Question on port matching

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fishmens67 said:
Personally ,I think this is a waste of bandwidth. :rolleyes:..
A matched port is the best, so why debate anything less.
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It shouldn't need this many pages..but sometimes it takes the right messenger or many messengers?

Its emphasizing the ol..'whatever ya do, dont it like this' advice.

What people need to focus or realize ...is the source of the pressure wave/signal is the port/cylinder...so having the manifold bigger, to a point, is GOOD.
Think about the intake port window 'for simplicity ' SUCKING... like a ***** on the manifold runner...
Which would you want then after understanding it lamens style...
Matched perfect of course..but if not..then Bigger, slightly .020

It's so beyond most people because there's this thing where you only have so many cfm lets say. ..224 cfm... but you have really good air...as in shape...the port is completely working.. and you make a little more power than you should have going off of c f m alone.
We know it takes air.... we know it takes fuel...but we arent just sticking a tube with a petcock pouring in....so yeah..we also know how important mixing the 2 are to get them to burn complete.
Balance or abundance
 
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rumblefish360 said:
Absolutely! Now -

How does the larger intake port to a smaller cylinder head port help and by how much or percentage is the intake port larger than the head port?

The ability of the intake or not, is not of or in question here. The question is, stated above.
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Either dead nuts matching or intake manifold window slightly, example -.020 bigger.


As to how much bigger you can go before it's detrimental to power I have not tested so that's something you need to consider when playing with this stuff to error on the safe side
 
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fishmens67 said:
Personally ,I think this is a waste of bandwidth. :rolleyes:..
A matched port is the best, so why debate anything less.
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That’s not the debate. I happen to agree with you.

MOPAROFFICIAL said:
Either dead nuts matching or intake manifold window slightly, .020 bigger.
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First, I’m not trying to be a stick in the mud when I continue on, so, with that said….

.020 is not the same restriction as it would be on a different port window. Let’s do extremes for fun.
In the left corner… a as cast 302/328 head! (LMAO, sorry, had to do it…) and in the right corner… a max wedge head….
Let’s do some percentage mathematics….. .020 will do for the base common intrusion.
As to how much bigger you can go before it's detrimental to power I have not tested so that's something you need to consider when playing with this stuff to error on the safe side
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Pray for me to win LOTTO so I can come over and pay you a 6 digit income to do nothing but test until my money runs out.
 
rumblefish360 said:
That’s not the debate. I happen to agree with you.

First, I’m not trying to be a stick in the mud when I continue on, so, with that said….

.020 is not the same restriction as it would be on a different port window. Let’s do extremes for fun.
In the left corner… a as cast 302/328 head! (LMAO, sorry, had to do it…) and in the right corner… a max wedge head….
Let’s do some percentage mathematics….. .020 will do for the base common intrusion.

Pray for me to win LOTTO so I can come over and pay you a 6 digit income to do nothing but test until my money runs out.
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Heres what I think about what you're saying/asking...
You need to compartmentalize the system.
It's not about the difference between .020 restriction on a small window versus a big window. Same effect there.
You have to apply everything that you've learned or think you've learned... based on your understanding of it...see each feature as a chain working together.
Understand the manifold itself.
The intake manidfold runner...make it matched all the way up to the plenum area
..but if the short turn of the intake manifold i call the flange isnt shaped right...it wont see the flow it could...and could theoretically not flow with the head.
Flow impedance aside... think about the effects on fuel suspension/re suspension and what happens to both air and fuel with A. Too small a manifold window then with B. Matched... then C. Slightly bigger..which just so happens to in particular cases help suspend/re suspend the fuel..or may be its suspend more fuel up into the central air stream. We have watched vids to see the port is wet..fuel is moving in suspension and across the surface...so imagine lifting that fuel into the stream where it will mingle with the air and light off perhaps more complete/faster..screw how I even described it.. think fuel injector.
Don't think small hole velocity , that's the ports job...think flow as much as the head and not creating dead spots where fuel and or air vorticies /whirlpool/stagnate.

