porting/polishing?

[jdaniels]

@KrazyKid

porting a head changes velocity, volume, laminar flow… lots of shit I don’t know so I wont even bother playing off like I do. What I will tell you is, just making ports bigger isnt how proper porting is accomplished. Infact some builders add material back in in areas to change it around to accomplish the goals they are after.

what motor is this we are talking about anyway?

Also polishing the manifold and head to a mirror finish isnt a good idea either… fuel will condensate on the walls. the small casting pits create a turbulent flow on the surfaces, which help the cold fuel to not come in contact with the hot walls and condensate.

porting the throttle body will more than likely upset the CPU because it knows how big it is supposed to be, and is metered to flow XXX into the manifold. again different platforms respond differently.

Flow is measured rather than guessed, the minute changes aren’t likely to cause issues. The only thing I can think of would be the TPS voltage vs MAP kpa table, and unless the flow is changed substantially there shouldn’t be a problem.

You are correct to state that you do not want a mirror finish on the intake ports. As far as the manifold goes, you can port and polish the plenum, but the runners are better left rough. You CAN swirl polish them, but you are better off just sticking to cleaning up the casting marks.