Forced Air Induction/ thoughts?

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RicksRides

RicksRides

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Feb 22, 2012
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osceola IN
I was thinking how to cheaply get a little extra out of a motor. As most of us know the more air you move thru an engine with hotter spark and more fuel gives more power in the proper combination.
What if you took a velocity stack and installed a fan in it forcing air down the intake? Should work for 2 and 4 stroke. They make some pretty nifty little 6 and 12 volt fans. Am I wrong?
 
BarelyAWake

BarelyAWake

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Jul 21, 2009
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I don't usually just say "use the search" as it's rude... but when I did it to provide some links, there were so many returns (key words: blower, supercharger, turbo, "ram air", "forced air", etc.) that I kinda glazed over a bit lol

Suffice to say you'll need to narrow the parameters down a bit, what type of motor & what type of forced induction (which fan/turbo/blower)... but if you're referring to say the basic in-frame two stroke & say a 12v PC fan - "fans" can't provide positive pressure as the blades stall (lay one face down on a table for example) & even if it could, two strokes are a bear to try forced induction with as the charge tends to blow right through the ignition chamber & out the exhaust port...

...then again, if you're talkin' a four smoker, there's potential in something like this: http://www.mbe-motorsports.com/catalog/product_info.php/cPath/21/products_id/265

but...

BarelyAWake said:
While the turbo is real & there's even fuel injection kits for it... after extensive amounts of company time wasted *innocent look* I've been unable to find any real data beyond the rather unfortunate - like that in fact this turbo most likely isn't suitable for anything much smaller than a 200cc. While I found some leads & info for it's use on as small an engine as a 125cc and even a 5hp Briggs (largish displacement but low power & RPM) and even as small as a 70cc "Monkeybike" - those projects were incomplete at last posting (or never made to work), and that was sometime in 2009... which doesn't bode well.

There were additional mutterings amongst some turboheads that single cylinder engines are notoriously hard to effectively turbocharge, that the pulsed exhaust makes for excessive lag, that it takes it far too long to spool up to the point of diminishing returns.

BTW, there's also the IHI RHB31, the TD025M-03C, & the Garrett GT12 - all of which seem to have similar specs & sizes, all of them have been used on various gokarts, motorbikes & atv's, none can I find any reference to being used successfully on smaller engines than 125-200cc...


Yet... it's possible it could work, pressure/boost is ofc adjustable and with some dedicated tinkering there's some potential - this is such a niche hobby that just because I can't find someone that's done it doesn't mean it can't be done, just that it hasn't been done *shrug* Such is the way of experimentation lol
Click to expand...
as a followup (old post) I found that every example of homemade "forced air" with fans & such were highly questionable, as in there was no proof it did anything at all, not really a surprise given the low/no pressures involved. There has been some examples of converted smog pumps & whatnot, but again due to scale there's little relevant.

Eventually although I found a RC (airplanes) outlet willing to custom fabricate an actual blower small enough for a 50cc four stroke, the projected gains were comparatively insignificant - with a bit more research I found that I could get well over four times the "boost" (power increase) for the same investment by simply going hybrid, adding an electric hub motor & battery pack to my four stroke powered project...

...food for thought anyway ;)
 
Desert Rat

Desert Rat

New Member
Jul 30, 2012
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Apache Junctoin Az
RicksRides said:
I was thinking how to cheaply get a little extra out of a motor. As most of us know the more air you move thru an engine with hotter spark and more fuel gives more power in the proper combination.
What if you took a velocity stack and installed a fan in it forcing air down the intake? Should work for 2 and 4 stroke. They make some pretty nifty little 6 and 12 volt fans. Am I wrong?
Click to expand...
See what you think of this
http://www.ebay.com/itm/170893481368?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
might work?
 
RicksRides

RicksRides

Member
Feb 22, 2012
864
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osceola IN
Ok lets try a different angle then, most of us know about Nitrous Oxide: The air we breathe is 19-20% oxygen, NOS is 35% and medical Oxygen is 99.9%. So, basically the next Question is what about introducing pure Oxygen into the mix. Raising the purity of the oxygen but not the volume of air? I know the nitrous is there for cooling the chamber.But if you raise the oxygen purity 5% or so. The HP output should be increased?
 
