[steve25]

From what I can tell Stan from going over all those numbers from that article it seems like they are all over the place !
Just look at the peak flow of the intake test done on the 6X head.

It’s said that it flowed 167 cfm.
At 28” I know they flow between 205 and 210.

If you go to convert that 167 and use the conversion for a test at 15” you end up with 228 cfm which is way too high.

Then if you use the conversion for a test at 20” ( 1.18 ) your result is 197 cfm which is too low.

If you use the 1.06 conversion to go from 25” to 28” then that’s only 177 cfm .
So you be the judge!

[Stan Weiss]

Originally Posted by steve25

From what I can tell Stan from going over all those numbers from that article it seems like they are all over the place !
Just look at the peak flow of the intake test done on the 6X head.

It’s said that it flowed 167 cfm.
At 28” I know they flow between 205 and 210.

If you go to convert that 167 and use the conversion for a test at 15” you end up with 228 cfm which is way too high.

Then if you use the conversion for a test at 20” ( 1.18 ) your result is 197 cfm which is too low.

If you use the 1.06 conversion to go from 25” to 28” then that’s only 177 cfm .
So you be the judge!

Steve,
Thanks. That is why I ask. I could never get a good read from trying to compare his numbers to other numbers what his depression was.

Stan

[johnta1]

In Pete's article he states it was 12"/H2O measured at.

[steve25]

John if one uses the accept conversion of 1.53 to go from 12” to 28” then that same 167 cfm jumps up to 255 cfm, very wrong!

[steve25]

Just to be clear about all this, once Dave started working and learning from Pete they had a SF600 bench and did test at 25”.

The numbers from the HPP shoot out where done on the flow bench of the specialized motor service shop which was a home built bench so to speak.

As I understand it Jerry the owner has closed up and retired.

The flow numbers in that HPP shoot out is still a valid comparison within itself, but that’s it!

[mgarblik]

When Pete was working on his porting VHS video, he used my Edelbrock heads for part of the vid. I flew out to Riverside, CA and spent about 10 days in sunny CA. It was a fantastic experience spending time with him and his friends. They had a Superflow 600 bench at that time with standard Brazinski fixtures, radius intake plate and no pipes for the exhaust. Their test pressure was 25" at that time. This was the winter of 1995, I think. Having learned from him and Joe Mondello, their approach was a little different. Pete loved his dividers, templates, shaping valves and little gadgets. And of course several cigarettes going at all times. Joe Mondello had just incredible vision of where the air needed to go and how it could most easily fill the cylinder. Then he would carefully remove the obstructions with skill and precision and speed like I have never seen in my life. Operating a Dumore grinder with one hand like an electric pencil. He was not a Pontiac specialist, but could certainly produce a very nice set of heads for one. It was Mondello's vision that he wanted to share. This is why he was so involved with wet flow theory to produce a visual image of what he was seeing in his head. Probably why he and Darin Morgan were so connected for several years as well.

[Gach]

What Pete we talking about…. Pete McCarthy ?

[johnta1]

I was.

[mgarblik]

Originally Posted by Gach

What Pete we talking about…. Pete McCarthy ?

Yes, Pete McCarthy.

[Gach]

That was a great learning period…. great book too.

[Stan Weiss]

This show 167 CFM flowed at different depression would be at 28" water
12.0 255.1
12.5 249.94
13.0 245.09
13.5 240.51
14.0 236.17
14.5 232.07
15.0 228.17
15.5 224.46
16.0 220.92
16.5 217.55
17.0 214.32
17.5 211.24
18.0 208.29
18.5 205.45
19.0 202.73
19.5 200.11
20.0 197.6
20.5 195.17
21.0 192.83
21.5 190.58
22.0 188.4
22.5 186.3
23.0 184.26
23.5 182.29
24.0 180.38
24.5 178.53
25.0 176.74
25.5 174.99
26.0 173.3
26.5 171.66
27.0 170.06
27.5 168.51
28.0 167

Stan

[steve25]

Thanks for the above Stan.

This should help a lot of folks out with there questions.

[steve25]

My best guess folks is that the flow numbers in that shoot was done between a depression of 19 to 20”.

[sdbob]

Thanks Steve. One set of nos 73-74 SD heads I bought where from H O Racing back in mid 70s. They had more than one set for sale. At the time I figured they bought several nos sets and flowed benched them and picked the best for NHRA racing. So I'm seeing your results,thanks Steve.

[johnta1]

On the flow tests by Pete, I seem to remember that HPP had an addendum/correction about the tests, seemed it was leaking or something?
I couldn't find it in my notes, probably have to look at the mags to find it.
The tests were in 1991 so probably in 1992 issues?

It may have been talked about on some thread here on PY also I think?

I know I liked the SD heads even stock, they worked so much better than D-ports. (even at low compression)

[Stan Weiss]

Originally Posted by steve25

Just to be clear about all this, once Dave started working and learning from Pete they had a SF600 bench and did test at 25”.

The numbers from the HPP shoot out where done on the flow bench of the specialized motor service shop which was a home built bench so to speak.

As I understand it Jerry the owner has closed up and retired.

The flow numbers in that HPP shoot out is still a valid comparison within itself, but that’s it!

Steve,
Would you happen to know anything about that bench? Some home built benches are floating depression. For this reason the software I wrote with David Vizard lets the User enter a different depression for each intake and exhaust lift.

Stan

[steve25]

John, yes they noted in the flow test for each head in the shootout if the head had any valve stem leakage taking place, or seat leakage which would then produce better flow numbers.




Stan, I kinda recall that Pete did a brief review of that bench at SMS, but I forget if it was in the beginning of the shoot out article for HPP or if was in his later articles for Pontiac Enthusiast.

If I have the time tonight I will look back through the issues I have of PE, unfortunately I do not think I have the full shoot out article from HPP I only have the flow test results from those two separate shootout articles.

[PAUL K]

I believe the numbers in the HPP article were screwed up because of a mouse nest built inside the flow box. From what I understand they considered the numbers consistent for comparison but not relatable to any known test pressure.

With that being said, I think if one wanted to convert the numbers to a specific value a mathematical formula could be used based off a known number of a specific stock head.

[johnta1]

Here's a link to the test (Part I & II)


Ultimate Pontiac Head Flow


What Paul said does sound familiar.

[Skip Fix]

I thought I remembered there was a rat nest or something in the flow bench they found after the test also.