Ultra High Flow, Low Cost, 8V Head Project
11-22-2013, 12:30 AM
#91
this CAD drawing from the V2 school of tribology is my estimation of "where to start" here.
red lines would be smoothed/radiused out (is this the "short side radius work" that people talk about often, that sharp corner just above the valve seat on the inside bend?) - valve guide maybe trimmed on that side along with some aluminum around it to make a thinner protrusion
red spray would be smoothed down casting line
green spray slightly ovaling out the port to promote flow around the valve guide protrusion
green lines, perhaps minor shallow cnc cuts on the "floor" on the short radius as a sort of flow-director for flow attachment around the bend?
red lines would be smoothed/radiused out (is this the "short side radius work" that people talk about often, that sharp corner just above the valve seat on the inside bend?) - valve guide maybe trimmed on that side along with some aluminum around it to make a thinner protrusion
red spray would be smoothed down casting line
green spray slightly ovaling out the port to promote flow around the valve guide protrusion
green lines, perhaps minor shallow cnc cuts on the "floor" on the short radius as a sort of flow-director for flow attachment around the bend?
11-22-2013, 07:41 AM
#92
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I don't know about that. Cutting a stock head apart only shows you the obvious things. It doesn't make up for the lack of years of port development work. Case in point... my JME head using stock 951 valves, stock lifters, on a 2.5L engine using stock pistons, with a ported intake, a SFR header/3" exhaust and a 60-1HiFi turbo made 400 RWHP at 17psi, 415RWHP at 18psi. I have yet to see any 2.5L make those numbers at those boost levels... which is clearly shows a top end that flows very well. No big valves. No big boost. No big displacement. That's why he got the big money for his work. It's all in the data. And the data doesn't come cheap. It's from years of engineering work, testing, and development. TonyG
PS: I am in no way bashing your efforts either Tony, the work you have done on your car is nothing short of amazing. Just saying that is not a possibility for 99% of the 951 crowd.
11-22-2013, 09:19 AM
#93
I still feel that the biggest issue with the port is those valve guides and material around it, in the picture with the red, I'd remove that material, cut down that guide and you really can open up that port, as it is now, your gonna get some vacuum behind the valve and swirl, so the back half after the guide isn't really flowing well. But again I'm no pro and we will find out soon what the best flow is
11-22-2013, 11:34 AM
#94
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11-22-2013, 12:58 PM
#95
Rennlist Junkie Forever
Understood and agreed.
As far as secrecy goes... I think it's more about protecting a specific design from being copied. I this case a port shape. And people have spent a lot of time and money finding the port shape that works for them and don't want to simply give it away. Their business model is to sell that design. So what you're paying for is a copy of that design, which is based on their investment in R&D.
The saying goes... "it's all about the data....". That holds true for all aspects of race car development.
That said, I think it's great the people are here doing their own development work irrespective of their financial status. The ability to do your own R&D makes it all that much more rewarding in the end.
Concerning the JME head: I never did any testing on the JME head that I purchased. But I do know it had stock 951 valves and was based on a N/A core. And based on the fact that it made so much power at such low boost levels indicates that certainly flowed well. The point being that a N/A core is probably the place to start and that you don't necessarily need larger than stock valves to make great power.
TonyG
As far as secrecy goes... I think it's more about protecting a specific design from being copied. I this case a port shape. And people have spent a lot of time and money finding the port shape that works for them and don't want to simply give it away. Their business model is to sell that design. So what you're paying for is a copy of that design, which is based on their investment in R&D.
The saying goes... "it's all about the data....". That holds true for all aspects of race car development.
That said, I think it's great the people are here doing their own development work irrespective of their financial status. The ability to do your own R&D makes it all that much more rewarding in the end.
Concerning the JME head: I never did any testing on the JME head that I purchased. But I do know it had stock 951 valves and was based on a N/A core. And based on the fact that it made so much power at such low boost levels indicates that certainly flowed well. The point being that a N/A core is probably the place to start and that you don't necessarily need larger than stock valves to make great power.
TonyG
Tony: From conversations with Shawn I knew this is only the beginning. He is not just cross sectioning a head for display. He is going to attempt to educate people on what needs to happen to make improvements to the intake tract and document everything with pictures. While he might not achieve levels obtained by JME or MM, at least he is sharing. 20 years ago, I could understand all the secrecy, but not now. I think you missed the point of my post. I applaud Shawn for the effort, whether good or bad. Shawn is extremely sharp, my money would be on him to succeed. How many other people do you know that whipped up a custom home garage flow both controlled by a hand built and self programmed control circuit? Not everybody has a ton of cash (like you) making it possible to buy the best of everything. IMHO, what he is going to do here on a relatively limited budget is amazing. Keep up the good effort Shawn!
PS: I am in no way bashing your efforts either Tony, the work you have done on your car is nothing short of amazing. Just saying that is not a possibility for 99% of the 951 crowd.
PS: I am in no way bashing your efforts either Tony, the work you have done on your car is nothing short of amazing. Just saying that is not a possibility for 99% of the 951 crowd.
11-23-2013, 09:48 PM
#96
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11-23-2013, 11:01 PM
#97
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FWIW, I am finding Shawn's project fascinating reading. Thx for doing such a thorough job of documenting everything and thx to all the other you have provided additional experience and insight. Although much of it is a bit over my head I have been learning so much from following/reading all the posts/threads related to this project.
11-26-2013, 06:29 AM
#98
http://www.pistonheads.com/GASSING/t...+jobs%3F&mid=0
From that reading it appears to me, that getting an ultra high flow head is serious science and a bit more than just working with a dremel. Without the proper knowledge you can screw it up easily or at least most of the efforts are in vain. This explains to me, why some people say headwork on a 944/951 is not worth the effort. Probably they didn't get it right.
