OMG! Airbox fan

[Scooter33]

Man you guy's are a tough crowd. You guy's picked a person to do a review on our product and then you bash what he has to say about the results!!!

I realize it took me darn near two years to deliver a product to him for a review but that is beside the point. I am trully saddened that everybody thinks they know everything because they can put it on paper and that's the way it is. Period... That kinda slams the door on future technology.? Someone said that the jet kit that is included only effected 1/4 throttle. The truth is that the a/p diaphragm changes the squirt duration from .7 sec. to 2.5 sec.

That is a lot of fuel. The truth is, we couldn't get enough fuel through the regular circuits to keep up with the fan so we had the change the a/p.

I could swing back all day long but that isn't what I want. If anyone has any questions just call us or p/m me.

Kelstr- I am sorry if these guys make you feel that you have wasted your time, but I am glad that you liked our product and we thank you for your time:thumbsup:

[davidl9999]

Scooter, if you would just please explain how the fan is helping make power and not blowing fuel out the carb vents at the same time, that would go a very long way towards helping (me, at least) understand why your product should work at all.

For me as a consumer, regardless of the physics behind your product, it's one thing to hear about how great something is, and quite another to drop $250 to find out that it doesn't work - which unfortunately happens way too often in the aftermarket product market. Even if it does work as you claim, it's apparently not AMA legal, so what are we supposed to do with it as racers?

Case in point: I paid $20 for a White Brothers FCR fuelscrew for my '07 WR250F. Unfortunately, it didn't work because the taper of the screw wasn't "quite" right - at least for my bike. I had to spend another $35 for a GYTR fuelscrew that had the correct taper for my bike. Now both companies are well respected, and both products are no doubt engineered in a quality manner, yet only one worked. My fuelscrew fiasco only cost me $55 and I had a working fuelscrew with a spare left to ebay to someone that may or may not have the same issue I did. Fast forward to today and this thread: How would someone feel paying $250 for a fan that physics says shouldn't work - and has been shown not to in the automotive arena? Maybe offer a performance guarantee and stand behind it?

[frogman]

Sorry Scooter, some members here are real farkin' a-holes.

I believe some of them have been educated beyond their intelligence.

They miss the whole concept and seem to think your system is a true supercharger, and try to apply all their "acquired knowledge" on the subject of supercharging.....

But its not a supercharger, I know what it is, its a boost system, designed to overcome or eliminate the effects of drag on airbox/filter airflow. Its a good idea, and its going to sell.

Good luck to you Scooter, they told the Wrights their contraption would never fly...

[WheelsUp]

Good luck to you Scooter, they told the Wrights their contraption would never fly...

The Wrights had science on their side.

[frogman]

The Wrights had science on their side.

Sure they did, both Wilbur and Orville had degrees in Aeronautic Engineering. :bonk:

[YZ250F06]

If it doesnt work, do we get a refund?

Thats basically the ultimate question

[oldnbold]

My jury is still out and undecided about this. Pro: When Kelstr talks, I listen as he seems to have decades of experience on making things go faster. Cons: the laws of physics seem to be against this invention.

I'd like to see some before and after dyno runs to sway my vote.

[Mutu]

I must say this idea seems quite rediculous to me.

Good luck getting suckers to cough up $250 for a $5 computer fan.

For $250, you could get a nitrous system to play with, or even buy a REAL TURBO. Both of which are rediculous on an MX bike anyway.....

[frogman]

Test results reposted, so they don't get lost in the multi-page shuffle.

well we all have been waiting for this fan to be tested , Scott the engineer and producer of this product has got a working kit all sorted out and he sent me a kit to install it on a new stock yz250f and give some feed back to what was found.

the bike that was used was a new 07 yz250f that had no time on it at all ,

it still had the titty's on the tires and the chain had not been adjusted yet, and it is all stock -----everthing stock .

i first got used to the bike stock , i put in a 30 min moto on the Motoland track in Casa Grande AZ,

the yami was great ---the kyb stuff works good as deleiverd, the clutch and chassis are also top knotch , i was able to go out and rip very hard on this bike in a lap or so --. ( i do like the yz 250 f yami anyway and have spen alot of time on them and they are really fun and easy to ride----the new tires from bridgstone are really cool on this bike , also a bonus ! )

then i came in and proceded to install the kit ,------Scott has now made the kit where you use a different stator for the extra a/c power to run the very cool high out fan ( way better than trying to use a battery pack ? )

he also uses a rectifier to wack the a/c wave in half to only use the dc side of it to run the dc fan ----real normal stuff !

so you pull the flywheel with a puller that is supplied in the kit , install the stator , re-install the wheel and you are done there .

