Perfect Spot Redux

Remember that perfect spot I found for the high voltage fuses a couple of days ago? It had a couple of threaded openings in the strut mount, easy access and clearly designed for the fuses, right?

Well, turns out it was also the perfect spot to mount the throttle. It was right in line with the accelerator cable and just the right distance away. It allowed a gentle angle for the cable and once in place, very good feel for the pedal.

I'm once again using the Evnetics Throttle Pot. I used it on the eBugeye and the evTD. It has been bulletproof and easy to set up using the existing pedal and cable. Unfortunately, Evnetics has moved on to other markets, so this may be my last one.



Working around the aluminum mounting plate, I snagged a finger on the sharp edge (ouch) so I added some door edge guard strips to make it "finger safe". Makes the whole installation look pretty neat.

So what to do with the fuse mount that got displaced? Found another perfect spot for it with another threaded opening, this time on the frame rail. I had to employ the "wire stretcher" since the new mounting point is a bit father away from the firewall. It looks like it was designed for the spot as well with the added bonus that it's within easy reach of the charger cable. The other fuse will attach to the air conditioner positive cable. I used fairly stiff 6 gauge wires to span the distance to the battery pack under the hatch and the high voltage wires from the charger and A/C compressor appear to be 10 gauge, so once again, overkill is always appropriate.

Cool, Man!

The cooling system is complete. The plumbing is a hybrid of 3/4" heater hose and elbow fittings to connect the catch tanks, pumps, motor, and inverter, 5/8" heater hose for the charger with 3/4 to 5/8 adapters, and AN8 hose and fittings to and from the heat exchanger.

Starting with the forward pump, there's an elbow to get the hose pointed at the charger and a 3/4 to 5/8 step down to get the correct size.

Notice the AN8 fitting and return hose from the heat exchanger. 

The 5/8" hose charger inlet is on the right and the outlet is on the left,

looping through another 3/4 - 5/8 step up sleeve and elbow into the motor inlet. 

the motor outlet leads to an AN8 adapter

that connects to the heat exchanger.

The heat exchanger is a dual core Derale unit with the upper core serving the motor and charger cooling loop and the lower core taking care of the DMOC inverter. The inverter had to be removed to install the plumbing on the front of the motor.

While the inverter was out, I decided to rotate it 180 degrees to get the plumbing connections on the same side as the pumps, primarily to free up space on the opposite side for the air conditioning compressor fittings. You'll see soon why that was necessary.

Unfortunately, that meant I had to chop up the artistically curved underside of the mount to get clearance for the protrusion on the bottom of the inverter. My grinder skills pale in comparison the Robert's, but what it lacks in grace and beauty, it makes up for in utility. The good news is that after the inverter is connected to the motor and secured, the mount will be out of sight.

With the inverter and its cooling loop installed, you can see that if the inverter inlet and outlet had remained on the opposite corner, it would certainly have left no space for the A/C fittings. As it is, it leaves scant clearance for the power steering pump. If it seems that there an awful lot of hose clamps, there are! The cooling system used twenty five clamps in addition to the ten I also installed today on the power brake vacuum lines.

I set up my test rig to make sure all those clamps were doing their job. Good news - no leaks!

The systems took almost a gallon of coolant, and after about a ten minute run, all the air bubbles seemed to have worked their way out. I was most pleased that the time I spent last month calibrating the PWM signal generators paid off. Those tiny controllers held their settings and ran the pumps at about half speed in near total silence. I've since learned that the pins exactly match a three pin computer fan cable. That will make for an elegant installation that, again, no one will ever see.

Random Bits and Pieces

Now that the Porsche's in my garage, it's been pretty much a full time avocation. I confess I wasted way too much time trying to find a home under the hood for the contactor box in order to avoid running an extra set of high voltage lines rear to front for the charger and air conditioning compressor. Alas, there's just no room in the inn and I ran that wiring, along with the contactor control wiring, through the firewall and along the floor through the cabin. Not much to see, black on black, and that's good news. It exits under the rear seat back.

I decided to use a 12 volt battery to avoid parasitic loads on the main battery pack while the car is parked. I bought a fresh Bosch group 91 12 volt battery. That's the OEM replacement size, a bit shorter and wider than a standard car starter battery, so it fits perfectly in the battery box with room for the power brake vacuum pump. Both are secured by the single bolt in the center of the space, which happens to be an M8x1.00. I'm getting an education in metric nuts and bolts. This one is a fine thread as opposed to all the ones I had in my bolt box which are M8x1.25 course thread. Only 34 cents, but an hour of trial and error until I finally gave up and went to the home store and rummaged through their hardware aisle.

The rest of the power brake vacuum system was also installed including the pressure switch that controls the pump and the vacuum reservoir. I used existing threaded holes I found in the motor bay that made mounting pretty convenient.

