Camshaft discussion: CFM requirements by RPM.
#302
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Originally Posted by Cstraub
Black,
Your welcome. J-rod, that is the first time I have ever seen Ed give any "specs" out. You better mark this day.
Chris
Your welcome. J-rod, that is the first time I have ever seen Ed give any "specs" out. You better mark this day.
Chris
Well...
There's a few times where I get weak...
BTW... nothing from Watson Racing yet...
Why is it your customers are slow paying???
Ed
#303
6600 rpm clutch dump of death Administrator
Originally Posted by Cstraub
Black,
Your welcome. J-rod, that is the first time I have ever seen Ed give any "specs" out. You better mark this day.
Chris
Your welcome. J-rod, that is the first time I have ever seen Ed give any "specs" out. You better mark this day.
Chris
Ed, and Chris both. Thank you both for your input. Hopefully discussions like this will help folks think about more than just LSA.
I do think its interesting though...
Chris:
233 Int.
229 Exh.
Max HP at 6100 will pull till 6500
Max Torque at 4300
Ed:
.585" Int - .575" Exh
232* Int - 234* Exh @ .050"
111* LSA - 110* ICL
Of course depending on lobes design and rocker ratio, these could be identical cams.
#304
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Beast,
for the Absolute LS6 2.75 head listed above that flows 294 cfm at .600, my ghetto math says the following...
383/2*6800 divided by 1728 = 753 cfm needed
753/8 is 94.2 per cylinder
to get 94.2 in per cylinder with 294 of flow w/intake
94.2/294 = .320 out of 720 degrees of rotation
720*.320 = 230.4 degress of intake duration
~230.4 of intake duration which is actually smaller than most 383 use. Of course very few heads can flow like Jay's or TEA's.
for the Absolute LS6 2.75 head listed above that flows 294 cfm at .600, my ghetto math says the following...
383/2*6800 divided by 1728 = 753 cfm needed
753/8 is 94.2 per cylinder
to get 94.2 in per cylinder with 294 of flow w/intake
94.2/294 = .320 out of 720 degrees of rotation
720*.320 = 230.4 degress of intake duration
~230.4 of intake duration which is actually smaller than most 383 use. Of course very few heads can flow like Jay's or TEA's.
#306
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Damn those numbers at .050" are a bitch....just can't tell what is going on.
Thanks for participating Ed and Chris. It is greatly appreciated.
Maybe our next conversation should be a discussion on how poor of a performance metric horsepower is....
Thanks for participating Ed and Chris. It is greatly appreciated.
Maybe our next conversation should be a discussion on how poor of a performance metric horsepower is....
#310
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This will get you the velocity and acceleration curves, the cfm is fairly easy after that.
You can see how it is much easier to do in an application...
You can see how it is much easier to do in an application...
#313
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Originally Posted by 99 Black Bird T/A
Looks simple enough to crunch.
What does each of the variables stand for? I'm guess r is radius but have no idea bout b,w, t etc.
Thanks
What does each of the variables stand for? I'm guess r is radius but have no idea bout b,w, t etc.
Thanks
#314
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Originally Posted by 99 Black Bird T/A
Beast,
for the Absolute LS6 2.75 head listed above that flows 294 cfm at .600, my ghetto math says the following...
383/2*6800 divided by 1728 = 753 cfm needed
753/8 is 94.2 per cylinder
to get 94.2 in per cylinder with 294 of flow w/intake
94.2/294 = .320 out of 720 degrees of rotation
720*.320 = 230.4 degress of intake duration
~230.4 of intake duration which is actually smaller than most 383 use. Of course very few heads can flow like Jay's or TEA's.
for the Absolute LS6 2.75 head listed above that flows 294 cfm at .600, my ghetto math says the following...
383/2*6800 divided by 1728 = 753 cfm needed
753/8 is 94.2 per cylinder
to get 94.2 in per cylinder with 294 of flow w/intake
94.2/294 = .320 out of 720 degrees of rotation
720*.320 = 230.4 degress of intake duration
~230.4 of intake duration which is actually smaller than most 383 use. Of course very few heads can flow like Jay's or TEA's.
