E
ed_ma61
Guest
i disagree. port divider edge should be a rounded profile, help prevent boundary layer flow separation from a sharp leading edge
Porting and polishing heads on the 1uz's..
- Thread starter jibbby
- Start date
The 1UZFE EGR Delete Kit is available for sale here.
i disagree. port divider edge should be a rounded profile, help prevent boundary layer flow separation from a sharp leading edge
nah i know that!
we're talking about the little port divider "on the way" to the back of the valve that most people sharpen to a razor blade?
boundary layer separation - google it
In taliking to Gas motorsport and others .. There is low flow around exhaust ports especially..
There are cast ridges inside exh ports just under seat, on the inlet the ports are bigger than valve seats...
i disagree. port divider edge should be a rounded profile, help prevent boundary layer flow separation from a sharp leading edge
Pro
New Member
- Messages
- 1,574
- Location
- Republic of Western Australia
and i'm with ed - round that divider!
i will be focusing on smoothing out the short turn on the inlet and raising the roof on the exhaust port a little.
i've found (with extensive googling and reading this site) that those little bits alon will improve flow and gas speed substantially.
i will be focusing on smoothing out the short turn on the inlet and raising the roof on the exhaust port a little.
i've found (with extensive googling and reading this site) that those little bits alon will improve flow and gas speed substantially.
XR8tt
Active Member
- Messages
- 2,758
- Location
- Sydney Australia
Pro
New Member
- Messages
- 1,574
- Location
- Republic of Western Australia
nah i know that!
we're talking about the little port divider "on the way" to the back of the valve that most people sharpen to a razor blade?
E
ed_ma61
Guest
XR8tt
Active Member
- Messages
- 2,758
- Location
- Sydney Australia
E
ed_ma61
Guest
XR8tt
Active Member
- Messages
- 2,758
- Location
- Sydney Australia
Mine are done much like these.. Around the centre..
http://www.lextreme.com/forums/showthread.php?t=6409&page=5
Don't know if it was the right thing to do but I tried to make both ports the same. I have another set of heads.
Learning big time in this dept...
http://www.lextreme.com/forums/showthread.php?t=6409&page=5
Don't know if it was the right thing to do but I tried to make both ports the same. I have another set of heads.
Learning big time in this dept...
jibbby
New Member
- Messages
- 3,824
- Location
- Santa Monica, California
Wouldn't a sharpened razor edge on the divider sections split the airflow better then a rounded polished edge?
With a rounded edge there is more material mass to slow down the airflow at the split point, no?
Then again if you look at most airplane wings they all have rounded edges rather the razor sharpened edges, hmmm?.. Once again, I am stuped on this discusion and just trying to apply logical sense... I also would venture to guess the best Y and X cross sections splits on the exhaust systems are usually better when sharpended rather then rounded, no? Maybe JB can answer that....
With a rounded edge there is more material mass to slow down the airflow at the split point, no?
Then again if you look at most airplane wings they all have rounded edges rather the razor sharpened edges, hmmm?.. Once again, I am stuped on this discusion and just trying to apply logical sense... I also would venture to guess the best Y and X cross sections splits on the exhaust systems are usually better when sharpended rather then rounded, no? Maybe JB can answer that....
E
ed_ma61
Guest
boundary layer separation - google it
XR8tt
Active Member
- Messages
- 2,758
- Location
- Sydney Australia
Aha I can see why you didn't explain it...
In taliking to Gas motorsport and others .. There is low flow around exhaust ports especially..
There are cast ridges inside exh ports just under seat, on the inlet the ports are bigger than valve seats...
Attachments
JustenGT8
New Member
- Messages
- 2,432
- Location
- Canberra, Australia
Yup you want the flow to 'attach' itself to the runner wall....this becomes the boundary layer and effectively smoothes the path for the rest of the flow and minimises turbulence. Where the boundary layer separates you get much greater turbulence and effectively a smaller port diameter for clean flow.
Kinda counter intuitive but the more rounded leading edge poses far less risk of boundary layer separation
Kinda counter intuitive but the more rounded leading edge poses far less risk of boundary layer separation
jibbby
New Member
- Messages
- 3,824
- Location
- Santa Monica, California
This is deep....I think I just busted a brain cell trying to figure this all out... Let me take a shot at it anyway...
As the air travels thru the ports due to a specific design of bends and turns perhaps prior to the dividing point, this inturn flows the traveling air closer to the runner walls so the split point becomes less of a factor or the rounded dividing point can be made to influence the airflow to stay closer to the walls which benefits the air flow overall.. Something like that in some cases anyway I hope...
So in effect it falls on the design of the heads and runners, angles and bends as to whether you should sharpen or round the dividing split points in some cases... I know there is alot more that can go into this theory but this is the only one I can comprehend for right now....
Back to the spent exhaust flow as another example: If the air is swirling thru a relatively straight designed exhaust system then perhaps a sharpened point divider (X member) may be the more effective choice like in our crossover exhaust systems in our stock SC's and Soarer cars for best exhaust flow....
Ps. Be nice Ed, as I know I am not at the level of comprehension that you are at in regards to this discussion.....
During this discussion in Physic's class in college I was suffering from a nasty hang over from the night before and actually fell asleep during this lecture..:sleeping: ..Oooops, My bad...
As the air travels thru the ports due to a specific design of bends and turns perhaps prior to the dividing point, this inturn flows the traveling air closer to the runner walls so the split point becomes less of a factor or the rounded dividing point can be made to influence the airflow to stay closer to the walls which benefits the air flow overall.. Something like that in some cases anyway I hope...
So in effect it falls on the design of the heads and runners, angles and bends as to whether you should sharpen or round the dividing split points in some cases... I know there is alot more that can go into this theory but this is the only one I can comprehend for right now....
Back to the spent exhaust flow as another example: If the air is swirling thru a relatively straight designed exhaust system then perhaps a sharpened point divider (X member) may be the more effective choice like in our crossover exhaust systems in our stock SC's and Soarer cars for best exhaust flow....
Ps. Be nice Ed, as I know I am not at the level of comprehension that you are at in regards to this discussion.....
During this discussion in Physic's class in college I was suffering from a nasty hang over from the night before and actually fell asleep during this lecture..:sleeping: ..Oooops, My bad...
