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davesimon

the power now

58 posts in this topic

Hello. I was asked to come on here and explain how the power now works and answer any questions. It works for 2 reasons. One, at low throttle openings, air can only be pushed under the slide the small amount it is open, however, the pressure front from the airbox side rams into the complete back side of the slide. The air only has millisesconds to fill the cylinder and really doesn't need any restrictions. Well, a flat slide in the way is a big one. The air that hits the back of the slide has to turn downwards and hit the flowing stream at 90 deg trying to blend with it. This downwards air retards the forward movement of the air sneaking around the bottom of the slide and hurts it filling the cylinder instead of helping it. When the air stream on the box side is sliced in half, as with the Power Now, it cuts the amount of destructive air in half. Velocity also goes up automatically by slicing the air stream, but this accompanied with the lessening of the interrupting air stream, means you have a stronger, FORWARD flowing stream of air. Someone asked about top end power and tuning. There is no tuning because of a more laminar flow. If more fuel is required to meet more air then it occurs automatically because of lower surface pressure on the fuel orifices. This is never the case though. Top end power goes up one HP because the plate keeps the air stream from automatically spinning as normally happens when air goes from a larger to smaller diameter, via a taper. Remember, spinning is not moving forward as fast as it could because it is wasting time and energy spinning. Hope all this helps. Any questions just ask. Thanks, Dave Simon

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Dave, could you post some pictures of the Power Now on this forum, or do you have a website that has some pictures? I would like to see just a pic of the Power Now and some pics of it installed on the bike to see how it looks.

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The air that hits the back of the slide has to turn downwards and hit the flowing stream at 90 deg trying to blend with it. This downwards air retards the forward movement of the air sneaking around the bottom of the slide and hurts it filling the cylinder instead of helping it.

you speak as if there is A) no boundary layer effect at the back of the slide, and correspondingly :) air has some huge mass which results in it "hitting" the back of the slide. all this sounds like you are applying "water hammer" physics to air flow. at atmospheric pressure there is very little inertial component to the air flow. and it is highly laminar at typical flow rates in the carb boot. in fact, if as you describe "velocity also goes up automatically by slicing the air stream" you are implying by definition a increase in the reynolds number as well. thus the assertion that performance will somehow increase "because of a more laminar flow" is hard to qualify. your product(?) decreases the intake aperture size, which for a given mass flow rate (i.e. same engine power) will increase air velocity, and thus increase turbulent flow. there is no way around that--the entire bernoulli family says so.

i'm still weighing how a higher source impedance (smaller intake tract) "helps" cylinder filling. in a single cylinder engine, with no intake cross-pulsing, i'd think that the lower the intake impedance, the better. as for the "plate keep[ing] the air stream from automatically spinning", that's rubbish. again, at the velocities we are talking about, and the minor inertial mass of the fluid, this so-called "spinning" (aka ANY non-homogeneous flow pattern) is quickly damped in a few linear inches of flow. ps: does not "spinning air" to some degree increase atomization and air/gas mixing, thus producing a more even and a more complete combustion (=more power)?

finally, you should consider the following. suppose the slide was not normal to the direction of flow. instead, imagine that the slide was "canted" away from the flow, and was drawn up at an angle. would this not also mitigate the problem of the "air [...] hit[ting] the back of the slide"? besides the non-linearities introduced and some machining/sealing/operational issues, do you see any drawbacks to the "slanted slide" carb idea?

anyway, just trying to get the facts straight here.

the wrooster

ps, it's been a while since advanced fluid dynamics, design of turbines, and aerodynamics. but not that long. darcy-weisbach and moody still come to mind when i water my lawn.

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English guys, English!

The relationship of the earth spinning on its axis at 2400 mph, at a relative air temperature of 78 degrees, with a 5 mph wind from the southwest on Friday, during leap year, with a 200 pound rider, slightly dehydrated with decrease performance depending on the surface tension of the soil and tread pattern of the tire, depending on the number of clicks of compression and rebound that are applied,....etc.

ben

[ April 25, 2002: Message edited by: armourbl ]

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Dave,

Can you post some comparitive flow bench results and velocitys to substantiate your post. If you have dyno results it should show up in acceleration tests.

