[steve25]

Here’s some results from testing 5 of the ports .

4 of the 5 where on the shallow plenum side and 1 runner tested on the deep plenum.

The runner I tested on the deep plenum was one of the two that has no line of sight with the plenum when viewed from the flange.

Runner 1 and 7 looked to me like they would flow the same.

Don’t beat me up for not testing all 8 ports because anyone who has flow tested an intake knows what a flat out major PIA it is and how time consuming it is.

Just making an adapter to clamp to the flow bench and allows the intake to be bolted on, and that works for both the drivers and passenger side of the intake is a 2 hour job!

Here are the flow results @ 28”, and this was with no Carb bolted on.

Runner 8. 272

Runner 2. 269

Runner 3. 269

Runner 5. 300

Runner 1. 271

I also checked the runner height dimensions at the flange and what they neck down to at the point where a major change in size takes place.

All of the runners at the flange are 2.10” tall.

1. 1.850”
3. 1.948”
5. 1.946”
7. 1.850”
2. 1.755”
4. 1.815”
6. 1.858”
8. 1.752”

[RocktimusPryme]

Is the big discrepancy for #5 abnormal, or is that built into the pontiac design?

Alternatively, is it common on either other brands of aftermarket intakes or factory intakes to have ranges that large between ports?

[steve25]

It’s normal for a tall aftermarket duel plane like this which has been cast with more gradual area transitions and bigger radius bends.

In off the shelf form this intake should support 535 to 540 hp, with a 1” or better spacer I would guess that up to 560 hp could be made.

[Steve C.]

Refreshing to see testing done like this, and as eluded to it is a lot of work.
Good job !

As an example briefly take note the amount of work done here in similar testing by Rocky Rotella:

https://www.hotrod.com/how-to/hppp-0...ntake-manifold

Regarding the comment the testing done with no Carb bolted on.

Here is some information that that I brought up in a similar thread that has a tid bit on how the carb might affect results.....

Head flow and the intake manifold are interconnected. The intake effects the total air flow, as does the carb.

Rocky Rotella had some articles published in High Performance Magazine that involves the subject of total air flow thru the intake system. In conjunction with the article he tested the Performer RPM intake as cast on a stock SD-455 cylinder head that flowed an average of 237 cfm at .550" lift. Flow bench tested the RPM intake was just over 92 percent with the SD head. If the percentages stay true as flow goes up, you need head flow in the 260 cfm range to get 240 cfm into the engine. He also tested the flow through carburetors. His Holley HP950 and a Cliff Ruggles modified QJ reduced flow by about another 5 percent. If the QJ is stock, the reduction can be as much as 7 percent depending on the angle of the secondary air valves.

Anyway we can see it can get very involved when you consider the impact of the intake manifold and carb on total airflow.


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[Half-Inch Stud]

Real nice data, thanks!
Yes, PIA to prep a measure.

I went hobo and just go for port noise, and Relative manometer reading. Never got going for cfm calcs because the depression is an "industry STD talking point" whereas the Intake depression range-of-need could be 12" thru 60" depending what the issue you are chasing. 28" is a nice standard though, and really matches well to PMD's 0.3" thru 0.45" stall=choke mode. That which is more evident with noise.

So, great to see a dual-plane measure ( big deal). My efforts with single-plane were boring as the noise was always low when the heads were free of the pushrod bulge. No noise means no learning of a problem. As-if no flow problem. Yet the brain knows 2 robs 1 & 7 robs 5 on Street use. So the alternative is..low-noise choke-free Dual-planes rock!

[Half-Inch Stud]

Question on the Speedmaster manifold test adaptor method: was there a head involved, or some sort direct CYL dump, or some sort of ideal port mold?

I think every manifold has 4 runners with opportunity to enhance a Head stall, while the other 4 runners don't induce stall, for a head with a pushrod-bulge propensity to stall/choke flow. This is basic, but needs socialized.

[steve25]

Steve.C , yes I wish I had a Q-jet to bolt on for the flow testing because I am sure that as normally takes place the shallow Plenum flow number I got would have been reduced some, at least on the runners that feed off of the rear of the Plenum.

Half-Inch-Stud
My adapter plate I made allowed the manifold runners to flow into a 4.250” cylinder bore adapter.

[Half-Inch Stud]

Originally Posted by steve25

.....My adapter plate I made allowed the manifold runners to flow into a 4.250” cylinder bore adapter.

A range of probable discharge coefficients could be assumed to show a range of higher runner flows.

[steve25]

So Half-Inch-stud given this accepted definition of “ discharge coefficient “

Please provide me with the theoretical number you think I should see in regards to the way I had my flow test set up working ?

Thanks in advance.

[i82much]

any idea how this compares to the edelbrock RPM or a T2?

[steve25]

I unfortunately have no idea about what the Edelbrock flows, but the T2 ports flow far more evenly and with a at least a 1” spacer it flows better .

[Steve C.]

