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#1
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Cylinder head dimples/golf balls Q
I watched a David Vizard video the other day around head porting and tests he has done. Very interesting stuff indeed.
He said dimpling/golf balling the head while extremely expensive has great benefits but did not elaborate. I thought i saw some photos of heads that had this type of work done and certainly looked unique. what's the benefit of it? would you do it to the intake manifold as well? anyone ever have it done or know someone that has? is it something that only works with big cam lifts or large CFM heads? how complicated is it to do? and if it's that beneficial why wouldn't aftermarket cylinder heads have that as an option to buy if its something a CNC machine can do? After seeing Davids video and mentioning of the golf balling, i did a quick youtube search about golf balls and there are many out that explain why they have dimples, however i haven't had a chance to watch them. I'm sure there is a science to that, and is that why its applied to heads? |
#2
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PY has had some discussions on this.
(along with the grooves in the head chamber/deck) I think more people/porters are using a rough grind now on ports and chambers?
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John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
#3
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Would defeat the purpose of dimpling to begin with. Polishing the chamber is to prevent carbon buildup. Dimpling on the combustion side of the chamber enhances the swirling of the intake charge. Carbon buildup in the chamber would negate swirling. All the dimpled combustion chambers I seen( ARCA and NASCAR) have polished combustion chambers.
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“It takes considerable knowledge just to realize the extent of your own ignorance.” Dr. Thomas Sowell |
#4
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Quote:
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“It takes considerable knowledge just to realize the extent of your own ignorance.” Dr. Thomas Sowell |
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#5
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https://www.facebook.com/groups/clio...3040043844660/
Does dimpling intake ports work? Opinions here: https://cliosport.net/threads/does-d...ork-no.817453/ A fwiw, Jim McFarland published quite a bit in Circle Track magazine including tech material on dimpling. https://www.motortrend.com/how-to/en...ixture-motion/ "Of course, and we sometime get a little push-back on this notion, there's always the approach whereby the surface texture of the inlet track (manifold runners, cylinder head ports and combustion space (chambers and piston crowns) can be roughened (or dimpled) to create little eddys or Von Karman rings that energize flow surface boundary layers and improve fuel atomization. In this regard, and as a point of interest, I've heard from some engine builders that have given this approach a chance and were pleased by the results. Might give it some thought. It's not magic." https://www.motortrend.com/how-to/en...y-faster-burn/ .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE Last edited by Steve C.; 06-22-2022 at 11:19 AM. |
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#6
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Mythbusters a few years back covered a Ford Focus in clay, and dimpled the surface for aero, They said it helped more than just a percent point on drag.
26 MPG without dimples, 29.65 MPG with dimples, Here's a clip from that episode: https://www.youtube.com/watch?v=VUiGhyHC-1A Car makers say the reason for not making it, is they don't believe it would sell. |
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#7
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I believe Meaux did some back to back dyno tests and the dimpled ports made more power on the application he was testing.
There should be more golf ball experts in cylinder head r&d
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1963 Cat SD Clone (old school) streeter 1964 GTO post coupe, tripower, 4speed (build) 1965 GTO 389 tripower, 4 speed, driver 1966 GTO dragcar 1966 GTO Ragtop 1969 Tempest ET clone street/strip 1969 GTO Judge RA lll, auto 1969 GTO limelight Conv. 4speed go and show (sold) 1970 GP SSJ 1970 GTO barn find..TLB…390 horse?….yeh, 390 1972 GTO 455 HO, 4 speed, (build) 1973 Grand Safari wagon, 700hp stoplight sleeper 525ci DCI & 609ci LM V head builds Last edited by J.C.you; 06-22-2022 at 12:50 PM. |
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#8
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"It works on golf balls because those fly through the air."
Let's talk dimple porting. Effective practice or unnecessary wallet-lightening? Is the juice worth the squeeze? https://www.facebook.com/EngineLabs/...254091/?type=3 "At the risk of oversimplification, these are similar to the effects of dimples on a spinning golf ball. In the case of the golf ball, they tend to provide flight stability (as opposed to no dimples). In an engine's inlet air/fuel charge path, they can help put fuel that has become separated from the air stream back into some measure of suspension for combustion enhancement, certainly when compared to un-combusted fuel that passes directly out the exhaust system." From the Jim McFarland Mixture Motion link I posted above. .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE Last edited by Steve C.; 06-22-2022 at 01:35 PM. |
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#9
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thanks for the info guys, some good replies
and very odd about dimpling a car and actually trying it.... who would have thought that |
#10
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Here is a link to Larry Meaux's thread (not sure if you have to join this one though):
Rough Texture Some of the pics are missing now. (photobucket) I think there are some golf ball dimples in there also.
