Piker Porting (Intake Manifolds)

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my68barracuda said:
A question, do you have data from a flow bench that indicates the changes made to the walls are beneficial or even make an impact? Or are the changes made simply an eyeball interpretation of what you think the air flow likes?
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Air hates corners. Anything more than 7-8 degrees and the air will separate from the wall and cause turbulence.

As much as air hates corners, fuel hates it exponentially more. It is heavier than air, so trying to slow it down to make a corner will change the pressure in the port and the heavier fuel will fall right out the air. Once that happens, it’s hard to get that fuel back into the airstream.

So big corner Radii, minimize the turns, use a burr finish, keep the cross section changes to the absolute minimum because those changes cause pressure changes right there and the fuel will drop out of the air stream and get the tune up clean and they will make more power on less fuel. Every time.
 
Here are a couple of pictures of the last single 4 I did.
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I threw in the cow picture for no good reason. I just like it.
 
Everyone does it differently. At first glance I don't like some of what I see or read. Jmo

To be clear I do like the roof/flange to runner in Tim's 2nd to last pic, right before the cows. I question knife edges though.

I would not knife-edge any of those divider walls. What works in a port works in the intake manifold for the most part.. you stick to that thinking you can't **** it up.
If you get into a situation where you can't tun out a plug... that's because of the work you did here. You're fuel distribution and flow, if they're all over the place...so is your tune and detonation sensitivity.
I know... I'm making it sound harder than it is right. Maybe Iess is more in this case.
 
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MOPAROFFICIAL said:
Everyone does it differently. At first glance I don't like what I see or read. Jmo

I would not knife-edge any of those divider walls. What works in a port works in the intake manifold for the most part.. you stick to that thinking you can't **** it up.
If you get into a situation where you can't tun out a plug... that's because of the work you did here. You're fuel distribution and flow, if they're all over the place...so is your tune and detonation sensitivity.
I know... I'm making it sound harder than it is right. Maybe Iess is more in this case.
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Actually, the cylinder to cylinder distribution is about as good as it can get with this intake. There is a plate that goes on it that I don’t have a picture of.

The knife edged divider is much better than not getting the opening correct.
 
@Rat Bastid have you tested any of the turtles at the bottom of the plenum?
Pic stolen from www for reference.
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12many said:
Per RB’s recommendation, divider straightened removing material from upper and lower inside wall, a little from the middle of the outside wall. Blended down into the runner 1-1/2” or so. Three to go:thumbsup:

Left divider not straightened yet, right is completed:

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What I did on my Victor was cut back the bottom of the divider to get it straight and more perpendicular . Not sure if that was the right way but its the approach I took . It also opened up the bottom of cyl 2,3, 5 and 6 plenum openings to allow a little more area for flow. Those inside ports are often starved for flow ...so I have read .
 
Wilson and others sell them, I have yet to ever try one but the thought is interesting at least.
 
Rat Bastid said:
Actually, the cylinder to cylinder distribution is about as good as it can get with this intake. There is a plate that goes on it that I don’t have a picture of.

The knife edged divider is much better than not getting the opening correct.
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Have you tried dulling that some after getting the cross section where you want it? I know benches aren't everything but I do see the most when I just roll the flange/plenum roof into each runner ' smooth or not the flow doesn't care but the fuel does care' ..and theres tq in its re animation. But thats where the ankle deep ends. Is it not a super highway in the middle of the port anyhow. I'm going to do some maybe worthless/marginally complete testing 'I'm knocking myself here' with clay or jb weld might be more surface accurate..some knife edges and see what the dye does..maybe food color in gasoline so I can blow my motors up and burn my house down..lmao but spray dye into it and is it just going to eddy wet down the walls 'more so in some ports' with a knife edge and or will a less sharp divider wall promote more equality.
I usually start by flow each and write down where they're at 'cfm' and then I start checking the cross-section openings if I see wide margins..and start at the plenum/flange roof to runners a corner at a time. Takes forever. I don't like to do a bunch of work all at once for all I know I end up lop siding things ...so I take a long time to do what I do ask anybody. I can tell you that widening a port more than needed will knock the balls off a motor.
 
