Why an engine makes more power off a burr finish

[twl]

I think that the video clearly shows the burr finish flows more air in that particular application. That didn't have any statement made about fuel atomization or any of that. It flowed more air, and that was what they intended to show.
So, while it might also have advantages for mixture too, this was an air flow demonstration.

Regarding flow into cylinder at TDC it can only fill the volume of the chamber, and the rest goes out the exhaust valve. You have X chamber volume at TDC and an open valve.

[groberts101]

I think that the video clearly shows the burr finish flows more air in that particular application. That didn't have any statement made about fuel atomization or any of that. It flowed more air, and that was what they intended to show.
So, while it might also have advantages for mixture too, this was an air flow demonstration.

Regarding flow into cylinder at TDC it can only fill the volume of the chamber, and the rest goes out the exhaust valve. You have X chamber volume at TDC and an open valve.

But maybe there's more to it than that though.. like how does a burr finish affect the 5th cycle? Or maybe.. just maybe.. it can even affect pumping losses to some small degree?

Would love to see spintron testing of an engine with burr finish applied in the full induction and exhaust systems too see what if any additional merit there may be for dry flow alone.

[ClassAct]

A bump for 2021. Darin Morgan gave a webinar on 01/20/2021 and durning that discussion he concurred with what Nick, Chad and Larry have been saying...burr the intake and intake port...and he said he didn’t think you can make it too rough.

Surely, Darin isn’t a liar or a stooge. He certainly wouldn’t waste his time propagating an error.

Of course, you all should watch the webinar for yourselves and hear what he says.

Certainly, if I have said something that Darin did not say, or if I have inferred something which he did not infer, I apologize in advance to all of you and more importantly for making it appear Darin said something he did not say.

I’ve watched both his PERA webinars, and IMO he is very clear on intake runner and port finish.

[RevTheory]

Yep, I watched it and that's exactly what he said.

[maxracesoftware]

A bump for 2021. Darin Morgan gave a webinar on 01/20/2021 and durning that discussion he concurred with what Nick, Chad and Larry have been saying...burr the intake and intake port...and he said he didn’t think you can make it too rough.

Surely, Darin isn’t a liar or a stooge. He certainly wouldn’t waste his time propagating an error.

Of course, you all should watch the webinar for yourselves and hear what he says.

Certainly, if I have said something that Darin did not say, or if I have inferred something which he did not infer, I apologize in advance to all of you and more importantly for making it appear Darin said something he did not say.

I’ve watched both his PERA webinars, and IMO he is very clear on intake runner and port finish.

 

this Video was in July 6, 2018

Darin gets into it starting here about 4 valve heads and the Chevy IRL engine:
https://youtu.be/zHjAgtxstcM?t=4173


ClassAct ,
Darin Morgan gave a webinar on 01/20/2021
please post the Links to the PERA webinars

i haven't seen the PERA webinars Videos

[steve cowan]

I have listened to those pod casts several times as well,I won't discredit anyone but I don't think those guys would paint every application with a broad brush ?? DM has also said that fuel can sit in the plenum floor of a burr manifold and fuel can spin in a vortex and not come out of the divit.
I remember this thread and will re-read it again but I remember it got off to a rocky start LOL.
I put this subject in the controversial subject the same as low lift flow and 50deg seats.
I am interested in what it does to boundary layer conditions,what CSA changes are required for a burr finish induction tract etc
I have not seen anyone burr finish the SSR instead it is a bit smoother in that area,interesting subject for sure.

[Rick!]

i haven't seen the PERA webinars Videos

https://www.pera.org/webinars/

[ClassAct]

i haven't seen the PERA webinars Videos

https://www.pera.org/webinars/

Thanks Rick for the link. I didn’t think to post it in my post.

[ClassAct]

A bump for 2021. Darin Morgan gave a webinar on 01/20/2021 and durning that discussion he concurred with what Nick, Chad and Larry have been saying...burr the intake and intake port...and he said he didn’t think you can make it too rough.

Surely, Darin isn’t a liar or a stooge. He certainly wouldn’t waste his time propagating an error.

Of course, you all should watch the webinar for yourselves and hear what he says.

Certainly, if I have said something that Darin did not say, or if I have inferred something which he did not infer, I apologize in advance to all of you and more importantly for making it appear Darin said something he did not say.

