" polishing ports to a mirror finish. This actually does more harm than good. Remember it is not only air which is flowing but atomised fuel along with it. The problem with fuel is that, since it weighs more, it's difficult to keep it evenly mixed with the air as it follows the contours of the port."
" he next time you drive a car in the rain, notice that when the car is going 60 KMPH, the rain drops go up the hood of the car at walking speed. That's because the smooth surface of the car creates what's known as a boundary layer, and the portion of that layer of air that's nearest to the surface is almost still.
The same thing happens inside an intake port. Except instead of raindrops, it is fuel droplets that will run down the port wall slower than the air.
That causes a serious change in the fuel air mixture by the time it reaches the cylinder, ruining much of the engine's potential power. Polishing the port walls will ensure this happens.
Instead, by making a series of rough 60 grit lines that purposely go against the flow, the ‘boundary layer area’ will be turbulent, and the fuel will stay well mixed and suspended in the air.
Remember: Rough is Good !!"
Source:
http://auto.indiatimes.com/articlesh...,prtpage-1.cms
Now many a times i have see that shaving and shining the ports seem to be a std level 1 mod for almost all car entusiasts!
Can someone be kind enough to eliminate the doubt?
Thanks,
Madan