RPM, spray angle, bowl design

Before i continue saying anything else can someone set me straight here. The port volume discussion came up in regards to velocities effect on swirl correct? And swirl is mainly important in mechanically injected applications vs high pressure comon rail systems?
 
Ive seen it all now! The turbo inlet is sucking my hand in, so there must be vacuum in the engine....I guess it wasnt well thought out what was happening on the discharge of that turbo. lol
 
Heres a vid of my dads M37 with a 6BT in it. vac/boost gauge reads zero.

[ame]http://i1119.photobucket.com/albums/k623/khaoskustoms/76a6ffbb.mp4[/ame]
 
DIESEL_POWER said:
@ idle a diesel makes a tremendous amount of vaccumb, due to the internal design and high sealing qualities.

ever put your hand/paper/book close to the engine air inlet @ idle??--not smart
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Translation...

Wade fires up his engine without the intake pipe on. He inconveniently leaves his bible, The Haynes Repair Manual, with all his notes from all the phone calls to everyone else laying in the engine bay. It scares the living crap out of him as it all suddenly goes flying across the bay and gets sucked in the manifold. He is screwed now because all his knowledge just got sucked in the engine and now he has no directions on how to take it apart!! After pondering his situation for awhile, a 3-way light bulb on dim goes off above his head...VACCUMB...yeah, that's the ticket!
 
Dockboy said:
Translation...

Wade fires up his engine without the intake pipe on. He inconveniently leaves his bible, The Haynes Repair Manual, with all his notes from all the phone calls to everyone else laying in the engine bay. It scares the living crap out of him as it all suddenly goes flying across the bay and gets sucked in the manifold. He is screwed now because all his knowledge just got sucked in the engine and now he has no directions on how to take it apart!! After pondering his situation for awhile, a 3-way light bulb on dim goes off above his head...VACCUMB...yeah, that's the ticket!
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Happens to me all the time.


Posted via tapatalk if you know what i mean
 
Dockboy said:
Translation...

Wade fires up his engine without the intake pipe on. He inconveniently leaves his bible, The Haynes Repair Manual, with all his notes from all the phone calls to everyone else laying in the engine bay. It scares the living crap out of him as it all suddenly goes flying across the bay and gets sucked in the manifold. He is screwed now because all his knowledge just got sucked in the engine and now he has no directions on how to take it apart!! After pondering his situation for awhile, a 3-way light bulb on dim goes off above his head...VACCUMB...yeah, that's the ticket!
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Damn Greg,

Cut a guy with broke ribs a little slack. Of course I should know better than to read a Wade/Comp thread in my shape, I know laughter will occur!

That's just awesome!
Chris
 
JoeSix, I appreciate the generosity. I appreciate the people who are actually putting effort into the discussion.

Yes larger port volume will flow more air, but where does the line get drawn between velocity and pressure vs. volume and flow?
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I would look at the time it takes for either to fill a cylinder to say the least.
 
Dockboy said:
Translation...

Wade fires up his engine without the intake pipe on. He inconveniently leaves his bible, The Haynes Repair Manual, with all his notes from all the phone calls to everyone else laying in the engine bay. It scares the living crap out of him as it all suddenly goes flying across the bay and gets sucked in the manifold. He is screwed now because all his knowledge just got sucked in the engine and now he has no directions on how to take it apart!! After pondering his situation for awhile, a 3-way light bulb on dim goes off above his head...VACCUMB...yeah, that's the ticket!
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It just amazes me that he can cum-up (Wade speak) with all these dumb a$$ statement and think no one is going to know better!
 
Fahlin Racing said:
Lets clear this up for everyone, VELOCITY is SPEED, VORTICIES/VORTEXES are turbulence produced when SEPERATION OF AIR TAKES PLACE FROM THE PORT WALLS/FLOOR/ROOF BOTH SSR & LSR, VALVE SEAT&THROAT, VALVE HEAD as well as the guide area.

COMP, if you have an engine that is suddenly loaded gas or diesel, you WANT a port adequately sized to be able to recover easily to keep going. I believe air speeds are of higher important along with rotating weight especially in the realm of creating good throttle response.Technically we should be saying pounds of air into the cylinder but the only way we get that either is if the air charge is flowing properly both in least frictional loss and port routing.


