[Half-Inch Stud]

Originally Posted by 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.

Assuming a sharp runner exit, centered in the 4.25" bore then 0.61 works on paper, probably not in reality. Yet 0.99 or 1.0 works in reality but not on paper.

I'd say 0.8 is defend-able. So 270/0.8. = 337 cfm

[Stan Weiss]

Originally Posted by 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”

To calculate the true CD at the above listed flanges, one would need to know what the corner radius are. That said for #1 I get 0.4778 and for number #5 I get 0.5028. This is also based on the flow / cfm being at 28" of water.

Stan

[Steve C.]

"To calculate the true CD at the above listed flanges, one would need to know what the corner radius are"

Good point and one often overlooked. I'm guilty of just doing height x width when figureing a port area.

Similar situation as forgetting the ring area when calculating a compression ratio.
Often overlooked. That tiny, hidden space between the top piston ring, the cylinder wall, and the top of the piston.

Thanks Stan.


.

[Stan Weiss]

Originally Posted by Steve C.

"To calculate the true CD at the above listed flanges, one would need to know what the corner radius are"

Good point and one often overlooked. I'm guilty of just doing height x width when figureing a port area.

Similar situation as forgetting the ring area when calculating a compression ratio.
Often overlooked. That tiny, hidden space between the top piston ring, the cylinder wall, and the top of the piston.

Thanks Stan.


.

Steve,
You are welcome.

A good example would be a round port. Let use 2".

2 * 2 = 4 sq in

(2 / 2)^2 * pi = 3.14159 sq in or only about 78.5% of the raw calculation

Stan

[Region Warrior]

Ok looks good time ster ****.
Looking trade untouched Edelbrock RPM for a Warrior intake.
Dual 4 brrl Tunnel ram even better.
3 different hoods.
Sazall baby!

[Steve C.]

Bruce doesn't like them

https://www.speed-talk.com/forum/vie...64365&start=15

And note talk about cutting them in half.

Speaking of Equal length runners ......

Warrior / Dnash
According to Jim Hand:

R1 6.50"
R3 5.00"
R5 5.75"
R7 7.25"
R2 7.25"
R4 5.85"
R6 5.00"
R8 6.25"
Avg 6.11"

Average runner volume (cc) - 233
Plenium volume (cc) - 976

As a comparsion:
Victor average runner length 6.82" / Average runner volume 346 cc / plenium volume 946 cc

Most of the fast racers that used the Doug Nash (or Warrior) single 4 intake at some point added plenum volume to the plenum. Either by cutting the bottom off and adding there or by a bunch of welding and runner raising along with the bottom modifications.
The intake needs about 40-50% more volume on a 455= engine vs the 366 engine the intake was designed for.
Tom Vaught
https://forums.maxperformanceinc.com...d.php?t=774061



.

[steve25]

Here’s an interesting intake manifold story/ lesson I learned over 32 years ago with a guys stroked 360 Mopar.

I had ported up his Brodix heads to 315 cfm from there stock 265 to 270 cfm.

With the intake he was running the car was doing low 10s in the 1/4 mile, but he wanted to dip into the 9s.

At the end of the race season he came over with a new intake the he had one run on and it got him into 9s, but now he wanted even more.

In checking out this intake I thought that the expansion rate in the runners was crazy excessive.

I added clay to reduce the expansion rate and in the process picked up 20 to 25 cfm over what the intake did stock.

I then used up two complete bricks of Moroso epoxy to neck each runner down and get the expansion rate down to about 110%.

Well he bolts the intake on, goes out to the drag strip and the turns times equal to close to 100hp loss of
power .

I was stunned to put in mildly,

After that humiliation I learned and made a way to test for port velocity.

[Steve C.]

"The engine doesn't KNOW what shape the port is unless it's totally screwed up"

Curtis
Race Flow Development
http://www.raceflowdevelopment.com





.

[slowbird]

Originally Posted by Steve C.

Bruce doesn't like them

https://www.speed-talk.com/forum/vie...64365&start=15

And note talk about cutting them in half.

Speaking of Equal length runners ......

Warrior / Dnash
According to Jim Hand:

R1 6.50"
R3 5.00"
R5 5.75"
R7 7.25"
R2 7.25"
R4 5.85"
R6 5.00"
R8 6.25"
Avg 6.11"

Average runner volume (cc) - 233
Plenium volume (cc) - 976

As a comparsion:
Victor average runner length 6.82" / Average runner volume 346 cc / plenium volume 946 cc

Most of the fast racers that used the Doug Nash (or Warrior) single 4 intake at some point added plenum volume to the plenum. Either by cutting the bottom off and adding there or by a bunch of welding and runner raising along with the bottom modifications.
The intake needs about 40-50% more volume on a 455= engine vs the 366 engine the intake was designed for.
Tom Vaught
https://forums.maxperformanceinc.com...d.php?t=774061



.

