CP does have some roll in the amount of timing but stroke plays a bigger role. Its simple math. The smaller the circle(stroke) the more timming you can run because the piston travels less distance per degree of the crank.
High timing small displacement - does it matter
- Thread starter madmikeismad
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CP does have some roll in the amount of timing but stroke plays a bigger role. Its simple math. The smaller the circle(stroke) the more timming you can run because the piston travels less distance per degree of the crank.
Leiffi
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It also moves slower.
Fahlin Racing
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Interesting thoughts, good topic. Fuel composition too, yes, but I am sure that is the constant in this thread.
If you guys want to larger example use the KTA 6.25SX6.25B
Yes, in any engine for that matter but as you and many others know the roots on this statement are many, variable. Like its been said the seen change on a 5.9 vs a larger litre mill we have two capacities of instantaneous torque production obviously for purpose to weight duties. I am not sure but are both of these using open chamber crowns? Different speeds of the piston not only at BBDC, ABDC, mid stroke, BTDC & ATDC. Could the different bore sizes be dictating different pressure rises just on size alone, probably, in addition to the stroke length allowing more ingested charge to be heated by compression. In turn, may advance or retard the engine timing in addition to fuel delay time periods which can also be influenced by the surrounding combustion chamber surface temperatures as well as the charge temperature itself further changing heat absorption rates of not just the fuel but the surfaces making the combustion chamber in relation to timing of heat reduction by cooling and heat concentration within the chamber before our fuel ignites once it has reached the burnable state.
I am not sure what this engine is timed at but I know it used to be in a industrial JD engine, a good shot of the crown w/ burn pattern of the articulating piston. That is what is floating around my brain from your guy's conversation, explaining why will be taking a nice set of inputs mounted on engines and just watch the info roll for a fixed time.
Not sure how I would rate variables as far as how crucial each one is, but, what about the crowns in question? VW & etc.
If you guys want to larger example use the KTA 6.25SX6.25B
Yes, in any engine for that matter but as you and many others know the roots on this statement are many, variable. Like its been said the seen change on a 5.9 vs a larger litre mill we have two capacities of instantaneous torque production obviously for purpose to weight duties. I am not sure but are both of these using open chamber crowns? Different speeds of the piston not only at BBDC, ABDC, mid stroke, BTDC & ATDC. Could the different bore sizes be dictating different pressure rises just on size alone, probably, in addition to the stroke length allowing more ingested charge to be heated by compression. In turn, may advance or retard the engine timing in addition to fuel delay time periods which can also be influenced by the surrounding combustion chamber surface temperatures as well as the charge temperature itself further changing heat absorption rates of not just the fuel but the surfaces making the combustion chamber in relation to timing of heat reduction by cooling and heat concentration within the chamber before our fuel ignites once it has reached the burnable state.
I am not sure what this engine is timed at but I know it used to be in a industrial JD engine, a good shot of the crown w/ burn pattern of the articulating piston. That is what is floating around my brain from your guy's conversation, explaining why will be taking a nice set of inputs mounted on engines and just watch the info roll for a fixed time.
Not sure how I would rate variables as far as how crucial each one is, but, what about the crowns in question? VW & etc.
Fahlin Racing
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Not having any VW pistons myself, Google provides a good amount of crown pictures on that layout. Offset bowl, valve recessions etc. I don't see any lip for re-entrance on the ones shown, seems like a straight wall up to the recessed level of the crown. Thinking more on that large change of adjustment, on the 5.9 stated earlier, I would say the tuned position was just set even though there is more possibility there which I am sure has been in thought already. Peak of efficiency for the set application to meet standards?
madmikeismad
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I have no idea what you just said. lol
Turbo Performance
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Don't worry, I doubt he does either.
Fahlin Racing
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Yeah you go it :Cheer: :woohoo:, perhaps, in short maybe I should have said how would small bowl changes influence timing and not type what I was thinking, agreed.
Re-entrant lipped versus fully open crown perhaps.
Would displacement influence the actual bowl recess diameter, also? Leiffi?
I recall Weston?-Smokem saying the bowl depth is a necessary evil with the flycuts etc and further keeping the ring positions down. Others have used shallow bowls and higher ring positions. Do we consider the crevice volumes in the ringlands and 360 degrees of circumference of the piston? What is this outer area doing to our heat production? is it just allowing heat expansion or is it doing something else that has a direct of indirect benefit?
Re-entrant lipped versus fully open crown perhaps.
Would displacement influence the actual bowl recess diameter, also? Leiffi?
I recall Weston?-Smokem saying the bowl depth is a necessary evil with the flycuts etc and further keeping the ring positions down. Others have used shallow bowls and higher ring positions. Do we consider the crevice volumes in the ringlands and 360 degrees of circumference of the piston? What is this outer area doing to our heat production? is it just allowing heat expansion or is it doing something else that has a direct of indirect benefit?
Fahlin Racing
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My point, is delay angle on its own from rpm, or, does delay angle have a affect from rpm level low & high?
If delay angle is changed would this be a absolute in order of bowl design & injection or could it be solely owned by the turbulence developed within the crown regardless of minimal change in spray pattern?
Tell me, with a injection path from the orifices at the tip are we seeing a goal of streaming of fuel at the centralized location of the 'wall' of the piston bowl?
Are we seeing a more downward angled spray making more of a impingement on the crown but forcing the flow to climb the wall and tumble?
Are we seeing a higher or upward position possibly right at the crown deck forcing the flow to flow down the wall and tumble? I am sure this one would more likely over shoot the bowl slightly however would the quench area be strong enough to push the fuel that does miss back into the bowl to burn?
If delay angle is changed would this be a absolute in order of bowl design & injection or could it be solely owned by the turbulence developed within the crown regardless of minimal change in spray pattern?
Tell me, with a injection path from the orifices at the tip are we seeing a goal of streaming of fuel at the centralized location of the 'wall' of the piston bowl?
Are we seeing a more downward angled spray making more of a impingement on the crown but forcing the flow to climb the wall and tumble?
Are we seeing a higher or upward position possibly right at the crown deck forcing the flow to flow down the wall and tumble? I am sure this one would more likely over shoot the bowl slightly however would the quench area be strong enough to push the fuel that does miss back into the bowl to burn?
CurtisEmery
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Explain to us what delay angle is? Using normal lehmans terms will probably get you better responses on here.
Fahlin Racing
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Sorry,
Delay angle = amount of time in degrees of crankshaft rotation from initial fuel injection to when the fuel actually begins to ignite (stoich AF/R present). Basically its how fast the fuel will evaporate from liquid droplet to gaseous/ignitable state to be burned in our chamber. Ignition delay is another reference for it.
Delay angle = amount of time in degrees of crankshaft rotation from initial fuel injection to when the fuel actually begins to ignite (stoich AF/R present). Basically its how fast the fuel will evaporate from liquid droplet to gaseous/ignitable state to be burned in our chamber. Ignition delay is another reference for it.