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Author
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Topic: Anything to heads but flow numbers?
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CustomFastbackCA
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Member # 1369
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posted
 
 
question pretty much says it all. My 60cc Victor Jr.s flow 300 on intake and 226 on exhaust and was just wondering how they would size up to other heads and was wondering how to compare.
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www.CustomFastbackCA.com
1995 Dinan M3 Avus Blue Metallic
1967 GT Mustang Fastback (Eleanor)
Ask questions if you have'em, anyone who thinks they're too cool, know's it all, or doesn't want to look stupid has more problems than you.
Posts: 346 | From: Santa Clara | Registered: Jun 2002
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hidnn.o.s.
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Member # 1219
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posted
I believe it is all about how they flow and then how they match up in your "current" combo.
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R.I.P. Willie G. You are missed on this forum
Posts: 15950 | Registered: Apr 2002
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JoeT
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Member # 298
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posted
velocity, CC volume, runner volume, valve angle (inline, twisted,etc.)
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1984 Ford Tempo AOD--- RIP
Posts: 6785 | From: San Jose | Registered: Jun 2001
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hidnn.o.s.
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Member # 1219
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posted
Shade, doesn't all that add up to how well and how much they flow?
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R.I.P. Willie G. You are missed on this forum
Posts: 15950 | Registered: Apr 2002
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Stimson
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Member # 51
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posted
quote:
Originally posted by shade-tree:
velocity, CC volume, runner volume, valve angle (inline, twisted,etc.)
You listed the same thing here twice ![[Wink]](wink.gif)
Smaller runner volume gives you higher velocity.
Put it this way, on a boosted car, flow is pretty much all you care about since you're making your own velocity.
On a NA car, you want the highest flowing heads for a given runner volume. For example, a head that flows 300 cfm on the intake side with 240cc runners is not very efficient. A 205cc runner volume head that flows 300cfm is efficient.
In short, flow numbers with respect to runner volume are everything.
Posts: 2373 | Registered: Jun 2000
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CustomFastbackCA
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Member # 1369
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posted
pretty sure my heads are 210cc intake ports, so I am guessing they are effecient? How do they compare to AFRs (I'll save someone the joke of saying "they don't compare" by calling you on it).
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www.CustomFastbackCA.com
1995 Dinan M3 Avus Blue Metallic
1967 GT Mustang Fastback (Eleanor)
Ask questions if you have'em, anyone who thinks they're too cool, know's it all, or doesn't want to look stupid has more problems than you.
Posts: 346 | From: Santa Clara | Registered: Jun 2002
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yellow67stang
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Member # 903
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Who cares what they compare to AFR heads. You have a head now that can still pick up another 30cfm on the intake and 20 on the exhaust if you wanted to with very little work. If you build the combo right you could have a 700hp NA small block, easy. Non streetable though. So, there is a lot of potential with your heads.
Good luck with them
Eric
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I like cars.
Posts: 371 | From: Ca. | Registered: Feb 2002
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John91coupe
CAFords OG
Member # 18
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posted
That intake runner volume (210cc) seems a bit large for the amount of flow they have. Who did the porting? Another thing to consider is what the mid lift flow numbers are, maybe even more important than max flow numbers. As the saying goes, the valve see's .400" twice during an intake cycle, and only max lift once. BTW, my TFS TW intake runners are 195cc and max flow at .600" is 314 and 240 CFM. How are your heads at .400"? Mine are 272 and 197 CFM. Just for comparison sake.
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D-2R ProCharged R302 331
1.410 60 ft.
5.784 @ 122.92 1/8
8.953 @ 155.08
MM&FF Feature June 2003
Posts: 1361 | From: Grass Valley, CA | Registered: Sep 2000
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93PONY
Mr. Valve Events
Member # 60
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posted
quote:
Originally posted by st5150:
quote:
Originally posted by shade-tree:
velocity, CC volume, runner volume, valve angle (inline, twisted,etc.)
You listed the same thing here twice
Smaller runner volume gives you higher velocity.
Put it this way, on a boosted car, flow is pretty much all you care about since you're making your own velocity.
On a NA car, you want the highest flowing heads for a given runner volume. For example, a head that flows 300 cfm on the intake side with 240cc runners is not very efficient. A 205cc runner volume head that flows 300cfm is efficient.
