This was a interesting test to wake up to. 😎 I am so greatful you do this. For me the takeway is much more testing needs to be done here to really understand it. But for one guy on your own with no real backing. To do all this makes you a powerhouse in my eyes. Your awesome! Thank you.
Eric I love your attention to detail. You leave no stone un-turned. By the way, the HP improvement in this test blew me away. Much more gains than I expected!
I've listened to Darin Morgan talk about doing his bent burr finish and customers complaining that it looked horrible so he stopped. Personally I want to win races over winning best paint and interior, so whatever the hell works I want it.
Boundary layer, laminar flow velocity and turbulence. Key factors of an intake. Smoother finish thinners the boundary layer making the laminar flow CSA larger. Larger CSA slows the laminar flow velocity down @ lower RPM. Rougher finish agitates the turbulence @ higher RPM, so the feed into the combustion chamber decreases. On stock form, any intake can feed the engine @ lower RPM range. There's just enough laminar flow CSA to keep the flow rate in between the window of desired performance. Porting is to increase the flow into the engine @ higher RPM, by re-shaping the ports to keep the engine fed @ higher RPM. How smooth? it depends on the fuel system, and fuel used. Port/direct injection doesn't need the boundary layer, bcz there's no fuel in the port to be mixed. the heavier the fuel molecule is, and richer the mix itself, more boundary layer and turbulence is needed to keep the fuel in suspension all the way into the cylinder. What about the plenum? When you are circuit/oval racing, keeping your engine on constant high RPM for long periods of time, the plenum can create low pressure vortex under the carb. This sucks more mix into the intake, having a bigger charge for the opening valve, feeding more mix into the combustion chamber. BUT on a short burst; dyno pull or drag racing, there's not enough time for the vortex to happen, only too large plenum to mess the flow velocity on low RPM. On drag racing, the intake shape is the key. Equal shape and volume ports, less obstructions between the carb and the valve. "Ram Air intake". To get the best results, the piston needs to pull fresh charge through the carb, and the intake needs to mix the carge for optimal burn before it enters the chamber. And all this needs to happen evenly on every intake stroke while the time decreases when the RPM goes up, mostly between 4000 and 8000 RPM, the worst possible range for pulse harmonics, especially when the exhaust pulse is uneven. After you've fixed all that, comes the next problem: Different style intakes react differently to different bore and stroke. An intake that creates the perfect torque curve on one bottom end, is an absolute turd on other. And it matters if the C.I is made with bore or stroke, and what is the relation of those two. Longer stroke needs more laminar flow speed than larger bore. And the cam profile messes this equation every time. race car engine building is fun, they say.
In the 80's when I ran carbs I had a real time o2 sensor for tuning. I remember that the burr finished manifold required removing jet to get the same a/f ratio. This may also be the case here since the jetting was not changed. Great test Eric.
Your videos are always very interesting indeed and you put in front of us the numbers and those are indisputable. I'm from Italy and I wish there was someone that does this things here too, specially with old cars that where a normal guy can still work on without having too much equipment. One day I would really like to buy an old car and just work on it to have fun and of course to learn new things and skills.
I’ve always heard that you want to keep the intake finish, sorta rough. Then you want the exhaust finish smooth. You know why, but it’s interesting to see that you used the Dyno to try and prove the idea. Thanks for sharing your experience
Very interesting. Does seem to support the idea that the rougher finish improve atomization. Maybe thats why the smaller manifold works so good. At least partly the atomization would be better with higher airspeed in the runners. The same test of finish on that manifold would be very interesting.
You Just Confirmed...My Belief for 40 years....I always Noticed my 60 grit finished...Always Run stronger than the Burr Finish...Ive taken Burr finish manifolds...that were done nicely...And Finished them with a 60grit...And they Pick up Solid at the Track....👍🏻🏁🏁
I can’t wait to see what heads you use and the difference in power. You should try running the coolant lines from the front of the intake to the back to see if that makes a difference due to changes in cylinder temps
👍 Nice results for your efforts. If you do much work to dual plane intakes do you keep the same finish specifications? Rough on floor, crossbuff dividers & top, and 40 grit on sides? That would make for more interesting data on the Performer RPM. From your results I think I would probably do at least a rough finish on the floor.