RPM Intake Flow....

https://forums.maxperformanceinc.com...d.php?t=538209

With a relevant post by Rocky Rotella. He also made a comment regarding the Torker II intake.

Within the link in post #4 it mentions bolting the intake manifold to the cylinder head but it does not talk about the carburetor. Ideally it should include the carburetor.
It was in 2005 that Rockey mentioned to me that he tested with a carburetor and reported the reduction in flow I posted.

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[Steve C.]

Information from Jim Hand...

Average runner length:
RPM - 6.28"
Torker II - 6.06"

Average runner volume (cc):
RPM- 262
Torker II- 236

Average plenum volume (cc):
RPM- 1400
Torker II- 1195

He also lists the Flow Co-Eff on the RPM at 2.003 and the Torker II at 3.000


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[steve25]

Do you know the details as to how Jim measured those port volumes on the RPM?

Being a duel plane and the fact that on the lower plenum it’s dam hard to even see where a runner truly starts, at least on 2 out of the 4 runners I just gotta say that his numbers sound very large.

Here’s port volumes that Pete McCarthy got when testing a T2 back in late 94.

[Steve C.]

For the Edelbrock Performer RPM intake.

On the paperwork Jim lists the length for each individual runner. Since the port openings at the flange are the same (1.16" w x 2.18" w) and the general shapes are similar, he can proportion the runner volumes based on this.
On the paperwork I have on hand he lists the lengths and volume for each individual runner.

At least this is they way I understand it. And I have no clue as to how he did the measuring.

He also lists the Dia-Area at 1.74
And the runner dimensions at plenum - Width 1.48 / Height 1.93
Runner taper 4.18

For the plenium volume (cc) it is listed as this:
Vol 667
Vol 733
Total 1400

He provided me with similar material for the Torker II intake.

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[Steve C.]

I just took a look in the intake section of Jim Hands Pontiac book.

Jim and Rockey Rotella did a lot of this work together. Some, but not all, of this work presented here by me is listed in his book. Also a few tid bits of it in Rocky's Pontiac book.

A tid bit from Rocky.......

He measured the airflow capacity of many Pontiac intake manifolds on his flow bench.

https://www.pontiacdiy.com/wp-content/uploads/125.jpg

[P@blo]

Thanks for testing Steve25. Tom Vaught flowed an RPM through 300 cfm E-heads and the intake reduced flow by 3% or down to 291 cfm. Pretty close to what you saw on your results. One thing the SM intake does not duplicate the machined pattern at the bottom plenum. Not a deal breaker at $173 though but still wanted to mention it. Also,the SM high-rise HSD copy states the manifold supports 300 cfm heads. My hope is the mid-rise 6.5" tall RPM copy will support more cfm than that. Not sure why SM calls the taller RPM intake mid and the HSD high-rise?

https://forums.maxperformanceinc.com/forums/showpost.php?p=3073010&postcount=33

Steve C, reading your old posts about the different intakes available for our Pontiacs and how they perfomed on your engines was very informative. Thanks for that and have to say that you might be our resident intake guy

[steve25]

Tom flowed the Edelbrock rpm, or the SM?

[Steve C.]

Regarding the Speedmaster statement about their HSD copy supporting 300 cfm heads.

Maybe a clue....

That intake was developed and brought to market by Ken 'Ace' Brewer at Pacific Performance Racing back in 2005 with input from Dave "Big Injun" Anderson.
They named it the Tomahawk and Professional Products was the manufacturing partner at the time.

Their product literature stated "The Tomahawk Intake Manifold is designed to work with any cylinder head up to 300cfm"
They were talking about a 'AS CAST' Tomahawk with no port work.

I purched one from Ace and had it ported. That was the intake for my testing.

EDIT- The original PPR Tomahawk intake was based on a Holley Street Dominator intake modified by Dave Bisschop with plenum and runner work.
Except when desighed by PPR the Tomahawk 'as cast' for marketing reasons did not have the large port exit openings in order to be used on 'factory' cylinder heads.

P@blo
Thanks for the compliment.
For the most part my intake testing has been done during dyno testing of various engine combinations over the years.
But it's been said you don't race dyno's. The dyno results may not reflect track results.


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[Steve C.]

Some years ago I flowed a set of edelbrock heads with minimal intake port work that flowed 300 cfm at 28" of water on a SF 1200 bench that was calibrated to be within 1% of Ford's 3 million dollar bench.

http://www.flowsystemsinc.com/index_products.htm Then click on automotive then on Intake and exhaust manifold and cylinder head.

That being said, the VICTOR 850 Intake flowed within 1% of the head and the Victor 1050 flowed with-in 2%. The RPM was with-in 3% of the head. 97% times a 300 cfm head is a 297 cfm Intake. A Pretty Good Intake.

I also flowed a lot of other heads and intakes over a two day period. The Torquer II flowed about 262 cfm.

Tom V.

Source- post #33 here:
https://forums.maxperformanceinc.com...291+cfm&page=2


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