Escalade Motor Implant - Finally: From Gas Guzzler to Electric Marvel

So a long show this week.  Some say long and boring.  I would be wounded to think this is so.  Is not the entire world hanging breath abated for the next few minutes of every episode?  That is of course my fantasy.  Were reality to intrude I might be crushed.

This week, we flew into a flurry of work.  Some battery stuff, reassembled the pieces of Netgain Warp 9 we had been using as a visual aid.  It turns.

But of course, the lion's share of this weeks work revolved around finally installing the Siamese 11 inch motors in the Escalade and connected to the 6L80E transmission and torque converter.

In the end, I'm just terribly pleased with how this all came out.

The two motors are of course painted gloss black and have shiny aluminum end bells - perfectly color coordinated with the vehicle.  But even better, the overall LENGTH worked out so well it looks like it was all done on purpose.  We have about 1.5 inches between the reluctor ring and the front crossmember of the vehicle.

By shaving the stock engine mounts about a 1/4 inch each, the motor and mounting plates drop right in place.  And our adapter plate mounts perfectly to the transmission.

We DID have to add a spacer to the mounting plate to pull the torque converter out of the recess for it enough to not bind.  And actually when we did finally put it all in place, it DID bind.  We loosened the bolts around the transmission, jacked the motor UP and then jacked it back down, and heard a distinct "thunk".  Retightened the transmission bolts and the shaft turned like a dream.

We then went to our tiny access hole to insert our torque converter bolts.  We could see both the flex plate and torque converter easily and line up the holes in seconds.  But we could NOT get a bolt to start.

Brain wheeled out his air driven burr grinder and "expanded" the access hole a bit.  And finally we were able to bolt it together.

This week we'll add tranny fluid to the thing, and idle it with a 12v battery.  We'll let it sit for awhile and then add more tranny fluid.  It takes a bit to get it pumped into the new empty torque converter.

We had ordered a 6L80E torque converter from Professional Torque Converters with a lowered 1400 rpm stall speed.  This should more closely match the torque curve of our electric motors, and make our system more efficient at lower speeds. It will also reduce the heat (and thus losses) generated by the drive train.

The concept of  using a torque converter at all is largely to provide a hydraulic buffer between the electric motor and the AWD drive train.  Torque "lockup" apparently occurs in 2nd gear above 22 mph.  By having the "stall" speed - at which basically the two turbines are turning at the same speed anyway, somewhat below that, we hope to get a smoother transition to lockup whether we are accelerating briskly, or slowly.

The replacement torque converter arrived Friday morning - just in time.  We actually worked most of the day and shot the intro sequences quite late - finishing at 6:30PM.  Yes, I was late for the ballet.

In the end, the motor is very securely mounted in the truck. Looks like it was born to be there.  We've got a good line along the transmission and drive shaft.  The rubber mounts should minimize vibration.  It's almost the perfect length.  And of course it looks gorgeous in the vehicle.

With the motor mounted and the battery box in, balanced, and charged, we are actually moving into the area I like the most. Wiring up the controllers and the instrumentation.

We also have to do the environmentals - largely our water heater - along with a cooling system for the controllers.  So we will have two separate glycol systems - a bit complicated with two separate pumps of course.

So while much work remains, our past projects would indicate that we are actually 2/3 done with this project.  We should be rolling rather shortly.

No matter how many of these we do, I never quite get over it.  That this will be the largest passenger car I've ever seen done is no help there.  But truly, I always loved this vehicle anyway.  For me, at 280 lbs with knees and hips that aren't as young and pretty as they once were, it is very comfortable to enter and exit.  Onboard, I sit up quite high with superb visibility in all directions.  The seats are very wide and plush with air conditioning vented up through tiny holes in the leather and resistive electric heat available as well.

The GPS and entertainment are actually a bit sorry.  The GM GPS is actually good for a laugh, we used to enter a destination and howl over the route it provided.  There is no USB or iPhone connection.  So we may do some work on the console and replace the existing unit with a more advanced one - perhaps with a carputer interface and iPhone connections.  But this will all happen AFTER we have it fully functional with electric drive.

In the end, we should have reasonably comfortable seating for four adults, five in a pinch.  I think we'll have the usual 80-100 mile range in town.  But there is potential for some blue sky on the highway.

We noted on the Ford Edge a staggering 4.5 Amp hours at 250 volts or 1125 wH per mile.  The transmission has never been right on this car and so with 200Ah at 250 volts we hardly had a 45 mile range.

Incredibly, at 70 mph on the freeway this drops to 2.0 Ah or 500wH per mile - less than half.  The vehicle weighs 5000 lbs.  This is the REVERSE of our experience with the Speedsters and Spyder and Cobra.  How can this be?

A couple of things come to mind.  Mass is intractable.  It just is.  And it takes a definitive amount of energy to accelerate a mass - more mass, more energy.  The edge has 2.5 x the mass of the Speedsters.  But it is UNLIKELY that it has 2.5 x the frontal area.

And so while air resistance is a square function, the energy use profile does indeed invert - not because the vehicle is particularly good at rolling down the freeway at 70 mph - 500wH and 5000 lbs is almost exactly the 10:1 rule of thumb we use to estimate energy usage.

No, the issue is how very BAD it is at accelerating 5000 lbs from dead still to 35 mph.

I'm hopeful that the six speed 6L80E with a kind of extreme overdrive 6th gear coupled with our two 11 inch motors will give us an even better profile at highway speeds.  And so I would look for something like 70-80 miles per charge in town, but potentially 120 or even 130 mile range on the freeway.  This puts us in range of St. Louis - 110 miles away, with this truck.

We'll see.

Jack Rickard