I'm sure if done properly, the gains should be huge. I can't imagine, that the over 30 years old valve-/intake-/exhaust design of the 994-heads can't be improved.
Keep us up to date with your project.
11-26-2013, 08:04 AM
#99
Race Car
....getting an ultra high flow head is serious science and a bit more than just working with a dremel. Without the proper knowledge you can screw it up easily or at least most of the efforts are in vain. This explains to me, why some people say headwork on a 944/951 is not worth the effort. Probably they didn't get it right.
I'm sure if done properly, the gains should be huge. I can't imagine, that the over 30 years old valve-/intake-/exhaust design of the 994-heads can't be improved.
I'm sure if done properly, the gains should be huge. I can't imagine, that the over 30 years old valve-/intake-/exhaust design of the 994-heads can't be improved.
ANyway, the 2V head from the 944 had the best flow coefficient of any head in production for a long, long time. Mostly because of the shape of the head, and the height it allowed. While the iron heads in American V8's up through the 80's would respond well to any idiot porting them, the 944 head was so much better that it does indeed take someone who knows what they are doing to get improvement. The single biggest mistake people make is to think that bigger is better, and they end up making the short side radius smaller, which leads to separation, and a loss of flow.
11-26-2013, 08:22 AM
#100
67King,
thanks for the info.
for them who're guessing what the abbr. CFD stand for.
CFD: Computational fluid dynamics, a branch of fluid dynamics (Wikipedia)
Well, I had to look it up
thanks for the info.
CFD: Computational fluid dynamics, a branch of fluid dynamics (Wikipedia)
Well, I had to look it up
11-26-2013, 08:54 PM
#101
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Thread Starter
FWIW, I am finding Shawn's project fascinating reading. Thx for doing such a thorough job of documenting everything and thx to all the other you have provided additional experience and insight. Although much of it is a bit over my head I have been learning so much from following/reading all the posts/threads related to this project.
Shawn, thanks for sharing your project. May be this link below could be interesting for you. The guys from PistonHeads were discussing 3/5/7 angle valve jobs and head porting.
http://www.pistonheads.com/GASSING/t...+jobs%3F&mid=0
From that reading it appears to me, that getting an ultra high flow head is serious science and a bit more than just working with a dremel. Without the proper knowledge you can screw it up easily or at least most of the efforts are in vain. This explains to me, why some people say headwork on a 944/951 is not worth the effort. Probably they didn't get it right.
I'm sure if done properly, the gains should be huge. I can't imagine, that the over 30 years old valve-/intake-/exhaust design of the 994-heads can't be improved.
Keep us up to date with your project.
http://www.pistonheads.com/GASSING/t...+jobs%3F&mid=0
From that reading it appears to me, that getting an ultra high flow head is serious science and a bit more than just working with a dremel. Without the proper knowledge you can screw it up easily or at least most of the efforts are in vain. This explains to me, why some people say headwork on a 944/951 is not worth the effort. Probably they didn't get it right.
I'm sure if done properly, the gains should be huge. I can't imagine, that the over 30 years old valve-/intake-/exhaust design of the 994-heads can't be improved.
Keep us up to date with your project.
It has historically been an art, but with the prominence of CFD, it is now very much a science. Had a friend who won a bet while working on head design at Ford. The old guys who said it was an art could do whatever they wanted to a head and port. Todd designed a production one - as cast. Todd's had better flow numbers.
ANyway, the 2V head from the 944 had the best flow coefficient of any head in production for a long, long time. Mostly because of the shape of the head, and the height it allowed. While the iron heads in American V8's up through the 80's would respond well to any idiot porting them, the 944 head was so much better that it does indeed take someone who knows what they are doing to get improvement. The single biggest mistake people make is to think that bigger is better, and they end up making the short side radius smaller, which leads to separation, and a loss of flow.
ANyway, the 2V head from the 944 had the best flow coefficient of any head in production for a long, long time. Mostly because of the shape of the head, and the height it allowed. While the iron heads in American V8's up through the 80's would respond well to any idiot porting them, the 944 head was so much better that it does indeed take someone who knows what they are doing to get improvement. The single biggest mistake people make is to think that bigger is better, and they end up making the short side radius smaller, which leads to separation, and a loss of flow.
11-27-2013, 04:09 AM
#102
As for the CFD. From my amateurish point of view.
It would be interesting if someone could pick up a laptop and copy of some decent CFD software on it and compare the given 944 head with the computerized CFD results.
Anyone here who could do that?
It would be interesting if someone could pick up a laptop and copy of some decent CFD software on it and compare the given 944 head with the computerized CFD results.
Anyone here who could do that?
12-03-2013, 12:50 AM
#103
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Thread Starter
Reworked the flow bench and made several software improvements. The bench is now giving very consistent and accurate results. I have compared results with a Superflow at 28" WC and the results are pretty much dead on 
I will be posting some stock head numbers in the next few days. Had to add a MAF flow straightener and extend the piping a bit and make several software improvements (low pass filter, sample averaging, temperature compensation) to get the MAF readings consistent. Rogue gave me a lot of great input and it is much appreciated.
I will be posting some stock head numbers in the next few days. Had to add a MAF flow straightener and extend the piping a bit and make several software improvements (low pass filter, sample averaging, temperature compensation) to get the MAF readings consistent. Rogue gave me a lot of great input and it is much appreciated.
12-03-2013, 02:14 PM
#105
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Great work Shawn looking good! Looking forward to the results, flying out in a few hours be back in three weeks, maybe you will have some results by then.