Thanks

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All of the science talk is nice, however there are times when the physical models are so complex as to get in the way of the phenomenom.

Anyone have a model of how differently shaped/sized dimples in a golf ball effect the aerodymanics? (- oops - I meant aerodynamics! LOL!) What works better sometimes simply works better despite the models.

It would be nice to get a dyno plot though before I plunked down my hard earned $$. Or if this kind of thing doesn't show up on a dyno, then maybe a review from someone who can spare the extra cashola!

BTW - the only thing that comes to mind when I water my lawn is "it sure would be fun to roost through this patch of grass."

[ April 25, 2002: Message edited by: skthom2320 ]

[ April 25, 2002: Message edited by: skthom2320 ]

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You guys are great with the questions and concerns. I must say that I was caught off gaurd by this blurb coming out in the magazine so soon, so all is not completed yet. There is a website under construction. The address is World Power Racing.com. It will have the pictures and some horsepower stuff. This type of response increase is really kind of hard to see on anything other than a sensitive engine dynos. A rolling wheel dyno doesn't show you much here because you just yank the throttle wide open. To recreate small throttle openings and response type stuff is nearly impossible with a human working the trottle. Mr. Wrooster. You're alright. You can question it all and we can argue for days, but sometimes things just work. For anyone who reads this, if you want to try one and for some reason don't like it, then I'm happy to refund your money. It is now in writing for everyone to read and I don't think I can get fairer than that.

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Dave, good to see you here so quickly. Personally, I found your introduction and the desrciption of the Power Now to be quite informative in laymen's terms. As we discussed via email, it appears even stronger to me to be a variation on a dual plane intake manifold from the muscle car era and on even into recent automobiles as built by Honda. I have several questions, but would like to zero in on one area in particular. As the Power Now pertains to large B/S(bore/stroke) ratios such as the 426, and given that the engine is already finely tuned for low end throttle response, would the rider notice a substantial increase in low-end power? What I'm getting at, is what would the rider "reasonably" expect to change after installing the Power Now? Also, would there be an additional benefit to be achieved if a fuel such as VP MR2 is used in lieu of pump gas?

By the way, I noticed that you didn't post your credentials as you described in your email to me. Perhaps a short background on yourself might lend a little credence to your information.

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WRooster, you must be aware that the first FCR carb was a slant slide design, as used by the early YZF, WRF, DRZ, RFS, etc. Or were you just making a point?

Originally posted by wrooster:

finally, you should consider the following. suppose the slide was not normal to the direction of flow. instead, imagine that the slide was "canted" away from the flow, and was drawn up at an angle. would this not also mitigate the problem of the "air [...] hit[ting] the back of the slide"? besides the non-linearities introduced and some machining/sealing/operational issues, do you see any drawbacks to the "slanted slide" carb idea?

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The price is $69.95. The biggest thing you will notice is that the bike pulls harder,sooner and you can run down further in each gead without the motor having the tendency to lurch and want to stall when you do so. This means there is more room for error on the riders part and less shifting because you could pull out of something in 4th gear where before maybe you had to go to third. Enduro riding is improved because you don't need to have a hand on the clutch at all times when negotioating tricky stuff in fear of stalling, and you get the instant blurb of power way down there to get over the sideways groing tree limb which you swear at the time your going over the bars was stragically placed by satan so he could have a good laugh.

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Dear Gentelman. I have a power now on each of my bikes, which are the YZF 250 and 426. I got some before he sold out. They work fantastic no matter what kind of riding you are doing. I think this wrooster guy and any nay sayers are funny. You have not even tried it. I am an engineer at Boeing and have to say that what Dave Simon said makes more sense than your 50 year old physics book explanation. Where do thing technology comes from? Change. New things are always discovered. I ride the 426 at Glen Helen and other motocross tracks around the area. If anyone has ever bee there, you know there is a tight right that shoots up a long hill to another right. I use to have to come around the turn in third to keep the power up to make it up the hill. With the power now, I do it all in 4th. I have never been able to pass so many people at once. On the 250 I do enduros and ride Bean Canyon. Anyone ever try to ride Bean when there is no traction? I can do many more off the small,slow straight up hills now in 2nd instead of in first and on the clutch all the time. You can feel some top end inprovement on this bike as well on those long sand uphills. I know because I make them now instead of running out of juice in mid hill. To end this, all I have to say is, what else can we 4 stroke guys for $70 bucks that works this well and doesn't increase the noise?

