godlameroso wrote: ↑01 Oct 2017, 17:48
MrPotatoHead wrote: ↑01 Oct 2017, 07:35
NO!
Port Dimpling is nothing but snake oil and no one in F1 does it because of this.
Is It? I've seen it on a few flow benches to know it flows a few more cfm than a standard port job. It's not a huge improvement but it is worth a little power. Not sure if the costs are worth it though.
There is more to what makes a good port than cfm though of course.
While I’m sure there are some specific cases where dimpled ports might flow more in general it only helps if there is something wrong with the port.
All you are doing is increasing the thickness of the boundary layer in the port. This tends to make the port look smaller which can sometimes increase velocity, but in general it’s nothing but hype.
BMW actually publishes a white paper on it back in the 80s and found zero gains from it. If it was worth anything F1 engine builders would have been using it for decades. After all cost is no limit on F1 cylinder heads when it comes to increasing performance.
I’ve personally asked dozens of the best head porters in the world about it and they all have the same opinion that I do.
I’ll save the politics about why port dimpling is pushed by one brand of CNC Machine as this isn’t the place for that.