Hi All,

About to change the headers as all the flexible joints are breaking down and I know the diameter of the header pipes especially the up pipe are crucial. Can anyone spread some light on preferred diametres of these. V3 STI running a VF34 at 1.5 bar and a decat with 550 injectors. The Harvey up pipe measures 44mm inside

 

For you,, something real slow spooling, don't need too much competition!
Is that box up and running yet?

 

Yip, all fitted and working, got 99 through the speed trap at Curborough but more tail happy which doesn't suit me.