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Buell Forum » Knowledge Vault (tech, parts, apparel, & accessories topics) » Engine » Intake: Intake Tract, Airbox, Filter, Manifold, Gaskets » Velocity Stack Challenge - The Results » Archive through July 27, 2004 « Previous Next »

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Darthane
Posted on Monday, July 26, 2004 - 07:35 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

LOL...nah...most 'youth today' wouldn't have apologized (or even have realized that they were being offensive in the first place).

...someone has to try and bridge the gap between you toothless old farts and the young whippersnappers! hmm...am I being offensive again? -=ponders=-
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Buckinfubba
Posted on Monday, July 26, 2004 - 08:44 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

old farts are better......they've been aged and have a better more staunch smell
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Blake
Posted on Monday, July 26, 2004 - 10:22 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

You mean "stale" smell.
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Buckinfubba
Posted on Monday, July 26, 2004 - 11:12 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

stale ...staunch
tomato....tamata
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Firebolt020283
Posted on Tuesday, July 27, 2004 - 02:18 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

well if being an old fart means u smell im glad im the yungin of this board
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Jens
Posted on Tuesday, July 27, 2004 - 05:59 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Thanks for your friendly comments.

Some things in addition:

The stock Buell XB Airintakesystem has from my point of view, no Ramaireffect in any way. The left Airchannel has a coolingeffect for the rearcylinder. That 90 degree Rubbersnorkel will never get a real pressure because the air from the scoop is going straight out on the back. On road speed measurements with GPS on unlimited german "Autobahn" and on the Racetrack shows also in high speed the same like the Dyno: A significant plus in power with the FAST System.

Bikes who havent done that with airbox, run in fifth gear with open air now in the limiter. By the way, the ECM will not able to handle a Ramaireffect in Open Loop we think.

Airboxmodification liked discussed (again I have no problems with home brewed solutions)will work. They makes a plus of 2-3 HP depending what Bike and what configuration. Drill also holes in the button of the lower airbox, that after a rainride when you brake, your aircleaner dont get a cup of water... With the radiation heat you have to live in that case.

We run a 5 Track datarecording on our testings and checked one day also the temeratures under the Hood. There are of course big differences if you ride with stock (closed) or modificated (or different) open Tankcovers in the temperature under the hood. We say for normal Roaduse the FAST system works well with the stock Tankcover, because the clearences to the frame, along the Gasfillbody and (without airbox)in the rear also the original snorkel hole, are more than enogh to let the engine breath. For the Racetrack, were you seek the last HP we prefer a Tankcover (like our Turbotankcover in the beginning developed to find room for the Intercooler) with big openings to lower the airintake temperatures.

Jens
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Firebolt020283
Posted on Tuesday, July 27, 2004 - 06:13 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

im probly gonna sound stupid for making this remark or it wouls just plain out look ugly but if you want more air and every thing couldnt u just put the fast system and leave the cosmetic cover off too??
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Glitch
Posted on Tuesday, July 27, 2004 - 07:48 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Thanks again Jens.
You've got me sold.

Firebolt, I think what Jens said was you could do it, but with minimal, if any boost.
Looks to me the main thing is to keep the heat out and speed up the air going in.
We get enough air in, but the velocity stack speeds up the air going into the engine.

Darth, OK, you're wise beyond your years, must be that international traveling...
That, and your parents obviously did a good job.
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Blake
Posted on Tuesday, July 27, 2004 - 09:28 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

A velocity stack actually slows the peak airspeed entering the throttle body. A smoothly radiused/curved inlet (velocity stack) provides smoother flow with less pressure loss and with no flow separation from the edge of the throttle body as it enters.

The velocity stack allows more intake air flow by providing a more efficient (smoother, less restrictive) path.

It also provides added length to the intake tract which helps provide optimal cylinder fill through harmonic interaction with cam/valve timing and any exhaust scavenging effect that might also be present. : )
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Buckinfubba
Posted on Tuesday, July 27, 2004 - 09:28 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Jens
well cool then , i had yet to hear of any test on this , other than the one done on an air strip somewhere here, that did show a psoitive pressure in the airbox. Can't say who did the test because I ain't supposed to know it happened but the info came from what I would call a very reliable source.

I ain't arguing anything here, I was just bring soemthing up, thats all
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Zip
Posted on Tuesday, July 27, 2004 - 10:55 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Aw Come on Bubba, you can tell me who did the test ... Nobody's listening... and I won't tell a soul
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Glitch
Posted on Tuesday, July 27, 2004 - 11:05 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Thanks Blake, at least I wasn't completely wrong.
I guess my explanation wasn't written very well.
What I meant to say was The velocity stack allows more intake air flow by providing a more efficient (smoother, less restrictive) path.
I had heard Kevin Drum talk of the optimal cylinder fill through harmonic interaction with cam/valve timing and any exhaust scavenging effect that might also be present, but I forgot that part. I remember him showing his bike with a tuned intake and exhaust.
Man I love the BadWeB!
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Firebolt020283
Posted on Tuesday, July 27, 2004 - 01:07 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

ok im a little confused blake said it slows the air flow wouldnt that go aginst every performance idea ever done to the intake of an engine (ram air, force winders for the older bikes, turbos, bigger carbs and throttelbodies)?????????
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M1combat
Posted on Tuesday, July 27, 2004 - 01:44 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Well, if you have high velocity but inconsistent pressure you may end up with less overall a/f mix entering the cyl. By inconsistent pressure I mean inconsistent cross section as you look down the intake. More pressure to the front/back/side or wherever. They are both worth something, but gaining velocity at the cost of volume isn't good. Volume is what you want.