It's really simple..but takes a bunch of detailed explaining that leads to the facade of over thought out idea...lets make it harder than it is with cherries on the top kinda thing.
Just make the runner as big or within. 020...or to over complicate it more... make the floor slightly bigger, straight wall perfectly aligned as well as the roof... do whatever ya I want...idk. it does make or break my day. Good luck.
:popcorn:
 
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By "flange " do you mean the carb mounting base to plenum ? Or the short turn of the runner ?
 
mbaird said:
By "flange " do you mean the carb mounting base to plenum ? Or the short turn of the runner ?
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I see the intake manifold as 1st the flange the carburetor bolts to.... just below, the bottom of the flange.. is the short turn 'its upside down' and just below that..the open area is the plenum from there the runner mouths/runners themselves.

Tomato tomatoe
 
How much do you want me to write the check for ? :)
MOPAROFFICIAL said:
Heres what I think about what you're saying/asking...
You need to compartmentalize the system.
It's not about the difference between .020 restriction on a small window versus a big window. Same effect there.
You have to apply everything that you've learned or think you've learned... based on your understanding of it...see each feature as a chain working together.
Understand the manifold itself.
The intake manidfold runner...make it matched all the way up to the plenum area
..but if the short turn of the intake manifold i call the flange isnt shaped right...it wont see the flow it could...and could theoretically not flow with the head.
Flow impedance aside... think about the effects on fuel suspension/re suspension and what happens to both air and fuel with A. Too small a manifold window then with B. Matched... then C. Slightly bigger..which just so happens to in particular cases help suspend/re suspend the fuel..or may be its suspend more fuel up into the central air stream. We have watched vids to see the port is wet..fuel is moving in suspension and across the surface...so imagine lifting that fuel into the stream where it will mingle with the air and light off perhaps more complete/faster..screw how I even described it.. think fuel injector.
Don't think small hole velocity , that's the ports job...think flow as much as the head and not creating dead spots where fuel and or air vorticies /whirlpool/stagnate.

It's really simple..but takes a bunch of detailed explaining that leads to the facade of over thought out idea...lets make it harder than it is with cherries on the top kinda thing.
Just make the runner as big or within. 020...or to over complicate it more... make the floor slightly bigger, straight wall perfectly aligned as well as the roof... do whatever ya I want...idk. it does make or break my day. Good luck.
:popcorn:
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I would say the first thing people should do... is the put a carburetor gasket and some studs in the intake manifold and make sure that the flange is even open as big as the carburetor gasket AND that the divider 'if dual plane' is really centered and thin enough.
 
So another variable is the shape of the intake runner. A tunnel ram has a straight shot to the head port whereas a single/dual plane there is a bend .
Imagine standing in an alley way between 2buildings on a windy day... thats a tunnel ram. Now step around the corner just 1'.. the wind is no longer blowing on you . Thats a single / dual plane.
The point is that with a single/dual plane there wont be equal amounts of flow around the window.

Is my thinking flawed ?
 
mbaird said:
So another variable is the shape of the intake runner. A tunnel ram has a straight shot to the head port whereas a single/dual plane there is a bend .
Imagine standing in an alley way between 2buildings on a windy day... thats a tunnel ram. Now step around the corner just 1'.. the wind is no longer blowing on you . Thats a single / dual plane.
The point is that with a single/dual plane there wont be equal amounts of flow around the window.

Is my thinking flawed ?
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Flow is very general, but let's call it that for now. Btw I'm not going to sit here and speak as if I'm the end all master, I'm not.

You have the right idea and if you watched those videos...you'll see it.
So to one side in, hits inside curve...then to the outside it exits.
 
If you were to put a head on the flow bench and turn it on and hang a string with a ball in the end it doesn't just flow where you hold it unless its gods gift. Let's say directly in line with the floor ,maybe through part of the port....or with the roof.. think the straightest path ... so if you drop it at the floor it will lift up and hang right in the middle of the port on our production heads...or where the short turn is more directly aimed.

