Cam Induced Velocity Question(s)
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From: Rockville, MD
Cam Induced Velocity Question(s) ive got a "working" spreadsheet that can calculate, to some degree, the velocity and pressure of air moving through a runner based on RPM and cam duration but theres a flaw or 2.
1) it only uses duration (essentially it assumes fully open at x duration). i need a way to plug in the entirety of the valve timing events plus the lift. ultimately looking at using calculated ramp rate, maybe a "mm/s" sort of measurement.
2) airspeed seems to be half of what it should be. i get this from page 9 of this pdf: http://www.profblairandassociates.co..._to_basics.pdf
3) because of the flaws, the pressure also seems to be low.
i THINK if instead of one duration at one rpm, its all the durations at that rpm.. though, that still leaves the lift issue on the table. ideas?
1) it only uses duration (essentially it assumes fully open at x duration). i need a way to plug in the entirety of the valve timing events plus the lift. ultimately looking at using calculated ramp rate, maybe a "mm/s" sort of measurement.
2) airspeed seems to be half of what it should be. i get this from page 9 of this pdf: http://www.profblairandassociates.co..._to_basics.pdf
3) because of the flaws, the pressure also seems to be low.
i THINK if instead of one duration at one rpm, its all the durations at that rpm.. though, that still leaves the lift issue on the table. ideas?
Dynomation I use Dynomation for what you are trying to do. I will tell you that it takes a lot more than the program to get accurate results. You need an accurate flow bench and actual cam data obtained via Cam Doctor or equivalent. I also have another software package that I use to alter the cam profiles, lobe separation angles, rocker ratios and so on.
Forget the spreadsheet. It is a waste of time without accurate data to work with.
http://www.proracingsim.com/dynomationmainpage.htm
Steve
Forget the spreadsheet. It is a waste of time without accurate data to work with.
http://www.proracingsim.com/dynomationmainpage.htm
Steve
ive got a "working" spreadsheet that can calculate, to some degree, the velocity and pressure of air moving through a runner based on RPM and cam duration but theres a flaw or 2.
1) it only uses duration (essentially it assumes fully open at x duration). i need a way to plug in the entirety of the valve timing events plus the lift. ultimately looking at using calculated ramp rate, maybe a "mm/s" sort of measurement.
2) airspeed seems to be half of what it should be. i get this from page 9 of this pdf: http://www.profblairandassociates.co..._to_basics.pdf
3) because of the flaws, the pressure also seems to be low.
i THINK if instead of one duration at one rpm, its all the durations at that rpm.. though, that still leaves the lift issue on the table. ideas?
1) it only uses duration (essentially it assumes fully open at x duration). i need a way to plug in the entirety of the valve timing events plus the lift. ultimately looking at using calculated ramp rate, maybe a "mm/s" sort of measurement.
2) airspeed seems to be half of what it should be. i get this from page 9 of this pdf: http://www.profblairandassociates.co..._to_basics.pdf
3) because of the flaws, the pressure also seems to be low.
i THINK if instead of one duration at one rpm, its all the durations at that rpm.. though, that still leaves the lift issue on the table. ideas?
__________________
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
Thread Starter
TECH Veteran
iTrader: (12)
Joined: Dec 2004
Posts: 4,354
Likes: 0
From: Rockville, MD
I use Dynomation for what you are trying to do. I will tell you that it takes a lot more than the program to get accurate results. You need an accurate flow bench and actual cam data obtained via Cam Doctor or equivalent. I also have another software package that I use to alter the cam profiles, lobe separation angles, rocker ratios and so on.
Forget the spreadsheet. It is a waste of time without accurate data to work with.
http://www.proracingsim.com/dynomationmainpage.htm
Steve
Forget the spreadsheet. It is a waste of time without accurate data to work with.
http://www.proracingsim.com/dynomationmainpage.htm
Steve
im not trying to get it perfect or even some sort of quality that would get it sold. im doing this for my own knowledge and maybe to spread in the community. i know that theres much experienced based "voodoo" but it all has a scientific reason for working or not working. that and i like learning so..
one question i had but forgot was: is there such thing as compressible and non-compressible flow of the same medium through the same "tube?"
