Why an engine makes more power off a burr finish
Moderator: Team
Why an engine makes more power off a burr finish
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.
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.
-
- Guru
- Posts: 1163
- Joined: Thu Feb 23, 2012 11:44 pm
- Location: Australia
-
- Guru
- Posts: 6382
- Joined: Tue Jul 24, 2012 11:15 am
- Location: Roseville, Michigan (just north of Detroit)
- Contact:
Re: Why an engine makes more power off a burr finish
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).
http://www.rmcompetition.com
Specialty engine building at its finest.
Specialty engine building at its finest.
Re: Why an engine makes more power off a burr finish
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/
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/
Re: Why an engine makes more power off a burr finish
Can you tell us more about how he went about proving it?69434 wrote:It doesn't my engine builder of 30+ years proved it.
Re: Why an engine makes more power off a burr finish
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.
ALL of my manifolds are burr marked because it works.
Re: Why an engine makes more power off a burr finish
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?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.
Re: Why an engine makes more power off a burr finish
I have fully burr finished heads out there.CGT wrote: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?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.
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!
Re: Why an engine makes more power off a burr finish
Cool stuff. This is new to me.
What tool do you use to apply the burr?
What tool do you use to apply the burr?
Re: Why an engine makes more power off a burr finish
Many years of R&D with porting & a flow bench.CGT wrote:Can you tell us more about how he went about proving it?69434 wrote:It doesn't my engine builder of 30+ years proved it.
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/
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/
Re: Why an engine makes more power off a burr finish
Do the sheet metal manifolds have a burr finish?cspeier wrote:I have fully burr finished heads out there.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 several members on this forum with my manifolds, maybe they will chime in.
I even do it to sheet metal and tunnel rams!
'69 Camaro-N/A-23°-SBC-2988#
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/
Re: Why an engine makes more power off a burr finish
Do the sheet metal manifolds have a burr finish?
mine do
Re: Why an engine makes more power off a burr finish
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/
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/
Re: Why an engine makes more power off a burr finish
No burr finish here
'69 Camaro-N/A-23°-SBC-2988#
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/
Best 1/8 mile pass 5.753 @ 119.92
http://www.dragzine.com/news/homebuilt- ... -1969-z28/