You forgot to take into account the valve stem.If one has the newer 7mm valves in the 1.9 head you get flow a flow area of 979mm^2 and one a 1.6 with 8mm stems you get 857mm^2That's 14% increase in flow area right there, also port design is better on the 1.9 heads.
i went to the 1y engine because i was told that the valves had 7mm stems...bad thing that of being hard or expensive to increase compression,i was tempted to do a weird franken engine,just because...
...BTW your Bieber avatar is awesome.-Malone
Flow benches can give you the answer you want it to give, It's just a matter of how you set up the test. It's not just the entrance shape of the port that is different. Does he flow test with the correct bore size and with the inlet manifold?Off course your guy gets better numbers on O shaped ports, he is used to working on air cooled engines The valve spacing is different on the 1.6 vs 1.9 head so there is room for bigger valves in the 1.9 head, big advantage if going all out!
Yeah, that is kind of what the machinist was saying trev. It isn't about bigger port, or straight shot, it is about velocity. If you speed up the air right as it enters the cylinder that is best. He seems to think the hydro 1.6 head has the best shape for that as cast and after porting. ....in other news, my head is being welded as we speak. I will post flow numbers when it is in my hands.
Quote from: carrizog60 on December 21, 2012, 06:02:17 pmi went to the 1y engine because i was told that the valves had 7mm stems...bad thing that of being hard or expensive to increase compression,i was tempted to do a weird franken engine,just because...drop a 1.6 head on it if you want more compression..