Head flow testing.
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Foxy said:
Yeah, at some point Jim will get bored with motorcycle heads and start flow testing the other heads, the ones you pee into. :mrgreen:
marinatlas said:
It didn’t take long for others to turn this page into toilet humour, did it :!:
Putting that aside, it is well know that the water drains down a plughole in opposite directions depending on whether you are in the northern or southern hemisphere, and neutral at the equator.
It would be of some interest if anyone this side of the moon had found if it has any beneficial or adverse, or even neutral effect on the gas flow in the inlet ports depending on whether you have a swirl effect on the inlet port right, or left hand and you are in the opposite part of the world :?:
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marinatlas said:
Bernhard said:
Agreed.
Bernhard said:
Spot on.
Bernhard said:
I really doubt there is any significant effect as it lacks the time and/or distance to make any difference. The applied and measurable effects I am aware of are as mentioned with water running down a drain, long range artillery and underground mine hoist balance ropes.
Maybe someone who is into making and marketing Norton shit should come up with a bolt-in fix for the 32mm Norton heads, the RH4 and Combat etc.. It would be similar to what Norton did on the early 650 and 88ss bikes, a pair of metal sleeves that would go into the port and knock it down to a smaller size. They could even be made eccentric to put more thickness at the bottom, raising the port floor and increasing the short-side radius and not dropping the roof as much. If sold with flow and dyno charts, could be the best and cheapest bolt-on for a lot of Commandos out there....
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Fascinating head porting article with imperfection features that may apply somewhat to Nortons
http://www.theoldone.com/articles/h22a_head/
http://www.theoldone.com/articles/h22a_head/
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Bernhard said:
The coriolis effect is too weak to affect little things like drains and plugholes. The shape of the basin and any movement in the water has a far greater effect.
If you go to the equator in Africa and a guy with a basin charges you money to watch the water going down anti clockwise in the north, then steps over the equator and it goes the other way.... you've been scammed. He's swirling the water himself :wink:
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Foxy said:Heres a pic of a golf ball port job done, supposedly creates a laminar flow. Wondering Jim if you ever had a tinker with this concept?
As far as I know the dimples on golf balls only work when the flow is separating from a body with abrupt changes in section... like a golf ball. If a body ( or port wall) is streamlined with smooth changes of direction, the dimples will be counter productive.
At east , that's what I've read. If someone has flow bench tests to show otherwise, Id be interested to see them.
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Duh, vortex generators and dimpled surfaces are proven in lots of different port flows and wing streamlining, but duh it only works where AND when boundary layer gets so thick and sluggish it swirls back on its and blocks the desired port flow or wing drag reduction. But but but, There Are Two Reasons For Textured flow surfaces. One is more flow or speed per pressure difference in bends, the other is more turbulence to return fuel to air flow off the wetted walls in bends. These two functions can be combined of course but easy to confuse. Dimples in a bend are fuel turbulizers and generally bigger than, vortex generators, lips, points, grooves, before a bend, that are more thin boundary layer engergizers/turbulizers to allow more boundary layer to get swept up with the main flow and hand tighter in bends faster before tumbling eddies backwards against flow. Feul injected close to valve or direct in chamber fuel injection may not get any improvement with the 'golfball' port example as texture appears in a bends large radius so its more a wet fuel lifter than flow increaser.
If ya read last article closely might catch the special note about the desired MIS-MATCH of carb manifold and head. I know of 3 examples that a lip, misalignment or rough intruding gasket made a great improvement and comnoz is one of them. Fun stuff experimenting with flow tricks and treats.
If ya read last article closely might catch the special note about the desired MIS-MATCH of carb manifold and head. I know of 3 examples that a lip, misalignment or rough intruding gasket made a great improvement and comnoz is one of them. Fun stuff experimenting with flow tricks and treats.
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Foxy said:Heres a pic of a golf ball port job done, supposedly creates a laminar flow. Wondering Jim if you ever had a tinker with this concept?
Yes I have experimented with that. The only place where I have seen a slight improvement in flow was when it was done on the short side radius as it curved toward the seat. I didn't find much difference but I haven't spent much time with it either. I have thought I would like to play with the idea some more now that I have the port mapping system and see what I could do. Jim
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According to HOBOT's reference, the dimples offered a 3.7% increase in power. For a Norton with 80 RWHP that equates to an additional 3 HP.
It would be interesting to see where these numbers come from and to see a comparative analysis to the NACA duct on the port floor that Lotus and others have tried. Bench flow and dyno comparative results would be good to see.
It would be interesting to see where these numbers come from and to see a comparative analysis to the NACA duct on the port floor that Lotus and others have tried. Bench flow and dyno comparative results would be good to see.
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i challenge you to a bow and arrow duel at 1000 paces Dance's!
So 80 hp or 83 hp, hm, best pilots can feel 5-10%, but clocks even less. I suspect any builder would be jumping up and down by removing friction for extra an 3.7%.
These texture features can help but who knows how much or if hurts flow, in every style head. Surely you racers have had pleasant surprises on various or expedient combos. Ask comnoz about his manifold bolt mis-match flow surprise. That may be a clue for a few more percent in already hi flow tuned heads.
Here tease these guys about sloppy fit
http://speedtalk.com/forum/viewtopic.ph ... d5a1f8142b
So 80 hp or 83 hp, hm, best pilots can feel 5-10%, but clocks even less. I suspect any builder would be jumping up and down by removing friction for extra an 3.7%.