then you remove the air filter, and the air filter holder in the box , then you pop the fan assembly in the box and tighten up the band and you get a shorter air filter bolt and cadge and you install your factory air filter .

it all fits very nice , clean , and professional looking .

then you install a different pilot jet, leak jet, and a pump diafram -----all included in the kit-----.

then i fired the bike up , warmed it up again ( it took me 1 1/2 hrs to install the kit for the first time----after now i have done it i can do it in 1 hr )

on the track the bike had a different exhaust sound ( deeper ), the bike would come up on the power quicker with less clutch work , and it had more mid -----and really had more on top , ------the fan spins harder with more rpm , kinda cool when using the bike electrical system ----the more rpm the more current , so the faster the fan spins .

the fan will spin 5,000 rpm at top current of 2.5 amps.

the thing works better than i though it would , it felt like a big motor in the mid ----but it would still spin to the moon and made good overrev because you are still using a nice light stock size piston !

there are several really big long jumps right out of corners that were really hard to make on the stock bike ,-----with the fan installed the bike could easily carry 4th gear and clear them -----as when stock the bike had to stay in 3rd and you had one hell of a time getting the ft wheel over .

i have to say the thing is real , and it does help power no doubt.

i really feel that with a pipe, and a modded motor the thing would really work well there also .

i took and put the bike back to stock ( except i left the stator in )--and then i ran it again to see if i could tell if the stator would pull the motor down at all ,---( there was no difference from stock stator to mod stator )

the bike ran just the same stock ( it was easy to tell when you took it off and then road the thing that it was back to being week in the mid and top again .)

it took along time to get this test going , but i feel like Scott has really put a huge effort in getting the kit streemlined and doing away with the battery pack .

this alone is worth the weight.

i asked him to make one for my crf250 honda , and he said he is trying but the honda air box is so screwed up that it will be a nightmare to come up with a set up for it -----the yami is just such a nice designed box and the system really fits nice ?

[davidl9999]

So I should drop $250 based on a subjective test without any objective data and without the possibility of a refund if it doesn't work for me as kelstr said it did? And even if it works as stated, I still can't race with it. And what happens to the bike if the fan fails? What happens if it fails on the face of a jump? How crappy does a bike run 20 miles in the desert when I'm trying to get back to camp with a sick bike? Even if it fails un-crappily, or won't cause a crash racing with it (not that that's possible per AMA rules), how hard is it to get parts and what would repairs cost?

I'm not laughing, nor am I trying to be a dick about it - or a "farkin' a-hole" as you so kindly put it . I'm serious here.

If it works as advertised, and fills a marketable niche, I'm sure the product would do well. I'm just not seeing it yet.

Designing and marketing a new product is admirable and takes a lot of guts, effort, and $$. Useful aftermarket products are well received by consumers - even if it takes a while to catch on. In the end, we all benefit from new advances - even if they're not useful to us individually. I don't read that people are doubting Scooter33's intentions, quite the opposite. However, the overall response in this thread seems to be that no one wants to get burned if things don't work as they're supposed to. I know that I don't. This is the one thing that consistently doesn't seem to be addressed by Scooter33 in this thread.

[TMX]

Man you guy's are a tough crowd. You guy's picked a person to do a review on our product and then you bash what he has to say about the results!!!

It's not 'bashing', it is pointing out and taking issue with a severely, if not fatally, flawed test method. As the designer/manufacturer, this should concern you greatly.

If your product performs as you claim it does, you should have no problem commissioning and posting the results of an independently performed and verified dyno run with the following info:

1 - stock engine

2 - engine with jet kit only

3 - engine with jet kit AND fan

This is a very simple request that will put this thing to rest once and for all. Hell, if it were my product I'd be camped out at the door of the dyno shop as we speak.

That kinda slams the door on future technology.?

Not a all, but you need to understand - and I suspect that you do - that when you introduce a product that logic and science both suggest should not work, some of us need a little more proof than 'because I said so'. You've obviously put a lot of time and effort into developing this product, so much so that the lack of real dyno results is a glaring, if not suspect, omission.

Just dyno it, post the results, and end this.

-B

[SUnruh]

here is the math:

(2.54 (centimeters per inch) x 12 inches) ^ 3 = 28316.846 cubic centimeters in a cubic foot.

since cfm and rpm both use minutes this makes it a cake walk.

our motor turns 13,500 rpm.

divide by 2 to get the times the valves are opened = 6750 rpm.

i am not taking into account the duration that the valves are actually open.

6750 rpm x 250cc = 1687500 cubic centimeters per minute is required by the motor at the rev limiter.

