#21  
Old 06-23-2022, 08:16 PM
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Steve is correct Jim McFarland wrote a lot in Circle Track about using them on heads chambers. He also worked at Edelbrock and told me he helped designed the Pontiac Torker original for Q jets.

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Old 06-23-2022, 09:51 PM
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Quote:
Originally Posted by Half-Inch Stud View Post
So, with dimples, there is a detached layer created that allows the goldball to fly/travel rather straighter.
It sounds like the dimples have some straightening effect, but the main purpose is to reduce wake and make the ball fly farther. That article says a golf ball with dimples will fly twice as far as one without. That’s pretty nuts. Again, no relevance to automotive applications (unless you’re dimpling your body panels like Sirrotica suggested), but still nuts.

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Old 06-25-2022, 08:14 PM
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Don’t go into ports often, but when I do, dimples are there….
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Old 06-25-2022, 09:02 PM
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Quote:
Originally Posted by J.C.you View Post
Don’t go into ports often, but when I do, dimples are there….
Obviously someone believes there's an advantage to pock marks in the port, that's a lot of effort, for no return on investment..........

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  #25  
Old 06-26-2022, 03:21 AM
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Quote:
Originally Posted by Brentco View Post
It sounds like the dimples have some straightening effect, but the main purpose is to reduce wake and make the ball fly farther. That article says a golf ball with dimples will fly twice as far as one without. That’s pretty nuts. Again, no relevance to automotive applications (unless you’re dimpling your body panels like Sirrotica suggested), but still nuts.
I used to golf a lot and I believe the dimples act as sort of high pressure- low pressure areas all over the ball. Like a airplane wing. You have it spinning which helps keep it straight due to gyroscopic/bullet effect and all the high-low pressure areas giving it lift, but in all directions.
So the ball goes farther.
Not sure what any of this has to head porting though. Hard to believe the juice is worth the squeeze.
Maybe it is, who knows ?

  #26  
Old 06-26-2022, 08:44 AM
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We did a lot of Cylinder Head flow testing on accurate Engine dynos with top notch Emissions equipment and never saw
the "bang for the buck" ANYPLACE.

We monitored Tumble and Swirl, did lots of flow testing and head design testing, and the number of valves, size of valves, and valve lift all had a lot of different effects depending on the engine design, so generic statements are fine but not really helpful for lots of combinations that do not fit the model.

Tom V.

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Old 06-26-2022, 10:43 AM
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If the dimple are coated, then the fuel will vaporize. Maybe a NiB magnet in each dimple. Yea.

So, back to the basics:
4-Cycle the straightest intake port with best port/head angle and valve/head angle wins the optimal VE. Wheter direct-port FI or carb'd the only diff will be mixture richness to compensate for chamber fuel dropout.

Time the Exhaust lobe/valve closing to define EGR effect at cruise, scrub compression to mitigate ping, and time the overlap boost at higher rpm. Time the exhaust reflection to enhance the EGR effect at cruise, yet the reflection magnitude kept low to remain insufficient to cause reversion and mitigate reversion at idle to cruise, enhance reversion magnitude (timing about the same mechanically, but not thermally!) to enhance overlap boost at desired rpm( converter initial stall rpm!). Or run open exhaust at the Collector peak pressure zone to promote overlap boost.

2-Cycle: consult an expert. Carb throat CSA, length, crankcase volume&shape, crank shape, port windows (big strategy there), slug dome shape, Head mini-dome shape, proper mix vs pre-mix , and every subtlty you can imagine to keep the slug from burning a hole just when the max boogie is reached.

Shape and time the exhaust reflection for desired powerband vs rpm, or run 1.5" long open exhaust, of near equal CSA as the exhaust port, no flare.

  #28  
Old 06-26-2022, 02:17 PM
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Even with a EFI calibration you still get some "wetting" of the runners prior to the intake valves.

The Calibration guys do the following:

A Throttle blade change, read by the TPS sensor, tells the calibrator whether to add or decrease the pulse width to the injectors for that event.

If fuel is pulled from the runner walls or plenum, the calibrator has the injector reduce the pulse width for that series of combustion cycles, until the HEGO says the air/fuel is where it needs to be for Stoich operation again.
The Government requires running at stoich all the time.

Tom V.

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Last edited by Tom Vaught; 06-26-2022 at 02:32 PM.
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