Diy Head Port And Polish

[Dale FZ1]

most of the Jap cylinder heads are good from the factory and only need a little clean up

RB heads fit under this umbrella for most people's needs. Rules probably change a fair bit if you're wanting to exceed 500rwhp / 375rwkW.

All the little bits like port matching are great little improvers of flow efficiency on both sides, likewise those bumps in the exhaust ports. The inlet ports are quite large, and given you're talking forced induction there is probably not that much gain from spending wads of time and $$ in that area. Those exhaust ports look to be where the better results are had IMO.

[marksuxass]

I don't understand the appeal of a mirror finish. All the best jobs I've seen on well built engines have been finished with 120grit on a flapper wheel. Mirror finished can be bad, you are prone to a sticky fuel / air / gunk residue on the inside walls of your intake chamber etc if there is a mirror finish. You need a light abrasion given by a flapper wheel with a grade that isn't too fine in my opinion (Newbie / Novice at best) though I have seen some expensive engine builds, along with backyard builds and most in-between.

If you look closely/read what has been written in this thread, the inlet port you talk about isn't polished but finished in 80grit. Exhaust/combustions chambers have only been polished. Just doing what my tuner has suggested.

Think of a golf ball if you don't believe him

See above.

[GTSBoy]

See above.

Which would be fine if it were true. Golf ball dimples are not about drag, they are about lift. Everyone keeps touting the drag myth. In reality, the dimples do in fact grab a thicker boundary layer (as argued by the drag reduction people), but the actual reason that a dimpled golf ball flies further than a non-dimpled golf ball is that the ball is spinning, and the thicker boundary layer causes more lift (the lift results from the back spin). More lift means more flight time and so it goes further.

If you pitch a dimpled golf ball and don't back spin it, then it will go almost exactly the same distance as a non-dimpled, non-spinning ball.

Rough surfaces on inlet ports are a completely different story and not really about the aerodynamics. They are really about providing a surface that does not "wet" the way that a polished surface does when atomised fuel hits it. The increased turbulence and thicker boundary layer around the rough surface do play a part in that.

[zoidbergmerc]

Dimples on golf balls also help with accuracy and flying straight.

Edited November 9, 2011 by zoidbergmerc

[wolverine]

Dimples make chicks look cute too.

[t_revz]

Dimples make chicks look cute too.

+1

[Driftnuttz]

Getting close to putting it in......