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Originally posted by bearing:

[QB]Dear Gentelman. Where do thing technology comes from? Change. New things are always discovered.

Well that's good enough for me. I like the "sometimes things just work" explanation too. Where do I send my money? :)

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My money is tight, so I'll wait until I hear numerous testimonials from TT members I'm familiar with and trust.

ben

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Having more hours on the flow bench than I care to talk about, I have the same concerns as Wooster.

But, and this is a huge BUT, Ive seen things that worked on the track that DIDNT on the dyno. Something that takes a full second off your lap times make cost you hp on the sheet. Ive seen igitions that wouldnt work on paper making huge HP in real life IE (energy transfers and sub-coiless igs.) Id like to see more data on the "power now". Not to quote a song but, Id like to take a different attitude like "I wanna know what are you gonna do for me?"

What Id like to know is where did the idea come from and why? If you've got the patent pending your locked in with nothing to loose, right?

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davesimon,

hey cool. i'm just trying to figure out what the story is here. i, and i guess others, don't waste too much money on MX mags. instead we buy aftermarket parts. :) got some pics?

scottf,

actually, i didn't know about the "slant slide" precursors to the FCR. when i wrote the post i was wondering if the "advantage" of the slant slide (via application of davesimon's explanation) would be offset by another problem -- namely, the trailing turbulence when the slide was half open. in the other words, the air would have to tumble up and back to maintain the pressure behind the slide.

bearing,

I think this wrooster guy and any nay sayers are funny. You have not even tried it. I am an engineer at Boeing and have to say that what Dave Simon said makes more sense than your 50 year old physics book explanation.

a "50 year old physics book"? 50!?! the basic equations of fluid flow were developed in the 1700's. i used to do research for boeing CAG (i'm sure you know what that acronym means) and in between discussions regarding the toray fiber layups on the 777 vertical stabilizer i learned that *most* of the engineers at boeing were top notch. so in a world full of hucksters and snake-oil-salesmen i'm admonished by you for asking technical questions of a vendor making some interesting claims? maybe mr. davesimon is really on to something here, and if you reread my original post i didn't say he wasn't. i'm a ween-- i make hypotheses, do research, look for explanations. what's keeping you up?

the wrooster

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Hello. Everyone should know that I'm not on here as some cheap ploy to rack up sales. A memeber by the name of Boit said there was interest on this site and maybe I could help answer some questions. I don't know who the bearing guy is but obviously he is one of the first customers. I can put dyno stuff on here and on the website, but you should know that I can stick any graph on there I want. Really, why would you trust it? And why doesn't anyone seem to trust Dirt Bike magazine that tested it in the first place? Do you really think they would say it's bitchin if it sucked? There is a bigger story coming out in the next Dirt Bike which may answer some concerns.

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This is reminding me of a mod I tried a couple years ago. It was talked up big time on DRN and may still be on the KDX site. It involved a guy boring out the carb., installing a different needle and installing a horizonal divider in the throat of the carburetor. Sent this guy my carb. and $150. Ran worse when I got it back than it ever did before. After many hours of jetting I installed my original needle and ended up with it jetted pretty much the same as it was when I sent it in. Biggest difference I saw was wasting all that time shipping and jetting instead of riding. Not to mention being out $150.00. Sold the bike but I still have that needle, Lord only knows what it fits.

Steve

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I am an engineer at Boeing and have to say that what Dave Simon said makes more sense than your 50 year old physics book explanation

So your the reason Boeing lost the Joint Strike Fighter? LOL OH My God!!

[ April 26, 2002: Message edited by: sceptor ]

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