Decipher flow chart?

[bnsfmachinist]

Happy 4th of July boys!

Looking for a bit of help deciphering this flow chart I have for my D1AE-GA 351C heads. This port/polish/flow work was done by Air Flow Research in 1982 for my father and the heads have come into my possession and I'm running them now. I've always wondered what these figures mean because I've never seen a flow chart like it. Hand written on it says 400cfm on intake side and 300 on exhaust side. I would assume that was measured at the given max lifts on the chart? .700 and .600 respectively? If that's so, then what do all these other numbers at different lifts represent?

I figured it would be work wise to understand this chart for when the day comes I want a custom grind cam! Hope somebody out there knows what we're looking at!

[kansas stocker]

I'm thinking that the numbers in the chart are percentages of the 300 and 400 disks in the flow meter. Just my guess.
Pete

[bnsfmachinist]

Interesting theory! I can't dispute it, but if the represent percentages, then that would reflect less than "advertised" (if you will) flow at those lifts on the given valve?

[ss3011]

Originally Posted by kansas stocker

I'm thinking that the numbers in the chart are percentages of the 300 and 400 disks in the flow meter. Just my guess.
Pete

I agree, it is a typical SuperFlow sheet .

[bnsfmachinist]

Okay cool, I like to hear the word "typical" in a discussion about this type of thing.

So how specifically does one read it? Does info on the sheet (other than written 400/300cfm) reflect 400cfm (INT) and 300cfm (EXH)? I guess I'm looking for a baseline.

Are we looking at something that demonstrates: 400cfm was supplied on the intake side and the flow rate was 85% of 400cfm at .700 lift?

I suppose long story short is, how do I relatively accurately, translate the numbers on this sheet into CFM flow rates at specific lifts.

I may be reading too deep into this, if it's a typical flow sheet I suppose I could supply to a cam grinder and they'd know exactly what they're looking at?

Other than that, it's to satisfy my curiosity as someone who is new to this world. Thanks guys so far, look forward to more insight!

[ss3011]

There isn't enough information on the sheet to know the exact flow . A few missing numbers are , Temperature , and the test pressure . Typically the test pressure is 28" , but some flow benches won't pull that depression, so lower depressions are used then scaled to 28" for comparison . Temperature is used to create a correction factor, and there maybe other things that I am forgetting that contribute to that correction . So the best you can do with your sheet is to multiply each test point by the percentage and create a graph of Lift vs. Flow , for the Intake and Exhaust . So as an Example for the Intake , you would multiply 400 x 70% = 280 cfm .

[V M Kauffman]

To make anything out of this flow sheet you also need
1. Bore size of the cylinder head fixture
2. Was there a radius intake flow entry
3. Was there a exhaust pipe on exhaust and was head turned around
4. What was actual flow for the 400 scale
5. Was air speed checked
Just some of the items you need

[CFMCNC]

Have some one reflow test the head with modern data aqusition like Superflows FlowCom.Bill C.

[bnsfmachinist]

Thanks guys for the replies. Glad to see folks out there can make heads & tails outta this flow chart!

Given the issue of missing information, I think for true accuracy's sake I'll have these heads flowed again.

[dwydendorf]

I would also assume that those numbers are the percentages of 400 cfm and 300 cfm at 28 inches respectively. I have used at least 3 superflow benches to flow the same head casting number and it is typical numbers for those heads.