Author Topic: port mapping (easy way)  (Read 324 times)

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Offline 1manband

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Re: port mapping (easy way)
« Reply #30 on: October 29, 2015, 09:46:00 pm »
tool (file is just above the graph picture)
&
graph
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Offline 1manband

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Re: port mapping (easy way)
« Reply #31 on: October 29, 2015, 09:48:07 pm »
.....have to re-size a graph to go with it (above) .......or just use the one in the article.
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Offline 1manband

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Re: port mapping (easy way)
« Reply #32 on: October 31, 2015, 09:31:03 pm »
.......attached the program again.  previous posted file would not open. 

1.  first download and save the file onto computer.
2.  find file.
3.  right click with mouse, then select 'extract all'...........should open to allow typing in numbers.

....added a graph

file below.
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Offline 1manband

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Re: port mapping (easy way)
« Reply #33 on: December 12, 2015, 11:45:39 am »
updated version 1.1
-a fix and an added graph and some notes
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Offline 1manband

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Re: port mapping (easy way)
« Reply #34 on: December 12, 2015, 12:22:20 pm »
50cc stock porting

TA conditions where it runs out of air at 11400 rpm.......(stock referenced info from magnus' site).
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Offline sharkey

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Re: port mapping (easy way)
« Reply #35 on: December 12, 2015, 05:51:29 pm »
You have done alot of work in this thread.  I appreciate the time you put into it. 

I still rationalize this work the old way, non duration measurement style.   

Offline Chris-PA

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Re: port mapping (easy way)
« Reply #36 on: December 12, 2015, 06:53:43 pm »
I started doing a modification for more square ports, but I've been a bit lazy working on that I'm afraid! 

I still wonder how much these port relationships hold without a pipe.  The pipe effect is so dominant that all porting becomes an exercise in optimizing the pipe, and near as I could tell all the work being discussed was about piped bike engines.  I'm not convinced that the optimum ratios of intake//exhaust/transfer time area would be the same without a pipe. 

Offline 1manband

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Re: port mapping (easy way)
« Reply #37 on: December 13, 2015, 10:43:26 am »
You have done alot of work in this thread.  I appreciate the time you put into it. 

I still rationalize this work the old way, non duration measurement style.   

my goal is not to change the way anyone does things, just to present things that i currently have an interest in.  different way to skin the cat is all.

for me, I look at using time*areas as giving me a clearer idea of what is going on.

Couple quick examples to illustrate this:

Take two ports, one of them being exhaust, other being intake, both being equal in port window area.  Say the exhaust port open duration is 160 degrees, the intake duration being less at 155 degrees.
When using time*areas, you would be able to see that the 155 intake port, has about 30% more exposed open port area, than the 160 exhaust port with a 5 degree longer duration.

Another reason to would be to see blowdown a bit clearer.  Blowdown is more than degrees duration, it is also an area.  The area of the exhaust port exposed before the transfers just start to open.  When the exhaust port for just one example, is widened, the blowdown is changing, even though the degrees still remain at say, 17.

I could post some screenshot examples of these things if anyone is interested.

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Offline 1manband

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Re: port mapping (easy way)
« Reply #38 on: December 13, 2015, 10:45:39 am »
I started doing a modification for more square ports, but I've been a bit lazy working on that I'm afraid! 

I still wonder how much these port relationships hold without a pipe.  The pipe effect is so dominant that all porting becomes an exercise in optimizing the pipe, and near as I could tell all the work being discussed was about piped bike engines.  I'm not convinced that the optimum ratios of intake//exhaust/transfer time area would be the same without a pipe.

Chris, I do have a program that will account for rectangles w/rounded corners shape already.  Thing is, it adds about a thousand rows to the program, this will make the program way too big to post.  It also becomes very time consuming to take the required motor measurements.  You are welcome to it, let me know.

This thread, is about the Jenning's method of time*area.  Keeping in that theme, I presented it in that regard, along with his recommendations for the port time*area ranges.  My point being that I did not want to put a “spin” on his work, but to present it using his information as he originally had done, in case anyone would travel down that road in the future.

Agree with the point that he was writing about piped motors.  After him, Blair also wrote about piped motors.  I don't see that being a stumbling/stopping point to using time*areas at all.

….much like using degrees, nowhere have I seen written that you “have” to set the exhaust port at 190 duration.  Easy to scale down the range for what you want.  Time*area is just a tool, an accurate beneficial tool, but still just a tool.

FWIW, the stock motor example above is dead nuts on Blair's recommendations, for all but the intake port, if that helps.  Blair's work is another can of worms to unravel however.
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Offline countryhog

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Re: port mapping (easy way)
« Reply #39 on: February 01, 2016, 05:28:44 pm »
Good stuff
now is never here but the past is always present.
semper fi ya'll

 

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