#315
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Originally Posted by 99 Black Bird T/A
Beast,
for the Absolute LS6 2.75 head listed above that flows 294 cfm at .600, my ghetto math says the following...
383/2*6800 divided by 1728 = 753 cfm needed
753/8 is 94.2 per cylinder
to get 94.2 in per cylinder with 294 of flow w/intake
94.2/294 = .320 out of 720 degrees of rotation
720*.320 = 230.4 degress of intake duration
~230.4 of intake duration which is actually smaller than most 383 use. Of course very few heads can flow like Jay's or TEA's.
for the Absolute LS6 2.75 head listed above that flows 294 cfm at .600, my ghetto math says the following...
383/2*6800 divided by 1728 = 753 cfm needed
753/8 is 94.2 per cylinder
to get 94.2 in per cylinder with 294 of flow w/intake
94.2/294 = .320 out of 720 degrees of rotation
720*.320 = 230.4 degress of intake duration
~230.4 of intake duration which is actually smaller than most 383 use. Of course very few heads can flow like Jay's or TEA's.
#316
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I have a 2000 v6 camaro A4
Heads with intake might flow say 170ish, the max ive seen or heard ported heads for my car flow 235-240ish with no intake
from the getto math I came up with
(231ci/2)*6200rpm/1728= 414cfm
414/6 cylinders= 69cfm per cylinder
69/170 cfm(head flow)= .405
.405*720= 292 duration
that would be a huge cam
unless my head flow numbers were off by over 50cfm more which I know cant be
anyone know whats wrong (besides missing 2 cylinders)?
ohh yea lift is limited to about .520 with stock heads
Heads with intake might flow say 170ish, the max ive seen or heard ported heads for my car flow 235-240ish with no intake
from the getto math I came up with
(231ci/2)*6200rpm/1728= 414cfm
414/6 cylinders= 69cfm per cylinder
69/170 cfm(head flow)= .405
.405*720= 292 duration
that would be a huge cam
unless my head flow numbers were off by over 50cfm more which I know cant be
anyone know whats wrong (besides missing 2 cylinders)?
ohh yea lift is limited to about .520 with stock heads
Last edited by jmorgan; 05-08-2004 at 03:00 PM.
#317
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Originally Posted by J-Rod
I am, I am.
Ed, and Chris both. Thank you both for your input. Hopefully discussions like this will help folks think about more than just LSA.
I do think its interesting though...
Chris:
233 Int.
229 Exh.
Max HP at 6100 will pull till 6500
Max Torque at 4300
Ed:
.585" Int - .575" Exh
232* Int - 234* Exh @ .050"
111* LSA - 110* ICL
Of course depending on lobes design and rocker ratio, these could be identical cams.
Ed, and Chris both. Thank you both for your input. Hopefully discussions like this will help folks think about more than just LSA.
I do think its interesting though...
Chris:
233 Int.
229 Exh.
Max HP at 6100 will pull till 6500
Max Torque at 4300
Ed:
.585" Int - .575" Exh
232* Int - 234* Exh @ .050"
111* LSA - 110* ICL
Of course depending on lobes design and rocker ratio, these could be identical cams.
(@.050)
Intake Duration - ID 234/.588
Exhaust Duration - ED 230/.582
Lobe Center Angle - LCA 111
Intake Centerline - ICL 109
This was before the experts posted theirs. "I'm learnding"
#318
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Originally Posted by 99 Black Bird T/A
Looks simple enough to crunch.
What does each of the variables stand for? I'm guess r is radius but have no idea bout b,w, t etc.
Thanks
What does each of the variables stand for? I'm guess r is radius but have no idea bout b,w, t etc.
Thanks
#319
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Originally Posted by critter
Black Bird and Carvinta - you can find answers here. Rollins gives the derivation and tells what the variables are. Good stuff.