Port size

[hissingsid]

Hi just wondering what size is the port on a standard 172 at it's smallest after the split? had a engine developed from a standard a 140 head and I'm starting to think it may be to small, mine is 24.3mm at the narrowist part.

 

[sideways danny]

inlet? exhaust? not sure what you're asking really :S

 

[hissingsid]

on the inlet side after it splits into to at it's smallest piont before the valve.

 

[sideways danny]

oh i see. Do you mean you started with a non CNC'd port megane coupe F4R head then? I dont have measurements, but i'd expect a significant difference having seen both

 

[hissingsid]

oh i see. Do you mean you started with a non CNC'd port megane coupe F4R head then? I dont have measurements, but i'd expect a significant difference having seen both

Yes.
Thanks

 

[stan*]

Std is 25mm diam, so mcsa is 982mm^2 for the whole port.

Theoretical calcs would say thats sufficient for about 195bhp (mcsa alone, not considering transition/turbulence/velocity etc).