Am I reading this correct, Jim measured the Warrior plenum at 976cc vs the Victor at 946cc?

[Dragncar]

I was wondering the same thing. I have both, the Warrior looks puny in comparison. Worked great with iron heads and 2" of spacer though.

[68azbird]

Been 10.29 @ 129 with a Warrior with 3 inch spacer on a 400 with D ports back in the day.

[Steve C.]

Acording to the material Jim furnished to me and what is published in his book...

Warrior Single 4-bbl

Avg runner length 6.11"
Average runner volume (cc) - 233
Plenium volume (cc) - 976

Edit- The topic mentioned here: https://forums.maxperformanceinc.com....php?p=6219608
.

[P@blo]

So would adding a spacer to the SM mid-rise or Crosswind intake to match the RPM plenum volume change flows? I’m thinking it would be a wash at that point.

[Steve C.]

Some related conversation here....

Formula to determine plenum size
https://www.speed-talk.com/forum/viewtopic.php?t=1142

A well modified Holley Street Dominator intake can compete favorably with a Victor intake with similar port work.
You can presume the same with a Tomahawk intake.

Example....

I did some back-to-back dyno testing with the Victor intake and the Holley Street Dominator intake that was modified by Dave Bisschop with plenum and runner work.
And probably VERY similar to the prototype for the original Tomahawk intake by PPR.

The HSD intake with my HP950 carb and a 1/2" open spacer made 589.4 hp at about 5700 rpm on the dyno, this was on a previous pump gas 4.210 stroke 462cid street engine.
With the same engine & carb my Victor intake with 1/2" carb spacer made 600.9 hp at 6000 rpm.
Both intakes had a port entrance opening about 2.300" tall, and were properly port matched to the cylinder heads in use.

I know peak numbers don't express the whole story, really need to look at the HP curve.
And the same with the torque.


.

[Stan Weiss]

Originally Posted by P@blo

So would adding a spacer to the SM mid-rise or Crosswind intake to match the RPM plenum volume change flows? I’m thinking it would be a wash at that point.

Remember that the flow bench only tells you what the air is doing, unless you have wet flow bench.

Stan

[P@blo]

Thanks Stan, something to keep in mind.

I measured a SM mid-rise for height and get ~1" taller than a HSD give or take a 1/16". Keep in mind my mesurments were a little crude measuring from the bench the intake was resting on and having the coolant crossover hanging over the edge. Bench to carb pad more or less. Strange thing is the RPM is advertised as 7.5" tall and the SM says 6.5" but must measure the lower part of the water crossover I assume. No way the RPM is 1" taller? If anyone had an RPM they could measure that'd be great to confirm.


SM
front 5-7/16"
rear 5-15/16"

HSD
front 4-7/16"
rear 4-15/16"

Port openings
HSD 1.86/1.88" x 1.02/1.06
SM 2.10/2.08" x 1.10/1.15"

The runners on the SM intake are a lot better than the HSD. I suppose that is because SM uses a permanent mold process which is an improvement over standard casting. Port dividers on the HSD look like they were made by a kid in shop class or something.

[P@blo]

Another link on the original Crosswind. Note post 10.

https://forums.maxperformanceinc.com...osswind&page=2

[steve25]

Spacers add Plenum volume .

They also change the tuning length of the runners .

More volume also helps to dampen reversion pluses so air flow back into the runners restarts sooner.

More plenum height above the roof of the runners helps the air fuel mixture turn into the runners so the runner area becomes more efficient.

All of these pluses as in

Ram effect
Shock wave tuning
Better velocity gradient
Better mixture and reduced reversion

These details at times can make a 50 hp difference with 10 to 15 being a low end average.
Over square motors like the 455 with racing cam’s need a lot of plenum dampening to come on the cam sooner, no less for added high rpm hp.

[Skip Fix]

Here is a height comparison for you all of all intakes I have.
Front/rear
SR 72 HO intake 5" / 7"
Performer 5 3/8" / 6 1.2"
Holley SD 5 3/8" / 7 3/16"
Tomahawk 5 5/8" / 7"
Torker I 5 7/8" / 7"
Torker II 5 7/8" / 7 1/16"
RPM 6 9/16" / 7 13/16"
Victor 8 9/16" / 8 9/16"
M/T crossram Driver side 7 7/16" / 9 1/16"
M/t crossram Passenger 7 1/4" / 8 3/16"
SD Bathtub reproduction 7 7/16 / 9 3/8
Warrior Tunnel ram 10" / 10 3/4"
FWIW my SR HO intake the plenum depth is between what Rocky Rotella published on the 69-71 vs 72.

[Skip Fix]

Straight edge on carb pad measured at front and rear valley pan walls RAIV head on a zero decked 557 block