These texture features can help but who knows how much or if hurts flow, in every style head. Surely you racers have had pleasant surprises on various or expedient combos. Ask comnoz about his manifold bolt mis-match flow surprise. That may be a clue for a few more percent in already hi flow tuned heads.
Here tease these guys about sloppy fit
http://speedtalk.com/forum/viewtopic.ph ... d5a1f8142b
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HOBOT, my great and worthy opponent; 1,000 paces each - that's nearly 2,000 meters. I'll take you up on a day that I am not too busy.
Squeeking out a few horsepower here or there becomes significant as you approach the upper practical limits of a Norton engine build.
Dimples in ports has always intrigued me and I suspect these are enhancements for less than "ideal" ports. As I stated earlier, it would be good to see some comparisons of the NACA port floor versus dimples on inside bend; both bench flow and dyno results. I suppose a lot has already been done already with Computational Fluid Dynamics (CFD); maybe an SAE literature search might shake something out.
Squeeking out a few horsepower here or there becomes significant as you approach the upper practical limits of a Norton engine build.
Dimples in ports has always intrigued me and I suspect these are enhancements for less than "ideal" ports. As I stated earlier, it would be good to see some comparisons of the NACA port floor versus dimples on inside bend; both bench flow and dyno results. I suppose a lot has already been done already with Computational Fluid Dynamics (CFD); maybe an SAE literature search might shake something out.
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hobot is not a proper name that deserves any capitalization. I'm just a pilot so dependent on real builders to advance Commando "style" engines. My hobby project is to put down smug leaning elites in a hurry and not lost ground in the opens. Racing has a lot to do with cheating w/o getting caught. The few articles I've read on this texture stuff implies its only detectable in the already maxed out engines and the more maxed out the more these little things add up. When it happened to me on 2 stroke outboard and Ms Peel, it was a dramatic surprise improvement.
Try a simple experiment, make manifold gasket that intrudes into the air flow 1/16" in a ragged saw tooth, especially on the lower half. Another way is putting a bigger carb on a smaller manifold w/o blending all the lip away, especially at the bottom.
Get the head and bike dialed in and rider that's familiar with it and lets get in on.
Try a simple experiment, make manifold gasket that intrudes into the air flow 1/16" in a ragged saw tooth, especially on the lower half. Another way is putting a bigger carb on a smaller manifold w/o blending all the lip away, especially at the bottom.
Get the head and bike dialed in and rider that's familiar with it and lets get in on.
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Have not found online references but spraying paint or dusting power like Bon Ami into intake then open to see where its hanging up or collecting on surfaces can guide lips and texturing placement. Bon Ami never scratched anything just polishes it cleaner.
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hobot said:
No worries, I was just shouting :lol:
hobot said:
I hear black helicopters in the distance. Time to put the tinfoil hat back on.
hobot said:
Interesting stuff (flow & fuel dispersion) but I am asking myself why the dimples in intake ports is not prevalent in internal combustion motors (race or otherwise)? Besides the extra machining required, I am wondering (out loud) if there are some performance drawbacks to dimpling.
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Interesting stuff (flow & fuel dispersion) but I am asking myself why the dimples in intake ports is not prevalent in internal combustion motors (race or otherwise)? Besides the extra machining required, I am wondering (out loud) if there are some performance drawbacks to dimpling.Hm, rational comment, keep that self med going eh. I've studied this enough now to make some sense out the principles and where it might apply but its a chaotic situation that only trial and error can show if worth it or not. The basic trade off is the drag of the roughness/dimples/cross hatching or the projections, lips, groove vs the extra streamlining or fuel re-energizing.
Aircraft and cars use yard strips to see where and when eddies occur. I get to see this on my Gravel travel dusting leading and trailing surfaces. All's I can think to indicate flow, collisions and eddies inside head is spray paint or powder after a spray of wd/40?
Fuel droplets mass throws them to outer radius of bend or blasts them into chamber surface and rising piston crown. This is where dimples and cross hatching has helped get fuel back in flow. I think Norton intake blasts mostly strikes between the exhaust valve then bounces off to strike between the exhaust valve and plug. It would be better if blast hit the exhaust valve more.
Its about a thumb print area that gets my attention to mess up some how.
Maybe a patch of dimples or linear grooves cross wise to flow would stumble the the blast bounce off to let more of the blast flush over the hot valve. ???
I don't think this would interfere with basic swirl induced by our off set two valves. Swirl lasts longer than tumble as compression thickens mixture to almost honey like.
Here's what I think might apply to guide post, a shallow groove on one side or both depending which side of the guide might help the blast sweep into the chamber. Symmetric don't always apply in asymmetric paths, but mixture is flowing past both sides, so nothing for it but trial error measuring.
http://www.princeton.edu/~asmits/Bicycl ... mbined.GIF
I'd want to try spiral rifling like ridges in the manifold bend, as Victor
Viktor Schauberger did to run too big of logs in too little of water in log chutes. He got into vortex areo dynamics too with some of the Nazi saucer ships
I'd try a downward offset of the manifold to head for .05-06"-ish trip up lip.
A rough expedient gasket intruding was part of past Peels accidental spunk to flat run out form under if not locked in first. Another was standard 28-ish mm head that may of worked even better if shaved for 10-ish CR. If I ever put past Peel's combo together again I will for sure try it before and after a shaving to get sense of the CR effect in a mere factory Combat.
I'm holding out for a set of Antelope headers
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