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Post by rowdy235 on Feb 1, 2021 17:38:15 GMT -5
Hey guys, I was helping a buddy this last weekend with his Bronco that he put a Mega-Squirt fuel injection kit on, and I was pretty impressed. Made me think of the speeduino I won years ago and potentially adapting the unit to a chainsaw! Can read more about it here speeduino.com/home/ but the TL:DR is its a open source fuel injection system. I am thinking the perfect saw would be a C-Series. Since its a larger frame saw would have room to mount components and the fuel tank can be easily split to install a fuel pump inside. I'm working right now on the logistics of it and making up a parts list. I have my eye on a C-5 for sale locally too. Stay Tuned!
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Post by edju1958 on Feb 1, 2021 19:44:59 GMT -5
I love it! Don't know if you know this or not,but fuel injected saws are already out there.I found out from my local saw shop about 6 mo.ago,he's a Stihl & Husky dealer.Stihl has the fuel injected saws.
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Post by blythkd on Feb 1, 2021 20:59:35 GMT -5
I knew there was fuel injected stuff out there now but I had no idea there was an aftermarket fuel injection system that could be mounted to an old chainsaw engine.
Rowdy, their website didn't do much for me. Feel free to explain in more detail if you'd like to and have the time.
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Post by rowdy235 on Feb 1, 2021 21:48:16 GMT -5
Thanks guys! I’m hoping it’ll turn out good, even if its not super practical for everyday use.
The Speeduino is a board which interfaces with an arduino (hence the name) which is a compact computer generally used for robotics/automation, much like the raspberry pi. The board allows you to interface with a fuel injection system and control it. The easiest way to think of it is the system replaces an ECU like you’d find in any fuel injected car, except that it is is very customizable to work with all kinds of hardware, if that makes sense. The typical application is obviously for a car, but I see no reason why it won’t work for a chainsaw, several people have used it with a motorcycle.
I’ve about got everything worked out (or so I think). Does anybody have any ideas for how I could adapt a charging system to the saw to charge a 12v battery?
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Post by rowdy235 on Feb 2, 2021 19:42:39 GMT -5
Here are my ideas so far.
Inputs/Sensors:
Crank position sensor- So far this has been the hardest one to figure out. My current plan is a 3144 Hall effect sensor mounted under the flywheel. I plan to drill the flywheel at 12 evenly spaced intervals and install some rare earth magnets to trigger the sensor (will only install 11 as it needs a missing tooth).
Throttle Position Sensor- Sliding potentiometer attached to the throttle rod. Since the system is configurable, resistance is not super critical
Manifold Pressure- Sensor is built onto board! Will run hose to a fitting drilled/tapped into the intake elbow.
Coolant Temperatue Sensor- Going to pick up a cheap sensor from rock auto, but need ideas on where to mount
Intake Air Temperature- Same cheap sensor as above, but mounted in air box, maybe in the choke rod hole.
Oxygen Sensor- Oxygen Sensor from rock auto mounted into the muffler
Outputs:
Fuel Pump- Going to talk my cousin who manages Napa into letting me sift through some fuel pumps to find the most compact one. Will also get an in-tank pressure regulator. Hopefully I can shoehorn all this into the factory tank, but we’ll see.
Fuel Injector- Found a 50cc replacement motorcycle fuel injector on eBay for fairly reasonable. Plan to drill into intake elbow just above reed valve and install, may need to modify air box cover for clearance.
Idle air valve- Will drill/tap intake elbow for fitting and attach hose to solenoid valve. This will allow the computer to allow more air in (like opening throttle slightly) for fast idle.If I can figure out a PWM controlled valve, I believe the computer can use that valve to control the idle speed as well.
Ignition- I have a LS-style GM coil here begging to be used for something. It’s a little bulky so will have to get creative with mounting, but should work well. This will give the computer the ability to control the timing.
Unknown: I still need to figure out the electrical side of things. By my calculations between the fuel pump, computer, and o2 heater there will be a decent amp draw. Ideally I’d like to figure out a charging system of sorts so can go with a compact battery, but thinking about using a large-ish battery to start until I figure out exactly what the requirements are going to be.
Obviously need to figure out mounting of all the components, but that will come later. I’m thinking an electrical enclosure on the front of the fuel tank
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Post by edju1958 on Feb 2, 2021 20:18:25 GMT -5
Obviously a lot of thought & research has gone into this project.I have to admit that it's all way beyond my comprehension.I only have one question,the saw is already known for it's bulkiness & excessive weight.How much more weight will all these components add to the saw?I know this isn't something that you're looking to mass produce (I hope?) as a business venture,but you never know where it may lead.Maybe a job with NASA?Lol Only kidding Rowdy.
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Post by rowdy235 on Feb 2, 2021 21:48:32 GMT -5
Lol, I’m guessing it’ll pry look like something out of a sci-fi movie when I’m done! Honestly I’m doing this more for experimentation and fun than anything else. Don’t know if it’d be anything I’d ever want to mass produce, lol.
If I can figure out some sort of charging system and forego a large battery, I don’t think the system will add a large amount of weight. I am also hoping to keep the bulkiness down as well, most of the electronics will (hopefully) be contained in the enclosure on the front of the saw, I don’t think it will be any deeper than the bucking spikes. With the fuel pump in the tank, that shouldn’t add any bulk there. The only unknowns right now are the coil and fuel injector.
