Originally Posted by mpgmike
I am proposing that texturing the intake ports creates benefits, and have some data to support that claim. The chosen vehicle is screw threads. Dana44 from another forum uses the scallops caused by a chattering carbide bit as his vehicle and claims very positive results.
If other head porters were to take this subject seriously enough to devise their own tests, and perhaps their own frorm of texturing, this whole "port texturing" theory could be refined into very predictable data.
If this is as significant as I think, .
Intake port surface finish HAS been hashed & re-hashed over and over & over by alot of very noted head porters & engine builders. Your ideas are not new.... It's just that most of the ones playing with this stuff don't share their info/research.
What you are trying to do is create a thicker turbulent boundry layer. It looks great on paper, but every back to back test I have ever heard of on a dyno has showed absolutely zero difference. I know of one noted NHRA Pro Stock builder on the East coast here who was playing with wild textured surface finishes as recently as year ago and saw no gains. No offense, but go get your hands on some Nascar or current NHRA Comp Eliminator or P/S heads and see what they are doing for surface finish. I've had a bunch of Current Nascar P7 Dodge heads in my hands, along with CFE Comp eliminator heads etc. It's nothing "exotic" Most of that stuff is sand rolled with a 60 or an 80 roll to eliminate the "step over" lines from the CNC. Now there is some benefit to "chattering up" the intake seats at the throat area. This helps both with wet flow & also with slowing the airspeed slightly as it is crossing the seat angles.
Sorry, but just my semi educated opinion having ported alot of high end heads over the years, at least on a Naturally aspirated motor (the ones that actually take alot of thinking to make HP out of) There is no benefit ever been shown from a rough surface finish of any kind. And if it does'nt work in NA application like I said that takes everything you can to make power with, I really doubt you'd see any gain an a boosted application either. I used to beat my brain on this very subject for years, I would look at ports & swear a rough carbide intake port HAD to make more power than a smooth one... It just seemed "logical" And yet whenever I talked to guys who had tried it on the big $ stuff it never made anything. After seeing enough big $ heads in person that had very smooth sand roll intake ports, I came to the realization it has to be a pipe dream.
One thing I will say in your defense, is that it won't HURT anything..... so.... Add all the lines/texture you want. It definitely makes it look different/neat.
My best advice would be to start spending more time playing with valve seat angles/widths/top cuts/valve radiuses/back cuts, now there is some-where you can make or break a head power wise. 100 hours of reserach on the seats will yield 100X more power gains than playing with surface finish. ;)