[brian_]

I have a space in front of the motor which will have to deliver 2/3 my power in a 22"x22"x10" space. Any thoughts?

A 22"x22"x10" rectangular space has 80 litres of volume (4840 in³ or 2.8 ft³), which could ideally hold about 160 kg of cells (because lithium-ion cells have a density of roughly 2 kg/L), with a capacity of 32 kWh (because lithium-ion cells weigh about 5 kg per kWh of capacity); if that's 2/3 of your battery then your total capacity would be 48 kWh. In the real world you won't be able to pack cells in nearly that well (because they never come in just the right dimensions), and you need space for structure, cooling system, interconnecting wiring, and control devices (contactors, fuses, BMS components), so you might fit a bit better than half of that capacity if you find the right battery modules. I think you need more space...

For an example, two layers of modules in the VDA 355 format (355 mm long, 152 mm wide, and 108 mm tall) with four modules per layer (3 side by side and one turned 90 degrees to them) could barely fit in a 22" x 22" x 10" (or 560 x 560 x 255 mm) box, with an empty corner for wiring devices; the height would be marginal with cooling plates. At 2.2 kWh each, that would be 18 kWh; at 12 kg each, that would be about 100 kg plus structure, wiring, and devices. I used the VDA 355 format as an example because those modules are relatively small (sometimes called "shoebox" size), are an industry standard (which is rare in this industry), and are available from a couple of sources (including salvage from the Jaguar I-Pace); however, it's just an example to illustrate the packaging challenge.

Also, with the motor in front of the original transmission, "in front of the motor" is likely too far forward for all of that mass to allow for good handling.

 

[brian_]

Would it be viable to build a frame from front mounts to tail mound to replicate what the original distribution might have been?

It is a good idea structurally to use original mount locations, but the mount locations don't determine the weight distribution.

 

[brian_]

Optimum for handling is a 50:50 distribution.

50:50 is not universally the most desirable weight distribution, but it's a reasonable place to be. Did you mean optimum for this specific model of Volvo? Many vehicles routinely carry more weight on the rear axle when fully loaded, even with identical tires front and rear.

 

[brian_]

One reason for going with the original transmission was that an adapter and coupler had already been designed, so initial cost was favorable. I am also not sure the existing rear end would be able to handle direct drive in terms of rpm's.

The rear end will see the same speed regardless of the motor and/or gearbox ahead of it, because the axle input speed is directly proportional to the road speed, tire radius, and axle gearing.... regardless of the transmission.

Do you mean that it isn't practical to change the rear axle to much higher reduction ratio to enable direct connection of the motor to the axle's pinion shaft input? If the ratio is available, it will be usable.

The clutch might also provide a measure of flexibility in terms of "cushion" on alignment.

Not really. The clutch disk can provide rotational "cushioning" (they usually have a spring hub), but does not forgive alignment error.

Also, no pilot bushing was provided for the transmission input shaft - Is this typically omitted? It appears I could fit a bushing/bearing in the end of the coupler. Once I get it on, that is...

I don't know what is typically supplied with a kit, but if the transmission shaft is piloted in the flywheel or crankshaft (which it typically is in conventional longitudinal transmissions), you need that bearing or bushing.

 

[brian_]

In my view the Hyper 9 is not powerful enough to do a direct drive. The highest voltage version outputs 220 Nm.
The original B18 in first rear would put 3,1 x 150 Nm (ok, at higher rpms) = 450 Nm onto the driveshaft.

With clutch slipping, the engine can deliver that torque (through the clutch) at any road speed up to that corresponding to to the torque peak engine speed in the current gear.

Unfortunately for the Dana or Spicer axle there is no replacement rear diff gear to compensate that.

Availability certainly does vary greatly depending on the final drive (axle)! Most don't have a short enough gear set (high enough reduction ratio of the ring and pinion) to make sense as the only reduction for most electric motors.

In my rebuild I’m 100% sure I will eliminate the gearbox. That was a noisy and one pedal drive spoiling thing.
More info here Rear wheel drive EV conversion motor options - Voltvo

Interesting page - thanks for sharing that. It doesn't mention any final drive or tire information, which is a bit strange considering that they are critical to comparing motor and transmission combinations, when one of them has its own final drive.

I don't know what gearing is this PV544, but I have seen references to 4.56:1 (early years) and 4.10:1 or 4.11:1 (later years). With 4.1 gearing and 6.00 x 15 tires (26" or 660 mm tall, or 2 m circumference), propeller shaft (transmission output / axle input) speed at 100 km/h (60 MPH, 28 m/s) is 3440 RPM. For most reasonably sized electric motors, that's too low by a factor of about 2 to keep the motor in the most effective speed range, and so torque to the wheels at low speed is about half of what it could be.

 

[brian_]

I used a M400 gearbox without pilot bearing.

The M40 and M400 gearboxes are classic longitudinal designs, in which the input shaft clearly requires support at the front. That's what the pilot bearing (or bushing, but Volvo uses a ball bearing) are for, although one might get away with supporting and locating the splined shaft adequately.

 

[brian_]

How about putting a de Dion tube from a Volvo 340/360 at the rear?

An interesting possibility, but would the de Dion tube clear the drive unit? Following the same general design but with a custom beam (tube) is an alternative.

 

[brian_]

🤔 Not sure. The CVT in those cars is rather voluminous though.

Yes, but it's quite narrow at the back, so something like a Leaf drive unit might not clear the beam on the right-hand side where the de Dion beam bends forward and the Leaf inboard CV joints is displaced to the right to clear the motor.

Nice illustration.