IMO, as long as people engineer the drafting table designs, these flat runner layouts will not go far too fast. I believe port position is holding diesel intake & exhaust flows back from opimization as far as one part of the higher rpms picture. I see you are keeping Clay Smith's legend going, love it!

Swirl is induced naturally with two valve heads not matter what. 24 valve engines will produce tumble from the valve unless the port is designed to promote swirl coming out of the valve bowl. As our squish action, piston movment toward and away from TDC, the bowl should create both swirl and tumble at some point. As you have stated, swirl slows flow down when coming out of the head into our chamber, reason is its a long distance to travel, entailing a longer cam lobe duration may help the engine out.
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Sorry, just saw your reply to my post. I love the old Clay Smith design as well. I think it describes old hotrodders from the past like Rollie Free. I spent a week with Harvey Crane a few months back and his stories really brought to life some of the old legends I have heard about. I need to upload some stories he told about Gale Banks, Ed Iskendarian, Clay Smith, Pete Peterson and a few others. Old grudges die hard.

I know it is a small difference, but velocity is not speed. Speed is not a vector quantity, but velocity is as it denotes speed and direction. With that in mind, I should use the word speed more often unless I have a vector to describe the intake charge's direction. On the 2 valve heads always having swirl, you are correct(except for one freak I saw once) that is why I laugh when people say my head does not have swirl. We angles the port so that flow hit the cylinder wall to induce more swirl. Even if we did not do this, it would still have some swirl.

I really like the 4 valve heads I have been seeing lately, they have some swirl, but as the roof is raised and more air is using more valve area, swirl decreases dramatically. The flat ports, although they allow more swirl because the flow favors part of the valve, lose mass flow because they do not allow the entire valve to be fed correctly.
 
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The port volume discussion came up in regards to velocities effect on swirl correct? And swirl is mainly important in mechanically injected applications vs high pressure comon rail systems?
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Swirl is important in any engine really. It just isnt needed to be as strong at higher rpms. Although the strength at any rpm can be designed to be too much causing deficiencies in combustion. Like Diesel Power had mentioned Impingement is a good size factor most probably know little about, I know I am new to it.

As far as someone mentioning more volatile fuel, I think we would benefit from a fuel that allows a vaporizatoin process to be quicker than what is present simply because our burning cycle starts as soon as the proper fuel-air ratio has been achieved (delay angle) somewhere in the chamber. Which seems to be fairly quick from the beginning of injection. From then on our burn rate is regulated by the evaporation rate of the fuel droplet.

Our swirl action, created with squish, valve placement, and valve count plus bowl design will somewhat dictate our mixture rate and influence our pressure rise. I have recently read that in the compression ignition chamber rapid combustion at the beginning and as our burn becomes slower as the powerstroke continues because the oxygen content has become less. Pretty interesting!

Some on Impingement for something to chew on....

This is what Ricardo came up with after testing, once again from The I.C.E. In Theory and Practice Vol2
Ignition Delay in Engines
...there is another strong influence on delay, namely, the impingement of the spray on hot surfaces. If these surfaces are sufficiently hot, significant reductions in delay can be obtained by this means. In premixed charges, we have seen that the time between the completion of the compression process and the appearance of flame varies with fuel-air ratio. However, in the case of injected fuel, the term "fuel-air ratio" cannot be used in the same sense as in the case of a premixed charge. With fuel injection it is evident that, as long as the fuel is not completely evaporated, the complete range of fuel-air ratios from zero (no fuel) to infinite (no air, within the fuel droplets) must be present, and ignition will occur where the local fuel-air ratio is most favorable. Even the physical character of the spray will not affect the availability of a wide range of fuel-air ratios, and therefore it might be expected that, with a given fuel, the length of the delay period will depend chiefly on the pressures and temperatures that exist in the cylinder gases during that period and on the temperature of the combustion-chamber surfaces against which the spray impinges.
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Opinions on this occurrance?

JoeSix, I am curious on what you have to say on my last post.
 
Yup, that supports my experiences here too. Top end is good, low end is awful.

Cummins must have done a boatload of dyno hours on these things, tinkering with different values to balance everything out.
 
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