Interesting, thanks for keeping it humble and not turning it into a burr vs. 40 grit war. I think that anybody with 1/2 an understanding of engine building realizes that this test could go either way if repeated with even a modest change in the engine.
On my Volvo 5 cylinder na head. I have found that the 60 or 80 grit I use seems to cut away very fast. I've only been working on the exhaust port for now and plan to finish it with a much higher grit. I don't plan to port it, the ports will only be smoothed out from rough casting Marks. I am afraid of touching the valve bowl. The idea is to improve flow across the range not worsen it. Hope I succeed.
Im a hillbilly and did not take it wrong lol,. Great job and insightful info Eric.. Now I'm thinking to myself how will a burr finish work on my bread box tunnel ram.. Hmm lol
Perhaps the burr finish creates a thicker boundary layer, which means the passage that the air can flow through is smaller, and this increases flow velocity at lower RPM, but becomes a flow restriction at higher RPMs, at least vs the 40 grit.
My conclusion, on the "as yet seen" smaller manifold, would be velocity. Your dyno mule wanted more velocity, with it's given combination, than that Victor Jr. provided. Just a thought.
It makes sense the burr finish would be better at lower velocity/rpm and once the velocity was enough to prevent fuel dropping out, the rolled finish was better.
At 6200rpm the burr finished combination was moving more air than the 40grit, the burr combination was moving less fuel. If the burr combo was fuel corrected to match the extra airflow it would of made more power.
@@WeingartnerRacing looking through all the rpm points the burr combo consistently moved more air but didn’t have consistent fueling, when you look at the airflow being higher but the fuel flowing less that says to me that there was a change in booster signal, I’m going to stick my neck out and say that the day the burr combo got run the air temp in the dyno room was higher, either from just a warmer day or from environmental heat soak from multiple dyno runs. The air temp being higher can effect booster signal and also the airs density overall is less so the engine will make less power even tho it’s moving more air in cfm.
Great video, any chance you are doing one where you go smoother, to see if you get to a point where you start to loose power or flatten off on this combination?
*THIS would be an interesting topic to address* Old School/Wive's Tale/Rule of Thumb was that having TOO SMOOTH (too fine) of a finish (mirror-like) on the intake floor/runners would hurt Atomization of fuel in Carburetor applications. I wonder if the same rules apply to THE SAME INTAKE MANIFOLD using a Fuel injected setup with a 4150 or 4500 Throttle Body on top of the manifold, where no fuel hits the floor or runners, as the injectors are essentially spraying into the Cylinder Head entrances more or less, bypassing the manifold runners ?
i wouldnt say burr finish finish makes more power or less power too small of a difference at least in this around 1% but what it does show is it doesnt really matter what finish is used.
Thanks for doing the testing Eric👍 I remember on your second dyno session that you were down from the previous session with the same combo. And you put it down to weather being vastly different from first session. And the weather compensation wasn't being used as if I remember correctly wasn't looking to good either. How was your base line this time session 2 from session 3 ? The variation seemed pretty constant from session 1 to 2. Not being picky just interested and thanks for the content your creating 👍 Been following you from the start 👌
Great question. We had a control manifold that was used in the previous session and it made within 1hp. So it was much closer from session 2-3 than 1-2
Not enough to make a difference. They are also hard to read because on a carb deal at the start of the pull there is enough fuel in the bowl that it looks like it is not using much until the needle and seat opens.
What I take away from this video is a bit mixed. I couldn't help but notice the notation on the dyno sheets - and the sheet for the unmodified manifold Doesn't List a 1" tapered spacer and the other two do. The reference pull data or "control" isn't valid, or someone forgot the notation for the spacer on that sheet - so without clarification it throws that data out the window. The other two are within roughly one percent, so (as you mentioned) there's no clear winner. Some thoughts on the smaller manifold making more power; with a 190cc port and the relatively short cam timing, a smaller manifold might be matching the port size better in terms of flow - the charge not 'ganging up' at the port because the smaller (manifold) port velocity is higher and matches the flow velocity potential of the heads better - also putting cylinder filling about where that camshaft favors the power curve. Maybe - just thoughts!!!! I love working with airflow - so much is still a Black Art, so any progress in an as yet untried area is a bigger win yet!!!
