2001 Saturn SL1 Mod Thread

[stefanv]

Originally Posted by 19bonestock88

Nice work on the kill switch! I'm still trying to source a reasonably priced NC momentary switch for doing a kill switch in my Ion... Where can I find one? Hadn't found a good one yet...

Thanks!

The switch I used is NO, and it is used to energize a relay with NC contacts. I didn't want to run the fuel injector supply voltage all the way from the under-hood fuse block to the centre console and back due to power losses and more points of disabling failure (e.g. the wire breaking or coming off the switch). Also, in my experience, an NC switch is much more likely to fail open than an NC relay.

I did choose a fairly robust switch though, since it has to survive in the harsh environment of a car, and I didn't want the switch to become non-functional, even if it doesn't disable the car by failing:


https://www.digikey.ca/products/en?keywords=EG4724-ND

It's dust proof, water resistant, and its electrical life is rated at 200,000 cycles at 2A. It should last for its full rated 1,000,000 mechanical cycles in my application since it's only switching 0.25A.

[stefanv]

While driving home a few weeks ago, a cat ran across the road literally in the last few milliseconds. It darted out of the grass, across the shoulder, and right in front of the passenger side of my car. There was simply no way to avoid it, and as I looked in the rearview mirror, I saw a deceased cat and bits of plastic tumbling along the road.

Of course as a cat lover, I feel bad about the cat (and its owners, although given where I was driving, it was likely an unloved barn cat), but this is the Ecomodder forum, not the general Internet (which is primarily for and about cats), so on with the damage assessment...

I noticed immediately that my right side air dam extension was missing a cat-sized chunk. I neglected to take a picture while it was still on the car, but suffice it to say that the one piece extension was now two pieces.

I also noticed that there was a big crack in my grill block, with a small piece missing, and one of the metal mounting brackets dislodged. I'm not positive the cat caused this, but I think so, due to the flexing of the bumper.

But the worst thing was that my radiator intake-side shroud was broken. I noticed that the factory air dam was loose one side, but then discovered it was still firmly attached to the shroud, and that the shroud had a crack all the way up to just under the hood. It's possible that my air dam extensions prevented the factory air dam from bending backwards (it's flexible), and instead transferred the impact into the shroud.

I elected to just do quick patch repairs to get the eco mods back on the road, and will rethink the entire thing in the summer, perhaps using more flexible materials than the ABS I've been using.

This picture was taken after I patched up the shroud, using an aluminum plate, stainless steel screws, and outdoor-grade cable ties. This area is immediately behind the passenger side headlight (I removed both the headlight unit and its mounting bracket to get at the broken shroud):



I patched the damage to the grill block using a piece of the same ABS, held in place with screws and ABS cement. It looks a bit rough, but it actually looks better in real life (I had to crank up the low level contrast to make the repair visible in the picture):



Finally, I made a new air dam extension (and one for the other side too, since it had a small crack in it). Rather than using ABS, I used polypropylene from a boot tray. I'm hoping this will be slightly more flexible, but I'll probably make new ones in the summer out of vinyl (PVC):

[stefanv]

[arcosine]

You should take some heavy oil and pour some into the subframe on the left side, The right side is automatically done during oil changes. I think that's why the right side doesn't rust out. Impressive odometer, oh wait its km.

[stefanv]

Neither side is rusty. The car is sprayed every year.

[stefanv]

As my hyperkilometring evolves, I've found I use my kill switch more and more. When using it while rolling, I've usually restarted by letting out the clutch, but it's very hard to do this smoothly, since of course I can't match engine RPM to gearbox RPM when the engine isn't running yet. I think if you do this smoothly, it's hard on the clutch, and if you do it roughly, it's hard on the engine, transmission, and mounts. Thus, I've changed to restarting using the key.

The problem is, this is kind of awkward when in motion, so I came up with the idea of installing a "revive switch". It basically duplicates the process that turning the key to START does, but with just a button next to the kill switch. Here's the schematic of what I've done, added to a stretched diagram from the service manual:



There are two identical SPDT relays, with their coils wired in parallel, and powered by the RUN-only wire from the ignition switch. A pushbutton to ground is used to energize the relays. [Aside: The diodes are part of the relays. My kill switch relay didn't have one, and always produced a loud pop in the sound system when the button was released. Adding a diode completely eliminated that, so I ordered relays with diodes already installed this time.]

