Port Dimpling??
 

You know for years I've seen snippets of people dimpling their intake runners after porting. Logically it makes sense because it's the same system that a golf ball utilizes. When you think about its the basics of Bernoulli's principle. Basically what you're doing is reducing the size of the turbulence on the walls of the runners there by inducing laminar flow and decreasing the pressure of the air forced into the runner. As a result you have more volume of air at any given velocity to cram into the cylinder. Sharks also utilize these mechanics with there skin. We all have heard that a mirror finish will never flow as well and one with a light texture. I have yet to see a definitive study on a flow bench. Just claims and few sheets but not a in depth study? I think there is a chance of great power returns that can be gained here I might throw this into my already large pile of projects. ;-)

just spit balling :cheers:

David Hetrick

Re: Port Dimpling??
 

Cool looking!

I think you want controled turbulence not lessened.

Re: Port Dimpling??
 

That the idea John all surfaces crate turbulence this is taking large turbulence and making it smaller there by increasing the useable volume in the runner.

https://www.youtube.com/watch?v=XkaLsVOrBk0

Dave

Re: Port Dimpling??
 

according to the attached picture-
1-2 hp across power curve (ok, for no costs spared competition maybe)
replace valves every 20 hours???

Re: Port Dimpling??
 

I read that as 1-2hp attributed to the valves alone.

20 hours is not a bad cycle time in pro racing, well up to endurance racing anyway...

- Jeff

Re: Port Dimpling??
 

replies in red...
I wonder how they do with carbon build up on the intake valves?

Re: Port Dimpling??
 

I agree Mike I should have erased that text it seems a touch unresearched and that's one of my points.People make claims without research. I mainly wanted to show just the valves. concerning the carbon build up, with better laminar flow maybe the possibly of build up is less in theory.

Dave

Re: Port Dimpling??
 

I can do dimpled ports, you just don't clean it up with a flap wheel or cartridge.

Re: Port Dimpling??
 

HA!!!

Re: Port Dimpling??
 

Myth Busters dimpled the exterior of a car to see if it reduced drag? Who is first to dimple their Z? Gentlemen get your ball peen hammers and get a swinging.:D
http://i69.photobucket.com/albums/i6...pso3xm3vqu.jpg

It is kinda funny, this theory probably works but when you think of it in these terms i.e. a hail damaged car (lots of dimples) having a lower wind drag due to hail damage is funny.

Re: Port Dimpling??
 

What was the outcome? Did dimpling reduce the drag? Can you make the car draw or fade depending on the swing? Perhaps, even induce power fade?!

Re: Port Dimpling??
 

While I was joking, I was somewhat not....everyone gets excited about pretty porting but top porters will often tell you what looks nice and what flows can be two different things...

Larry Meaux

In 2010 I talked my best engine building customers into letting me try something I’ve wanted to test for the last 30 years or so. I took one of my old chipped up and slightly bent Alumina Burrs and rough ground just the entire intake ports on a big block Chevy Dart head all the way to the bottom valve job angle cut. Back on the dyno the engine gained almost 15 HP on a 950 HP engine. You could theorize that the intake ports are slightly now larger and it should have made more horsepower.

We kept testing this on the next 5 or 6 various types and engine CID sizes, grinding over the previous 60-Grit finish with the rougher alumina burr finish and gaining anywhere from 10 to 15 HP and lower BSFCs and sometimes shifting Peak HP RPM point 100 or 200 RPMs higher.

Textured manifold runner
Textured manifold runner
After those test results I talked another Engine Builder into trying out the rough carbide finish. That engine/car was previously tested on his chassis dyno as a baseline. I originally ported and polished the ports and chambers with 60-Grit finish in the baseline test. Next I rough carbide finished the intake and exhaust ports and chambers. Back on the chassis dyno it gained 17 rear wheel horsepower which is about 20-25 engine flywheel horsepower.

Re: Port Dimpling??
 

If I am interpreting the data correctly, the dimples on the golf ball are not actually for its drive distance per se. It is because the "dimples" create little pockets of low pressure "air" and air to air contact has less friction and allows the ball to fly straight and not wobble in the air. I can see where this possibly too simplistic explanation could also apply to the roughing up of a surface thus creating miniscule pockets of low pressure air that move less slow but allows faster moving air to slide off of it as opposed to all the air in the chamber moving at the same slower speed against a smoother surface. Does that sound right or am I full of it? Keep it PG gentleman.

Re: Port Dimpling??
 

Yes you are right in the ball park excuse the pun. This is also possibly why CNC heads are more favorable over hand ported. They may have the similar amount of material removed but the even lines in cnc porting probably has similar effect to the dimples like I said I need to grab a junk yard head and do some playing on the flow bench.

Dave Hetrick