In short, flow numbers with respect to runner volume are everything.
Wow! Right on Sawson! This is one of your best technical posts IMO!
Let me just throw out one more thing.... Cross-section of the port also matters. This ties in with velocity.
EI, a smaller cross-section port that flows 300cfm is more efficient then a larger cross-section port that flows 300cfm. Even if the CC volume is the same.
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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John91coupe
CAFords OG
Member # 18
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posted
quote:
Originally posted by 93PONY:
Let me just throw out one more thing.... Cross-section of the port also matters. This ties in with velocity.
EI, a smaller cross-section port that flows 300cfm is more efficient then a larger cross-section port that flows 300cfm. Even if the CC volume is the same.[/QB]
Yep, that is definitely true and I see your point, especially with the TW valve being rotated toward the intake port and having a shorter runner length. It is difficult to compare apples-to-apples in this case so as usual..."the devil is in the details". My intake port has a 1262 cross section so there are a lot of variables to consider.
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D-2R ProCharged R302 331
1.410 60 ft.
5.784 @ 122.92 1/8
8.953 @ 155.08
MM&FF Feature June 2003
Posts: 1361 | From: Grass Valley, CA | Registered: Sep 2000
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JoeT
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Member # 298
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posted
Different heads are going to flow differently based on their shape and porting, it's conceivable to have a low velocity for a given cross section/volume and a high velocity for the same.
But generally speaking you can say low volume=high velocity, I was just trying to point out a list of the variables involved. ![[Whoo Whooooo!]](graemlins/woowoo.gif)
[ April 08, 2003, 03:17 PM: Message edited by: shade-tree ]
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1984 Ford Tempo AOD--- RIP
Posts: 6785 | From: San Jose | Registered: Jun 2001
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Stimson
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Member # 51
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posted
Actually 'cross section' alone gives you less info than just saying 'volume'. cross section = width X hight of the port. volume = length X hight width of the port. When you say volume, cross section is already accounted for.
For example, two heads could have the same hight and width ports, but one heads ports are longer than the other, thus having more volume and (probably) less velocity.
That Ford Muscle artical is pretty sweet.
http://www.fordmuscle.com/archives/2003/02/afr/index2.shtml
I ever noticed how the GT40X heads out flow the Edel 6037's on the exhuast side.
Posts: 2373 | Registered: Jun 2000
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CustomFastbackCA
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Member # 1369
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posted
Info that I got from Coast High where I got my heads: Stage 2 will flow 290cfm on the intake and 222 on the exhaust @ .700 lift-------at .500 lift they are 275cfm intake and 208cfm on the exhaust. They come with 2.05 intake valves and 1.600 exhaust valves. Here's my cam: 
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www.CustomFastbackCA.com
1995 Dinan M3 Avus Blue Metallic
1967 GT Mustang Fastback (Eleanor)
Ask questions if you have'em, anyone who thinks they're too cool, know's it all, or doesn't want to look stupid has more problems than you.
Posts: 346 | From: Santa Clara | Registered: Jun 2002
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FasterDamnit
Bad Attitude
Member # 442
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posted
The chebby NASCAR SB2 heads and the LS1 heads have tall skinny "Cathedral window" shaped intake ports that make a small cross section at the roof, where you want that big velocity. So by playing w/ the port shape, you can have velocity that is not directly tied to volume. Obviuosly that shape works pretty well. Ahh, to have a flowbench and stereo lithography at my disposal. I would love to play w/ empirical testing of all kinds of head and intake stuff.
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'92 LX T5
Looked stock, went 11's 11.90 at 115mph.
'65 Mustang 347
www.fordmuscle.com
Livin' in the Carolina Pines
Posts: 2971 | From: NorCal | Registered: Sep 2001
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FasterDamnit
Bad Attitude
Member # 442
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posted
quote:
Originally posted by st5150:
For example, two heads could have the same hight and width ports, but one heads ports are longer than the other, thus having more volume and (probably) less velocity.
Well, not entirely. If you move the same mass of air thru a 1" diameter by 4" pipe at 14psi (differential w/ the output side of the pipe), and then do that w/ one that is 1/4" diameter by 16" at 14psi, which one will have the higher velocity at the exit?
