homemade supercharger project

unknownbmxa88 · May 19, 2013

first off left me start off by saying:
I AM NOT TRYING TO SUPERCHARGE A 2 STROKE
PLEASE READ EVERYTHING BEFORE YOU COMMENT

my bike is currently powered by a honda gx35 35cc 4 stroke.
these engines are notorious for running rich, and i also have been encountering this problem.
I also live at about 4500 ft above sea level so the air is fairly thin up here.
i had an idea the other day and this is what i have.

i had a electric motor from a vacuum cleaner. i took the fan wheel and housing

i got the idea of turning this into a belt driven supercharger for the honda.
my plan is to make a wheel about the size of the fly wheel and run a belt from the flywheel to a wheel that drives the fan wheel. the fan wheel is very light, and made of aluminum. i also plan of machining some of the extra material from the flywheel to help offset the power loss by driving the fan wheel. the wheel on the engine will be about 4-5x larger then the wheel on the fan, so the fan will run about 5 times faster then the rpm of the engine.
@7000 rpms the fan will be at around 35,000 rpm.
i have installed an air filter on the intake of the fan housing and i will fabricate an output tube that will be routed to where the filter on the carb was.
i have been helping out at a machine shop so ill be able to machine small parts, as well as a pulley wheel to attach to the flywheel.
ill also make a bracket to hold it, with a 90 elbow to go into the carb

now from what i have read on the internet, and based on my understanding..is there any reason that this wont work?
any critics have any comments?
i dont see why this wouldnt work. it seems like it will work.
i understand alot of fine tuning will come with this..and i am not expecting it to work right away, and i plan on trying to come up with dyno tests after each improvement..

comments?

Trey · May 19, 2013

A guy suggested this to me as a joke. I did think about it though, and figured the tolerances of my kit engine wouldn't take it. That Honda though...
Good thinking on sourcing the vacuum- it looks good. You're right about the tuning, but barring some solid advice you receive to not do this, I think this is an awsome idea!
I will be following along for sure. Did you build a dyno?

bairdco · May 19, 2013

i hope it works. that'd be freakin' awesome!

one thing i've read about home made superchargers, though, is about plastic fan blades shattering, melting from fuel, etc, and getting sucked into the intake, which would suck...

unknownbmxa88 · May 19, 2013

i was thinking of doing it in a couple of different ways,

buying a bicycle trainer on craigslist or finding one, and running the first gear while i film my speedometer and plot the speed second by second. then putting it into a speadsheet and graphing it. lol or just seeing if i get a higher top speed with it.

people might tell me its stupid to try but the dont have access to a machince shop or have the sweet fan wheel i have...

unknownbmxa88 · May 19, 2013

bairdco said:
i hope it works. that'd be freakin' awesome!

one thing i've read about home made superchargers, though, is about plastic fan blades shattering, melting from fuel, etc, and getting sucked into the intake, which would suck...

this is why im happy my fan is aluminum.

Trey · May 19, 2013

Have at it my friend!
Can you make note of the vacuum model and fan part number, or some such thing? If this works, I bet they will get hard to find.

PS There's a guy at Big Sky village on a gas-bike- 7,500*!

unknownbmxa88 · May 19, 2013

you know i dont remember what the vacuum brand was but it was a really cheap one. i think it was the cheapest one at target 2 years ago. when it stoped working i took it apart to maybe salvage the motor for a generator but decided it wouldnt work and i almost threw it away. it was sitting in my shed the other day and i got the idea when i saw it.
im almost temped to keep the major detail on how to do it to myself so i could sell a kit if i get it to work and i can prove it...prolly wishfull thinking.

Trey · May 19, 2013

Ya know, that might actually be a good idea. If you could design a kit, even a bunch of pre-existing parts together to start, you might have a game changer here. I've been around lawn equipment of many kinds, and there aren't any of these around that I've seen. There's always a reason if no one else has done it, but that doesn't mean you can't make it happen. Work it out first, then decide.
Dang- I should've kept my mouth shut so I could do the same thing you work out!

