Friday, April 30, 2010

Engine Compartment Trays

In previous posts I described mounting the motor-transmission assembly and the battery box located where the radiator used to be.  Now for the rest of the components.  It's a bit of a Tetris puzzle, but the other components that I want to place in the engine compartment include:

  • DMOC445 motor controller
  • RM4 fluid heater with pump
  • DC-DC converter
  • Zivan NG3 battery charger
  • Vacuum pump and reservoir (for power brakes)
  • Accessory battery (standard 12V starter battery, or a smaller version?)
  • 2 electrical boxes for relays, shunts, connectors, etc.

Of course, none of them were really designed with the Saturn engine compartment in mind, nor were they designed to nest together well.  After hours of head-scratching and experimentation with various placements, we came up with a plan that gets everything placed reasonably well with the exception of the Zivan unit.  So it looks like the Zivan will be relegated to the trunk after all.  Here's the layout schematically.

The components are mounted to 2 trays that are affixed to various frame members in the engine compartment.  It was manufactured in 2 pieces so that they could be easily loaded/unloaded.  The main tray will be attached to the passenger side frame (near where the original upper engine mount was located), to the subframe in the center-rear of the engine compartment (just behind the steering rack), and to the angle iron welded in place to support the radiator battery box.  This tray will hold the DMOC controller, RM4 fluid heater, the vacuum system reservoir, and the 12V electrical box.  A second tray bolts to the main tray in 2 locations (front and rear of the engine compartment) and to the driver side frame (near the transmission torque rod mount).  This tray will hold the DC-DC converter, vacuum pump, a U1 accessory battery (wheelchair battery), and the high-voltage electrical box.  It was possible to rearrange the components so that a standard Saturn starter battery would fit, but why carry the extra weight when I won't need to start anything?!?  The U1 size should be plenty big to act as a capacitor between the DC-DC converter and the various 12V loads in the car.

Here's the main tray installed.
This is a close-up of the rear extension, showing the tray attached to the subframe behind the steering rack.
 Here's a close-up of the attachment to the radiator battery box rear support.

Here's a view of the second tray installed.  Notice that the bell housing sticks up above the tray, complicating placement of some of the components.  This tray is bolted to the main tray on the left and screwed (self-tapping screws) into the main car frame member on the right.
 I don't have a good photo showing the trays installed with components in place.  I'll update with good photos once everything is mounted in place.

Most of the components are simply bolted through the angle iron bottom of the two trays, often with rubber mounts, but the fluid heater and vacuum pump were extra challenging.

The fluid heater doesn't have any straight edges.  It looks a bit like two tapered cups joined together at their rims.  There is a flange which runs along the axis of the heater with 2 holes drilled into it that is meant to be used to mount the unit.  This flange does not look beefy enough to me, and I was worried that it would not hold its own weight considering the vibrations and g-forces of a driving car, so I opted to use a "riser" pipe clamp (McMaster-Carr PN3065T54) around the lower tapered surface.  The riser clamp bolts were welded to two pieces of angle welded vertically to the bottom of the tray.  By the way, McMaster-Carr has without a doubt THE best website in the world.  I am continually amazed at how easily I can search for items, and how easy it is to order things.  Plus they've delivered to me the next day every time, without fail.  They rock!

Anyway, here's a picture of the fluid heater with the rise clamp.  You can barely see the "mounting flange" on the left side of the unit.

The idea is to bolt the riser clamp to little uprights welded into the main tray in the back left corner (looking at it from in front of the car).  In order to keep it from hitting the hood, the bottom of the heater will actually descend below the tray by a few inches.  It fits nicely just behind the motor casing but still above the drive shaft.  It might be hard to see here (kinda dark - I need some photography lessons), but this picture shows the heater installed in the tray.  You can see one of the angle iron pieces to which the riser clamp is bolted.
The vacuum pump also presented some challenges.  Not because it is difficult to mount, but it's just awfully big, and I wanted to keep it close to the brake booster.  I ended up actually mounting it vertically, next to the brake booster and master cylinder, with the business end up.  I'm not totally enamored of the location, but hopefully it will work ok for now.  I think it will clear the hood, but I haven't tried it yet.  My eyeball says it's going to be close.  I don't have a great picture of this yet, but I'll take lots of pictures once all the components are installed.  The vacuum reservoir is going to hang down from the main tray to the right of the fluid heater between the motor casting and the firewall.  There's room there, and I plan to just use 4" pipe clamps attached to the back of the tray.

Here's a picture of the DC-DC converter and accessory battery approximately in place.  This also shows the approximate location of the high-voltage electrical box.  Again, the lighting leaves a lot to be desired.

Next step: drill mounting holes in the trays, paint them up, and install them.

Wednesday, April 28, 2010

Rear End Upgrade

Upgraded rear suspension
Back in November of last year I wrote about the proposed battery locations and extra load expected on the rear axle.  Once I finalized those proposed locations, I ordered new springs from Springworks to accommodate the extra weight.  Over the winter I swapped them out.  No use putting old struts inside the new springs, so I changed them as well, even though I had no idea if they had been replaced before.  The changeover was a breeze - I was able to use a real (wall-mount) strut compressor at a friend's shop.

Here's a picture of the old strut assemblies with one of the new springs.  Notice the new spring is variable rate.  I'm not sure if it will make a difference in the ride or not, but my recollection is that it wasn't any more expensive.

Here's a picture of the new strut assemblies.  The strut mounts actually looked ok, so I didn't end up replacing them.

Since I had the rear suspension off, I also replaced the broken sway bar link on the driver side.  Here are pictures of the broken link and replaced links.

The car hasn't been on the ground yet since the swap-over.  It'll be interesting to see how level the car sits once the batteries are installed.

Tuesday, April 27, 2010

Checking back in...

Will this car ever be done?  I'm beginning to wonder.  I'm even wondering if it will ever be on wheels again!  It's been on blocks so long that I'll bet the frame is permanently sagged.  Certainly the doors don't open and shut like they used to.  Oh well, I'll worry about that when I'm getting ready to roll it out into the elements.  Also, clearly I'm not cut out to be a blogger.  It's been nearly 3 months since my last entry!  And there wasn't much there either.

So, here's what's happened in the past 3 months:

Battery boxes

  1. Cut and painted all the plywood that will be the "box" part of the battery boxes.  I previously showed the angle framework for these boxes.
  2. Discarded my original "battery hold down system," designed and installed a new one that I like a lot better.
  3. The new battery hold down system meant redesigning the lids.  That is done as well, though the lids have not yet been painted.

Engine compartment

  1. Fabricated trays to hold engine components, including DMOC, DC/DC converter, fluid heater, vacuum system, and accessory battery.


  1. Fabricated and installed PVC pipe through center "hump" to run battery cables from rear battery box to engine compartment.
  2. Fabricated brackets in trunk for the Zivan charger.
  3. Replaced rear struts - new struts and new heavier springs (for additional 800 lbs on rear axle).
  4. Replaced front and rear brakes (rotors, pads)
  5. Re-wired the garage where the car is stored.

Ok, so here's where the rubber meets the road.  I am going to try and be more diligent (have I said this before?  Probably, but I don't want to look back and check.  Too embarrassed!), so firstly I'll write a few retrospective entries to explain what's happened over the past 3 months then see where I go from there.  I've also got to do better with taking pictures.  The problem with working alone a lot is that I don't ever think about documenting what I'm doing, so I'm not sure how good these retrospectives are going to be....

Plunging back into the blogosphere I go.