200cfm x 28316 = 5663200 cubic centimeters per minute

5663200 / 1687500 = 3.355 times the amount of air the fan produces more than the motor needs.

HOWEVER, it says 200 cfm with no backpressure. ah, but there IS backpressure. 3/4 the time the valves are closed!

now, there may be some benefit with the fan helping to get the air wall moving once the valves start to open.

but here is another monkey wrench, does an oiled air filter allow this 3.35x more air to flow through it?

what about the airbox openings themselves?

what happens when the fan dies?

[CRM114]

The amount of air the fan can flow has absolutely nothing to do with this problem. Nothing, nothing, nothing. Totally unrelated. And backpressure doesn't come into it either. CFM vs Pressure is much like the oft-misunderstood difference between horsepower and torque. You can come up with a device that flows 10,000 cfm and that won't raise the pressure one whit. In fact, Bernoulli's principle dictates that the faster the flow, the lower the pressure.

P + p v^2/2 + p g y = constant

where P = pressure, p = density, v = velocity, g = gravity, y = delta(height) for non-viscous incompressible flow.

The fact that it is equal to a constant means that as v increases, P must decrease. And vice versa. Yes it's an equation and I'm sure some of you hate equations and think anyone who cites one is an egg-headed moron who doesn't know one end of a screwdriver from the other. But the egg-headed morons at Yamaha who designed and built the engine in your bike in the first place used Bernoulli's equation (actually something more complicated) to build the thing. It's also the reason that planes fly, pumps work, baseballs curve, etc.

A hand operated bicycle pump has a very low flow rate but can pump air well over 100 psi. A hand held hair dryer flows over 200 cfm but won't raise the pressure at all. Any argument about how much air this CPU fan will flow vs how much air the engine needs is completely meaningless. The only specification that matters is how much 'pressure' this fan will produce at a given flow rate. Superchargers and turbochargers aren't fans, they're pumps.

Try this. Get an empty water bottle and try to push air into it. How much are you raising the pressure? Push with your diaphragm. Try it with your tongue. Try to push out the needle of a tire pressure gauge by raising the pressure in your mouth. You can't even get an overpressure of one psi. Take a floor box fan and push it against a wall. All the air just blows out the space between the blades and the frame. All this little CPU fan is doing is blowing air into a bottle. Sit back and blow into the mouth of a bottle from about two inches. That's what your getting. All arguments about CFM without citing a pressure at that flow rate are moot so lets not have any more. The guy who did the product review. Take the fan and duct tape a tube to it. Neck it down to a tire pressure gauge that measures in 1 psi increments. Let us know how much this CPU fan raises the pressure.

I respect that this fella is out there trying to make a product. And the idea is interesting. But if it works, it should be backed up with hard data. The kind that you put on a graph. Not pictures of a bike roosting in a corner or some guy claiming it made his bike faster. It's a CPU fan for god's sake. If this idea is good, he'll have no trouble finding investors who'll give him money so he can get dyno time. Hell, if I thought it was a good idea I might put some money into his company. Unfortunately, I think it is a dead end. Too bad, it's a cool idea and I'd have liked it. Now if he really wants to make a difference in offroad motorcycle riding, he'll come up with a lightweight, compact, aftermarket electronic fuel injection system that will forever do away with jetting, flooding, and fuel starvation at extreme angles. I would spend $400 on that.

Keep Ridin',

John

[SUnruh]

crm,

100% correct.

air flow is one thing, air pressure is another.

[Scooter33]

I have a few minutes to address some of your guy's comments.

Refund of product:

I wish i could offer this but does fmf or procircuit offer one on there products? I will however, give you a one year warranty on the fan itself.

Consumer fraud:

I know this goes on and that is the last thing I want to do. I would be an idiot to try and sell this concept for the last two years just to make a few dollars.

Dyno:

I have done this many times and I have gained 2hp, but then once I arrive at the track the bike won't run worth a darn. I believe this is caused from me using the a/p as a main jet source. A typical dyno run last about 4-5 seconds. My a/p squirts for 2.5 seconds then I go lean on the dyno. If I can find a dyno that will allow me to do comparison runs in about 3 second pulls then it would be a good comparison tool for all of us. So far I haven’t been able to find one set up that way. I have tried making my runs in 2nd or 3 gear to speed up the pull but bikes don't make peak hp readings unless you use 4th gear, witch is closer to a 1:1 ratio.

ama:

As far as the ama is concerned I haven't even been in contact with them about our product. I just figured that there are plenty of people out there that don't ride ama sanctioned events. I will make my plea to them though and see what response I get.

cfm:

The cfm for this fan is 200 in an OPEN AIR ENVIROMENT. I have not flow tested the air through the boot, I do know that air flow is not a problem. In no way is there any flow restrictions caused by the housing.