When the really is not energized, the RUN-only wire (orange) goes through the normally-closed contacts of the first relay, and from there on to the RUN-only section of the fuse box. Likewise, the RUN/ACC wire (brown) goes through the normally-closed contacts of the second relay, and then on to the fuse box. Both of these wires were previously connected directly to the fuse box.

When the "revive" button is pushed and the relay is energized, the power from the RUN-only wire is redirected to the starter circuit instead, and the RUN-only part of the fuse box no longer gets power (as it shouldn't during starting). Likewise, the RUN/ACC part also no longer gets power (as it also shouldn't).

As far as the rest of the car's electrical system sees things, exactly the same thing has just happened as if I'd turned the key from RUN to START.

Here's how it looks under the dash. I fashioned a small mounting plate for the relays out of 1/8" aircraft plywood, and bolted it to a metal rail close to the wiring harness:



Here you can see the two buttons. The yellow one was formerly my kill switch, but is now the revive switch. The more aptly coloured red one is the kill switch now:



I did run into one snag... The schematic I had, from what appears to be a scanned version of the service manual, had the brown and pink wires from the the ignition switch swapped. So pressing the button disconnected stuff that was supposed to remain powered during START (like the BCM), and did not disconnect stuff that should have been (like the audio system). The engine cranked, but wouldn't start.

At first I thought I'd run afoul of the PassKey II security system, but after much Googling and pondering the symptoms, I came to the conclusion that this wasn't the case. I went back and monitored the voltage on each wire out of the switch in each switch position and discovered the error in the wiring diagram. After some more Googling, I found another diagram on SaturnFans.com (in black and white, but with the colours labelled), that had them indicated correctly. After rewiring, everything worked. Unfortunately I now have an unnecessary splice in the pink wire.

[oldtamiyaphile]

Originally Posted by stefanv

As my hyperkilometring evolves, I've found I use my kill switch more and more. When using it while rolling, I've usually restarted by letting out the clutch, but it's very hard to do this smoothly, since of course I can't match engine RPM to gearbox RPM when the engine isn't running yet. I think if you do this smoothly, it's hard on the clutch, and if you do it roughly, it's hard on the engine, transmission, and mounts. Thus, I've changed to restarting using the key.

Correctly bump starting shouldn't be hard on the clutch. It takes 1/10th of a second to spool up around 40kg of mass inside a small engine. It takes about a second of slip to get a 1000kg car moving from a stand still. The wear rates aren't even remotely comparable.

[Grinder74]

I always did like a double clutch action. You learn just how far to let the clutch out to get it turning. Do it fast clutch out and back in, engine get up in rpm and release clutch. Some cars idle up fast initially and at the slower speed it can match up. I did it for years in my SC1.

[stefanv]

Originally Posted by oldtamiyaphile

Correctly bump starting shouldn't be hard on the clutch. It takes 1/10th of a second to spool up around 40kg of mass inside a small engine. It takes about a second of slip to get a 1000kg car moving from a stand still. The wear rates aren't even remotely comparable.

The difference is in the speed delta. To get the car moving, you're starting with an 800 or so RPM/difference (engine speed 800 RPM, driveline speed 0). To restart the engine at speed, the difference is around 2000 RPM (engine speed 0, driveline speed 2000). So that 1/10th of a second is probably about equivalent to 1/2 a second of getting a car moving.

[oldtamiyaphile]

Originally Posted by stefanv

The difference is in the speed delta. To get the car moving, you're starting with an 800 or so RPM/difference (engine speed 800 RPM, driveline speed 0). To restart the engine at speed, the difference is around 2000 RPM (engine speed 0, driveline speed 2000). So that 1/10th of a second is probably about equivalent to 1/2 a second of getting a car moving.

The RPM delta doesn't matter. You only need to transfer X newtons to get an engine cranking. During a bump start, the greater the speed differential, the shorter the required contact. Same energy transfer= same amount of wear.

You can try this (in someone else's car of course). Sit on a hill, hold the car on the clutch at idle. Increase RPM. The car doesn't move because regardless of RPM, you're only transferring the same number of newtons.

Slip time is what wears out your clutch, not RPM.

The reason people think it's RPM is because from a standing start engine and road speed will take longer to match if you release the clutch at higher revs.

Besides which, I can bump start my car from around walking speed in 3rd. That's about a 200rpm delta.