Is 42mpg too low a goal?

[Istas]

stevey: I'll wire in that capacitor as soon as I get home (I'm an hour away from the nearest store that would have something like that out here in rural Montana).

I've looked as well as I can at the MPGuino, and as far as I can tell nothing's touching or soldered to what it shouldn't be, but I've never really worked with electronics before, and in addition it's a pre-built that has the plastic sandwiched between the screen and the circuit board, and clear glue elsewhere. It could have been some shoddy wiring connections causing the excessive heat before (I had trouble hooking wires into the provided connector: yesterday when I put the switch in, I also scrounged a floppy drive power connector from an unused computer PSU, so that is no longer an issue; it's not pretty, but it should be solid).

I also have two heatsinks on the on-board voltage regulator, so that should help if it is getting too hot, and should also help on hot days. (and I have the backlight turned off during the day too, I didn't know about that before, was still getting it wired in before looking at the functions)

I'll check today for other warm components.

McTimson: I have the ground for the MPGuino going to the ground for the stereo unit.

Yeah, I didn't know about/realize there was a constant power to the stereo before when I was wiring it. And now, I have the power coming directly from the battery. Shouldn't that be even better as far as unpolluted sources of power go?

eco-gen: Yeah, heh. But it's a small price to pay in order to keep MPG data intact. (just kidding!)

If it's going into the computer, there has to be a way to read and record that data somehow, even if it involves hacking into something and/or writing an entire program in a programming language I don't know. But I'd have to get a laptop first before worrying about it anyway.

I went for a short drive last night, and saw that the indicated speed was jumping around quite a bit, as much as from 60 mph to 69 mph, and it was doing it quite frequently as well. It might go 60-69-62-60-63-60-64-61-60-60-67-62-60 etc, as the values showing up on the display. Irritating. I really must look into the speedometer, never have before because I understood it to be more expense than it was worth. (I'll start with that clip down on the transmission side, as suggested by eco-gen)

I'm going to try some B-A-B testing today, if it's not too windy (as I already have the mods that I've made, on the car).

[Doofus McFancypants]

Just read whole thread - awsome build.
I also love the unfinished look.

keep up the great work - I am taking notes !!

where did you get the Metal? how hard is it to work with and attach?

Steve

[Istas]

Doofus: Thank you! And nice username. I did read the "what's your name mean" thread.

I got the metal at Lowe's. It's galvanized sheet steel. It comes in rolls, iirc it can come in 10" wide, 14" wide and 20" wide, possibly more sizes. I got the 20" wide as it fit my needs (and you can always cut it smaller, but hard to cut it bigger: you can rivet segments together if you want but it's easier and faster to just start with the right size if you can, obviously).

The hardest part about working with it is cutting it without cutting your hands, and cutting it in the right shapes (a bit difficult to cut nuanced curves in sheet metal with tin snips), and then dealing with the sharp edges (I've started using flat-grip pliers to bend over about an eighth of an inch of metal to 90 degrees, a flathead screwdriver to fold it in to an acute angle, then a hammer to flatten it out: you can see what the finished result looks like in my pic of the airdam/undertray while it's off the car in an earlier post).

However, it's -great- for being able to bend into shapes you want it in, without needing a heat gun or anything like that, and if you get it wrong you can just bend it back (with the help of a hammer if necessary). It's thin and doesn't have the corrugated center, so it's easy to bend, and to bend small bits. It's also quite sturdy if even somewhat supported. It's easy to connect to itself, or other objects, with pop-rivets. You don't have to worry about heat at all (the undertray I put on my car is a couple of inches from the exhaust headers), nor do you have to worry about it possibly getting more brittle over time (due to sun exposure or whatnot, like some plastics might).

I've had 5 sheet metal patches on my car, the older ones for over a year or two, and so far only one of them has shown any rust at all. So rust is definitely an issue, but i imagine this could be mitigated by slathering the cut edges with rust bullet or something similar.

[QuickLTD]

Your creation reminds me of this in a good way LOL

Landmaster - Wikipedia, the free encyclopedia

[fit7ad]

Linear regulators produce a lot of heat when stepping down from a high voltage. Assuming the 5V load is drawing 200 mA and the battery voltage is 14V, 2.8W is drawn from the battery and only 1W is used by the load. The rest of the 1.8W is dissipated as heat in the regulator. That's quite a bit without a proper heat sink and sufficient air flow. This can't be avoided without using some type of switching regulator.

Originally Posted by stevey_frac

Get yourself a 10 uF ceramic capacitor, and wire it from the power to the ground as close to the MPGuino as you can. That will go a long way towards removing any high frequency noise from the board.

The 5v regulator shouldn't be putting out much heat. The MPGuino can't be using that much power, and typically, small 5V regulators are at least 80% efficient. I would check really really closely for some kind of short? I honestly don't have any experience with the MPGuino, but i'm a computer engineer, and really hot components on this kind of thing sets off my 'something is wrong' alert system. Also, check for other warm components. Most chips these days can run very quickly and produce no discernible heat.

[Istas]

fit7ad: It's actually 20 mA, not 200. And an extra 20 for each of the 3 levels of brightness (which i leave off during the day, and level 1 is all that's necessary at night). The heatsink seems to be working as it's getting warm. I think it helps even if heat wasn't the problem I was having.

Still need to fix the beeping-horn problem though, waiting until getting home to tackle that.

[QuickLTD]

Did you get any work done on that foam airdam piece?

[Istas]

The nearest place where it might be available is an hour away in Missoula. I don't think it's worth driving all the way over there even if they have the item I'm looking for (I didn't call). I might stop if I see a Lowe's or Home Depot or whatnot on the way home, but the effect will be not enough to justify driving 110 miles to get the foam.

[QuickLTD]

Agreed, I thought you already had it. My mistake.

[Istas]

Hah, well, this is fun. I have another gas leak. I think it's from the fuel tank itself this time. So no calibration on the way home, and I'll probably be only filling the tank half way at each gas station, since it seems to have been exacerbated by filling the tank.

The perils of owning a rusty 17-year-old car.