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intake manifold flow # vs. head flow #

ChargerST

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When does the intake manifold become the choking point on the intake side of an engine with high flow cylinder heads? Trick Flow 240s flow 310 cfm @ .500 lift and when looking at the intake flow numbers posted on the Hughes website (http://www.hughesengines.com/TechArticles/4portedintakemanifoldsupdated08272007.php) only a few manifolds can keep up. iirc the intake manifold should flow 20% MORE than the heads - that basically means hardly any manifold flows enough for the Trick Flows.
Is this correct, are the Hughes numbers wrong, does it even matter?
 
Why would it have to flow 20% more? Is that just accounting for port taper?
 
Personally, I don’t feel that flowing the manifold by itself is info that translates well to anything useful.

Flowing the head with the manifold attached is probably more useful, although I’ve done some tests where the manifold that flowed the best on the heads......wasn’t the one that made the most power.

I try and select the manifold that seems like a good match for the rest of the combo, and how it will be used.

On builds where the hp/ci is better than what the typical hot street combo puts up....... then porting the manifold can to start show some worthwhile gains.

But on something that’s barely 1hp/cu...... it’s probably not going to be a very good “bang for the buck”.

One test I did was between a big single plane vs a big dual plane, on a pretty big motor with decent heads.
Both manifolds were flow tested attached to the head, with the dual plane flowing significantly less(30-ish cfm).

The power difference on the dyno was less than the flow difference would suggest.
7ft/lbs of TQ, and 29HP....... on a 700hp motor.
 
Hey Charger,...that +20% manifold # probably based on some possible Runner wall frictional flow loss effect...Does anyone know of an affordable "virtual" Dyno product that will accurately calculate that issue + tuned runner & plenum to valve timing events on tq & hp curve ?
 
Hey Charger,...that +20% manifold # probably based on some possible Runner wall frictional flow loss effect...Does anyone know of an affordable "virtual" Dyno product that will accurately calculate that issue + tuned runner & plenum to valve timing events on tq & hp curve ?

Dynomation6 has some features doing wave action simulation that uses port cross section area, port length, taper, and plenum volume as inputs.
Not sure if you consider $500 affordable for the software?
http://www.proracingsim.com/purchasejac2.htm

Download the users manual for free. A bunch of good information is in the manual even if not using the software.
http://www.proracingsim.com/downloads/Dynomation-UsersManual.pdf
 
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I'm playing with this as we speak using a set of TF270's and a 6-Pack Eddy Intake.... Flowing as I'm Porting the Manifold attached on the Bench. I've been at it a few weeks, NOT seeing big gains, maybe 20 cfm so far opening the manifold to Max Wedge size back a good 4-5 inches in.
But then again,
I didn't see huge losses either when I began by placing a std Port Radius Inlet on the Max Wedge Port TF270's, which seemed to suggest the Losses I did see with the std Port manifold attached before Porting was indeed further into the Manifold itself.

Too early yet for any definitive answers.... but we will be Dyno'ing the Engine when done same as we always do so we'll see......
and I will try to remember to come back here, post some data from the beginning for discussion.
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Nice work Bob!!

The real test for how effective the manifold porting is, is to test it on the engine against an unmodified manifold.
 
Nice work Bob!!

The real test for how effective the manifold porting is, is to test it on the engine against an unmodified manifold.

Oh for sure !
And I may have gotten a little ahead of myself as apparently the Customer has two 6-Pack manifolds, albeit, we we only received the one.
just say'in....
I maybe should have Flowed both up front and determined 'best' to start with.
But no matter, I can Flow the other one later for comparison..... and then hopefully if Dyno time allows, bolt on the Un-Ported 2nd and see what happens ?
 
When does the intake manifold become the choking point on the intake side of an engine with high flow cylinder heads? Trick Flow 240s flow 310 cfm @ .500 lift and when looking at the intake flow numbers posted on the Hughes website (http://www.hughesengines.com/TechArticles/4portedintakemanifoldsupdated08272007.php) only a few manifolds can keep up. iirc the intake manifold should flow 20% MORE than the heads - that basically means hardly any manifold flows enough for the Trick Flows.
Is this correct, are the Hughes numbers wrong, does it even matter?
Well, if you believe Hughes outright.....

Tunnel rams are really really good....

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2C78D103-4CF2-42DF-AEF5-85B0B0EFA389.jpeg
 
Yeah judging what Dominic Thumper said after going to a TR and 2x 650's, he would never go back to 1 of his Dominators.
 
I'm interested in how well the ported six pack intake works. My buddy and I are building a 438" low deck with a flat tappet, hydraulic cam, 228/232 @ .050. I keep looking at the Performer RPM on the bench and wondering if gasket matching the ports would net any noticeable power increase. I realize to glean accurate results it would have to be flowed, ported and compared to a baseline but in lieu of that, would "just doing it" have any adverse effects?

Seems like even if a particular intake is ported there may not be any significant power increase from that alone. Am I understanding correctly that if porting picks up significant power then perhaps the combination is not matched correctly?

Also, stupid question but when you scribe lines outside the ports, how do you determine placement? Do you go by the port size of the heads? Putting a gasket down seems pretty arbitrary and inconsistent from side to side and even front to back.
 