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'92 LX T5
Looked stock, went 11's 11.90 at 115mph.
'65 Mustang 347
www.fordmuscle.com
Livin' in the Carolina Pines
Posts: 2971 | From: NorCal | Registered: Sep 2001
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Stimson
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Member # 51
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posted
Either way, how does calculating the volume not take in to account the 'cross section' ?
I think we're getting off topic and nit picking over a trivial detial ![[burnout]](graemlins/burnout.gif)
Posts: 2373 | Registered: Jun 2000
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FasterDamnit
Bad Attitude
Member # 442
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posted
quote:
Originally posted by st5150:
Either way, how does calculating the volume not take in to account the 'cross section' ?
I think we're getting off topic and nit picking over a trivial detial
Becuase simply calculating the volume does not take into account the shape of the port. Until very recently, most intake ports were pretty close in their overall shape. But the examples I cited are a departure and show that if you simply knew the volume w/out knowing about the changes to the shape, you would not correctly predict the velocity, hence the mass of air able to flow thru the port.
Posts: 2971 | From: NorCal | Registered: Sep 2001
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93PONY
Mr. Valve Events
Member # 60
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posted
For a second there I actually thought st5150 'got it'.
Ah well.....guess I have to try harder...
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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Stimson
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Member # 51
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posted
Jim- "simply calculating the volume does not take into account the shape of the port"..... volume = area of one surface multiplied by the length. I still don't see how this has nothing to do with the shape of the port. It actually has everything to do with the shape.
Shaun- I want to make a 450 rwhp beast out of my LX, can you show me how its suppose to be done "right"? ![[Big Grin]](biggrin.gif)
Posts: 2373 | Registered: Jun 2000
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93PONY
Mr. Valve Events
Member # 60
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posted
Volume = length x height x width
TW's have (by far) shorter intake runner lengths. Given the same intake CC volume as a typical 20degree in-line head, the cross-section of the TW head will be larger. Get it?
BTW, your beast will NEVER hit 450. ![[Razz]](tongue.gif)
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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FasterDamnit
Bad Attitude
Member # 442
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posted
quote:
Originally posted by st5150:
Jim- "simply calculating the volume does not take into account the shape of the port"..... volume = area of one surface multiplied by the length. I still don't see how this has nothing to do with the shape of the port. It actually has everything to do with the shape.
What shape? Cylinder? Trapezoidal? Cubic? Tesseract? Still blind?
Make a port that is basically a conventional squarish cubic form w/ the same volume as the SB2 intake port. Put in the same size valve. Which one wil flow better and make more power?
Shape matters a LOT. And you can't define that w/ simply gving "volume = area of one surface multiplied by the length."
Posts: 2971 | From: NorCal | Registered: Sep 2001
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JoeT
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Member # 298
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posted
quote:
Originally posted by 93PONY:
Volume = length x height x width
really? your ports are perfect rectangles?
I would say in the real world a rectangle with eliptical edges is a better cross section.
nitpick all you want but cross section is simply one detail, it's not constant, and "volume" does not already include it because there are infinite possibilities for an intake runners shape given a specified volume.
and where do we calculate the cross section? entry? exit? short side radius? in the combustion chamber? lol.
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1984 Ford Tempo AOD--- RIP
Posts: 6785 | From: San Jose | Registered: Jun 2001
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Stimson
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Member # 51
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posted
Actually volume does include the cross section regardless of shape. Triple intergrals.... its just the sum of the boundries set on the X and Y axis for Z length. 3-D stuff is just impossible to explain on a 2-D message board, I'm gonna forfeit the match and get some real work done
Of course this way of calculating volume takes a very long time for irregular shapes.
I'd say this is damn hard to explain online, but a very easy concept to explain with pen and paper in real life.
Joe brings up a good point about where you measure cross section.... that's the Newtonian way of looking at things. I likes ![[patriot]](graemlins/patriot.gif)
The real question is.... how much more RWHP is a 99 cent bag of ice worth compared to minor nit picking of port size?
Posts: 2373 | Registered: Jun 2000
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93PONY
Mr. Valve Events
Member # 60
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posted
Good points guys.
I was just trying to make things simple & easy for the regular board folk.
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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