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Wet Flow Test Pic...................AFR Chevy 235

General engine tech -- Drag Racing to Circle Track

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Cylinder Head Works Inc.

Re: Wet Flow Test Pic...................AFR Chevy 235

Post by Cylinder Head Works Inc. »

So I see that the term "Wet Flow" is different to everybody reading this thread.........know lets think about creating an Industry standard "Wet Flow test"
what do I see as relevant and this is my "Opinion Only " the Burn Pattern....!!!!

Image

So if a test could be developed to simulate this burn pattern.............would that be a "KEY" to understanding???
Looking at this pic my opinion is that ...........Simple Arrow Dynamics of high and low pressure streams or areas are playing a far greater role than meets the eye.I would even venture to say that the liquid fuel is being held in this region marked "area # 1" regardless of the RPM in a "Suspended State "Giving the notion that the Boundary Layer in this region has NO ACTIVITY for a hight of .070 just before the seat. Have you ever watch a light rain hit your windshield... form a bunch of droplets and just seat there as your driving just twitching a bit.

So lets say..........water and dye formula is being atomized so Fine that when tested in a SWIRL environment it leaves the same trace as gasoline regardless of the specific gravity....what's that say ???? The air has Weight and 2 valve engines have Swirl some more than others thats what needs to be investigated. I need to go to bed ......John
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by Ron E »

eric, water will give you patterns and help your understanding. It does replicate burn patterns. It's cheap, won't explode and can teach you a lot. I'm still waiting to hear from the guy who has wetflow so refined that water is no longer useful.
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by eric's 327 »

Ron, I understand that. I was just thinking and asking questions - not criticizing anyone.

John, can I still come over for BBQ and Tequila? I thought of a few more questions but I'm not sure I want to ask them.

Eric
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by blaktopr »

Ron E wrote:eric, water will give you patterns and help your understanding. It does replicate burn patterns. It's cheap, won't explode and can teach you a lot. I'm still waiting to hear from the guy who has wetflow so refined that water is no longer useful.
The one thing I need more info on is the lift amount/curve associated with with burn patterns. Basically, what is the dominent area. Or, once there is a particular motion generated up to full lift, does it remain or still change. So does the burn pattern follow only past convergence lift. Of course the differences can be found between a solid roller at .900 lift, then .600 down to a hydro flat tappet at .510.

Water no longer useful. You are making me think too much here Ron.
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by BrazilianZ28Camaro »

Cylinder Head Works Inc. wrote:So I see that the term "Wet Flow" is different to everybody reading this thread.........know lets think about creating an Industry standard "Wet Flow test"
what do I see as relevant and this is my "Opinion Only " the Burn Pattern....!!!!

Image

So if a test could be developed to simulate this burn pattern.............would that be a "KEY" to understanding???
Looking at this pic my opinion is that ...........Simple Arrow Dynamics of high and low pressure streams or areas are playing a far greater role than meets the eye.I would even venture to say that the liquid fuel is being held in this region marked "area # 1" regardless of the RPM in a "Suspended State "Giving the notion that the Boundary Layer in this region has NO ACTIVITY for a hight of .070 just before the seat. Have you ever watch a light rain hit your windshield... form a bunch of droplets and just seat there as your driving just twitching a bit.

So lets say..........water and dye formula is being atomized so Fine that when tested in a SWIRL environment it leaves the same trace as gasoline regardless of the specific gravity....what's that say ???? The air has Weight and 2 valve engines have Swirl some more than others thats what needs to be investigated. I need to go to bed ......John
John
Is possible that the carbon buildup in the arrowed areas is due the heat transfer from the exaust port by the common wall, "boiling" the fuel at that point with the intake valve closed?

About the wet flow videos, have you fellas observed the air is being sucked only on the left side of the "cylinder"?

The air shouldn't be sucked from all the perimeter of the cylinder to not influence the mixture travel to one side only?

Just trying to learn a bit :)
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by automotive breath »

Cylinder Head Works Inc. wrote: So if a test could be developed to simulate this burn pattern.............would that be a "KEY" to understanding???
.....John
In addition to understanding how the wet flow relates to the carbon deposits after run time, I believe it equally
important to understand temperature variants especially as it relates to ignition. When I see signs of combustion
in the intake tract like on the back side of this intake valve I try to understand the source of the heat. The
ignition temperature of gasoline is ~232 degrees C (~495 degrees F).

Image
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by automotive breath »

Cylinder Head Works Inc. wrote: So if a test could be developed to simulate this burn pattern.............would that be a "KEY" to understanding???
.....John
I believe variances in cylinder pressure, combustion rate and mass fraction burned are equally important parts of
the equation. In the grafts below of a healthy 355 you can see the combustion rate is very fast from ~15 degrees
BTDC to ~10 degrees ATDC. During that short period ~50% of the air fuel mixture is burned. Combustion slows
considerably for remaining 50% of the available air fuel mixture as it continues to burn all the way to EVO. It is
my opinion that burning of the first 50% of the mixture will result in a different carbon pattern than that of
the last 50% of the mixture.