👍 Hey Mr Weingartner, Have you asked TrickFlow if you could get a sample of their new SBC single plane intake for large cubic inch engines? Would be nice to see it compared to all that you've tested so far. Keep up the good work.
I only use the sanding rollers to give everything a nice uniform finnish. Usually intakes I will do a 60 grit (just a personal prefernce) now as for Exhaust and cumbustion chambers I try to go for a "glass" feel just to keep carbon deposits down and stop detonation. I am no means a pro head porter but I have goten good flow numbers with heads that I have done. Probably not the best but they seem to make decent improvments, I jysy bought stuf too try and cut valve seats i am going to practice on a junk head I have with valve cut angles.
That's a cool video and I was very curious on the finishes because seems like some people do very aggressive burr, then 40 grit also do you do 60 grit. But awesome results I am glad that your original idea actually made more power than just burr
I know you said don't take it as gospal but it's still cool to see your work and seeing Dyno results. And I am curious to see what manifold did good I was thinking wait is it the victor jr because that one is small. And i was like well how did the Motown manafold do.
@@chevyrc3623 Up till this point the Victor Jr & Mowtown haven't been in his testing. There's a lot of other intakes I would have liked to have seen tested (Holley 300-36, Weiand Speed Warrior Air Gap Style, P P Crosswind, Dart Dual Plane, Brodix HVH 1016, RPM Air Gap, Victor Jr 2975 vs 2900, Tean G 7530, Strip Dominator 300-25 vs 300-110, Mowtown, Dart, Bowtie Single plane) but good luck getting all those together at the same time. Expensive plus the poor guy would have gone to multiple days of testing on each set of heads.
@@WeingartnerRacing 👍 Nice. Round 3 promises to be an interesting video. Holley 300-110 vs 300-25 might be interesting to test spacers on the 25 to see if it can be better overall than 110 since you can add different types of spacers to get to the same height. Were you able to test a regular Victor Jr 2975 vs the port matched 2900? Kind of strange that Edelbrock lists the intake gasket size as a 1206 but when you look at the stated port dimensions the 1205 is a much closer fit.
I wonder if the reason you got the result you did was that the manifold was pretty well matched in cross-sectional area to what the engine wants In theory, the rougher the surface finish, the deeper the boundary layer will be, and the part of the port where air flows through smoothly will get smaller In fact, looking at the graph comparing the burr to the 40 grit looks like it might back that up, with the burred finish showing a small advantage below 5000 RPM At least, that's the theory. Of course, in theory, theory is as good as practice... Bottom line: wonder what results you would have seen if you'd had an overly large manifold on the engine. Perhaps the burr finish would have matched or even picked up over the 40 grit? As always, more of these data points being put up seems to raise as many more questions as it answers. Interesting video, and really good looking work in the manifold!
Back when Extrude Hone was being developed it was in all the magazines. I tried to get an intake manifold done and couldn't get them to answer the phone. This was way before the internet. I would love to see dyno and cost comparisons.
Even the Simplest test Comparison can get unexpectedly Complicated....Intake Finish with Jetting Optimization seems to be Need here.......I know dyno testers Prefer Individual Componet change test Comparisons but Intake Finish can be Linked to Jet size as in System A/F tuning Effect on ultimate Power.....Intake Finish Only Power measurements may be an Incomplete conclusion.....
@@WeingartnerRacing Some are indeed sceptical. But after 1 race that changes. Also what you did is something I do pretty long now after 10 years ago I tried improving an Ls7 head with radius seat on intake and grit 60. Airflow improved but power was 2-3 percent less..... esspecially in lower revs. Last year did a BBC with assymetrical seats on intake. Angles where droplets of fuel are smashed along and port almost complete burr finish. Radius seat where only air and tiny droplets flow. Difficult to make but results were awesome. Similar an Ls of which after overhauling diameter of intake throat was increased by machine shop 0.040" and seats were 0.010" deeper than new and with bit different shape. Engine lost 30 hp. After seats were replaced , with right shape, diameter and depth , and port roughened on specific areas it regained 38 hp first run . Also engine responded more normal to fuel changes / ignition. Its in the details....
I think it has to do with the transition of airflow into the runners under dynamic conditions. How fast can the flow be established into the runner when the demand comes on?
