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Post by sweepleader on Feb 23, 2021 8:36:23 GMT -5
I wanna see it with the decals on, done or not. That is the first thing I would have done... :{)
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Post by rarefish383 on Feb 23, 2021 12:03:50 GMT -5
Just so it doesn't flat line!
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Post by Mr_Huns on Feb 25, 2021 20:37:46 GMT -5
That's great. What model Tektronix scope do you have. I have an entry level TDS1002B that I got in college. I would love a 4 channel, but I just can't justify it to my CFO. I know that old, air cooled, D-jetronic fuel injection had a MAP sensor and 2 sets of points in the distributor. One set fired the coil and the other fired the fuel injectors. Metered fuel volumes were delivered based on cylinder head temperature, RPM, throttle angle, and Manifold Absolute Pressure voltage. The injection points used to get gummed up all the time. When Germany switched to L-Jetronic in the mid 1970's they fixed that problem. They went to one set of points and fired all the injectors, bank style, every other time the coil fired. Neither system used an oxygen sensor. They just delivered fuel open loop from a predefined fuel map that was pretty much all analog comparators. Here is a guide if anyone is interested: www.lonestar912.org/912%20Tech%20Data/912E%20FI%20Technical%20Manual.pdfThat is for the Porsche 912. I can tell you from my literature the L-Jetronic was available on the 914 in 1974 and I believe it is the same a VW 411. It is a very popular 1980s fuel injection system, without cam or crank sensors. I also worked on a 2015 Ski Doo MXZ 800 snowmobile this week. It had oil injection into the crankcase to lubricate the bottom end and direct injection next to the spark plug for the top end. The PCM calculated the fuel mixture for each paart of the engine to deliver the correct mix ratio in the combustion area. They call it E-tec ski-doo.com/content/ski-doo/en_US/community/ontrack/E-TEC-Engine-Origins.html
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Post by sparky on Feb 26, 2021 16:46:41 GMT -5
If it does flat line where do you connect the jumper cables to "jump"start it?
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Post by rowdy235 on Mar 9, 2021 16:36:23 GMT -5
Just a little update. Fuel injector came in, took a while because I had to order from China. And here's my idea for mounting. Just need a properly sized hole in the intake and some kind of bolt to hold securely, shouldn't be too hard. I'm hoping to be able to use the factory fuel hose location, but may need to enlarge for the thicker (pressure rated) hose.
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Post by sweepleader on Mar 9, 2021 16:47:35 GMT -5
I would be inclined to mount it 90 degrees to where you show it, squirting straight down into the engine, or at the carb inlet, squirting in of course. You might cut off the inlet end of the carb and modify it to take the injector but save the throttle area. That would be pretty much the way the old throttle body injection, TBI, worked.
I would not mount it like you show as it would be squirting across the air flow, you would have a lot of fuel stuck to the far wall and not a lot going into the engine as vapor. That might completely defeat the purpose of high pressure spraying.
Maybe. It is your project and I think it is great to try so do it the way you want.
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Post by lesorubcheek on Mar 9, 2021 18:03:07 GMT -5
I would be inclined to mount it 90 degrees .... Nice pun, well sorta a pun, inclination and angles and stuff... OK, my sense of humor is odder than usual today. Anyway, this notion of where to mount the injector got me thinking. So, there's still gonna be a reed, can't really do direct injection. If like TBI, not sure how important manifold length will be to atomization. Started thinking it may not matter where it is mounted since the piston is still really gonna suck in atomized fuel/air anyway. Then again, for better mixing with air, might it need a longer tract, possibly back where the carb sits? Maybe an offset bracket bolted to the manifold spraying straight in.... but then that may not be good for air flow. Again, just thinking out loud. I'm sure whatever you come up with is going to be amazing. Dan
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Post by rowdy235 on Mar 9, 2021 22:28:02 GMT -5
Thanks for the input guys. The more I think about it the more I think it would be more efficient to have the injector pointing down. The only issue is figuring out how to cover the top, since it will protrude past the top of the air box for sure. Maybe if the project goes the full length I can fab up a custom air filter cover to cover it. Dan's idea of modifying the carb may just work. Will have to look into that.
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Post by sweepleader on Mar 10, 2021 7:24:54 GMT -5
The prototype normally does not look all that great. If I was trying to do that, I would get it working first, then worry about what it looked like. Be sure to remember it is your project and you can do it how you like. :{)
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Post by rowdy235 on Apr 23, 2021 20:45:17 GMT -5
Well, in what could be the slowest project in HOH history I finally made some progress tonight. Couldn't think of any way to make the fuel injector seal in the elbow without fabbing a piece of tube onto it to seal with the o-ring. Figure I may do that down the road, but for the prototype I just drilled a hole the right size and used some seal all. For those who don't know its a fuel proof sealant. I may still add some reinforcement to "hold" the injector, haven't decided on that yet. But in any case we have a throttle body! And also got a ROUGH mockup of what I want to do with the fuel pump. Still need to figure out mounting. The plumbing will consist of a line coming out of the pump going to a "t" with one line going into the top of the fuel pressure regulator and the other going to the fuel injector. The line that goes down from the pressure regulator will be removed to allow gas to flow back into the tank. Ideally the T fitting would be at the injector, but since theres only a couple inches between the injector and the tank, don't think it'll be an issue. Also think I'll be able to modify the "sock" that attaches to the bottom of the fuel pump to work.
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Post by Brennan on Apr 24, 2021 0:17:31 GMT -5
Just wow, this is epic. Couple things, where the injector mounted the spray pattern is most likely going to hit the walls on the intake tube leading to atomization issues. You may want to bench test it to see just how much contacts, generally the pattern is between 10-35 degrees. As for a battery, remote control car lithium polymer batteries would be the way to go IMO, they’re cheap and easy to get at a local hobby store and super energy dense. They can be had in just about any size to fit a space. The one I have will put out an amp for 4.3 hours without falling below 11.1v and is 5.5x1.75x1.25 inches. Make it swappable and you would just have to switch it with each tank of fuel probably. They do require a low voltage cutoff but that should be easy to program into the arduino. Another option would be to use something like a Milwaukee m12 battery that has built in protection circuitry. If you haven’t solved your throttle blade control yet again look at your local hobby shop. Pwm servos come in many sizes and strengths. Something for doing flap movement on a model plane would probably do nicely. I very much look forward to seeing this progress along. Maybe a little faster than my sxlao resto lol.
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Post by rowdy235 on Apr 24, 2021 15:42:57 GMT -5
Thanks! Guess I’ll just have to see how the fuel spray works. Probably will end up doing something different with the intake in the end anyway. That’s a good idea on the li-po batteries, I have a cousin who is into RC cars that could pry spare one for testing!
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Post by protocol1 on Jun 18, 2021 21:00:26 GMT -5
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