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Deflectors in inlet ports
Posted: August 19th, 2007, 12:37 am
by superbike
I have seen objects welded into ports on Harleys and a few American v8 heads. Guy would you have any understanding on what they might be doing in this downdraught head ?
Posted: August 19th, 2007, 2:49 pm
by Guy Croft
Chris, hi
could say:
1. Bounces air off short side rad and improves airflow
or
2. Improves fuel mixing
but
3. in view of your experiments with blocking off barrels and examining flow in each - I wonder now if it is to stop vortex formation?
!!
GC
Posted: August 20th, 2007, 8:22 am
by superbike
Guy Croft wrote:Chris, hi
could say:
1. Bounces air off short side rad and improves airflow
or
2. Improves fuel mixing
but
3. in view of your experiments with blocking off barrels and examining flow in each - I wonder now if it is to stop vortex formation?
I have tried replicating from clay (dont know wether metal would be a closer representation due to its more solid mass) When there in such a position the flow picks up by 3 cfm but it only seems to work if you dont blend the seat into the port floor. On my version it seems to work best for airflow positioned at the splitter section not the seat apex as pictured.
I will have to get the tecnoweld out this week and try.
!!
GC
Posted: August 20th, 2007, 6:06 pm
by superbike
I actually found a few hours to spare today and tested 2 totally stock heads using the same test (1 valve shut at a time). One was 30cfm lower at 15mm lift just like my improved versions. I also tried the air deflectors in a number of places and no difference was made.
They must be there for fuel optimisation