I should add that I saw a Hendricks manifold for 18deg Chevy back in those days, and they had a very aggressive finish, but smoother on top and down the runners, etc. Just like you're doing it. I'm guessing they knew what they were doing.
Nice work Eric. Good talking to you last week. And I'm with you, little shocked that it picked up. Not much, but still an increase.
This was a interesting test to wake up to. 😎
I am so greatful you do this. For me the takeway is much more testing needs to be done here to really understand it. But for one guy on your own with no real backing. To do all this makes you a powerhouse in my eyes.
Your awesome!
Thank you.
Eric I love your attention to detail. You leave no stone un-turned. By the way, the HP improvement in this test blew me away. Much more gains than I expected!
You’re spot on about the ‘customer standpoint’ that’s for sure.
I've listened to Darin Morgan talk about doing his bent burr finish and customers complaining that it looked horrible so he stopped. Personally I want to win races over winning best paint and interior, so whatever the hell works I want it.
It's a lazy way to finish the surface using a sanding roll shows every bump..
Boundary layer, laminar flow velocity and turbulence. Key factors of an intake. Smoother finish thinners the boundary layer making the laminar flow CSA larger. Larger CSA slows the laminar flow velocity down @ lower RPM. Rougher finish agitates the turbulence @ higher RPM, so the feed into the combustion chamber decreases. On stock form, any intake can feed the engine @ lower RPM range. There's just enough laminar flow CSA to keep the flow rate in between the window of desired performance. Porting is to increase the flow into the engine @ higher RPM, by re-shaping the ports to keep the engine fed @ higher RPM. How smooth? it depends on the fuel system, and fuel used. Port/direct injection doesn't need the boundary layer, bcz there's no fuel in the port to be mixed. the heavier the fuel molecule is, and richer the mix itself, more boundary layer and turbulence is needed to keep the fuel in suspension all the way into the cylinder. What about the plenum? When you are circuit/oval racing, keeping your engine on constant high RPM for long periods of time, the plenum can create low pressure vortex under the carb. This sucks more mix into the intake, having a bigger charge for the opening valve, feeding more mix into the combustion chamber. BUT on a short burst; dyno pull or drag racing, there's not enough time for the vortex to happen, only too large plenum to mess the flow velocity on low RPM. On drag racing, the intake shape is the key. Equal shape and volume ports, less obstructions between the carb and the valve. "Ram Air intake". To get the best results, the piston needs to pull fresh charge through the carb, and the intake needs to mix the carge for optimal burn before it enters the chamber. And all this needs to happen evenly on every intake stroke while the time decreases when the RPM goes up, mostly between 4000 and 8000 RPM, the worst possible range for pulse harmonics, especially when the exhaust pulse is uneven. After you've fixed all that, comes the next problem: Different style intakes react differently to different bore and stroke. An intake that creates the perfect torque curve on one bottom end, is an absolute turd on other. And it matters if the C.I is made with bore or stroke, and what is the relation of those two. Longer stroke needs more laminar flow speed than larger bore. And the cam profile messes this equation every time. race car engine building is fun, they say.
Interesting results Eric. Keep up the great work!
In the 80's when I ran carbs I had a real time o2 sensor for tuning. I remember that the burr finished manifold required removing jet to get the same a/f ratio. This may also be the case here since the jetting was not changed. Great test Eric.
Your videos are always very interesting indeed and you put in front of us the numbers and those are indisputable. I'm from Italy and I wish there was someone that does this things here too, specially with old cars that where a normal guy can still work on without having too much equipment. One day I would really like to buy an old car and just work on it to have fun and of course to learn new things and skills.
I’ve always heard that you want to keep the intake finish, sorta rough. Then you want the exhaust finish smooth. You know why, but it’s interesting to see that you used the Dyno to try and prove the idea. Thanks for sharing your experience
Very interesting. Does seem to support the idea that the rougher finish improve atomization.
Maybe thats why the smaller manifold works so good. At least partly the atomization would be better with higher airspeed in the runners.
The same test of finish on that manifold would be very interesting.
Air skips over the top through the "boundry layer"...no surface contact at higher speed.
