ElectriCharger Plans

[JTSpeedDemon]

I picked up an air blower at an amateur radio convention in Irving Texas and I picked up this DC 12V 2.94A air blower for $2. It's designed for cooling electronics, but I've got better plans...
I hereby dub it the ElectriCharger! Pretty cool,eh?

I plan to build a sealed box around the carburetor on my engine, the use the ElectriCharger to pressurize the air in the carb and thus make a blown Briggs!
Tell me what you guys think!

 

[Tpdingo]

That's never going to produce the static pressure you need, nor the speed required. Its a computer fan, not a turbo charger. That isn't enough for you, I can go full 'sid on you and give you the math to back it up.

To make any significant amount of boost you are going to need a horsepower or more. Thats 745W right there. Maybe if your lucky you might be able to get away with a half-horsepower. Thats 325W. Your fan...less than 50W full load. Not sure how you're going to get boost from that.

Secondly, for compressing air without positive sealing pressure like a roots blower, you would need that rotor to be spinning around 20K RPM minimum. For some serious boost, it would need to spin as fast as a real turbo, so probably north of 100K RPM. I have that fan myself, it does 5-7K.

tl;dr- makes a good face blower in the summer, not so much a engine blower.

 

[JTSpeedDemon]

Well, we'll see how well it works, but either way, I'm thiinking it would also kind of have a cold air intake effect.

---------- Post added at 03:29 PM ---------- Previous post was at 03:23 PM ----------

If I overvolt it to up to 24V, how well would it take that? What kind of voltage would give me that speed without destroying the motor?

---------- Post added at 03:40 PM ---------- Previous post was at 03:29 PM ----------

Also, I found on Ebay some tiny electric motors that can spin up to 44,000 RPM at 3V(at least that's what it says)
https://www.ebay.com/itm/Micro-DC-3V-44000RPM-High-Speed-8mm-Mini-FK10B-Tiny-Electric-Motor-DIY-Parts-/283308127489
so at 12V, that should give enough speed, and if I maybe somehow make a reduction box and do multiple motors, I might be able to pull it off.
Any thoughts?

 

[karl]

I boosted a 208cc engine with a leaf blower, it took an 8hp walk behind blower and a vaccuum cleaner hose.

Just hook the fan up, put the kart on a jack, volt as much as you can, and if it makes any boost, it will blow the fuel out the bowl and stall the engine.

You will not reach that point with a 36watt blower, as Tpdingo said, but experiment! Have fun!

 

[JTSpeedDemon]

Ok, I'm also thinking of putting a sprocket on the clutch end of the crankshaft, and chain driving a custom blower or the likes.

---------- Post added at 03:57 PM ---------- Previous post was at 03:52 PM ----------

Also:

The best thing to do, if you're going to boost it, is to build a box around the carburetor that seals between the carburetor and manifold. The compressed air will pressurize the air inside the box and the carburetor, instead of just the air in the carburetor. This is necessary with a carbureted system, because without this pressurized air would enter the carburetor and force the gas down the jet and then force it out of the bowl around the float seal. This however is not necessary with a fuel injection system since the injectors are responsible for fuel delivery and there is no float bowl.

---------- Post added at 03:57 PM ---------- Previous post was at 03:57 PM ----------

Or is he incorrect or what?

 

[Tpdingo]

Ok, I'm also thinking of putting a sprocket on the clutch end of the crankshaft, and chain driving a custom blower or the likes.

---------- Post added at 03:57 PM ---------- Previous post was at 03:52 PM ----------

Also:


---------- Post added at 03:57 PM ---------- Previous post was at 03:57 PM ----------

Or is he incorrect or what?

Oh he is right, but that implies that the box is getting real positive air pressure and not some wind from a fan.

Also note that:
1: Its plastic blades not metal. At 20K+ RPM, the rotor will probably blow itself to pieces.
2: Those fans are designed for air flow, not static pressure. To cool a computer you want as much air moving as fast as possible, and a computer case doesn't provide much resistance.

If you really want to go full e-turbo, go get a real turbo charger and connect the shaft to a BIG RC airplane motor which can spin one of those things up to probably a few dozen RPM no issue with a small belt.

https://www.youtube.com/watch?v=G8XT00GpKuE

This guy did exactly that, and that big motor can put out 3.6KW! That's over 5HP and it spins at 21K RPM!! Obviously a smaller turbo and motor would be necessary for a little briggs but its totally possible.

 

[65ShelbyClone]

Well, we'll see how well it works, but either way, I'm thiinking it would also kind of have a cold air intake effect.

The engine already has that though. If the fan isn't adding power via air compression, then all it stands to do is absorb power and heat the air.