I’ve watched both his PERA webinars, and IMO he is very clear on intake runner and port finish.

 

this Video was in July 6, 2018

Darin gets into it starting here about 4 valve heads and the Chevy IRL engine:
https://youtu.be/zHjAgtxstcM?t=4173


ClassAct ,
Darin Morgan gave a webinar on 01/20/2021
please post the Links to the PERA webinars

i haven't seen the PERA webinars Videos

This entire topic is beyond fascinating to me. Because all of my reading, all of my flow bench testing, all of the “science” says that a burr finish would reduce airflow, and thus decrease power.

I learned early on a flow bench will lie to you if you let it. With that said...dyno and track proven results are the ultimate arbiter of what works and what doesn’t. At my age, the why is inconsequential.

I think I have finally, after trying off and on for more than 10 years to get a burr finish that I think will work. It isn’t easy. I killed quite a few burrs getting the two I have “just right” for my grinding technique. I’m going to send this set out and see how it does.

I do know ALL the intakes I do from here forward will be burr finished, and the customer doesn’t get that option. I view it the same way Chad does...get one somewhere else.

I only brought this thread back because of the recent webinar by Darin on the 20th and he also gave another webinar that’s on the PERA.org site that IIRC was from December 2020.


I can’t thank you, Chad, Darin and the rest who have put this out there, essentially for free (actually its all FREE and you can’t beat that) and taking all the flaming arrows that you get from the book and lab crowd.

Again, thanks to all of you for putting this out there.

[Ks Fats]

Burr prep could be a topic in itself; my finish sure doesn't look like Chads or Carnuts. When I screw one up too bad a 1" taper roll @ 36 followed by a quick hit with some 60 on a stick usually saves it, still doesn't look as good but for now its the best I can do.

[hoffman900]

When one looks at the Kaase video with the clear manifold, it makes you wonder how carburetors even work at all with all the liquid fuel all over the place, especially with throttle transitions and shift recovery.

I think there are a lot of things you could do that wouldn’t necessarily work on a flowbench that will make the engine be more efficient and improve the combustion process. Burr finishes on a carbureted engine seems to be one, combustion chamber shapes are another.

[ClassAct]

When one looks at the Kaase video with the clear manifold, it makes you wonder how carburetors even work at all with all the liquid fuel all over the place, especially with throttle transitions and shift recovery.

I think there are a lot of things you could do that wouldn’t necessarily work on a flowbench that will make the engine be more efficient and improve the combustion process. Burr finishes on a carbureted engine seems to be one, combustion chamber shapes are another.

That’s an amazing video and you’re certainly not wrong. It’s amazing this stuff runs as well as it does. We constantly fight to overcome crazy stuff like wet flow. I’m sure there is power there. The burr finish is (I think) one way to help clean a bit of that up.

Figuring out how to get a burr finish that helps and looks even remotely decent is not nearly as easy as it seems. It’s taken me countless hours of trying and incredible frustration bending burrs and such.

I will find out soon enough if I have helped or killed this set of heads and intake.

[Leftcoaster]

The wet fuel debate might be clarified by running a carburetted burr finish inlet manifold and head combination, then swapping on a similarly burr finished efi manifold with injectors and tuneable ecu - - has anyone tried this?

[hoffman900]

The wet fuel debate might be clarified by running a carburetted burr finish inlet manifold and head combination, then swapping on a similarly burr finished efi manifold with injectors and tuneable ecu - - has anyone tried this?

I don’t think there is any debate. Look at the ports of a F1 engine and other factory programs. Honda has a white paper on looking at fuel adherence in the port using a fuel with a staining component, from their F1 program over a decade ago.

Carbureted engines have problems with fuel puddling that a properly set up injection system doesn’t have. Just takes a different approach.

[williamsmotowerx]

The wet fuel debate might be clarified by running a carburetted burr finish inlet manifold and head combination, then swapping on a similarly burr finished efi manifold with injectors and tuneable ecu - - has anyone tried this?

I don’t think there is any debate. Look at the ports of a F1 engine and other factory programs. Honda has a white paper on looking at fuel adherence in the port using a fuel with a staining component, from their F1 program over a decade ago.

Carbureted engines have problems with fuel puddling that a properly set up injection system doesn’t have. Just takes a different approach.

I haven't seen the Honda data. What's their view on this? Is it a direct smooth to rough comparison?