RicksRides

RicksRides

Member
Feb 22, 2012
864
6
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osceola IN
BarelyAWake said:
I don't usually just say "use the search" as it's rude... but when I did it to provide some links, there were so many returns (key words: blower, supercharger, turbo, "ram air", "forced air", etc.) that I kinda glazed over a bit lol

Suffice to say you'll need to narrow the parameters down a bit, what type of motor & what type of forced induction (which fan/turbo/blower)... but if you're referring to say the basic in-frame two stroke & say a 12v PC fan - "fans" can't provide positive pressure as the blades stall (lay one face down on a table for example) & even if it could, two strokes are a bear to try forced induction with as the charge tends to blow right through the ignition chamber & out the exhaust port...

...then again, if you're talkin' a four smoker, there's potential in something like this: http://www.mbe-motorsports.com/catalog/product_info.php/cPath/21/products_id/265

thats cool,,,,, but steeply priced for a cheapskate like me
Click to expand...
 
maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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You start messing with pure oxygen induction, I'd suggest you buy a LOT of spare pistons and cylinders. (and I'd also armor plate the underside of the gas tank...)
 
L

locutus_1

New Member
Oct 31, 2010
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california
RicksRides said:
I was thinking how to cheaply get a little extra out of a motor. As most of us know the more air you move thru an engine with hotter spark and more fuel gives more power in the proper combination.
What if you took a velocity stack and installed a fan in it forcing air down the intake? Should work for 2 and 4 stroke. They make some pretty nifty little 6 and 12 volt fans. Am I wrong?
Click to expand...

not worth it.. its a waste of time.. people make turbos for these bikes all the time or 5 hp motors and i laugh because there is no gain.. you have no boost you need 15 to 20 psi of pressure.. alittle fan wont do anything nore will a pipe..

i tell everyone these motors are all the gusto you will get.. enjoy what you have
 
B

bowljoman

New Member
Aug 7, 2010
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The 50CC world speed record is held by a turbo charged case-reed running a six speed, so it is possible with the right amount of money.

If you want cheap 2 stroke power , forget the china gurls. Get a qualified engine and build out a transmission. I know the bikers around here will get irritated but its true. Anything else besides the kit-engine.

Zennoas , chungyangs, hesuangs, any damm engine but the kit engine....

You want power? run a shift-kit. I put one together for 90 bucks and I doubled my speed. Image a tired chinese throw-away scooter engine going 40mph+ just by shifting.

If your engine power-range is narrow like the kit, gears are the only good answer. We are building up a 46CC/3-speed combo that should break 60MPH on my vehicle. The engine will be stock and not using an expansion chamber.
I roll my eyes every time I see someone put on a 100-220 CC motor on a bike frame, only to reach 35mph....

Forced air induction on a tiny engine is very expensive. Go gears or go home.

I await the flames....
 
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Goat Herder

Goat Herder

Gutter Rider
Apr 28, 2008
6,237
20
38
N.M.
In my own experience. Morini engine or Morini clone no extra silly contraptions or extra chain crap to wear out. After market American Tomar clutch.... done.

I ran all kind of gear contraptions for the most part. What I have is very simple it always works and is simply the quickest, simplest, lightest, smallest out there hands down....


The kiss principle.
 
maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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memphis Tn
I'm waiting for someone to design a two or three-speed conversion for the ht motor, maybe like the ones used on rc vehicles?
 
Y

young grease monkey

New Member
Sep 20, 2011
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Chicago
If you're after power on the cheap, expansion chamber and porting and maybe a better carb is the best option. Look at jaguar's website, someone help me with that link. The easiest way to get real gains with forced induction would be a small centrifugal supercharger, and it would need to spin up to 60k rpm before you see real gains. The only way to do this would be a cnc custom made unit with super high speed ceramic bearings. And you don't have to worry about fuel delivery if you put the supercharger between the carb and engine. Oh and the exhaust needs to have a choke on the end because running boost will require more back pressure.
 
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M

Mr. OrangeConeRacing

New Member
Feb 19, 2013
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Wichita KS
If you just have to have forced induction, spinn the head around backwords and port match it. This will help to restor the power lost in effort of sucking air into the motor. This is basicly a ram air, but you will never get enough air to creat any boost. Just freeing up lost power is all, probibaly improve fuel milage also. You could also look into adding an HHO kit.
 
Y

young grease monkey

New Member
Sep 20, 2011
362
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Chicago
Hho is a gimmick, but luckily you can increase power easily with an expansion chamber and porting. I suggest the sbp pipe because it is adjustable to any bike and power characteristics you want. I gained a lot of power just by cutting the gaskets to match the ports. Stock gaskets block the ports and create turbulence which limits top end power and speed. If you really want to get into it, you can do what is called crank stuffing. You fill up empty space in the crankcase to increase the crankcase compression, which gives big top end gains.
 
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