If I overvolt it to up to 24V, how well would it take that?

It won't. The windings and control circuit inside will get destroyed very quickly if not immediately.

I admire your enthusiasm, but uncountable numbers of people have gone down the path you're headed and the ones who made it work are a rare exception, not the rule. Here's one account of that long expensive road: http://www.superstreetonline.com/how-to/engine/0406tur-knight-turbo-electric-supercharger/

Electric supercharging is still not practical as a primary boost source due to motor cooling and the giant amounts of electric current needed. It takes about 1hp to compress 12hp worth of air at 15psi.

1hp = 746W.

746W at 12v is (746 ÷ 12) = wait for it.......62 amps. That assumes 100% efficiency.

 

[JTSpeedDemon]

Would lots of capacitors in series accomplish that?

 

[voided]

They sell soda can sized turbos.. you can also do a smog pump off of a old chevy .

I’ve seen one guy pressurize the bowl a certain way to keep the bowl from getting sucked dry.

 

[65ShelbyClone]

Would lots of capacitors in series accomplish that?

How are you planning to charge them? To what peak voltage? What would the minimum functional system voltage be? Caps don't work like batteries; battery voltage stays relatively constant for a large part of the discharge whereas capacitors' voltage decreases on a slope or curve depending on the load type.

 

[Tpdingo]

How are you planning to charge them? To what peak voltage? What would the minimum functional system voltage be? Caps don't work like batteries; battery voltage stays relatively constant for a large part of the discharge whereas capacitors' voltage decreases on a slope or curve depending on the load type.

Well not just the voltage thing. You forgot two much much bigger problems.

1: THEY'RE REALLY EXPENSIVE!!
2: THEY'RE CAPACITY IS TINY!!

A D battery sized super capacitor has a less than half the capacity of a standard AA battery.

The overvolting thing won't work either. I've let the magic smoke out of a few fans this way. Your not dealing with any old motor, it is very much computerized and specialty driven.

Consider this...if you want full e-turbo, get a 350W motor from china, and its motor controller. Set up the motor to run the turbo charger and put a battery configuration on it, some small few hundred watt-hour battery and call it day. What I would seriously recommend instead of the setup you are looking at is setting it up like a normal turbo and adding the motor in as a pre-spooling device. Since the motor is BLDC, it provides nearly 0 drag when not in use unlike brushed motors.

 

[65ShelbyClone]

You forgot two much much bigger problems.

1: THEY'RE REALLY EXPENSIVE!!
2: THEY'RE CAPACITY IS TINY!!

I didn't forget; how can cost and feasibility be determined before knowing what the functional requirements are?

 

[JTSpeedDemon]

Right now, I'm thinking of getting a blower and stick a sprocket on there to drive it from the clutch end of the crankshaft. probably something like a 45:1 gearing.

 

[Budget GoKart]

hey thats smart jt that would be cool if i could 3d print one for a predator lol

 

[Tpdingo]

hey thats smart jt that would be cool if i could 3d print one for a predator lol

I have a 3D printer...and unless you did a Lost PLA cast of the part, then there is no way in **** you could make a part strong enough. I have a small siren I printed and the handle can barely support 30W of mechanical power flowing through it.

For the driven turbo, 45:1 is probably excessive. 30:1 would probably be better. 162,000RPM is pretty **** fast for a turbo, cutting it down to 108K is better. If you do go through with this...I wanna see this. Will it be just a supercharger or a mechanical pre-spool turbo? If it is the latter, I would recommend using a clutch of some sort that allows you to disengage the motor when it gets above a certain RPM or just to purely cut external power....maybe a clutch based blow-off valve?

 

[Budget GoKart]

i can make a model in inventor or blender that is printable but i dont have a printer so there would be shipping and paying to do most likely which i can do free models we could do bolt up ones and it shouldnt be hard just need good gearing (i dont know how to make gears yet im still learning)

 

[Tpdingo]

i can make a model in inventor or blender that is printable but i dont have a printer so there would be shipping and paying to do most likely which i can do free models we could do bolt up ones and it shouldnt be hard just need good gearing (i dont know how to make gears yet im still learning)

Like I said, the part wouldn't be strong enough. It would need to made from metal.

 

[Budget GoKart]

But for a test plus there are metal rc parts that are useable

 

[JTSpeedDemon]

Most likely if I go through with a crank driven supercharger, I will probably have to extend the keyway. My only real problem that's keeping me from initiating this project, is that I need money(As always)
I plan to start a lawn mower repair business as people here in Texas always need their grass cut, but I've already done a lawn mowing business, and I'd rather repair the mowers and equipment.

 

[Budget GoKart]

Yea sounds like a good plan post a couple adds and ask neigbors