Tuesday, September 9, 2008

Making a DIY homemade Supercharger

Originally I wanted to make my own small engine supercharger. Or at least find out how difficult it is to make one. There are other alternatives for small engine superchargers such as smog pumps, crankcase vacuum pumps, and the chevy oil pumps. But all of those would have trouble supplying a decent amount of pressurized airflow to a small engine.

I think a small roots type supercharger would work out nicely for a small motor, but the thing is that there does not exist any. So i decided to make my own.

After some planning and drawing diagrams on random pieces of scrap paper i realized that it isn't as difficult as originally planned. the rotors are actually quite easily made. The only hard part is attaching the gears to the thing, because currently i have no ability to make gears.

I decided to mock up some blower rotors in wood first as an experiment to see how easily i can get it to somewhat resemble an supercharger.

Making that was surprisingly easy, all i needed was 2 hole saws for the inside and outside diameters. I cut out cylinders with one hole saw and used the other hole saw to notch the center part for the rotors to be attached to, basically 6 equidistant notches in a circle made the center part. Looking at this design i realized i could just use a hole saw to cut out the center part from a plate of metal and then weld/solder/braze/glue cylinders of tubing onto the center, and i would have some easily made roots supercharger rotors.
I could extend this step to make rotors as long and big as my drill press could handle, could be an interesting project later on when i start making them for bigger and bigger engines.

Now the next step is making some gears to prevent the rotors from constantly grinding each other. The rotor case should be easy enough to make, using a fly cutter to bore a hole. Making gears is the hardest thing for this project. I will try to make some gears from wood as soon as i get some gear tooth cutters.

My emphasis here isn't really on precision, mostly the bang for buck rating. If I can make boost on a wood roots blower i would use a wood supercharger hehe. Of course if the wood one doesn't last as long as expected then i would try to remake everything in some other cheap material such as plastic or mild steel.

Friday, September 5, 2008

Turbocharged Gas powered skateboard

A gas powered skateboard is nice... but not nearly as nice as a turbocharged gas skateboard. The skateboard comes with a 52cc 2 cycle engine usually used on tiny underpowered scooters, which is not nearly as powerful as it should be. So of course I will need to increase the power.

Originally I was thinking about using a small supercharger for the skateboard, a supercharger would probably be easier to install in this application, no ducting needed for a total smaller and lighter package. Because they do not make superchargers small enough for a 52cc engine I would be using high flow chevy oil pump. Those gear pumps act in the same way as positive displacement roots pumps, and since there would be 2 cycle oil in the gasoline, lubrication wouldnt be an issue with the gear pump.

In the end i decided against a positive displacement blower for the skateboard because 2 cycle engines need something akin to backpressure to function properly unlike 4 cycle engines which works better without any backpressure. If i was using a lot of supercharged boost, the pressurized intake charge would just blow out the exhaust and i would need some type of exhaust restriction to prevent that from happening, even a standard 2 cycle exhaust waveguide/resonator would not be able to create enough pressure to keep the intake charge in the cylinder. So if i was gonna use the exhaust restriction method then might as well use a turbo to use up some of that exhaust pressure.

Which led me to the purchase of a Mitsubishi TD02 turbo off ebay.
Some people might be thinking, wait a second, 2 cycle engines dont have pressurized oil, how are you going to keep the bearings alive. Well sleeve bearings dont really need pressurized oil to function, of course having pressurized oil would be best but im not aiming for a 100,000mile before rebuild lifespan from this skateboard. Have you ever looked in a lawnmower engine or something like that? Those use splash lube for everythign and it runs fine. I will also be using heavy weight quality synthetic oil to keep the bearings alive, like 50+wt oil.

I might also be adding on nitrous oxide for added horsepower in the future if the turbo is not enough. But i would need to upgrade the engine internals before that.

Wednesday, September 3, 2008

Documenting Projects

I always liked reading about interesting odd little things people have made. So I decided to contribute to the internet with my own little projects.

I used to have a xanga blog I used for general stuff including the random stuff I made but it was also full of random useless posts, I will try to make this blog a lot more informative.

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