Ontopic A Thread About Butt Mustard, For Those Who Drive Automobiles

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Valve1138 said:
Nerd
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Arduino hardware is so cheap, I figure even if I find out there's some kind of hard limit that fucks me over in the long run, I'm not really out anything.

The kids like to play with the arduino sensors and stuff, so I'm really only cannibalizing a small part of the overall ecosystem here in the house by snagging one of the Unos.
 
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What is the goal of this?

"Because I can" is an acceptable answer.

Monitor things on the fly for fine tuning later?

End up with sort of "efficiency", "fun", and "white knuckle" modes?

Or monitoring things that an old-school set of gauges can't tell you?
 
HipHugHer said:
What is the goal of this?

"Because I can" is an acceptable answer.

Monitor things on the fly for fine tuning later?

End up with sort of "efficiency", "fun", and "white knuckle" modes?

Or monitoring things that an old-school set of gauges can't tell you?
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My current gauge cluster doesn't have an ethanol content display, and I need to monitor that, as I can't go much above 50%, or I'll run out of fuel injector.

Also because I wanted to.
 
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I assume "run out of injector" refers to needing more alcohol to get the same energy as a smaller amount of old-school fossil gasoline.
 
HipHugHer said:
I assume "run out of injector" refers to needing more alcohol to get the same energy as a smaller amount of old-school fossil gasoline.
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No, it's just that where λ=1 for gasoline it's about 14.7 parts air for 1 part fuel, with ethanol, it's about 9 parts air for 1 part fuel.

Given that I'm flowing about the same amount of air, it takes a lot more ethanol to maintain a stoichiometric burn in the cylinder (largely because ethanol brings a lot of its own oxygen to the party).

So, at E50, where I'm about 60% duty cycle on the injectors for regular 91 octane, I'm at about 85% duty cycle. >85% duty cycle is a line I don't really want to cross.
 
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Makes sense with different air/fuel mix and air is constant-ish, at least without choking if off.
 
Jehannum said:
Since E85 is about 108 octane, I can stuff a whole fuckload more air and timing in without detonation.

The winning play is to throw some 1000cc/min injectors in, but that's a project for some other time.
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How does temperature get mitigated with the alcohol?

Actually, nvm. I think what I saw as drawbacks are really benefits.
 
HipHugHer said:
What is the goal of this?

"Because I can" is an acceptable answer.

Monitor things on the fly for fine tuning later?

End up with sort of "efficiency", "fun", and "white knuckle" modes?

Or monitoring things that an old-school set of gauges can't tell you?
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He's trying to build the Knight Rider car and call it Kip. Don't Hassel the Hoff
 
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Jehannum said:
Because I'm too cheap to buy an AEM serial gauge for $200, I decided to waste my time building one with an arduino. I have half the project done - I defined the (very simple) state machine and the data I care about displaying (also wrote a simple library for managing values and statistics over time: https://github.com/Jehannum505/StoreManage). It's got two buttons - one to switch units between SI and imperial, and one to toggle a hold on the current display (otherwise it'll swap between the 3 measurements - Ethanol content, MAP reading, and water temperature every 8 seconds). It updates the display every 1/4 second.

Now I'm going to go and plug a serial cable into my AEM S2 and let it puke data into a file so I can figure out how to parse it.

Then comes the real fun of packaging it up. I'll probably 3D print the cases, because once you've got a 3D printer, every problem requires a new dildo.

View attachment 5828
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Awesome.

Dumb thought: if you push/hold the button for 3 seconds, it switches between SI and freedom units. Saves a button.

There's all sorts of different displays available on adafruit, maybe there's some cool-ass OLED dsplay you could poke in a small 3D printed pod that fits neatly in the car. Then build and sell that shit. Might also be worth learning PCB design if you want to make a sellable product, it's pretty easy.
 
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dumb thought #2: maybe put that 2nd button back in, because there's no obvious way to clear the max/min/avg. Maybe you want this so you can bring the car up to temperature then clear it.

dumb thought #3: maybe buy a modern car with an OBD2 port and do this using a $5 bluetooth adapter and an android phone ;)
 
gee said:
dumb thought #2: maybe put that 2nd button back in, because there's no obvious way to clear the max/min/avg. Maybe you want this so you can bring the car up to temperature then clear it.
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The data display is something I've got to think through, but the min/max/avg thing was what occurred to me initially. Not sure I need to clear it, but maybe it's a good idea.

dumb thought #3: maybe buy a modern car with an OBD2 port and do this using a $5 bluetooth adapter and an android phone ;)
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ungravy.
 
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7 months in with the Q5: I wish it had a stick and was as hoonable as the old A4 wagon in the snow, but other than that, very happy with it.

Not that my opinion matters, it's the gf's rig and she's happy with it.

Wish it was professional grade though.
 
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