Evil minds never rest... I am building a forced air ram unit for my carb.

[Wevil Knievel]

I am using a 24 vdc high output computer fan hooked to my independent 6 vdc accessory coil and reduced down to the size orifice of the carb intake hole. The way I am going to over come the airflow deficiency is leave enough room for it to draw naturally but as my motor winds up so will the fan and it will hopefully generate enough air flow to blow into the carb hole. I may have to experiment with different voltage fans but I bet I can make it work.

Shuffles off into my diabolical laboratory... Heehee!

 

[Karl Snarl]

Not being mean, but it won't work. You'll have better luck with a velocity stack and free flowing filter. So many people over the years have come up with the same idea. Those little fans don't provide any boost at all. If you want more oxygen in the chamber, check out nitropropane. Just dump in the tank, rejet, and wham instant power. Gotta use more then they recommend though to get any real gains. Or try some Nos, which is what nitropropane supplies, just in a liquid form. I have a post on nitropropane I'm currently running. Nothing scientific wise, just seat of the pants dyno.

 

[Chainlube]

I am using a 24 vdc high output computer fan hooked to my independent 6 vdc accessory coil and reduced down to the size orifice of the carb intake hole. The way I am going to over come the airflow deficiency is leave enough room for it to draw naturally but as my motor winds up so will the fan and it will hopefully generate enough air flow to blow into the carb hole. I may have to experiment with different voltage fans but I bet I can make it work.

Shuffles off into my diabolical laboratory... Heehee!

Sounds like an electric supercharger, but your design needs a little love. If you want to find out if you can make any kind of boost with your fan, try to pop a balloon by using it to blow it up.

 

[Cisco]

PC cooling fan adaptors available for 92mm to 60mm, and 60mm to 40mm. There are many choices for 12v, 92mm fans. One fan I saw claimed 175 cfm. Will it create any positive pressure when your throttle is open, and your engine is revved up? I'm not sure of the math (volume x RPM)? Anyway, don't let anyone discourage you. Go for it!

 

[Cisco]

 

[Street Ryderz]

I am using a 24 vdc high output computer fan hooked to my independent 6 vdc accessory coil and reduced down to the size orifice of the carb intake hole. The way I am going to over come the airflow deficiency is leave enough room for it to draw naturally but as my motor winds up so will the fan and it will hopefully generate enough air flow to blow into the carb hole. I may have to experiment with different voltage fans but I bet I can make it work.

Shuffles off into my diabolical laboratory... Heehee!

Fun little experiment but also just a waist of time and money since that's not how a 2t works, also the 6v coil is only 3 watts so I don't see how you could run a 24v fan that will draw more than the coil can put out, and then there is the fact that the intake is not constant with 2 strokes it's a pulse/resonant wave where most of the velocity is from atmospheric pressure rushing back in through the carb body as the vacuum is below it. Jetting relies on this pressure to draw the fuel and pull up a metered amount to get the a/f mixture needed per pulse and you can not add more air pressure than what atmospheric provides with any type of fan, there is plenty of information online about this and better ways of improving the induction that actually work.

 

[Wevil Knievel]

I appreciate all the in put and ideas. The fans I am playing with need very minimal amps and what I am doing is to only boost the air flow not control or meter it.

Ive opted for a smaller fan and some tubing so that at higher rpms it blows a little extra air into the carb. I know the proper way to do this would be to re-jet my carb. Its more out of curiosity than a real performance upgrade.

Ive gotten it to work somewhat. I just need to find a way to mount it so that it is stationary. It only works at high rpm which seems to minimize the top end sputter. But you are all correct. Its not really a fix more than just an experiment.

But its fun to play with. Thanks everybody!!

 

[Karl Snarl]

I appreciate all the in put and ideas. The fans I am playing with need very minimal amps and what I am doing is to only boost the air flow not control or meter it.

Ive opted for a smaller fan and some tubing so that at higher rpms it blows a little extra air into the carb. I know the proper way to do this would be to re-jet my carb. Its more out of curiosity than a real performance upgrade.

Ive gotten it to work somewhat. I just need to find a way to mount it so that it is stationary. It only works at high rpm which seems to minimize the top end sputter. But you are all correct. Its not really a fix more than just an experiment.

But its fun to play with. Thanks everybody!!

I know all about playing. lol. I have been playing with nitropropane the last few weeks, which also might take away tht rich sputter for you. Do I really need to be messing with nitro on these bikes, nah not really, but it's just really fun to be playing with rocket fuel and a bike. Maybe you could try some different intakes/cowlings designs for your fan experiment. Maybe even one with a little vane that is controlled by flow, that turns up or down the fan speed. Also they make a little 12v turbo fan thing for like $50 for pocket bikes. You might be interested in playing with that. Not saying any of it will work, but if you are playing might as well have options.

 

[mountain80]

Interesting, maybe consider an edf motor setup from the rc world, they generate HUGE CFM....

 

[Wevil Knievel]

Ive ditched the fan idea and opted for the simplest of ideas. Its an abs sink drain pipe and the 3/4 size drink jigger out of a travel bar. (The hour glass shaped stainless steel mixing jigger thing.)

It actually works better than anything else Ive put together so far. It only functions at higher speeds so it is self regulating and no moving parts. I will try and make a video of how it works but my vid/editing skills suck so I will have to see how it goes. But it works pretty good so far.

And thank you everybody for all of your input it is really helped me sort of reconfigure my design and my ideas behind it.