Why an engine makes more power off a burr finish

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Fatpig
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Why an engine makes more power off a burr finish

Post by Fatpig » Thu Nov 20, 2014 10:34 pm

Forgivin-ness prease if this has been smashed before, I had a good lookie around for it.

Can someone please explain why an engine makes more power off a burr finish in the intake port/runner.
All literature of flow in pipes whether turbulent or not results in an energy loss down stream if the surface is not as smooth as possible.
I understand boundary layers (turbulent and laminar) from Fluid Mechanics by Frank M. White etc.

I'm assuming it has to do with the increased shear from the increased boundary layer (due to surface roughness) doing something with the fuel that is suspended in air resulting in a net power gain?

Please don't hold back with the technical stuff

Thanks again
F.P.

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Re: Why an engine makes more power off a burr finish

Post by whtrthanu » Fri Nov 21, 2014 12:05 am

golf balls!

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Re: Why an engine makes more power off a burr finish

Post by Cubic_Cleveland » Fri Nov 21, 2014 2:46 am

Have a look through this thread.

viewtopic.php?f=15&t=34837

Walter R. Malik
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Re: Why an engine makes more power off a burr finish

Post by Walter R. Malik » Fri Nov 21, 2014 9:10 am

That all depends upon whether or not the runner is flowing just air, (which is simply about surface tension), or also fuel, (which takes atomization into account).
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69434
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Re: Why an engine makes more power off a burr finish

Post by 69434 » Tue Nov 25, 2014 9:24 am

It doesn't my engine builder of 30+ years proved it.
'69 Camaro-N/A-23°-SBC-2988#
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/

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Re: Why an engine makes more power off a burr finish

Post by CGT » Tue Nov 25, 2014 9:43 am

69434 wrote:It doesn't my engine builder of 30+ years proved it.
Can you tell us more about how he went about proving it?

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Re: Why an engine makes more power off a burr finish

Post by cspeier » Tue Nov 25, 2014 9:58 am

This summer in the heat I went to the track with a fully smooth ported manifold I had done. I took my tools and burr marked it out in his trailer after we got a base line. Put it back on the engine, AT THE TRACK, same day, and made more runs.

ALL of my manifolds are burr marked because it works.

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Re: Why an engine makes more power off a burr finish

Post by CGT » Tue Nov 25, 2014 10:13 am

cspeier wrote:This summer in the heat I went to the track with a fully smooth ported manifold I had done. I took my tools and burr marked it out in his trailer after we got a base line. Put it back on the engine, AT THE TRACK, same day, and made more runs.

ALL of my manifolds are burr marked because it works.
Interesting, so Im assuming the difference was significant enough with DA and conditions taken into consideration to make you a believer? Nice test. Maybe the heads should be roughed up next?

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Re: Why an engine makes more power off a burr finish

Post by cspeier » Tue Nov 25, 2014 10:29 am

CGT wrote:
cspeier wrote:This summer in the heat I went to the track with a fully smooth ported manifold I had done. I took my tools and burr marked it out in his trailer after we got a base line. Put it back on the engine, AT THE TRACK, same day, and made more runs.

ALL of my manifolds are burr marked because it works.
Interesting, so Im assuming the difference was significant enough with DA and conditions taken into consideration to make you a believer? Nice test. Maybe the heads should be roughed up next?
I have fully burr finished heads out there.

I have several members on this forum with my manifolds, maybe they will chime in.

I even do it to sheet metal and tunnel rams!

Image

Image

Image

Image

edfiero
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Re: Why an engine makes more power off a burr finish

Post by edfiero » Tue Nov 25, 2014 10:47 am

Cool stuff. This is new to me.
What tool do you use to apply the burr?

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Re: Why an engine makes more power off a burr finish

Post by 69434 » Tue Nov 25, 2014 10:52 am

CGT wrote:
69434 wrote:It doesn't my engine builder of 30+ years proved it.
Can you tell us more about how he went about proving it?
Many years of R&D with porting & a flow bench.
I'm not a head porter, so to get into the intricate details of head porting he would know.
He's taught me a lot, but he's not going to give out all his secrets, even to me.
'69 Camaro-N/A-23°-SBC-2988#
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/

69434
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Re: Why an engine makes more power off a burr finish

Post by 69434 » Tue Nov 25, 2014 10:57 am

cspeier wrote:
CGT wrote:
cspeier wrote:This summer in the heat I went to the track with a fully smooth ported manifold I had done. I took my tools and burr marked it out in his trailer after we got a base line. Put it back on the engine, AT THE TRACK, same day, and made more runs.

ALL of my manifolds are burr marked because it works.

Interesting, so Im assuming the difference was significant enough with DA and conditions taken into consideration to make you a believer? Nice test. Maybe the heads should be roughed up next?
I have fully burr finished heads out there.

I have several members on this forum with my manifolds, maybe they will chime in.

I even do it to sheet metal and tunnel rams!
Do the sheet metal manifolds have a burr finish?
'69 Camaro-N/A-23°-SBC-2988#
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/

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Re: Why an engine makes more power off a burr finish

Post by cspeier » Tue Nov 25, 2014 11:03 am

Do the sheet metal manifolds have a burr finish?

mine do

69434
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Re: Why an engine makes more power off a burr finish

Post by 69434 » Tue Nov 25, 2014 11:10 am

Let's see a pic, every company I have looked at that make sheet metal manifolds don't have a burr finish, why is that?
'69 Camaro-N/A-23°-SBC-2988#
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/

69434
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Re: Why an engine makes more power off a burr finish

Post by 69434 » Tue Nov 25, 2014 11:12 am

No burr finish here
ProModManifold.jpg
'69 Camaro-N/A-23°-SBC-2988#
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/

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