Cstraub

iTrader: (1)

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

Ed Curtis

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

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.

99 Black Bird T/A

iTrader: (4)

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.

99 Black Bird T/A

iTrader: (4)

Wow Ed actually gave us a number of a cam....I'll mark this in my calander too Chris & J-Rod.

DenzSS

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....

Cstraub

iTrader: (1)

Glad I could input. Duration needs to be address from the seat duration all the way up the lobe. By selecting lobes that compliement the heads, a well balanced combinaton can be had by the end user.

Chris

J-Rod

DenzSS - Where is that math you promised us?

DenzSS

Doh. I'll get the equation written out this weekend.

DenzSS

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...

SScam68

iTrader: (20)

thats a nasty derivative

99 Black Bird T/A

iTrader: (4)

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

lsx24

iTrader: (45)

Yes, and sorry if I missed it inside the calculations but all are a function of t, but what do the 3 calulate in relation to t?

Beast96Z

iTrader: (21)

But as you can see, you had to add the larger heads to get the formula to work. If a person where stuck with poorer flowing heads, such as the heads in the first equation (275 w/intake) the cam would have to be in the 250* range according to the math. Then again, what about more CI eating up camshaft? Now we have a 383 with less camshaft than the 346. Can you guys hit on adding CI to the mix? I'd like to see how that factors into the equation.

verbs

Using your ghetto math I cam up with about a 218 intake duration for my car LOL!!

jmorgan

iTrader: (3)

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

BADFNZ

iTrader: (19)

The cam I came up with for this situation was:

(@.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"

critter

iTrader: (9)

Black Bird and Carvinta - you can find answers here. Rollins gives the derivation and tells what the variables are. Good stuff.

lsx24

iTrader: (45)

That's impressive. That'll take another couple mods to digest.

jrp

iTrader: (16)

this thread is , great info.