__________________
John Wallace - johnta1 Pontiac Power RULES !!! www.wallaceracing.com Winner of Top Class at Pontiac Nationals, 2004 Cordova Winner of Quick 16 At Ames 2004 Pontiac Tripower Nats KRE's MR-1 - 1st 5 second Pontiac block ever! "Every man has a right to his own opinion, but no man has a right to be wrong in his facts." "People demand freedom of speech to make up for the freedom of thought which they avoid." – Socrates |
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#11
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I talked to Don Johnston about this yrs ago. I saw pictures of this used on heads that supposedly came from Smoky.
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#12
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In theory, dimples would increase the turbulence of the layer of air along the surface of the head. However, it seems that dimples are very sensitive to size and shape, so it would likely take a lot of testing to get the optimum config to make them work, as well as precise manufacturing. As far as aftermarket cylinder heads go, I don’t think that a CNC would be able to make dimples, at least not uniform ones on the inside of a curved surface?
The main benefit of dimples on a golf ball, reducing drag, wouldn’t apply to heads. When the air is flowing around the exterior of an object like a golf ball (or the exterior of the car on Mythbusters) dimples reduce the wake behind the car and reduce total drag. Since the air is flowing through the interior of the head, there is no rear of the object, and no wake for the dimples to reduce. Dimples in a head would actually slightly increase drag, in theory, but also add some possibly helpful turbulence. https://www.scientificamerican.com/a...es-in-golf-ba/
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1976 Trans Am Buccaneer Red 468ci, 10.5:1 CR, 87 CC RPM CNC e-heads, HR 282/288, 230/236, 561/.573 lift, Johnson Lifters & HS 1.65 Rockers |
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#13
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Your comment that it would likely take a lot of testing to get the optimum config to make them work mirrors comments regarding Jim McFarland and his work.... he championed the use of strategically placed dimples in combustion chambers and on piston tops. Further, it may have worked for him using wet flow and computational fluid dynamics to develop. Those foolish enough to place random dimples on their pistons were no doubt disappointed.
Here: https://i.postimg.cc/9MQf7Zxq/Jim-Mcfarland-piston.jpg .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
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#14
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I wonder if all the big gas engine mfgs,International example ever fooled with 'dimples,and other ways ' to improve flow? I never witnessed any.
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#15
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John, My computer software say that Larry's site has a massive amount of Malware
installed on it. BEWARE BEWARE. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#16
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My dad had a quip-joke: " Golf would become interesting again of they used goldballs without dimples."
So, the ball will knuckleball through the air without the dimples. So, with dimples, there is a detached layer created that allows the goldball to fly/travel rather straighter. As for slicing/hooking the golf ball, the dimples perform like baseball stitching for the curveball. Flow for HP: darn sure the inhale tract needs to be straight from fuel intro to intake valvehead. Valve needs a certain angle for best flow past the valvehead. Smooth inhale tract is still best for least CSA, and texture causes an increased boundary layer thickness causing need for more CSA to flow same as smooth& straight. Combustion chamber: You must go figure that dimpling does ZERO for gaseous fuels like Propane, hydrogen, methane. However, i reserve an open mind to the effect on liquid fuels such as Gasoline and diesel. Dimple away, but oh my, that piston head sure drops liquid fuel no matter whut. A carefully controller experiment would perfor fine-grain "jetting" adjustments to measure the chamber dimpling advantage. A leaner "jetting" for same HP under load & rpm would reveal the advantage. However small or large the jetting to leaner was, that would be advantage for reduced carbon,wear,and efficiency. Surely ping could remain independent and behaved for same octane...right? LArry Meau's site was safe, but been awhile since last visit, so good to know not to use a home 'puter to visit. Last edited by Half-Inch Stud; 06-23-2022 at 01:17 PM. |
#17
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Quote:
What software is giving you this? I was logged into Larry's site this morning using FireFox as my browser and Avast as my AV and got no notice of any problem. Stan
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Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#18
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I use Firefox and a very good Virus Scanner Tool that gets monthly updates.
Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#19
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There's a BMW shop in the Kansas City area called Metric Mechanic. They have a patented process called Surface Turbulence, where they add concentric grooves inside the ports and on the valves themselves. They claim it increases flow numbers and improves atomization. I think the idea is similar to putting dimples in the surface.
I looked around on their website a bit and didn't find any specific information on how it's done (after all they have a patent on it so I suppose they don't want to give out too much information) but there are pictures of their modified heads and valves out there on the Web. |
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#20
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The only place dimples make sense in an engine is on any short side radius. The reason a golf ball flies further is that the dimples allow the air to remain attached longer, reducing base drag. On a SSR, dimples will allow air flow to remain attached longer, facilitating an easier turn into the cylinder.
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