jo hastigheten i delar av kanalen är nog nästan lika viktig som totala medelhastigheten nästan.
här nåra ord från darin morgan angående vad som är viktigast i en topp.
I wish I could lay out some quick and easy mathematical equations or some simple guide lines to help, but there simply aren't any. Anyone who states otherwise is analogous to an Old West snake oil salesman. This issue is complex and this is why people have so much trouble with it. I have seen in the past where individuals have tried to concoct irrational ratios or simple equations for advertising purposes, only to confuse and perplex people even more.
There is, however, one tuning variable in the induction system that is not only simple to grasp but just happens to be the most powerful of all. It’s AIR SPEED, or better yet, the average “mean” air speed. What I consider to be the five most important variables used to tune the induction system are listed below:
Average velocity
Individual instantaneous velocities
Shape/design (maximize a homogeneous velocity profile over the entire port and at the same time promote efficient flow)
Rate of velocity change
Air flow
Square ports have an uneven velocity profile causing the air fuel mixture to separate and fall out of suspension.
So it can be said that the most important rules regarding the induction system design are: Velocity, Velocity, Shape, Velocity and last but not least, Air Flow.
Velocity is the life of power! Without the correct air velocity, you can have all the flow in the world and the engine won’t make a lick of power. Air speed within the induction system is the most powerful tuning instrument in the head porter’s arsenal.
Most people think that my job as a head porter and induction system designer is to maximize air flow. Actually, flow is the last thing I look at. Surprising, isn’t it?
Everyone makes such a big deal out of flow numbers that you would think that would be first and foremost in my mind. The truth of the matter is that getting an intake port to flow air is easy. So easy in fact that I can teach just about anyone how to do it in a week or two. Teaching someone how to make the port flow a lot of air while at the same time producing a smooth, even flow with the correct velocities for a given engine combination takes much longer and is infinitely more complex. A good port design will flow a lot of air. The bad news is, a bad port design can flow just as much, if not more, air! If the flow is high and the air speed is too low, what are you missing?
Meticulous measurements are taken in order to plot the velocity gradients through the intake port. The air speeds must be correct or the port will not flow air on the running engine regardless of how much it flows on the flow bench.
Well, acceleration, lower E.T.s and a boat load of mile-per-hour for starters. When the velocity profile of the induction system is tuned properly to the engine combination and the RPM range in which it works, it will accelerate faster off the throttle stop, have faster and more consistent reaction times and just plain go faster from point A to point B. Many of my professional counterparts and I often discuss the fact that flow numbers have blinded the general public. Actually, The four words my professional counterparts and I hate to hear are: ” What do they flow”. When an individual calls me seeking my advice about his future cylinder head purchase, the words, “what do they flow” usually come up within the first minute or so of the conversation and tend to dominate that conversation for its entirety.
föresten din kam seglar nog över havet i morgon