Tunnel rams tend to be the hot ticket for that reason of straightest path.
 
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Hysteric said:
Airflow through a flow bench is not airflow through an engine.

What you think happens in an engine and what you think the air will do are 2 different things. A smaller intake manifold port (within reason) dampens reversion because the smaller port increases the velocity of the charge as it leaves the carb and through the manifold limiting the reversions ability to disrupt flow by continuing higher.

A slightly smaller intake manifold port allows the fuel on the walls to be re-entrained improving the mixture quality and strangely enough so does a smaller carb aka improved homogenization of the intake charge. Again what the flow bench tells you and what the engine sees are 2 different things. If the flow is both ways then the assumptions you make about it being only one way are clearly wrong.

Larry Meaux said that he had a hemi engine on his dyno that had a volumetric efficiency of 140%, only problem was it was losing 20% of that out the exhaust during the overlap period.......What you get and what you use are 2 different things.

Why didn't that streetmaster intake with its tiny port choke that 340 to death? The difference between it and the Airgap is huge yet it wasn't refelcted in the power at 5600 RPM if airflow is all that matters? 10 Hp difference........There's more to this than just raw airflow.
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No **** Sherlock. I don’t know anyone claiming a mismatch is a good thing. You are just too dull to grasp it.
 
rumblefish360 said:
You know this, I know this, Larry Meaux knows this, I’m sure a slew of top notch people in the field know this. They pass this information down into the hands of the people so they now know this, why RB can not properly plain his position against this is beyond me.

I started to go through everything he said to make a huge long post but grew tired of talking with a wall and have decided to throw in the towel on this subject.

If anybody thinks that a larger intake port up against a smaller cylinder head port is better (LMMFAO&HARD!)
Please do so have at it and if you could, prove RB correct, please do so school me. I’ll only say if it is not on a MoPar engine, then I REALLY DGAF.

MoPar only her peoples!

Have a great one everybody!
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Make the post and I will go through it point by point. Your problem is you can’t get your head around the simple fact that air doesn’t do what you think it does. There are only so many ways it can be explained.

The very first video I posted shows what happens when you have a square corner on the down flow side. It’s as simple as that one video, but you shot on the video because the flow was too slow.

This is why I just said at the beginning for the OP to not even bother with port matching. It’s done wrong so much hat has become the de facto way to do it.

I can’t make you spend the time to learn. Learning is hard.
 
Hysteric said:
Think of the port mismatch as you would a stepped header just different ends of where the combustion event takes place and then think about how you would design it to prevent reversion making its way back up the manifold runner.

Next time you look at the underside of your air cleaner lid look at that black stuff and think about how far that had to travel and against what to get there!
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Once again you are just flat wrong. Nice try though.
 
rumblefish360 said:
You know this, I know this, Larry Meaux knows this, I’m sure a slew of top notch people in the field know this. They pass this information down into the hands of the people so they now know this, why RB can not properly plain his position against this is beyond me.

I started to go through everything he said to make a huge long post but grew tired of talking with a wall and have decided to throw in the towel on this subject.

If anybody thinks that a larger intake port up against a smaller cylinder head port is better (LMMFAO&HARD!)
Please do so have at it and if you could, prove RB correct, please do so school me. I’ll only say if it is not on a MoPar engine, then I REALLY DGAF.

MoPar only her peoples!

Have a great one everybody!
Click to expand...


By the way, since you are humping this so hard, I want you to point out where I said to deliberately make the manifold bigger. Go ahead. You won’t find it. Again, your limited experience and inability to learn are handicapping you. Yet you have no issue calling you don’t know and you DGAF but you certainly get your 2 cents in.

One more time. Never ever make the manifold smaller than the port in the head. Ever. If, again IF you have core shift or some reason you can’t match the port, make the manifold bigger than the head.

And, do NOT make a bulge in the port at the flange. That is what I have said from the beginning.

Don’t do all the mental gymnastics to think that a smaller intake port has anti reversion capabilities because it doesn’t. Not even a little. If you did some basic study you’d already know that. Hysteric thinks it does, but he thinks a lot of things that are wrong.
 