You Just Confirmed...My Belief for 40 years....I always Noticed my 60 grit finished...Always Run stronger than the Burr Finish...Ive taken Burr finish manifolds...that were done nicely...And Finished them with a 60grit...And they Pick up Solid at the Track....👍🏻🏁🏁
I can’t wait to see what heads you use and the difference in power. You should try running the coolant lines from the front of the intake to the back to see if that makes a difference due to changes in cylinder temps
👍 Nice results for your efforts. If you do much work to dual plane intakes do you keep the same finish specifications?
Rough on floor, crossbuff dividers & top, and 40 grit on sides?
That would make for more interesting data on the Performer RPM. From your results I think I would probably do at least a rough finish on the floor.
Interesting, thanks for keeping it humble and not turning it into a burr vs. 40 grit war. I think that anybody with 1/2 an understanding of engine building realizes that this test could go either way if repeated with even a modest change in the engine.
On my Volvo 5 cylinder na head. I have found that the 60 or 80 grit I use seems to cut away very fast. I've only been working on the exhaust port for now and plan to finish it with a much higher grit. I don't plan to port it, the ports will only be smoothed out from rough casting Marks. I am afraid of touching the valve bowl. The idea is to improve flow across the range not worsen it. Hope I succeed.
Im a hillbilly and did not take it wrong lol,. Great job and insightful info Eric.. Now I'm thinking to myself how will a burr finish work on my bread box tunnel ram.. Hmm lol
Perhaps the burr finish creates a thicker boundary layer, which means the passage that the air can flow through is smaller, and this increases flow velocity at lower RPM, but becomes a flow restriction at higher RPMs, at least vs the 40 grit.
I agree with you... He is seeing a difference in airspeed
My conclusion, on the "as yet seen" smaller manifold, would be velocity. Your dyno mule wanted more velocity, with it's given combination, than that Victor Jr. provided. Just a thought.
First thing in my head, same. That's some pretty good size tunnels for them heads. Also if your 40 grit made more, then air speed a factor once again
It makes sense the burr finish would be better at lower velocity/rpm and once the velocity was enough to prevent fuel dropping out, the rolled finish was better.
Mr. W, what's your thoughts on adding port floor inserts in the old big port 4v Cleveland heads?
Use em they work
At 6200rpm the burr finished combination was moving more air than the 40grit, the burr combination was moving less fuel.
If the burr combo was fuel corrected to match the extra airflow it would of made more power.
Maybe but I doubt it. If you look at 6500 they are almost identical and it still made less power.
@@WeingartnerRacing looking through all the rpm points the burr combo consistently moved more air but didn’t have consistent fueling, when you look at the airflow being higher but the fuel flowing less that says to me that there was a change in booster signal, I’m going to stick my neck out and say that the day the burr combo got run the air temp in the dyno room was higher, either from just a warmer day or from environmental heat soak from multiple dyno runs.
The air temp being higher can effect booster signal and also the airs density overall is less so the engine will make less power even tho it’s moving more air in cfm.
Great video, any chance you are doing one where you go smoother, to see if you get to a point where you start to loose power or flatten off on this combination?
Not on this head combo.
For the power gain it is well worth the time or expense. Super info.
*THIS would be an interesting topic to address*
Old School/Wive's Tale/Rule of Thumb was that having TOO SMOOTH (too fine) of a finish (mirror-like) on the intake floor/runners would hurt Atomization of fuel in Carburetor applications. I wonder if the same rules apply to THE SAME INTAKE MANIFOLD using a Fuel injected setup with a 4150 or 4500 Throttle Body on top of the manifold, where no fuel hits the floor or runners, as the injectors are essentially spraying into the Cylinder Head entrances more or less, bypassing the manifold runners ?
Maybe I will test that one day.
Hey Eric , what power valve and jets you using with gas blocks on 1000 Demon sir? Thanks 🙏👍 the one you use on Dyno mule?
Found your video after watching Darin Morgan's PERA presentation
i wouldnt say burr finish finish makes more power or less power too small of a difference at least in this around 1% but what it does show is it doesnt really matter what finish is used.
This is great info , Thanks for sharing with us again 🙏
Thanks for doing the testing Eric👍
I remember on your second dyno session that you were down from the previous session with the same combo.
And you put it down to weather being vastly different from first session.
And the weather compensation wasn't being used as if I remember correctly wasn't looking to good either.