Supercharging:

I have said from the beginning that this is not a Supercharger nor was it ever meant to be. I know the difference. Like said axial fans provide cfm, not much pressure. This product does help the motor breath better which is obvious from the jetting changes.

I am sure I missed some issues and I will try to address them later.

[davidl9999]

I have done this many times and I have gained 2hp, but then once I arrive at the track the bike won't run worth a darn. I believe this is caused from me using the a/p as a main jet source. A typical dyno run last about 4-5 seconds. My a/p squirts for 2.5 seconds then I go lean on the dyno.

Scooter33, this engine behavior is completely understandable. It's also exactly why you cannot use a fan or any other sort of pressure pump on the intake side of a carb without re-routing the carb vents to the highest pressure area in the intake (somewhere before the airbox side of the throttle slide). The AP squirt overcomes the inverted differential pressure across the fuel circuits because it has a positive displacement pump behind it (the AP diaphragm), but the other jet circuits can't flow properly because they require the air pressure outside the carb be higher than inside the carb. The idea of making up for flow losses in the airbox and intake tubing, whether or not it can achieve a HP increase, would work "properly" with fuel injection because the fuel rail is maintained at higher than atmospheric pressure. As much as I'd like to see your product work, the physics involved doesn't support it in the configuration that you're using.

The next part is for my rider brothers (and sisters) who question why the eggheads (well, at least this one) have a problem with this setup:

Technically, I think that you're on the right track for trying to make up for the flow losses in the intake structure. If I understand you correctly, you're trying to make the airbox look to the carb as if the carb was sucking air without the airbox, filter, and boot connected to the intake bell. Hydrodynamics says that there's a certain amount of flow loss (W-sub-L) when moving a gas through a manifold (or pipe, in its simplest terms). Therefore, if you add enough "flow" energy to the gas to make up for the flow loss, the system will work as if the manifold didn't exist. It's a little more complicated than that, but you're essentially correct. Call it what you will, you have to raise the pressure of the gas in the manifold (because you add energy to it), and it's still a form of supercharging, albeit relatively mild. However I think that you'll be surprised at how much pressure and electrical energy are required to do this at high CFM flows.

To find out how much flow loss the intake stucture has, one could put the airbox, filter, and intake boot on a flow bench and measure the pressure drop across it at CFM flows corresponding to engine RPMs. A plot of flows would be an exponential curve with most of the flow loss occurring at high CFM rates. If you can nullify the pressure drop with a fan at all the RPMs (so you basically get a flat line of 0 pressure drop), the product will at least do what you say it will once the carb venting is addressed.

This link is useful to determine how much energy is required to "nullify" the headloss (H-sub-F; similar to W-sub-L) that you'd plot above:

http://www.lmnoeng.com/darcy.htm

The next issue in question is how much energy is required to do overcome Hf. A 12v 2.5A fan (I'm not going to call it a computer fan) requires 30 watts to drive it at full speed at 0% backpressure. Since we need about 66 CFM of flow, and a guesstimate (see above link using 6" of duct and 37mm dia.) of Hf is 107 (a factor of energy "lost" per cubic foot of air, see above link). This means that to make up for the headloss in a simple 6" 37mm pipe, you'd need to add 12 watts* of energy to the air (at 100% efficiency), but a fan is about 60% efficient at full power, so about 20 watts are required to make up the headloss just for a 6" very smooth 37mm pipe. It would seem that the flow losses from a complex structure of the airbox, filter, and boot would require much more energy than that. My guess is somewhere around 100 -150 watts (at 60% efficiency), but even if 30 watts is enough - that's cool too.

* (cfm x density x Hf/33,000ftlbs/HP) x 0.745kw/HP * 1000watts/kw

(66 x 0.075 * 107.7/33000) x 0.745 * 1000 = 12 / .6 = 20watts

So, while it's plausible for such a design to work, the energy balance seems to be off a bit and the carb venting needs to be revisited. And if you get a 2 HP improvement from 150 watts ( 0.2 HP) of input energy, that's a very good deal indeed! ?

[kelstr]

this little fan set up did work well , sure i could have done some dyno testing with it , but that can all be scued/slanted either direction a guy needed it to.

i wanted the tt yamaha guys to get a real world test on the same day with out the unit , then with the unit , on a new stock bike . ( even tho it did not have bridgstones tires on it )

so this is what i did because i was asked to , and if it did not work at all , i would have told you so .

i have no stake in this at all , ( i just begged and stole a bike sorta , put in a hard days work in and reported what i found )-------it made a good increase all across the power band very much like a good working pipe ( despite what the naysayers think.)