I also may have a line on a C-5!
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Post by edju1958 on Feb 2, 2021 22:08:34 GMT -5
I'm wondering if the fuel injection will add any HP?Obviously it'll be more fuel efficient.(I'd hope anyway)
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Post by blythkd on Feb 2, 2021 22:10:41 GMT -5
If you make this work I will be impressed even if it does look like Frankenstein, I mean Frankensaw! Sounds like you've already put a lot of thought into it.
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Post by rowdy235 on Feb 2, 2021 22:24:09 GMT -5
To be honest I’ve put a lot of thought into fuel injection for various cars, so a lot of this is just carry over lol. I am thinking between the ability to control the fuel mix and timing should see a nice boost in power. Maybe I’ll put it against my c91 when done to see the difference
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Post by blythkd on Feb 2, 2021 22:33:10 GMT -5
I really admire someone that can put together all this technology and make it work, especially adapting it from automotive to small engine applications. All the electrical/electronic details make my head hurt just to think about it, let alone try to make it all work together. I did built an automatic chicken plucker one time. It has a 1HP electric motor and an on/off switch!
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Post by sweepleader on Feb 3, 2021 13:15:07 GMT -5
For battery charging; You might try a diode attached to the points side of the coil and connected to the battery/system. The voltage there would likely be 100-200 volts so you will need to deal with that, and the current would be small. You might also add a second coil to the area of the flywheel, wound to get you closer to the 13.5V you need to charge the battery. Actually the voltage will depend on the battery you chose, lead battery would be 13.5 to 14.4, anything else would be different. My Kawasaki engine in my JD garden tractor has a separate alternator coil with a bunch of poles.
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Post by sparky on Feb 3, 2021 18:28:34 GMT -5
I don't know if maybe a coonhunters nite lite battery would work? The diode thing as mentioned could be the ticket also.
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Post by rowdy235 on Feb 3, 2021 21:16:01 GMT -5
I’ll have to look into how much power I can get out of the coil doing that. I bet a cheap rectifier/regulator would work, but the question is how much power is put out? I’m guessing less than an amp at 12v, but don’t have anything to back that up.
I do wonder if a stator from a 50cc moped would fit inside the flywheel? I know those have a 55w headlight, almost 5 amps at least, should be plenty for my purposes.
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Post by sweepleader on Feb 4, 2021 10:07:34 GMT -5
Gotta have magnets on the inside if the stator from the moped is to work, prolly have to change the flywheel...
Maybe get the efi working first, then worry about the power source. Which of course brings up the question, where do the factory efi saws get their power and how do they pump the fuel?
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Post by lesorubcheek on Feb 5, 2021 17:50:02 GMT -5
This is an incredible idea! Good thinking on your part to come up with it. The Speeduino looks like fun. Never played with an arduino, just a bit with a raspberry pi. Please keep us posted on your progress, this is gonna be incredible to see.
Dan
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Post by rarefish383 on Feb 7, 2021 7:30:56 GMT -5
At one time I had 4 Super 1050's and I had worked out plans for a gear or chain drive Super Charger. I had 3 room mates that worked in a speed/machine shop. They figured it wouldn't be hard to do. But, I got to thinking, I may be building a hand held explosive device, so gave up on it. Then I read somewhere that turbo's and super chargers would not work efficiently on a 2 stoke saw engine. I forget the exact reasons. I think it was the old Detroit diesels that were 2 stroke and super chargers worked on them.
I skipped over the link you gave, I'm going back up to read it.
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Post by rarefish383 on Feb 7, 2021 7:57:53 GMT -5
I like the idea, just as a tinkerer. I think along the lines of an old drag racer. The detail we went to, to get an edge, or a fractional increase in power. If we over built an engine and it blew up, so what, it was on the other side of the firewall. Will this increase the max RPM? Will a C series engine stay together under increased RPM and HP? Will it turn into the proverbial "Hand" Grenade.
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Post by sweepleader on Feb 7, 2021 15:59:19 GMT -5
More power would for sure make more rpms unless there was some limiting factor, like a governor or a light trigger finger. The only thing limiting the rpms of a standard saw is how fast air will flow though the ports and plumbing. If you add pressure, the air will flow faster. I would stand back from a free running saw, which would make it hard to use...
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Post by rarefish383 on Feb 7, 2021 18:12:28 GMT -5
More power would for sure make more rpms unless there was some limiting factor, like a governor or a light trigger finger. The only thing limiting the rpms of a standard saw is how fast air will flow though the ports and plumbing. If you add pressure, the air will flow faster. I would stand back from a free running saw, which would make it hard to use... That's the thing with car engines and power, the only restricting thing is the air in, and air out. You start throwing in boost and things can go sideways. That's why I shelved the super charger for the Super 1050. But, it's not totally off the board. Engine and fuel management is a little bit different. But, if your not going for more power why bother. I have a running C5 series and a running C7 series. Well, they both run on a prime. One is chipped and the other is points. I really like both of them. But, when you get to the point of actually putting the rubber to the pavement, let me know. You can have either one for the price of shipping. My cousin got two saws at an auction for $1, and gave them to me. A 330 and a C5. Turned out the C5 was a strong runner. I gave it to a friend and he put a 30" bar on it and uses it for milling. I'd like to see the C modded.
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