Posted: Mon May 29, 2006 10:25 pmGreetings to all! I have lurked about for a while and find this to be about the only site that talks about airflow with any candidness. I hope this topic will stimulate some good discussion.
As an introduction of myself, I am inquisitive by nature,and an enineer by profession. I have been in the field of performance, as a hobby / time consuming love, for around 25 years, the last 10 of which I have owned a Superflow 110 as well as other speed items (shop equipment, a water brake dyno and an interia dyno , low hp applications).
I have dabbled in porting, mainly in the area of single cylinder motors. The brunt of my knowledge is the basic shaping for better flow. The rules generally kept me from furthur modifications.
I now am persuing the automotive realm. My first project is the disection of a Ford v6 head. After making the initial measurements at .050" lift increments, I found the flow platues at around .300", and gains only an additional 10% up to .500". This tells me that the head is throat resticted and could stand a larger valve. But my concern went immediately velocity.
This is where I approach a new area. I really have never explored the velocity profile of a port. So what do I concentrate on and what equipment do I use? I see some of the items, software and hardware mentioned here and I am willing to step up to that level. Any toughts?
As my example goes, as I deleved into this mystery, I probed a little with a homemade verticle u - mamometer and a straight probe and a u probe. I am more confused. The u shaped probe showed literally no positive pressures but negitive. The probe is u shade with the opening facing the airstream. Another thing I found curious is that as I applied clay into the port, I could fill nearly half the port and not have an impact on overall flow! This leads to my topic title. Does this indicate the port SHOULD be filled in? If I reduced the port volume and do not impact the flow through the lift curve, wouldn't velocity increase? And won't that be good for low speed cylinder filling and ulitmately fuel economy and low speed torque? This head would be used on a street driven vehcile with the interest of improve gas mileage and good lowend torque . The motor would never need to produce power at or above 6000 rpm. And, according to the CSA calculator, the port should choke at 8100 rpm (if that is what the calculation provides - an rpm figure). So where to from here? That is the intriguing part of this - the problem solving.
As an introduction of myself, I am inquisitive by nature,and an enineer by profession. I have been in the field of performance, as a hobby / time consuming love, for around 25 years, the last 10 of which I have owned a Superflow 110 as well as other speed items (shop equipment, a water brake dyno and an interia dyno , low hp applications).
I have dabbled in porting, mainly in the area of single cylinder motors. The brunt of my knowledge is the basic shaping for better flow. The rules generally kept me from furthur modifications.
I now am persuing the automotive realm. My first project is the disection of a Ford v6 head. After making the initial measurements at .050" lift increments, I found the flow platues at around .300", and gains only an additional 10% up to .500". This tells me that the head is throat resticted and could stand a larger valve. But my concern went immediately velocity.
This is where I approach a new area. I really have never explored the velocity profile of a port. So what do I concentrate on and what equipment do I use? I see some of the items, software and hardware mentioned here and I am willing to step up to that level. Any toughts?
As my example goes, as I deleved into this mystery, I probed a little with a homemade verticle u - mamometer and a straight probe and a u probe. I am more confused. The u shaped probe showed literally no positive pressures but negitive. The probe is u shade with the opening facing the airstream. Another thing I found curious is that as I applied clay into the port, I could fill nearly half the port and not have an impact on overall flow! This leads to my topic title. Does this indicate the port SHOULD be filled in? If I reduced the port volume and do not impact the flow through the lift curve, wouldn't velocity increase? And won't that be good for low speed cylinder filling and ulitmately fuel economy and low speed torque? This head would be used on a street driven vehcile with the interest of improve gas mileage and good lowend torque . The motor would never need to produce power at or above 6000 rpm. And, according to the CSA calculator, the port should choke at 8100 rpm (if that is what the calculation provides - an rpm figure). So where to from here? That is the intriguing part of this - the problem solving.