Also, stupid question but when you scribe lines outside the ports, how do you determine placement? Do you go by the port size of the heads? Putting a gasket down seems pretty arbitrary and inconsistent from side to side and even front to back.

You hit the nail on the head regarding many manifolds, and in our experience particula
rily the performer rpm's, in that no matter when moved towards the front of the engine at least 2 ports are badly blocked at the rear opposite and towards the rear to then correct 2 ports at the front opposite seem to be way off..... if ever a manifold that needs severe correction from OOTB it would be the BB Mopar Eddy Performer rpm's in our experience anyways.

The way we port match is this
* we scribe vertical lines on the head identifying the center dividers and pinch sides of the ports
* we put the manifold on the engine/heads with Head Gskts and layers of tape to simulate the .020" thick valley pan and bolt it down.
* We then scribe along the top of the manifold putting lines on the Head landmarking the tops of the Ports
* We then landmark the Port center divider/pinch side side lines from the head onto the Intake to locate when the Port lines up.
* remove the Intake and scribe the Port verticals from above
* measure down from the top lines identifying where the top of the intake sat to the top of the Port on each pair of Ports and transpose onto the Intake to locate the port tops.
Takes awhile....
but it's the only way we've found to have accurate location of the Ports to Grind to ?
 
Takes awhile....but it's the only way we've found to have accurate location of the Ports to Grind to ?

Thanks for the detailed info on your method, much appreciated.

I've only tried porting one intake, a small block Strip Dominator. I'll admit that I just laid a gasket down on the intake face, centered it as best as I could then used a blue Sharpie to color in the space between the inside edge of the gasket openings and the outsides of the ports and ground away whatever was blue. Went pretty far up into the runner. Did not do anything to the plenum area except for smoothing out some rough parts of the casting. All that grinding did seem help the mismatch between the ports somewhat but who knows if it did anything else other than make a lot of aluminum dust.
 
When does the intake manifold become the choking point on the intake side of an engine with high flow cylinder heads? Trick Flow 240s flow 310 cfm @ .500 lift and when looking at the intake flow numbers posted on the Hughes website (http://www.hughesengines.com/TechArticles/4portedintakemanifoldsupdated08272007.php) only a few manifolds can keep up. iirc the intake manifold should flow 20% MORE than the heads - that basically means hardly any manifold flows enough for the Trick Flows.
Is this correct, are the Hughes numbers wrong, does it even matter?

It matters a lot if you're trying to make more than average power. The intake manifold is often a cork in the system since most people just buy an intake and bolt it on. I started to use Wilson ported intake manifolds a few years back and they really make a big difference. Costs a bunch of money but for someone who is serious about racing the price isn't out of line. Besides, the resell value is pretty good on Wilson intakes since people know how good they are.
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I'm playing with this as we speak using a set of TF270's and a 6-Pack Eddy Intake
How many cu in is the engine? HP goal? I had Jim (IQ52) do a little porting on my Eddy 6pack for my TF240's
 
How many cu in is the engine? HP goal? I had Jim (IQ52) do a little porting on my Eddy 6pack for my TF240's

505 Stroker
No clue on power on this one except above 600.... and why I'm playing with the 6-pack manifold/flowing etc.,
we'll see power when I get it finished and on the Dyno, and where if time allows ? I'd really like to bolt an untouched 6-pack manifold back on for comparison.
 
You hit the nail on the head regarding many manifolds, and in our experience particula
rily the performer rpm's, in that no matter when moved towards the front of the engine at least 2 ports are badly blocked at the rear opposite and towards the rear to then correct 2 ports at the front opposite seem to be way off..... if ever a manifold that needs severe correction from OOTB it would be the BB Mopar Eddy Performer rpm's in our experience anyways.

The way we port match is this
* we scribe vertical lines on the head identifying the center dividers and pinch sides of the ports
* we put the manifold on the engine/heads with Head Gskts and layers of tape to simulate the .020" thick valley pan and bolt it down.
* We then scribe along the top of the manifold putting lines on the Head landmarking the tops of the Ports
* We then landmark the Port center divider/pinch side side lines from the head onto the Intake to locate when the Port lines up.
* remove the Intake and scribe the Port verticals from above
* measure down from the top lines identifying where the top of the intake sat to the top of the Port on each pair of Ports and transpose onto the Intake to locate the port tops.
Takes awhile....
but it's the only way we've found to have accurate location of the Ports to Grind to ?

That is pretty much the same way I want to do it as well! But what do you do when the ports are so far off (front/back)? There is only so much you can grind away.. do you use epoxy to build up one side of the intake runner divider and grind on the other side - basically moving the wall a bit (if you understand what I mean)?
Thanks
 
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505 Stroker
No clue on power on this one except above 600.... and why I'm playing with the 6-pack manifold/flowing etc.,
we'll see power when I get it finished and on the Dyno, and where if time allows ? I'd really like to bolt an untouched 6-pack manifold back on for comparison.
I was given a 440 sixpack manifold that suffered a failed attempt to conceal a nitrous setup underneath it. Aside from the repairs i will have to make because of the nitrous, the raw casting has horrific core shift and misshapen ports. If this is typical of later production of these manifolds, good porting will make a substantial improvement.
 
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