Head flow - what counts?
Head flow - what counts? I'm not sure why this hasn't been done before. Maybe it will stir up a hornets nest...
There has been a lot of chatter on here about whose heads flow more, whose heads are better, whose numbers are bigger, and, from wizards, cautions that max flow numbers don't tell the whole story. In an attempt to illustrate this, I have created a couple graphs from the information at users3.ev1.net/~black_ops/heads and data from posts of a couple of heads not on the list. First, note that, given the rapid changes in the industry, these numbers were probably out of date the moment the spreadsheet was created. Don't try to decide whose head is better based on these graphs.
On the intake side, note the difference between TEA and MTI. They are essentiall the same at 0.550, but look at 0.400. The give the same max flow, but which do you think will probably work better? My money would go on TEA. Now, again, remember that this is for illustrative purposes and any of those numbers may have changed. Today, MTI heads may flow better than TEA, but at that point in time there is perhaps 10% difference in the midrange.
While you don't see that difference on the exhaust side, I would not be surprised to see the GTP heads perform almost as well as the MTI heads, given the similarity up to 0.400. The TEA numbers are high because of the pipe, as we all know. Once again, this graph is not representative of performance today.
Have fun, and feel free to disagree with my conclusions
TECH Apprentice
Joined: Jul 2003
Posts: 316
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From: bronx ny
Re: Head flow - what counts? this is a great post and must have taken a long time to make the graphs, but flat out you cannot trust the manufacturers advertised flows, it would be great if someone can make a graph based on flows at a shop with a superflow bench testing all the heads on the same bench, measure port volumes and then everyone will see why certain heads make more power then others
TECH Regular
Joined: May 2003
Posts: 474
Likes: 1
From: B'Ham Al
Re: Head flow - what counts? I'm not sure why this hasn't been done before. Maybe it will stir up a hornets nest...
There has been a lot of chatter on here about whose heads flow more, whose heads are better, whose numbers are bigger, and, from wizards, cautions that max flow numbers don't tell the whole story. First, note that, given the rapid changes in the industry, these numbers were probably out of date the moment the spreadsheet was created. Don't try to decide whose head is better based on these graphs.
Now, again, remember that this is for illustrative purposes and any of those numbers may have changed. Once again, this graph is not representative of performance today.
Have fun, and feel free to disagree with my conclusions ;
1. All of these heads WERE NOT flowed on the same bench at the same time
2.These flow #'s ARE NOT current flow #'s for each company.
3.These flow #'s ARE adverstied flow#'s. (from when & where)
Hmmmmmmm,maybe somebody's trying to stir something.
I'm thinking......
Why debate something that's not based on current facts?
Re: Head flow - what counts?
this is a great post and must have taken a long time to make the graphs,
but flat out you cannot trust the manufacturers advertised flows,
it would be great if someone can make a graph based on flows at a shop with a superflow bench testing all the heads on the same bench, measure port volumes and then everyone will see why certain heads make more power then others
Re: Head flow - what counts? Let me get this straight.........
1. All of these heads WERE NOT flowed on the same bench at the same time
2.These flow #'s ARE NOT current flow #'s for each company.
3.These flow #'s ARE adverstied flow#'s. (from when & where)
2. probably not
3. Actually I believe some are independent, as I have seen them before. Can't give a reference tho.
Hmmmmmmm,maybe somebody's trying to stir something.
I'm thinking......
I'm thinking......
Why debate something that's not based on current facts?
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TECH Regular
Joined: Jan 2002
Posts: 400
Likes: 0
From: Lincoln Park Mi
Re: Head flow - what counts? i cant make heads or tails of those things. trying to pick out the line with 3 dashes and a dot vs 2 dashes and a dot is straining my eyes. can you make the lines different colors instead?
I understand totaly what you are talking about as far as the peak not being the whole story, its similar to looking only at peak numbers on a dyno. there is a lot more to it than that. unfortunatly with heads flow isnt the only thing that matters, as you mentioned port size and velocity also play a factor (and im sure there are other things as well, like how much swirl is induced into the chamber). but like you said, cant graph what you dont know.
I understand totaly what you are talking about as far as the peak not being the whole story, its similar to looking only at peak numbers on a dyno. there is a lot more to it than that. unfortunatly with heads flow isnt the only thing that matters, as you mentioned port size and velocity also play a factor (and im sure there are other things as well, like how much swirl is induced into the chamber). but like you said, cant graph what you dont know.
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Verdad Gallardo TECH Regular
Joined: May 2003
Posts: 474
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From: B'Ham Al
Re: Head flow - what counts?
i cant make heads or tails of those things. trying to pick out the line with 3 dashes and a dot vs 2 dashes and a dot is straining my eyes. can you make the lines different colors instead?
Carl-I'm really not trying to give you any greif.With all the "head discussions" here lately,I think you might know where I'm coming from also.
Tony
On The Tree
Joined: Apr 2003
Posts: 143
Likes: 0
From: Bellevue, NE
Re: Head flow - what counts? i've been told that big flow numbers isnt all that counts i heard that the proper velocity of the air flow for your application is actually a bigger factor in how well the head performs
Re: Head flow - what counts?
i cant make heads or tails of those things. trying to pick out the line with 3 dashes and a dot vs 2 dashes and a dot is straining my eyes. can you make the lines different colors instead?
Re: Head flow - what counts?
Carl-I'm really not trying to give you any greif.With all the "head discussions" here lately,I think you might know where I'm coming from also.
In retrospect I think I should have changed the vendor names to A,B,C, etc, but like I said above, posting was an afterthought.
Re: Head flow - what counts? Critter, interesting post with a good disclaimer.
I would like to add the intake flow data is pretty much meaningless with out the intake in place. The LS6 intake has a very major effect and reducing the flow by as much as 50cfm. The LS1 intake is worse dropping the flow as much as 67cfm.
With that said, the intake data wouldn't really be meaningful even if it was on the same bench etc IMO. GM insists on evaluating intake flow with the intake in place. GM insists on evaluting exhaust flow with a pipe on exhaust. I think GM is on to something and raw flow data is of limited use.
I would like to add the intake flow data is pretty much meaningless with out the intake in place. The LS6 intake has a very major effect and reducing the flow by as much as 50cfm. The LS1 intake is worse dropping the flow as much as 67cfm.
With that said, the intake data wouldn't really be meaningful even if it was on the same bench etc IMO. GM insists on evaluating intake flow with the intake in place. GM insists on evaluting exhaust flow with a pipe on exhaust. I think GM is on to something and raw flow data is of limited use.