Image

Image
Last edited by automotive breath on Tue Mar 23, 2010 3:42 pm, edited 4 times in total.
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by GregGood »

I agree with BrazillianZ28 and Automotive Breath. The area of carbon buildup at *area 1* is due to the intense heat at that portion of the valve seat.
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by ProPower engines »

I see the heat in that area as an issue but is it possible to believe these are perhaps the aditives in the fuel used.
Although most of my stuff is alky fueled so we do not see that. I have seen this with the use of VP fuels in gas engines.
I have also seen other fuels used like ERC fuel and not had that buildup under the intake. Is it possible that different blends may have an issue vaporizing then the heated area causes a burn off affect specific to VP fuels.

Have any of you guys tested different fuels and compared the residue volumes left behind with out changes to the head.
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by FastFourierTransportation »

I'm surprised no one has brought up the fact that the intake gases spend less time flowing into the chamber than sitting, stagnant, waiting for the intake valve to open again. :?

Has anyone considered what happens to any mixture in the port as the valve closes, and where that mixture might linger? I agree that heat is what causes the carbon, but, if I had to guess, I'd say that the carbon is still there simply because some fuel landed there when the valve closed, got cooked by the heat, and, unlike the regions around it, didn't get enough airflow to blow the carbon off. :-k

I would say, when conceptualizing anything in this area, one must remember that an intake port spends less than 1/10th of every revolution at 28" Hg, and there are VAST changes in local pressure, which can cause fuel to precipitate in unusual patterns, since raising the pressure lowers the saturation capacity for fuel in the intake air.

Anyway, I just think we should step back and consider how unsteady the intake flow really is, before getting too worked up about dry, or wet, flow numbers with a constant velocity flow. I'm not saying I disagree with anyone; just reminding everyone to take time and think about what's really going on in the intake tract for a moment when considering flow, dry, or wet. :)

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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by GregGood »

I think that is already taken for granted. :mrgreen:
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by Cylinder Head Works Inc. »

Yes gentlemen your all right "temperature" thats why I picked this iron head to show, being iron retains heat. The funny part this particular engine lives between 4500- 8400 RPM on the Dirt Track, alot of Circle Track racers around here run Dart Iron Eagles and every set thats past by my shop has the tall tale signs of "Stagnant Fuel" in this region, just this pair was pronounced to grab my attention.

Know I now I'm going out on a limn by saying "Stagnant Fuel " and this is my opinion, but I have seen this on alot of heads Dart, World, AFR, Edelbrock, and it doesn't seem to mater what the application. Street /Strip, Fuel injected, Carb, Circle Track, or RPM band, all the readers reading this thread have to keep in mind that my market place here in Edmonton is virtually everything under the SUN, Mild to Wild so after a while one starts seeing patterns...... and its Not the Tequila !!!! Having said that I have to refer back to AFR " Wing " five years ago I started working on a set of GM Vortec Bowtie's the first ones that where introduced both small and large port I've had 3 sets pass my SF 600. Long story short I played with the "wing " to see if it made changes in the Wet Flow ....and it did , the wing changed the Wet Flow pattern in the chamber as well under the seat running from the short turn to exhaust, also the Swirl rpm was reduced by 1000rpm, sad to say the heads to my knowledge were never tested, lost touch with the customer when the Economic Wall Street Blunder Hit.

The "Wing" in practical application may only benefit older valve angle heads say 23 to 18 degree heads in a Wet Flow less efficient. Any thing after 18 degree would be considered "Modern" port More Efficient design build with Computational fluid dynamics (CFD) technology but what of the................... LS-7 Port ??????

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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by FastFourierTransportation »

Cylinder Head Works Inc. wrote:Know I now I'm going out on a limn by saying "Stagnant Fuel " and this is my opinion....
John Yelich
I don't think you're going out on a limb. :) The fuel MUST stop between valve events. Since that makes up the majority of every engine rotation, it makes sense that, over time, small amounts of stagnated fuel might accumulate, just a little bit at a time.

-Adrian
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by blaktopr »

FastFourierTransportation wrote:
Cylinder Head Works Inc. wrote:Know I now I'm going out on a limn by saying "Stagnant Fuel " and this is my opinion....
John Yelich
I don't think you're going out on a limb. :) The fuel MUST stop between valve events. Since that makes up the majority of every engine rotation, it makes sense that, over time, small amounts of stagnated fuel might accumulate, just a little bit at a time.

-Adrian
I think this would be the time where the discussion of vapor pressure, volatility, etc gets combined with pressures during all these events and the temps between chamber and carb especially during the overlap period.
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Re: Wet Flow Test Pic...................AFR Chevy 235

Post by automotive breath »

blaktopr wrote: I think this would be the time where the discussion of vapor pressure, volatility, etc gets
combined with pressures during all these events and the temps between chamber and carb
especially during the overlap period.
I'm thinking exactly the same thing!

Example; for a specific combination, what is the intake and exhaust port gas temperature and pressure at
the point in time when the intake valve begins to open? Is the exhaust gas pressure higher than intake gas pressure
and exhaust gas temperature > 500 degrees F?
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