2001 Saturn SL1 Mod Thread

[Grant-53]

I use the 0.005" plastic tarp material for a number of projects. Usually I bond some wire mesh between two layers of plastic sheet. A lip just above the rear window might help air flow too.

[stefanv]

I've been so happy with Torque, that I decided to keep using it instead of building an MPGuino or similar. In fact, I decided to go out an by an inexpensive 7" tablet to install permanently in the car. The tablet I chose was an Acer Iconia One B1-780, which I picked up for $110 at Walmart.

I'll post some pictures once I've installed it, but in the mean time, here's a screenshot of the layout I've come up with:



I have a darker version that kicks in at night.

I'll be using this primarily to run Torque, but also MapFactor Navigator (a great free off-line GPS app), and RocketPlayer (a music player app). I'm going to install it in place of my car stereo (the radio doesn't work anyway), and put in a small home-made amp to drive the speakers.

[oldtamiyaphile]

Car ready Android tablets.

https://www.carjoying.com/1-din-andr...avigation.html

Seem to get good reviews.

[stefanv]

Still working on the tablet installation. Radio is out, amp is built, but I still need to fabricate something to hold the tablet itself. I hope to finish that this weekend.

In the mean time, I've put my winter tires on the car. Before I did so, my fuel economy on the last couple of tanks has gone down a bit, I think due to lots of windy and/or rainy and/or cold weather. I expected it to get worse with the snow tires (it always has in the past).

However, as I was putting them on, I noticed that they had a max sidewall rating of 45psi, vs. the 35psi on my summer tires. I had the summers inflated to the full 35, and decided to try the snows at 40 for now. So far, for the first tank and a half, my fuel economy has improved by about 3% according to both Torque and calculations done at fill-up, despite the weather getting worse. This looks promising. I'm not sure I'll take them all the way to 45, since the ride is already getting a bit harsh.

[stefanv]

I sort of finished the tablet install in the car last night ...



Physically, it worked out well. The tablet fits the existing stereo opening almost exactly. I still need to black out the area behind the tablet, and I may make a front fascia for it to blend in better with the rest of the trim.

The tablet is held in place with strong magnets on the front face of the amplifier enclosure (which I designed and built specifically so that the tablet would end up at the proper depth relative to the dash bezel).

However, I ran into a few snags. First of all, there's a lot of noise coming out of the amplifier if the tablet is connected to the car's electrical system at the same time that it's audio output is connected to the amplifier. I've ordered an audio ground loop isolator to fix that problem.

The second problem is that the amplifier itself is picking up a lot of noise, such as the heating fan motor, and perhaps some ignition noise. The amplifier is completely unshielded, and gets its ground only through the stereo wiring harness. I need to enclose it in metal, and ground it more thoroughly.

[stefanv]

It's been a few months, and it's time for some updates!

There were two sources of electrical noise in the amplifier mentioned in my previous post. One was differering ground levels between the tablet and the rest of the car, caused by the switching power supply that was powering the tablet. I got around this using a very simple ground isolator (basically a pair of transformers), purchased from Amazon: https://www.amazon.ca/gp/product/B01M1671I0



That got rid of the noise coming from the tablet itself, but had no effect on the noise coming from the ignition, HVAC blower, and fuel pump. To deal with that, I installed a home made BHF (Big Honking Filter), consisting of an inductor and capacitor, as described here: San Antonio Hams



There's still a tiny amount of crackle when the HVAC fan is on low, and also a barely perceptible fuel pump whine. I'll fix these later by adding capacitors to each motor, but it's inaudible over the road and engine noise now.

[stefanv]

I've been doing some EOC and also turning off the engine at long stops, and until now, have been doing it with the key. The drawbacks to this are twofold:

1. There's always the possibility of overshooting the ACC position, thus locking the steering column.
2. If I want to keep the engine off with the clutch engaged, I have to leave the key in the ACC position. That means no instruments (e.g. speedometer) and no air bags.

A kill switch removes the need to use the key, and allows me to cut off fuel to the engine even when the clutch is engaged without compromising safety.

In my car, there's a single 10A fuse that provides power to the fuel injectors, and only the fuel injectors, so this seemed like an ideal place to wire in a kill switch. I did this using a pair of "Add-a-Circuit" modules, and a high-quality relay with a set of normally-closed (NC) contacts. Here's the schematic/wiring diagram:



The grey boxes with dashed edges are each one "Add-a-Circuit" module. The one shown in lighter grey is plugged into the fuse box in place of the fuel injector (INJ) fuse. The darker grey one is plugged into the primary (A) circuit part of the lighter one, in the opposite direction. 10A fuses are installed into the secondary (B) circuits of both. You can see in the diagram how the current to the injectors flows through both 10A fuses, the NC relay contacts, and the red wires (which are pre-installed on the Add-a-Circuits). Two fuses are of course redundant, and F2 could be replaced with a 20A or 30A unit, since its only purpose is to be a jumper.

A separate 0.5A fuse (shown as 1A in the diagram) provides power to one side of the relay coil. The small fuse is there so if there's a short in the coil circuit (or the wire to terminal 85 comes off and touches something grounded), that fuse will blow instead of F1, which would cut off power to the injectors.

The other side of the coil is connected to a long wire (green) which goes to a pushbutton switch on my centre console beside the shifter. Pushing this switch energizes the relay, opening the NC contacts, and cutting off power to the fuel injectors.



I gave careful thought to the design of the switch so that in the event that it fails, it's likely to fail in a way that the engine can run. If the relay fails to work, the cut-off just won't work. If the coil shorts out, F3 will blow instead of F1. There is still the possibility of course of the relay itself getting stuck open, or double the possibility of a nuisance blow because both F1 and F2 are in the circuit. However, if anything does fail, I just need to pop the hood, open the fuse box, pull the Add-a-Circuit out of the INJ fuse socket, and put a fuse back in its place.

[stefanv]

Here's a pic showing the actual kill switch (my wife calls it a "Kill Bill" switch, because it's yellow like Uma Therman's outfit in "Kill Bill").



I also remembered two additional advantages of using a kill switch instead of the key:

1. If I'm signalling and turn off the key, the signal stops until I turn it back to Run.

2. Likewise, the DRLs turn off while the key is turned to Acc, probably making other drivers think I'm flashing my lights at them.

[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...

[Daox]

Unless you're looking for something pretty, I recommend going with a nice snap action / limit switch. You can get them for about $1.50 on digikey. If you're looking for something pretty... it'll be a few bucks.

This one of the ones I use in my 3d printed shift knobs. It can be wired NC or NO.

https://www.digikey.com/product-deta...SW500-ND/83270