Rat Bastid said:
Make the post and I will go through it point by point. Your problem is you can’t get your head around the simple fact that air doesn’t do what you think it does. There are only so many ways it can be explained.

The very first video I posted shows what happens when you have a square corner on the down flow side. It’s as simple as that one video, but you shot on the video because the flow was too slow.

This is why I just said at the beginning for the OP to not even bother with port matching. It’s done wrong so much hat has become the de facto way to do it.

I can’t make you spend the time to learn. Learning is hard.
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No no no, learning is easy when you have the right teacher. Please move aside. It was a pleasure quizzing you in this. Though I don’t agree with you and even more so considering the point of view and direction you assume on the parts in question to the questioner. (That means like a poor archer, you have completely missed the mark.) In the mean time, I’m going to go and find grand-dads old paper work when he was building race engines.

Thank you, good night. Your done.
 
I’m not going to respond to you much more. Your acting like a butt hurt teenage girl. I’m jumping the thread for a reason. All of which you missed.

You ask me again… “I want you to point out where I said to deliberately make the manifold bigger”

Why? Did I say this, you go find it for me!

no wait, I’m not going to answer, your boring and missed my point of questioning you. I started questioning as if I don’t know anything and you failed to adequately explain your point of view on why and when this would be good and you double back a few times


Personally, I don’t think you even know what’s going on anymore

Goodnight!
 
rumblefish360 said:
A big thanks to @MOPAROFFICIAL

The man makes more sense in a few posts than a thread of multiple pages.
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Unreal. He says a a .020 mismatch is perfect. So you want a number? I already said that. ZERO is what you want. NONE. Get it yet?

If you can line everything up you don’t just make the manifold .020 bigger. You make it one continuous port, with the absolute minimum number of corners, and the correct amount of taper.

God DAMN. It’s not that hard. .020 means nothing.

Now ask me how much taper a port needs. And the answer is it depends. But they all need some taper, without changes in cross section.

.020 is the number you wanted, but it’s STILL wrong. There is no NUMBER. Make it all line up if you can. If you can’t, don’t make the intake smaller.

Better yet, just bolt the manifold on and don’t screw with it, because in the end it will most likely be wrong.

More engines have made less power because someone went on a forum and got bad advice. Don’t port match unless you understand that you can screw it up 100 ways and do it right two ways. The odds aren’t in your favor.
 
rumblefish360 said:
I’m not going to respond to you much more. Your acting like a butt hurt teenage girl. I’m jumping the thread for a reason. All of which you missed.

You ask me again… “I want you to point out where I said to deliberately make the manifold bigger”

Why? Did I say this, you go find it for me!

no wait, I’m not going to answer, your boring and missed my point of questioning you. I started questioning as if I don’t know anything and you failed to adequately explain your point of view on why and when this would be good and you double back a few times


Personally, I don’t think you even know what’s going on anymore

Goodnight!
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I explained it 10 ways and you still don’t get it. I posted at least 4 videos, and those didn’t work either. You are the professional argue king here. You want it your way. You can’t have it your way. I explained it so a simple minded dolt could get it.
 
rumblefish360 said:
No no no, learning is easy when you have the right teacher. Please move aside. It was a pleasure quizzing you in this. Though I don’t agree with you and even more so considering the point of view and direction you assume on the parts in question to the questioner. (That means like a poor archer, you have completely missed the mark.) In the mean time, I’m going to go and find grand-dads old paper work when he was building race engines.

Thank you, good night. Your done.
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I’m not your teacher. You didn’t quiz me either. You proposed your wrong understanding of airflow and expect me to make you learn.


You got issues dude. Go learn something and come back and we can have a discussion. Until then you are a giant waste of time.
 
Rat Bastid said:
I’m not your teacher. You didn’t quiz me either. You proposed your wrong understanding of airflow and expect me to make you learn.


You got issues dude. Go learn something and come back and we can have a discussion. Until then you are a giant waste of time.
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:rofl:
 
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