How was your base line this time session 2 from session 3 ?
The variation seemed pretty constant from session 1 to 2.
Not being picky just interested and thanks for the content your creating 👍
Been following you from the start 👌
Great question. We had a control manifold that was used in the previous session and it made within 1hp. So it was much closer from session 2-3 than 1-2
Thanks Eric for the reply, that makes it interesting👍
Cool video. Thanks for sharing.
So did the BSFC change ? That would say it's fuel related as apposed to air flow
Not enough to make a difference. They are also hard to read because on a carb deal at the start of the pull there is enough fuel in the bowl that it looks like it is not using much until the needle and seat opens.
What I take away from this video is a bit mixed. I couldn't help but notice the notation on the dyno sheets - and the sheet for the unmodified manifold Doesn't List a 1" tapered spacer and the other two do. The reference pull data or "control" isn't valid, or someone forgot the notation for the spacer on that sheet - so without clarification it throws that data out the window.
The other two are within roughly one percent, so (as you mentioned) there's no clear winner.
Some thoughts on the smaller manifold making more power; with a 190cc port and the relatively short cam timing, a smaller manifold might be matching the port size better in terms of flow - the charge not 'ganging up' at the port because the smaller (manifold) port velocity is higher and matches the flow velocity potential of the heads better - also putting cylinder filling about where that camshaft favors the power curve.
Maybe - just thoughts!!!!
I love working with airflow - so much is still a Black Art, so any progress in an as yet untried area is a bigger win yet!!!
All them were tested exactly the same with a a 1inch tapered 4hole spacer.
@@WeingartnerRacing
I wondered, didn't seem like a mistake you would make.
Good video
👍 Hey Mr Weingartner, Have you asked TrickFlow if you could get a sample of their new SBC single plane intake for large cubic inch engines?
Would be nice to see it compared to all that you've tested so far.
Keep up the good work.
I already tested that manifold in the first dyno session.
@@WeingartnerRacing Woops, pit of shame for me.
I only use the sanding rollers to give everything a nice uniform finnish. Usually intakes I will do a 60 grit (just a personal prefernce) now as for Exhaust and cumbustion chambers I try to go for a "glass" feel just to keep carbon deposits down and stop detonation. I am no means a pro head porter but I have goten good flow numbers with heads that I have done. Probably not the best but they seem to make decent improvments, I jysy bought stuf too try and cut valve seats i am going to practice on a junk head I have with valve cut angles.
Dumb question incoming. Have you ever polished the entire intake to a mirror polish, and checked airflow and power on a dyno?
Not dumb at all I don't think
No dumb questions, you don't know until you know!
I haven’t
That's a cool video and I was very curious on the finishes because seems like some people do very aggressive burr, then 40 grit also do you do 60 grit. But awesome results I am glad that your original idea actually made more power than just burr
I know you said don't take it as gospal but it's still cool to see your work and seeing Dyno results. And I am curious to see what manifold did good I was thinking wait is it the victor jr because that one is small. And i was like well how did the Motown manafold do.
@@chevyrc3623 Up till this point the Victor Jr & Mowtown haven't been in his testing. There's a lot of other intakes I would have liked to have seen tested (Holley 300-36, Weiand Speed Warrior Air Gap Style, P P Crosswind, Dart Dual Plane, Brodix HVH 1016, RPM Air Gap, Victor Jr 2975 vs 2900, Tean G 7530, Strip Dominator 300-25 vs 300-110, Mowtown, Dart, Bowtie Single plane) but good luck getting all those together at the same time. Expensive plus the poor guy would have gone to multiple days of testing on each set of heads.
I did test the
Vic jr
Motown 4150
Holley 300-25
Brodix 1016
Team g
Those were in round 3 except the Motown
@@WeingartnerRacing 👍 Nice. Round 3 promises to be an interesting video. Holley 300-110 vs 300-25 might be interesting to test spacers on the 25 to see if it can be better overall than 110 since you can add different types of spacers to get to the same height.
Were you able to test a regular Victor Jr 2975 vs the port matched 2900?
Kind of strange that Edelbrock lists the intake gasket size as a 1206 but when you look at the stated port dimensions the 1205 is a much closer fit.
