Boom! The classic potato gun harnesses the combustion of flammable vapor. Show us your combustion spud gun and discuss fuels, ratios, safety, ignition systems, tools, and more.
jimmy101 wrote:Ya, for electronic control a 555 timer would work great, or just a pushbutton switch though the reproducability would suck with a pushbutton.
I wonder if you can get the injector and pump off a junked car?
I wonder if it should be a direct injector or an indirect injector (on the car)?
A car garage should be able to scare one up, I would think...fairly common replacement item these days. Those things are tough as nails and even one whose nozzle is worn would serve the purpose on a spud gun quit well.
You would have to set up some kind of power transistor to drive the injector coil...the 555 probably couldn't drive it directly...wouldn't be hard though.
I'm not familiar with direct vs indirect injectors...I'll look it up...
Direct injection is into the actual cylinder itself (diesels and the experimental "gasoline" diesels use it.). Actually some advanced/efficient two stroke engines have a direct injection. Indirect (not very familiar with the term, but most likely...) are the injectors that inject fuel into the intake manifold, which are then sucked into the cylinder etc.
Using an injection system on a PC wold be a little crazy. A battery, fuel pump, the lines, a fuel rail(unless you rigg it differently) and the injectors themselfs, just to shoot a spud or w/e.
Propane is alot easier to use, but I see alot of people like to be different, and its pretty cool what you guys come up with.
When it comes to direct injection there is one key and very important engine that uses it... the (most)ROTARYS!!! gods gift to cars. How could you leave out the best thing about cars ever... sheesh...
Last edited by daxspudder on Wed Jun 11, 2008 2:08 pm, edited 1 time in total.
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For a fuel injection setup whether it be fr propane or gasoline wouldn't be too hard. I think the hardest part would be finding a way to secure the fuel injector into the cannon chamber. most fuel injectors used on cars today use merely an oring to seal both sides of the injector into the intake manifold ant into the fuel rail. the retaining bolts on the fuel rail are really what keep the injectors in position. that and they are not subject to the pressures of combustion. of you were able to thread both sides of the injector you could secure it into the chamber and then run a fitting from the injector to whatever fuel source. the injectors run on 12 volts so whatever you use to control it whether it be a pushbutton or a 555 timer it's have to be able to run that. however if a 555 timer cannot push 12 volts you could always use that to control a relay which is hooked up to the injector.
edit: thought you could take a threaded clean out cap drill your hole in the square deal in the cap and then epoxy the injector into it.
Yea, that's definitely going to get you at least a tazer.
<a href="">DONT TAZE ME BRO.. DONT TAZE ME... AHHHH</a>
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What if you were to put a volume of gas into a cylinder and pressurize it with the proper amount of air. Now you have the same basic idea as propane; in which you could build a meter pipe for....
I am building a sandrail with a 2.2 subie motor and the fuel system for that motor runs at 38 psi, the pump I bought cost me $100 and it will push 45 psi. To make the injectors work you will need a constant supply of fuel with no air bubbles. That means you will more than likly need a good size tank so that the return line is not creating to much cavatation (air bubbles) in the tank.
It would be a cool new setup for a spudgun, good luck.
If you put a "T" inline before the injector and put a check valve for say 39 psi to the return line going to the tank would work I've got access to a steel tubing machine for fuel lines I could start to work on the fuel injection system and if someone thinks of a better way to do the electrics let me know heck for propane you wouldn't even need a return line just regulate it to the injector psi requirements and and pull it out as a liquid
Yea, that's definitely going to get you at least a tazer.
<a href="">DONT TAZE ME BRO.. DONT TAZE ME... AHHHH</a>
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BigGrib wrote:... heck for propane you wouldn't even need a return line just regulate it to the injector psi requirements and and pull it out as a liquid
Not sure that would work. If the propane is regulated to ~40 PSIG you shouldn't get any liquid past the regulator at the types of volumes we are talking about for a spudgun. The injector should work fine (?) with gaseous propane.
It would be really cool if someone could get an injector to work.
