Cafe Racer Forum banner

21 - 40 of 55 Posts

·
Registered
Joined
·
1,898 Posts
champ
tell me about a "vortex type path"... sounds like you listened to a really good salesman.
i think your bike sounds different because of it's exhaust pipe. that being said, it's a fast exhaust pipe 'cause you've got me toasted between 12 and 1.
parks
 

·
Registered
Joined
·
1,898 Posts
champ
tell me about a "vortex type path"... sounds like you listened to a really good salesman.
i think your bike sounds different because of it's exhaust pipe. that being said, it's a fast exhaust pipe 'cause you've got me toasted between 12 and 1.
parks
 

·
Registered
Joined
·
237 Posts
I know what you mean, the sound changes because you change the movement of air through the ports. Most time its hard to tell a difference because airfilters and other panels cover the sound well and plus the if its the first time you heard that bike it will sound normal, but get a stock bike next to a ported bike and it will sound different, plus I'm guessing Champ is using velocity stacks and little paneling around the carbs probably make the sound much more noticable

22/m
1980 Honda CB750
1972 Oldsmobile 442
 

·
Registered
Joined
·
237 Posts
I know what you mean, the sound changes because you change the movement of air through the ports. Most time its hard to tell a difference because airfilters and other panels cover the sound well and plus the if its the first time you heard that bike it will sound normal, but get a stock bike next to a ported bike and it will sound different, plus I'm guessing Champ is using velocity stacks and little paneling around the carbs probably make the sound much more noticable

22/m
1980 Honda CB750
1972 Oldsmobile 442
 

·
Registered
Joined
·
1,898 Posts
champ
you still didn't tell us about the "vortex type path." you don't get off that (what he said) easy.
parks
 

·
Registered
Joined
·
1,898 Posts
champ
you still didn't tell us about the "vortex type path." you don't get off that (what he said) easy.
parks
 

·
Registered
Joined
·
237 Posts
lol I'll take this one too

vortex path is when an object is passing through air or water, its also considered "wake". When is forms a vortex, like a small tornado it sucks it air around it, cause that are to speed up around it causing the air to pass faster and easier over and basically gives a path for the majorilty of air to pass through. Jet fightes are prime examples of this. Jet fighters produce vortex paths at the wing tips, elevator tips, ect. this causes air to be pulled over the plane and gives the air a place to go too, this is very key because it brings down air resistance

This is also key in porting, by roughing up the sides, it causes the air to move in the center and creates a vortex path allow air to pass easier and faster.

The main key is to keep air moving at a near or above mach speed. Thats why small ports are great for low rpm and/or small displacement engines because it can create a high velocity and easier to get to mach speed which fills the cylinder up quickly, BUT it creates prblems because at high rpm or if its a large displacment engine the ports aren't big enough to flow the required volume of air needed. On the oppisite end of the spectrum to big of ports and you can't get to mach speed at low rpms, that creates bog, but at high rpm the air velocity speeds up and more power comes. Larger dispacment also helps the low end bog because your pulling a large amount of air in a large amount of room

Anyways, its complicated but thats the general idea

22/m
1980 Honda CB750
1972 Oldsmobile 442

Edited by - Psyco Diver 69 on Mar 17 2007 10:27:19 PM
 

·
Registered
Joined
·
237 Posts
lol I'll take this one too

vortex path is when an object is passing through air or water, its also considered "wake". When is forms a vortex, like a small tornado it sucks it air around it, cause that are to speed up around it causing the air to pass faster and easier over and basically gives a path for the majorilty of air to pass through. Jet fightes are prime examples of this. Jet fighters produce vortex paths at the wing tips, elevator tips, ect. this causes air to be pulled over the plane and gives the air a place to go too, this is very key because it brings down air resistance

This is also key in porting, by roughing up the sides, it causes the air to move in the center and creates a vortex path allow air to pass easier and faster.

The main key is to keep air moving at a near or above mach speed. Thats why small ports are great for low rpm and/or small displacement engines because it can create a high velocity and easier to get to mach speed which fills the cylinder up quickly, BUT it creates prblems because at high rpm or if its a large displacment engine the ports aren't big enough to flow the required volume of air needed. On the oppisite end of the spectrum to big of ports and you can't get to mach speed at low rpms, that creates bog, but at high rpm the air velocity speeds up and more power comes. Larger dispacment also helps the low end bog because your pulling a large amount of air in a large amount of room

Anyways, its complicated but thats the general idea

22/m
1980 Honda CB750
1972 Oldsmobile 442

Edited by - Psyco Diver 69 on Mar 17 2007 10:27:19 PM
 

·
Registered
Joined
·
3,453 Posts
Christ almighty! It's St Patrick's day! Why the fuck are you guys sitting around discussing head porting instead of getting sick on cheap bad green beer?
Ten years ago, when I helped move my friend Patty move to Chicago, Vortex was a well known gay bar in the boystown neighborhood (clubmans anyone?).

I'm actually ashamed theat I'm sober enough to respond ot this. My wife's upstairs (naked?). Goodnight all.
 
21 - 40 of 55 Posts
Top