Calculating cylinder fill
Calculating cylinder fill How can I tell when the cylinder is full based on basic info like head flow #, cam, intake, rpm.
Trying to spec out a cam for optimum area under the curve (DCR will be 8.6-9.0). The motor is a 6.0 ls6 intake, afr 205 heads (SCR=11.25:1), pace setter headers, full exhaust.
Trying to spec out a cam for optimum area under the curve (DCR will be 8.6-9.0). The motor is a 6.0 ls6 intake, afr 205 heads (SCR=11.25:1), pace setter headers, full exhaust.
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(Hope this isn't "Too Much Information, but you asked...)
"Full" in this context is just a point on a continuum of Volumetric Efficiency, from perhaps 75% in a really cheap and basic engine to 115% or more for a perfectly specced out race engine with all the parts working in perfect harmony. For the record, a typical definition of "full" would be 100% V.E., as per a measurement of air volume flowing into the engine (perhaps a conversion from the mass reading of the MAF) compared to the engine's displacement and RPM. For example, 100% V.E. for a 346 c.i engine running at 6,000 RPM = 346 x 6,000/2 = 1,038,000 cubic inches per minute, or 600 cubic feet per minute.
Your question really is: "How do I pick a cam/what cam is best for my engine and operating conditions? Phrased in this way, it has been answered here for many poster's applications and hopefully, with a few more of the blanks filled in, will be for you...
(If you meant: "At what crank angle will the cylinder reach maximum fill?", see above...)
"Full" in this context is just a point on a continuum of Volumetric Efficiency, from perhaps 75% in a really cheap and basic engine to 115% or more for a perfectly specced out race engine with all the parts working in perfect harmony. For the record, a typical definition of "full" would be 100% V.E., as per a measurement of air volume flowing into the engine (perhaps a conversion from the mass reading of the MAF) compared to the engine's displacement and RPM. For example, 100% V.E. for a 346 c.i engine running at 6,000 RPM = 346 x 6,000/2 = 1,038,000 cubic inches per minute, or 600 cubic feet per minute.
Your question really is: "How do I pick a cam/what cam is best for my engine and operating conditions? Phrased in this way, it has been answered here for many poster's applications and hopefully, with a few more of the blanks filled in, will be for you...
(If you meant: "At what crank angle will the cylinder reach maximum fill?", see above...)
Last edited by MadBill; Oct 22, 2006 at 02:56 PM.
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Yeah if you want a rough gauge based on stock tunes and configs download efilive and take a look at the stock VE tables. They will show you where each one peaks etc. You can also DL custom tunes and take a look at the VE for each cam type and mods.
Its not going to be exact and will only be as good as the tune.
Its not going to be exact and will only be as good as the tune.
This is what Ive come up with so far for high VE's early in the rpm but DCR is 9.42511739822109 Id like to keep the Ve's up but I dont see that DCR happening with 93 octane
http://img151.imageshack.us/my.php?...illsspects5.jpg
http://img151.imageshack.us/my.php?...illsspects5.jpg
I guess I should have phrased the question better or at least had a better idea of what I was looking for. Id like average maximum VE values from 3k-6k rpms while being able to run 93 octane max power at 6200-6400. This is for a truck trying to get the best 60ft possible and ET's.
I like my cake and I want to eat it too
I like my cake and I want to eat it too
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Originally Posted by 02sierraz71_5.3
I guess I should have phrased the question better or at least had a better idea of what I was looking for. Id like average maximum VE values from 3k-6k rpms while being able to run 93 octane max power at 6200-6400. This is for a truck trying to get the best 60ft possible and ET's.
I like my cake and I want to eat it too
I like my cake and I want to eat it too
Side note: You better use a better source than wiki if you're going to make a bold statement like the one in your sig.
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Originally Posted by treyZ28
Side note: You better use a better source than wiki if you're going to make a bold statement like the one in your sig.
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Originally Posted by DanO
Also, for a given engine, VE referenced at manifold conditions wont vary much, therefore the density of that air charge is of utmost importance.
Yep, EFI fuel tables are the only thing i've ever seen where density is referenced outside the engine and not in the intake manifold. When VE is referenced at the intake manifold it turns out VE actually creeps up at high vaccum conditions.
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Originally Posted by 02sierraz71_5.3
I did a paper on emissions a couple years ago the EPA has several studies regarding catalyst emmissions. You and I both know when you burn something it just doesnt go away. catalysts produce huge amounts of nitrous oxides as a byproduct the EPA has known this since the early 80's yet they are still mandated, its one of those out of site out of mind deals smog you can see the ozone you cant. Score another one for American bureacrat big business SNAFU
Aside from that, its not an "out of sight, out of mind" issue. Cat-converters do a great job of cleaning the emissions.
The more I learned about ICE and energy "production" in general, the more of a tree hugger I've become because I've realized how easy it is to make great improvements and the numerous alternatives available to us.
you could start running ultra lean A:F's but Nox would increase dramatically. Less emissions total, but more more NOx total. Less gas consumption (Id guess there is room for about 20% better fuel consumption). Its all about minimizing total and picking your battles. You aren't going to burn something and make magic fairy dust for emissions, so you pick what you want to an extent while trying to lower everything overall. :shrug:
Originally Posted by treyZ28
thread jack, but Id like to see what would happen to global warming without cat-converts.
Aside from that, its not an "out of sight, out of mind" issue. Cat-converters do a great job of cleaning the emissions.
The more I learned about ICE and energy "production" in general, the more of a tree hugger I've become because I've realized how easy it is to make great improvements and the numerous alternatives available to us.
you could start running ultra lean A:F's but Nox would increase dramatically. Less emissions total, but more more NOx total. Less gas consumption (Id guess there is room for about 20% better fuel consumption). Its all about minimizing total and picking your battles. You aren't going to burn something and make magic fairy dust for emissions, so you pick what you want to an extent while trying to lower everything overall. :shrug:
Aside from that, its not an "out of sight, out of mind" issue. Cat-converters do a great job of cleaning the emissions.
The more I learned about ICE and energy "production" in general, the more of a tree hugger I've become because I've realized how easy it is to make great improvements and the numerous alternatives available to us.
you could start running ultra lean A:F's but Nox would increase dramatically. Less emissions total, but more more NOx total. Less gas consumption (Id guess there is room for about 20% better fuel consumption). Its all about minimizing total and picking your battles. You aren't going to burn something and make magic fairy dust for emissions, so you pick what you want to an extent while trying to lower everything overall. :shrug:
I see what your saying in the end the real answer is alternative fuels which have been around just as long as the internal combustion engine hell the origional diesel (19th century) was made to run off of peanut oil and now adays people act like bio diesel was just discovered. Alternative fuels have been around for over 100 years the real enemy here are is ourselves for not doing anything about it and oil companies who put millions into washington through lobbyists and constituents to keep them in place. There is no big drive for alternative fuels and what is there is stifled by oil company money.
Hell, Brazil has mandated all cars be able to run e85 since the mid 80's, they grow the fuel themselves and they are a third world country. There is no excuse for us still using fossil fuels in automobiles the knowledge and technology have been around for decades. I could go on but Im gonna get off the box, it really irritates me to hear people complain about gas and its prices and wonder about why this is happening. They need to look in the mirror we are the reason for our oil problems by us buying oil we fund our enemies and we kill the environment. What the **** do people not see this.
/rant
