7M ported head pictures
- Thread starter BLACKCAT
- Start date
Sorry right now I dont have access to photobucket right now. But I have pics of mine posted in my thread. post #6 or 7 IIRC http://www.supramania.com/forums/showthread.php?t=74301
Doward;1157399 said:Think of a teardrop falling
Something every 7M owner should be well aquainted with
amichie;1157731 said:
Negative.
http://www.wonderquest.com/beer-streamline-size.htm
Unless your airflow is supersonic?
Sort of an "untechnical" question about a technical subject, but.....
What is the actual speed of the air going through our intake system under boost? Say 14psi, or 24 psi? Meaning through the IC and all of it's piping etc?
I honestly don't even have the slightest clue is why I ask. 100 Km? 500 Km? Anyone have an idea?
What is the actual speed of the air going through our intake system under boost? Say 14psi, or 24 psi? Meaning through the IC and all of it's piping etc?
I honestly don't even have the slightest clue is why I ask. 100 Km? 500 Km? Anyone have an idea?
Flateric;1157859 said:
"Critical" is around 304 Mph/ 0.40 mach and this will change based on pipe diameter/cfm.
2" = 585 cfm max = 304 mph = 0.40 mach
2.25" = 740 cfm max = 304 mph = 0.40 mach
2.5" = 913 cfm max = 304 mph = 0.40 mach
2.75 = 1100 cfm max = 303 mph = 0.40 mach
3" = 1300 cfm max= 301 mph = 0.39 mach
Holy crap thats way faster than I would have ever guessed! Thanks man!
So I was told that smoothing out and polishing the runners on a 7m was actually determental to performance because the pebbly texture was actually better for the supersonic air passing by it. This is obviously false.
I was told this by someone after they saw the litterally 2 weeks of polishing and port matching I had gone through and it's my belief he didn't want to endure the same dirty effort it was.
I personally felt it gave me a little better bottom end, better sounds and just felt "quicker", but didn't know if this was just wishfull thinking on my part after having been down two weeks. I'm not talking earth shatteringly better, but you know, it just felt like a positive change.
Certainly not a negative result by any means anyways.
So I was told that smoothing out and polishing the runners on a 7m was actually determental to performance because the pebbly texture was actually better for the supersonic air passing by it. This is obviously false.
I was told this by someone after they saw the litterally 2 weeks of polishing and port matching I had gone through and it's my belief he didn't want to endure the same dirty effort it was.
I personally felt it gave me a little better bottom end, better sounds and just felt "quicker", but didn't know if this was just wishfull thinking on my part after having been down two weeks. I'm not talking earth shatteringly better, but you know, it just felt like a positive change.
Certainly not a negative result by any means anyways.
You need to work out the actual CFM your Turbo is making at your maximum output then choose a size that keeps it below the .4 mach critical speed.
In the past I did all the calcs and came up with 2.5" as being the ideal for my combination at the time, I changed IC's and as it came with 3" In/Out I made new pipes to suit and to give me some more overhead.
I was fully expecting to experience more Lag either perceived or real and was surprised to find it spooled earlier so "theory" doesn't always play out in the real world!
Having said that Modern BB Turbo's have forced me to reexamine EVERYTHING I thought I knew
As for polishing the insides that's going to promote sticky laminar flow inside the plenum so a pebbly surface is better (think of a golf ball, dimples make them fly further)
In the past I did all the calcs and came up with 2.5" as being the ideal for my combination at the time, I changed IC's and as it came with 3" In/Out I made new pipes to suit and to give me some more overhead.
I was fully expecting to experience more Lag either perceived or real and was surprised to find it spooled earlier so "theory" doesn't always play out in the real world!
Having said that Modern BB Turbo's have forced me to reexamine EVERYTHING I thought I knew
As for polishing the insides that's going to promote sticky laminar flow inside the plenum so a pebbly surface is better (think of a golf ball, dimples make them fly further)