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Since Tim is already helping you guys predominantly I'm not going to change your program here or attempt to I just wanted to ask if any of you have any before and after numbers on these intake manifolds on the heads that they're going to be used on? Can you state the heads Peak air flow and then give the air flow with the out-of-the-box manifold flowed on it ...and then one more test after the all work is done?

Example.
Eddy head 285 cfm
Ootb victor bolted on= ***
Ported victor bolted on= ***

What would be even better...

Plenum roof to runner work only= ***
Divider work= ***
 
TT5.9mag said:
Wilson and others sell them, I have yet to ever try one but the thought is interesting at least.
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I saw an episode where they tested that turtle or similar turtle by Wilson and the episode told me that if you don't have enough plenum volume or are marginal already....that turtle hurts power.
Secondary from that if it hurts power simply by reducing plenum volume and its design shows no increase/offset then it's not a power gain.....it's a Band-Aid for two big intake manifold or plenum volume
 
I don't have a lot of money and I don't have a lot of time.

If your car goes faster, there ya go.
If you ever stop/slow down and figure out what exactly it was that made it go faster you could share that with us later.
The older I get ... I lose the desire to spend any time doing something for nothing.
I see people spend time in areas of a port/port windows... all kinds of stuff...but it doesn't do anything. Ime.Anything made bigger that doesn't flow a considerable amount more air ..is slowing down and or sacrificing power somewhere in the range.
 
mbaird said:
What I did on my Victor was cut back the bottom of the divider to get it straight and more perpendicular . Not sure if that was the right way but its the approach I took . It also opened up the bottom of cyl 2,3, 5 and 6 plenum openings to allow a little more area for flow. Those inside ports are often starved for flow ...so I have read .
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I did cut back at the bottom about an 1/8”
It would have been knife edged otherwise by the time I got things straight.
 
OK, for those that like to see this stuff, I’m done (besides a final look over and making any touch ups) with the back four runners, will duplicate the front and call the plenum good. All you’re seeing done here is the flange opening matched to the carb gasket, the flange sides radiused into the runner roofs, (approx. 7/16” radius) and the dividers cleaned up, straightened with blending into the runners about 1-1/2” finish for now is 40 grit.
Actual roof flats not touched beyond the radius, some burr/sand rolls for smoothing in the radius’s or roof/sidewalls as needed, very minimal.
Afterwards it’s back to the final port/head/gasket matching and blending etc.and that’s all I’m doing to it.

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12many said:
OK, for those that like to see this stuff, I’m done (besides a final look over and making any touch ups) with the back four runners, will duplicate the front and call the plenum good. All you’re seeing done here is the flange opening matched to the carb gasket, the flange sides radiused into the runner roofs, (approx. 7/16” radius) and the dividers cleaned up, straightened with blending into the runners about 1-1/2” finish for now is 40 grit.
Roof not raised beyond the radius, sidewalls blended as needed.
Afterwards it’s back to the final port/head/gasket matching and blending etc.and that’s all I’m doing to it.

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Nice work! You could charge for stuff like that. The only thing I would change is the finish. If you can master the burr finish you will make some more power and do it on less fuel.

You need a single cut burr that is 3/8 or so olive shape with a 6 inch shank. Very carefully and in small increments BEND the shaft. The closer to the collet, the more the burr will jump and be harder to control. I almost forgot. The closer you bend the shaft to the burr end, the more you have to bend it to get any burring effect. You have to do little bends and move up and down the shaft until find the sweet spot FOR YOU. Before you start bending the shaft, knock some of the teeth off on a piece of steel. You want the burr beat up a bit. Once you get a bend, start testing. Depending on you and how you hold the grinder and how you apply pressure with the burr to the surface will affect where and how much bend you need.

Burr speed and the pressure you apply to it can change the surface finish. Start with a beat up burr to begin with. You can bend (using small bends) several times and not have a failure. At least I haven’t, but I was sneaking up on it. Also, the size and shape of burr I suggested is what I use and I’m comfortable with. If you have a favorite size and shape of burr, that’s what I’d start with.

Soooo...between the bend, where it is, burr speed and pressure you can get a nice burr finish. The only way I know to get it is to just sneak up on it and test with bends, speed and pressure.
 
Rat Bastid said:
Nice work! You could charge for stuff like that. The only thing I would change is the finish. If you can master the burr finish you will make some more power and do it on less fuel.