I'd like to see same test on a 2x4 tunnel ram where there's no plenum floor
I wonder if the reason you got the result you did was that the manifold was pretty well matched in cross-sectional area to what the engine wants
In theory, the rougher the surface finish, the deeper the boundary layer will be, and the part of the port where air flows through smoothly will get smaller
In fact, looking at the graph comparing the burr to the 40 grit looks like it might back that up, with the burred finish showing a small advantage below 5000 RPM
At least, that's the theory. Of course, in theory, theory is as good as practice...
Bottom line: wonder what results you would have seen if you'd had an overly large manifold on the engine. Perhaps the burr finish would have matched or even picked up over the 40 grit?
As always, more of these data points being put up seems to raise as many more questions as it answers.
Interesting video, and really good looking work in the manifold!
Was there any difference in the CO reading on the dyno? Which finish would help more with fuel savings during yellow flags?
The fuel flow was almost identical.
Back when Extrude Hone was being developed it was in all the magazines. I tried to get an intake manifold done and couldn't get them to answer the phone. This was way before the internet. I would love to see dyno and cost comparisons.
Even the Simplest test Comparison can get unexpectedly Complicated....Intake Finish with Jetting Optimization seems to be Need here.......I know dyno testers Prefer Individual Componet change test Comparisons but Intake Finish can be Linked to Jet size as in System A/F tuning Effect on ultimate Power.....Intake Finish Only Power measurements may be an Incomplete conclusion.....
A rough finish grabs air. And air is slick on itself. See golt ball flow and dimple effect.
If it worked like that would have made more power not less. A golf ball flies through air. It’s not the same as air inside of a golf ball surface.
@@WeingartnerRacing not necessarily. It's still air flow.
I think it is a wet flow deal, rough keeps fuel in suspension
Maybe but ultimately we are after most power.
@@WeingartnerRacing I agree the better the fuel mixes the more power it makes. Next time I go into my engine I'll talk to you.
What’s with the 1” spacer hand written on test 2&3 and not one?
They all had a 1inch tapered 4 hole spacer used.
i do understand the if flooring it it will kick down or if you are racing logic, but there is some manual people still left in the world ;)
Downshift
@@WeingartnerRacing never!, i like the feeling of it rolling into power from idle 🤣
Fuel atomization?
So the lesson to be learned is take the intake out of the box and run it.
Diamond cut or straigh cut ? bit..
Single cut burr
Well fun an I agree with we just do not know.
Luckily my customers adore the BURR look!!!! 😅
Maybe but I guarantee at least one person that sees it thinks it’s garbage no matter how fast they go.
@@WeingartnerRacing Some are indeed sceptical. But after 1 race that changes.
Also what you did is something I do pretty long now after 10 years ago I tried improving an Ls7 head with radius seat on intake and grit 60. Airflow improved but power was 2-3 percent less..... esspecially in lower revs. Last year did a BBC with assymetrical seats on intake. Angles where droplets of fuel are smashed along and port almost complete burr finish. Radius seat where only air and tiny droplets flow. Difficult to make but results were awesome.
Similar an Ls of which after overhauling diameter of intake throat was increased by machine shop 0.040" and seats were 0.010" deeper than new and with bit different shape. Engine lost 30 hp. After seats were replaced , with right shape, diameter and depth , and port roughened on specific areas it regained 38 hp first run . Also engine responded more normal to fuel changes / ignition.
Its in the details....
It seems as though all you do is repeat the same apologetic bs instead of just presenting your material. Which is very good by the way.
It’s mostly because I don’t want to deal with argumentative comments.
Who you calling a Hillbilly?🙂 How about giving it a heavy sandblast finish?
I doubt I do that but maybe.
Algorithm
If you got the time, go right ahead and sand it smooth. Can't hurt. Hell, I prefer to sand it clean to make sure i got all the trash out.
The flakes that might come off that burr finish that might break off would keep me up at night to much. I would have to sand it.
Victor Jr?
I think it has to do with the transition of airflow into the runners under dynamic conditions. How fast can the flow be established into the runner when the demand comes on?
I should add that I saw a Hendricks manifold for 18deg Chevy back in those days, and they had a very aggressive finish, but smoother on top and down the runners, etc. Just like you're doing it. I'm guessing they knew what they were doing.