( i know i have paid $400.00 to $700.00 for pipes -----so --$375.00 for this in not out of line )( its actually put together real well )

what i liked the most is the mid, and top end power at the rev limiter .

the little bike was way easier to ride. ( it simply let the bike breath easier ---plain and simple )

so there you guys go . ?

R.P.P. is working to help the mxer by creating different products that are intersting and well thought out ,

some should not be as negative and they are , -------but some people are afraid of what they do not understand--------remember the monoshock yamaha, --

or the amp link,---almost all bikes use these designes today in some fashion.

------or transfer ports in a 2 stroke cylinder, --reed valves,-----water cooling, ----valving on a piston in the suspension -----all of these had all the same naysayers that tried to put all the correct math( or should i say wrong math ) on these products and call them no good ----

[davidl9999]

---remember the monoshock yamaha, ---

Yep, sure do! That P.O.S. had major suspension issues for the first couple of years, then it rocked!

(on the flip side, it was a major step up from the '70 DT1E 250 that I started on and it was sca-a-a-ry fast for this kid)

"...The net effect of this juggling is an over-dampened rear suspension, and no combination of preload adjustment and damping settings provides as significant improvement...Without a doubt, the new monoshock encounters the worst problems when confronted with abrupt, sharp-edged bumps. In this situation, the heavy damping won't let the shock respond quickly enough to keep the rear wheel on the ground." -Paul Dean, The Motorbike Archives, 1979.

http://motorbikearchives.com/content/view/64/2/

Even the world's finest motorcycle engineers design a poop sandwich - more than occasionally. Yet today, we all have monoshocks. Why? Partly due to manufacturing costs, but they're good performers today because riders disliked the product and it was improved until it was accepted as superior to dual shock designs.

That's no different than what's going on in this thread.

[kelstr]

Yep, sure do!

(on the flip side, it was a major step up from the '70 DT1E that I started on and it was sca-a-a-ry fast for this kid) :eek

That's no different than what's going on in this thread.

this is very true. ( and it was way better than my 1966 x6 suzuki hustler and my 74 DT1 175 i was riding at the time )

this fan has gone through some changes , as well as reed valves , suspension and engine design has.

so who is to say what this could turn into later on the fi bikes ,( it works now on a carb )

( even tho i really like the carbuetor,----"and only sequential fire port fi will suit me" -------but i am sure most of the fi at first will be t.b.i 1984 kawasaki , chevy , suzuki crap ------so i am sure this fan will work very much the same on those primitive t.b.i's as it does a carb-----with mapping of course)

so who knows where this could go .----i just think that the negative non thinkers that smoked R.P.P. are just being closed minded and might want to re-think this alittle more before they stick their foot in their mouth and be foolishly posting .

but i just tryied to give a fair equal test with some feed back .

[Rootuser]

The thing is here that I think needs to be re-iterated is the reason people are skeptical is because of the numerous products that have been sold to people that are just frickin plain rip-opps.

1. Tornado thingie that is supposed to improve your car's gas mileage.

2. Power Now Plus -- this actually REDUCES horsepower.

3. Winning a free X-box if you punch the monkey

4. Windows ME (or Vista even!)

5. Perpetual Motion Machines

You can always play on greed. I am very greedy. I always want more horsepower and torque. But as they say, a fool and his money are soon parted. So I am a born skeptic. To get people to buy in to this we really need to see proof in the form of dyno's and other non-subjective data. How the bike feels in the "seat of the pants" of one guy doesn't translate to how my own a$$ will feel about it.

Also, while all the math here is correct as far as I can tell, there are other factors not being taken in to consideration and one is the bend in the airboot. Since the flow is NON-linear on a lot of these bikes, you may need more pressure to push the same amount of volume? Is this the concept? This is like a ram air device that CAN work... but in this case I think there is normally more than enough volume and pressure to do what needs to be done (as there would be in a down-draft carb for example) and upping the pressure may actually cause a loss in overall horse power, especially at the top end when the air is REALLY flowing. At the low-end this may actually help by pushing air into a system that is still charging up its air intake. Thus maybe the "seat of the pants" feel mentioned in the review. What would be interesting is if the fan was dynamic. Pushing more air at the low and then less air at the high end to make sure you don't get blowback... I'd be LESS skeptical of a system like that because at least it would be thought all the way through.

For me the jury is out. I won't trash the product or endorse it. I'm just not sure yet. The math doesn't work out for me when I do it, but it's been a while since I took some of this stuff in college so I could be off.