As far as scavenging, too much is only as good as just enough. Velocity and scavenging work in such a way that as the exhaust valve closes the intake is still coming in. The velocity of the air pressurizes the cyl. just a tad and you want to close the intake valve EXACTLY as the pressure peaks. Of course, you can only get this to work correctly at the RPM you designed it to work properly at (unless you have VVT, then you can make it work at just about any RPM until something grenades : )).

AARON (or Blake)- Correct me if I'm wrong please : ).

edited by M1combat on July 27, 2004
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Firebolt020283
Posted on Tuesday, July 27, 2004 - 04:10 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

but that doesnt show it slowing the air flow down
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M1combat
Posted on Tuesday, July 27, 2004 - 04:10 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Oh, you were talking about a sharp cornered Vstack... Sorry.

Imagine water running over a waterfall. It will break with the ground as it goes over because of it's vector (horizontal) and the fact that it now needs to change direction. It won't do this at a sharp angle. The result (with a sharp angle) will effectively give you a smaller hole for the air to flow through. You still need the volume, so the air will have a higher velocity but will create more vacuum. As I recall, vacuum is bad for scavenging. Scavenging is good for power.

Is that what you were talking about Blake?

edited by M1combat on July 27, 2004
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Blake
Posted on Tuesday, July 27, 2004 - 04:12 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

I knew I shoulds'a drawn a picture... : )

Velocity Stack Flow
Velocity Stack Flow Verusus Short Sharp Inlet
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M1combat
Posted on Tuesday, July 27, 2004 - 04:15 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

The angle that air will contour to is 7 degrees yes? So it could be a sharp seven degree angle, but no more. I believe this is the reason that the tail section of race bikes is 14 degrees included? Sorry, a little off topic.

See my above post though : ).
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Blake
Posted on Tuesday, July 27, 2004 - 04:22 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

No. What I think you are referring to is the angle of taper for trailing edge flow wrt to the free airstream. A sharp (as opposed to blended/smoothed/radiused) angle that is not parallel to the airflow will almost always cause separation.
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Firebolt020283
Posted on Tuesday, July 27, 2004 - 04:25 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

like i asked what did u mean it slows down the air flow????
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Blake
Posted on Tuesday, July 27, 2004 - 04:31 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Airflow trying to fill the cylinders but subject to the smaller effective inlet opening on the left is forced to travel through the inlet at a higher speed than for the inlet with the velocity stack.

Realize that we are talking about airflow at the inlet, not at the intake valve.
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Blake
Posted on Tuesday, July 27, 2004 - 04:36 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Inflate a balloon by blowing through a straw. How fast is the air moving through the straw?

Then take the same balloon and stretch it over a paper towel tube and inflate it. How fast is the air moving through the paper towel tube?
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Firebolt020283
Posted on Tuesday, July 27, 2004 - 04:38 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

the towel tube it would go out faster but the straw would be ore pressureized kinda the same pricable be hind the tubo it pressurizes the air is that what u mean?
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Firebolt020283
Posted on Tuesday, July 27, 2004 - 04:39 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

i meant turbo
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Wyckedflesh
Posted on Tuesday, July 27, 2004 - 04:46 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

283 the velocity would be faster thru the straw, but the volume would be higher thru the towel roll.

edited by wyckedflesh on July 27, 2004
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Hogs
Posted on Tuesday, July 27, 2004 - 04:51 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Well guys all the High tech ..Mumble ...Jumble aside...is any of the stacks that were tested any good for a 12.. ? Since all were tested on a 9?? Also Do we get gains down low, midrange or up high orrrrrr all across the bd..? Blake whats your point on this?? Thanks
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R1DynaSquid
Posted on Tuesday, July 27, 2004 - 04:56 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

Inflate a balloon by blowing through a straw. How fast is the air moving through the straw?

Then take the same balloon and stretch it over a paper towel tube and inflate it. How fast is the air moving through the paper towel tube?


The size of the tube involved has nothing to do with the speed of the air nor the velocity. You can move air threw a straw at 300mph if you wanted to.

Its all about volume. But it all has to be matched, volume with no speed or velocity is no good and all kinds of crazy speed but no volume wont work either.
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Firebolt020283
Posted on Tuesday, July 27, 2004 - 04:57 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

ok i understand now thanks it makes sence to me now sorry for being annoying i just was tryign to figure out the concept behind it
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Blake
Posted on Tuesday, July 27, 2004 - 04:59 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

What if you try to blow hard enough into the straw to fill the balloon in the same time interval that it takes wiht the towel tube?

The air is then flowing through the straw MUCH faster. Yes it would require a lot more pressure differential between the straw's intlet and outlet (between your mouth and the balloon). Velocity and pressure differential are interdependent in airflow.

A better example would be to imagine the engine trying to intake (suck in) through a smaller diameter orifice, which is what in an uncontoured intake effectively creates. As a piston moves from TDC to BDC during the intake stroke it creates a vacuum inside the combustion chamber that ambient air outside the inlet tries to fill. Generally speaking the smaller the effective inlet, the higher the velocity at the inlet and the lower the amount of air able to flow into the cylinder.

Without a smooth contour and inlet orifice is less efficient, has greater pressure loss and thus results in less pressure available to fill the combustion chamber.
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Firebolt020283
Posted on Tuesday, July 27, 2004 - 04:59 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only) Ban Poster IP (Custodian/Admin only)

hey r1 why u gotta go and confusse me again
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