Good luck with it man.

bairdco · May 19, 2013

i've been toying with the idea of supercharging a china doll 2 stroke for a long time.

probably won't last long, but i've got enough beat up parts to make it possible.

you always get the people saying how it can't be done, or that it shouldn't be done, but do a google search and you'll find everything from minibikes to blenders.

if it has a motor, someone's done it...

maniac57 · May 19, 2013

The problem you will find is that your fan will have to be geared so high to provide any real boost that it will be unreliable and impractical if it ever works at all.
Theres a reason superchargers cost so much. They are far more than just blower fans in a case.
I tried someting like this several times back in my gokart days and all I got for my trouble was shattered fans and broken parts sucked into my engines.
I wish you luck, but don't expect too much.

unknownbmxa88 · May 19, 2013

maniac57 said:
The problem you will find is that your fan will have to be geared so high to provide any real boost that it will be unreliable and impractical if it ever works at all.
Theres a reason superchargers cost so much. They are far more than just blower fans in a case.
I tried someting like this several times back in my gokart days and all I got for my trouble was shattered fans and broken parts sucked into my engines.
I wish you luck, but don't expect too much.

yeah that was previously mentioned. i plan on having the fan motor geared up to 5x the rpms of the engine. so it should have some boost.

BlackIceBicycleWerks · May 19, 2013

Yes this is quite interesting. Seems more practical than a turbo to fit in a bicycle frame. The only problem I see is the same as evryone else. getting that fan to spin 35k reliably. That's VERY fast for any thing to be spinning especially because I do not believe it would ever spin that high of rpms in a vacuum but I may be wrong. I would love to see this work!

bowljoman · May 19, 2013

Awesome.

Just remember to put the carburetor on the intake of the super charger so you dont just blow bubbles into your gas tank

Or go full on and use fuel injectors.

belt might try to jump before it makes it to 35000 rpm.

unknownbmxa88 · May 19, 2013

bowljoman said:
injectors.

belt might try to jump before it makes it to 35000 rpm.

i do have small guage chain laying around. maybe chain drive would be the way to go..

dmb · May 19, 2013

yes the carb before the blower unless you can find a bowl less carb to use with a fuel pump. and if you do get it to run, no more than 20 deg advance tops. good luck on this fun project. dennis

unknownbmxa88 · May 19, 2013

just looked into EFI conversion kits...costs about 500$. not an option..stayin with the carb

breno · May 27, 2013

http://www.chinese-parts-canada.com/turbocharger_fuel_injection.html
this looks cute

BigBlue · May 27, 2013

Here's some food for thought on small scale superchargers:
http://www.rbinnovations.com/category_s/119.htm

The 2 companies listed above for 2 stroke fuel injection haven't been able to get their system working properly with a small 2 stroke engines. I've been following both companies for a few years.

The other issue is that your going to need at least 4 amps to run the system. No one has been able to develop a high amperage charging system for the HT. Maybe if your racing you could use a battery pack, but if your amperage gets depleted, your fuel pump won't put out the proper pressure and you'll end up with a damaged engine. Most of the posts that I've followed on the internet were failures with the above kits because the charging systems were not powerful enough to run the fuel pump, ECU and run the ignition systems.

Stihl makes a compact low wattage fuel injection for their cutoff saw, but the technology isn't available in the after market: http://www.stihl.com/the-world-first-stihl-injection-electronically-controlled-fuel-injection.aspx

Stay focused on the supercharger and you'll more than likely be successful.

Good Luck and look forward to your progress,

Chris
AKA: BigBlue

racie35 · May 27, 2013

RC electric ducted fans ....maybe the 70_90mm with a motor that has a kV of 3_4000 running on 11.1 v lipo pack...readily available and cheap....we did it on a go cart once....was a little much but it works

SuperDave · May 27, 2013

Mikuni carbs (like from a weedeater) are bowlless, and I think they come in sizes we can use. Easy to tune, easier than a CNS anyway. But I would mount the carb upstream of the blower anyway, or it may blow seals & gaskets. They aren't made to withstand pressure above atmospheric.

Please, please PLEASE make a video when you fire this up the 1st time, and if you survive, please post it online cause I wanna see it if it grenades! If you can't be a good example, be a horrible warning!

One of the reasons blowers (super or turbos) cost so much is cause of all the broken parts and engineering that goes into them, fine tuning, trial & error, working out the bugs to make it decent & reliable before they are released to the public (not to mention stitches, bandages & casts). You're starting out from scratch, so you got a steep learning curve. Good luck! Starting out with a pre-manufactured metal fan is a big leap, it's already balanced so maybe it won't fly apart right away. Too much boost will blow it up, or frag out the gaskets. Permatex Copper Coat is going to become your best friend! Start out small, with low ratio gearing, and increase the RPMs in small steps to avoid the 6 O'clock headlines. ("Bicycle parts and human remains rained down on the tri county area this afternoon after an intrepid inventor tried to supercharge a 2 horse bicycle motor to go faster...")

I once toyed with the idea of recycling a Kirby vacuum case & innards(cast aluminum) to use for a blower in my Chevette, but abandoned the idea for fear of lunching several motors before I got it right. It was a disposable car to begin with but I wasn't in a hurry to end it like that.

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