?

Its not terribly original from a drive line perspective but I hope it will be quick. Plan to at least autocross it and perhaps track it for time attack or drift. My expectation is a 3+ year build and ~$20k.

Tell me I'm crazy, or offer advice...

Here she is now:

 

[brian_]

Direct drive AC or BLDC motor...
Does anyone have any idea if anyone is working on breaking Tesla motors from their gear/IRS sub setup to be put into in-line mount applications ?

Not that I have heard of, but someone certainly could be.

An issue would be that the gearing would be all wrong: stock Tesla overall motor:wheel reduction is over 9:1, and top speed is still wildly high. Unless you're running at much lower voltage, you wouldn't be using the motor very effectively if you kept it in the bottom of its speed range with such tall gearing. For a Tesla (and most other production EV) motor, I would be looking for the shortest gearing (which for an 8.8 is perhaps 3.55 factory and 6.14 aftermarket), not the tallest stock ratios.

 

[dhymers]

Awesome, this is the kind of advice I want to get 🙂

Coming from the brushed dc experience I thought taller the better because the max rpm of those setups is about 6k and looking at the uqms thiers is about 7k but a much wider torque band obvs.

A 3.55, 3.73 or 4.10 makes things easier for procurement also.

Torque Trends is selling a 2:1 reduction gear, thats basically to push the final reduction close to 6 or 7:1 depending on rear ratio right ?

This really helps so I don't make expensive mistakes thankyou!

 

[brian_]

Coming from the brushed dc experience I thought taller the better because the max rpm of those setups is about 6k and looking at the uqms thiers is about 7k but a much wider torque band obvs.

Right, it's just a matter of suiting the gearing to the motor.

Torque Trends is selling a 2:1 reduction gear, thats basically to push the final reduction close to 6 or 7:1 depending on rear ratio right ?

Yes... or to whatever is suitable for the motor. Their big market for the ev-TorqueBox seems to be trucks which need a lot of torque to the wheels, and don't need high top speed; the net result is that they need more gear reduction than the stock final drive will provide. Someone with a lighter vehicle, smaller-diameter tires, and a higher desired top speed might not want the extra reduction with the same motor.

I think something like the ev-TorqueBox would be great for a lot of conversions (of conventional front-engine/rear-drive cars), but this particular design is bigger, heavier, and more expensive than necessary because it is designed to handle more torque than required for most cars.

 

[PAXtss]

Torque trend did a miata with motor in driveshaft tunnel- pretty sweet. It would be great to see a tesla motor or Leaf motor put in something like that.

 

[dhymers]

I suspected a torquebox was overkill for a car but yeah they did put one in the miata, no idea what rear ratio it was, miatas come with 4.3 or something I think.

I was considering consulting with Mitchell the owner for his 1hr fee as they are a uqm dealer. (he mentioned he would recommend a motor/inverter/gearbox or simply motor/inverter combo) much to ponder.

 

[brian_]

Torque trend did a miata with motor in driveshaft tunnel- pretty sweet. It would be great to see a tesla motor or Leaf motor put in something like that.

Yes, but it takes a big transmission tunnel - or one which is cut out and enlarged - to fit those motors. The ev-TorqBox is great for installations like that Miata, allowing the use of a smaller-diameter high-speed motor. Torque Trends doesn't specify the motor (just the manufacturer and power), and doesn't show a clear photo of it in the car, but in the photo of the ev-TorqBox the motor isn't even visible, so it must be small (9" or less?). The current AC Propulsion motor of those specs (150 kW, 13,000 rpm) would be the 150kW End Mount, but the manufacturer doesn't provide dimensions. Thunderstruck publishes a spec sheet for what might be a similar AC Propulsion motor which says 245mm dia x 350 mm long. An interface document indicates a motor diameter of 9.8", plus the air cooling shroud... and even that sounds like a tight fit for the tunnel of a small car.

 

[dhymers]

So I learned a couple of important things today. I had a chat with Mitchell and the bottom line for me is the Torque box does 3 things which are really helpful.

1 - Integrated parking pawl, DOT likes those.
2 - Once you get into the 6:1 and 7:1 ratios with an 8.8 2 things happen, the pinion may wear more due to lower tooth count (applicable to higher power and tire size off road applications but hey) and also you have to shim the ring gear. - Also I can keep factory lower ratios like 3.08 or 3.55.
3 - I don't have to have an adapter with yoke manufactured for the UQM motor, it would likely cost 4/5 the price anyway, why bother.

I'm looking at the power phase 135 HS which has a rpm limit of 10k.
Top speed wise I would like to maintain about 110-115 so a total ratio of 6.16 to 7.1 is where I'm looking.

I think I've just about adapted my head to looking for the sweet spot compromise between top speed, what speed torque will drop (around 50) and acceleration.