You need a single cut burr that is 3/8 or so olive shape with a 6 inch shank. Very carefully and in small increments BEND the shaft. The closer to the collet, the more the burr will jump and be harder to control. I almost forgot. The closer you bend the shaft to the burr end, the more you have to bend it to get any burring effect. You have to do little bends and move up and down the shaft until find the sweet spot FOR YOU. Before you start bending the shaft, knock some of the teeth off on a piece of steel. You want the burr beat up a bit. Once you get a bend, start testing. Depending on you and how you hold the grinder and how you apply pressure with the burr to the surface will affect where and how much bend you need.

Burr speed and the pressure you apply to it can change the surface finish. Start with a beat up burr to begin with. You can bend (using small bends) several times and not have a failure. At least I haven’t, but I was sneaking up on it. Also, the size and shape of burr I suggested is what I use and I’m comfortable with. If you have a favorite size and shape of burr, that’s what I’d start with.

Soooo...between the bend, where it is, burr speed and pressure you can get a nice burr finish. The only way I know to get it is to just sneak up on it and test with bends, speed and pressure.
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Excellent explanation of what it takes to a achieve the burr finish. I was looking at your previous post here with the pictures wondering how in the heck it’s done. I’ve seen various posts on it in the past, honestly haven’t researched it much but will. I am admittedly working with an older mindset when it comes to sand rolls etc for finishing. I’ve got some aluminum I can practice on when I get to that stage. Thanks :thumbsup:
 
I see the burr finish has been discussed here in the past and there’s a 71 page discussion over on Speed-Talk among other sites.
6” slightly bent single cut oval egg seems to be the preferred burr, but it’s got me wondering about the use of “rasp burrs” as an option as the finishes I’m seeing on examples look like a rasp type was used. Ripped, shredded, torn. Any of you guys experienced with doing the burr finish ever looked into what a rasp burr does on aluminum??

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12many said:
I see the burr finish has been discussed here in the past and there’s a 71 page discussion over on Speed-Talk among other sites.
6” slightly bent single cut oval egg seems to be the preferred burr, but it’s got me wondering about the use of “rasp burrs” as an option as the finishes I’m seeing on examples look like a rasp type was used. Ripped, shredded, torn. Any of you guys experienced with doing the burr finish ever looked into what a rasp burr does on aluminum??

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I have never tried those, but they may work. Maybe even without bending the shaft.
 
12many said:
I see the burr finish has been discussed here in the past and there’s a 71 page discussion over on Speed-Talk among other sites.
6” slightly bent single cut oval egg seems to be the preferred burr, but it’s got me wondering about the use of “rasp burrs” as an option as the finishes I’m seeing on examples look like a rasp type was used. Ripped, shredded, torn. Any of you guys experienced with doing the burr finish ever looked into what a rasp burr does on aluminum??

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Garbage, for wood.
 
If bending a 6” single cut oval and knocking teeth off is the only way to get that textured finish so be it. Rasp burrs are not just for wood. I’ve actually used a wood specific rasp burr (as well as a rasp file) on aluminum angle and fabricated 6061 brackets to round over cuts and shape corners, aggressively, in years past. It leaves a very coarse finish just doing that, using it in a typical way. Varying pressure can leave the finish relatively smooth or rutted/gouged. Used other ways it may be possible, maybe not. Use a Dremel and grind every other tooth down, make it coarser, I rule out nothing. The guy that came up with a bent single cut burr with teeth knocked off is an example. Experimentation. He may have already tried a rasp type burr and it failed, who knows

Here’s what a Nicholson “wood rasp” file can do in about 10 seconds on the surface using firm pressure and then the edge really laying into on some 6061 aluminum (looks like a Squirrel or Beaver gnawed on it)

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I’ll have to dig out my rasp burr and see what finish I can attain on scrap. Using a slow drill.
 
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MOPAROFFICIAL said:
I saw an episode where they tested that turtle or similar turtle by Wilson and the episode told me that if you don't have enough plenum volume or are marginal already....that turtle hurts power.
Secondary from that if it hurts power simply by reducing plenum volume and its design shows no increase/offset then it's not a power gain.....it's a Band-Aid for two big intake manifold or plenum volume
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Thanks for the explanation, any link to the episode you saw?
 
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