With the battery in place, I ran a heavy duty 12 volt cable under the car to feed the DC/DC converter in the rear. There was no more room in the conduit, so this cable was sheathed in corrugated plastic and run in parallel. When I get the car back to Pro Automotive, we'll put it on the lift and secure it to the outside of the conduit with heavy duty nylon cable ties. 

 

In the rear I found a well placed hole in the floor board just ahead of the DC/DC converter. It had a grommet that will be opened up to seal and cushion the cable passing through. I was able to clean and repurpose some of the original starter wiring for the connections.

Back in the front, I found mounting spots for the fuses that will protect the high voltage lines for the air conditioning compressor and charger. Again, there was a threaded mount point that made sense.

Finally, a threaded stud on the firewall presented an ideal location for the terminal block for the high voltage motor connections. The 1/0 cables from the contactor box in the rear will connect with the motor cables here. The terminal block is actually a repurposed fuse holder.

The plumbing for the cooling systems needs to be done before the inverter to motor wiring is done, so I think that will be tomorrow's order of business.

Baby Comes Home

Got the power steering pump installed and plumbed yesterday, also finished up the under car wiring, so this morning we tucked all the loose wires out of harm's way and called for the flatbed.

First order of business will be to clean a year's accumulation of shop dust and evaluate my sequence of events. It's far too easy to paint yourself into a corner and all the prerequisites and dependencies need to be worked out to minimize rework.

It's well situated in the garage and there shouldn't be any access issues. I'm guestimating a couple weeks to get the wiring and odd bit installations done. Robert will be working on the finish and paint for all the missing body parts while I'm busy here. I'm hopeful I'll be able to drive it back to Pro Automotive for the final reassembly in time to get a little road testing done before we load it up for EVCCON in late September. Stay tuned ...

Subterranean Tunnel

Taking advantage of time on the lift, I'm working at Pro Automotive for a few days so I don't have to work in the dark on my back under the car. I was happily surprised to find that the exhaust system on the Porsche ran right down the center line of the car, suspended from the torque tube.

A one and a half inch inside diameter piece of outdoor PVC conduit is perfect for getting the cables safely from the front to the back of the car. A couple of two inch muffler clamps secure the conduit to the existing tail pipe mounts. It's recessed into the tunnel and entirely above the level of the floor pans.


The conduit carries four cables. The two orange 1/0 cables are the positive and negative feed from the battery pack. The orange corrugated cable is the charger input from the J1772 charging port (both 120 and 240 volt). I'm using trailer wiring to handle the 12 volt traffic to the AVC2 and emergency contactor. The four 16 gauge wires are color coded and bonded together in a strip that makes it far easier to push through a conduit than individual wires.

There were screws sticking out from the rear seat pan that were very conveniently positioned to attach the cable straps. The cables pass through an existing two inch by four inch opening in the floor. A small plastic filler with two gland nuts will close the space and keep the cables away from any sharp edges.

I also picked up the custom power steering line that mates the Toyota MR2 pump with the Porsche power steering rack. That's another job best done while the car is on the lift, so I'll be back over at Pro Automotive on Monday to install that and finish up the charger wiring.

Light at the End of the Tunnel

Things are getting to their final place and it's looking like I'll be able to take over and move on to the wiring stage real soon now! The motor/inverter/charger assembly is in and seriously looks like it belongs.

The Power Steering Pump, Coolant Pumps, and Charger are all in view on the passenger side of the motor bay. The Air Conditioning Compressor and Brake Master Cylinder and Booster take up most of the space on the driver side. 

From the front it almost looks like the cam cover of a gas engine. 












The battery box is finished with its shiny aluminum skin all caulked and water tight, ready to have the battery packs mounted.

The DC/DC converter will be mounted between the battery box and the rear seat back. The cooling fan is virtually silent, so it shouldn't be an annoyance. The charging control circuit box will mount on the passenger side of the upper battery platform, and the precharge and motor contractor assembly on the driver side. Last pieces to be done before it returns to my garage are the A/C condenser and heat exchanger (radiator) mounts and the power steering hoses. The finish and paint on the front bodywork will continue while I do the wiring, and final reassembly will be completed after it's basically roadworthy. 

Fit and Finish in the Motor Bay

The rear motor mount is done along with the rear inverter mount. All has been painted and looks great!

The front motor, inverter, and charger mount has also been finished out nicely.

I mentioned earlier that we had to remove the DC/DC Converter mount that had been in front of the charger due to space limits. It will be mounted elsewhere in the motor bay. We'll figure that out after the motor is installed and we can see how much space is left.

The frame rails have been painted where Robert welded on the mounting tabs for the motor, coolant pump assembly, power steering pump, and air conditioning compressor. Robert is working on the aluminum battery box liners and hopes to have the Porsche over in my garage by the end of the week. I'll have roughly four weeks to do all the high voltage wiring and 12 volt circuits, dashboard, gauges and controls. Robert will be painting and finishing the fenders, nose, and hood while I'm doing the wiring. Target for finished and road tested car is mid September.