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 #20 on: October 20, 2015, 10:02:13 pm »
how it will work......
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Offline 1manband

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Re: port mapping (easy way)
« Reply #21 on: October 20, 2015, 10:14:43 pm »
......when i last looked into changing degrees into mm's or inches (a year or two ago)......a few of the programs that are available on the web, do not account for 'pin height' (called compression height these days).....and may lead you to some blunders or maybe they are just calc mistakes?  i don't know how they came up with their calcs.......be aware.
knowing where the crown and bottom of skirt position is, the important thing.
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Online srcarr52

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Re: port mapping (easy way)
« Reply #22 on: October 21, 2015, 09:38:57 am »
......when i last looked into changing degrees into mm's or inches (a year or two ago)......a few of the programs that are available on the web, do not account for 'pin height' (called compression height these days).....and may lead you to some blunders or maybe they are just calc mistakes?  i don't know how they came up with their calcs.......be aware.
knowing where the crown and bottom of skirt position is, the important thing.

They are probably calculating the compression height from a given squish clearance, stroke and rod length.

Offline 1manband

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Re: port mapping (easy way)
« Reply #23 on: October 21, 2015, 04:45:55 pm »
......when i last looked into changing degrees into mm's or inches (a year or two ago)......a few of the programs that are available on the web, do not account for 'pin height' (called compression height these days).....and may lead you to some blunders or maybe they are just calc mistakes?  i don't know how they came up with their calcs.......be aware.
knowing where the crown and bottom of skirt position is, the important thing.

They are probably calculating the compression height from a given squish clearance, stroke and rod length.

the first program i made solves it the way you are describing, the degrees change when you pick a your initial and/or final squish clearance that you will be using.

the 'free' programs that i looked at, at that time.....did not have a squish clearance option.  believe they must have worked from TDC=0 only?

whatever the reason, they were off.  at TDC and BDC, piston movement is minuscule, but if it's off there.....than that error widens as CA degrees get larger.

if anyone wants, am willing to share the formula.....and the more difficult aspect of making the formula work with their own program. nothing to hide.

the way i see things going.......in about 5-10 years, the motors will either be strato w/cats or DI.  this stuff is going away fast, and the more people that can keep it going, the better.

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Offline 1manband

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Re: port mapping (easy way)
« Reply #24 on: October 24, 2015, 05:59:15 am »
should have it done today. 
when done, it may have to be broken up into separate tiny files due to file size maximums.
don't know yet of the final file size.
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Offline 1manband

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Re: port mapping (easy way)
« Reply #25 on: October 24, 2015, 07:54:29 pm »
.......just about there.

decided to include 'blowdown' info.  it's not on the graph, but is important.  will take a bit o'time.

a couple of "pay to play" porting programs do not include this.  imo, would stay away from those.

screenshot so far from what i completed just today.

----------------
weird .......got booted to windows screen when trying to post photo.


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Offline 1manband

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Re: port mapping (easy way)
« Reply #26 on: October 25, 2015, 09:36:54 pm »
.....just an update.  getting closer, one step forward two steps back.

using math formula's found previously on the www, led me down to an area calc that is not accurate enough, when checked against my other program.  believe i have got it sorted out now.

cannot add the blowdown portion to go along with the program using jennings calcs alone.  only way i know of doing so, would be converting portion of the program to be bmep based.  have done a straight bmep program in the past, but it's mixing apples and oranges here......i don't have the time.

will be adding a couple of extra features:  one will allow for timing adjustments to be made by either trimming the piston crown or skirts.  the other will show timing changes as the cyl base is machined.  does not make up for lack of blowdown.....but all i can do!

this can consume quite a bit of time......its like trying to get a 100 on a 500 question math test.  lol.


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Offline countryhog

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Re: port mapping (easy way)
« Reply #27 on: October 27, 2015, 08:58:02 am »
excellent work
now is never here but the past is always present.
semper fi ya'll

Offline 1manband

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Re: port mapping (easy way)
« Reply #28 on: October 27, 2015, 07:36:54 pm »
.......got the piston crown/skirt trimming figured out. 

had to scratch the base cut/cylinder dropping tool.  i am limited in working with degree measurements as inputs in the program.  measuring it all in mm is much easier imo.  too many additional calcs and time needed.

think staying w/old school in the ways of jennings is a better 16:1 theme anyway.

putting the finishing touches on the extended graph. 

the points WILL fall on the graph. hahahahaha. 

trying to make sure there are no bugs, by checking everything. 

program is small enough to post here.  though about adding some interactive graphics.......but it would make it too large to post.

filling up a tumbler and giving the eyeballs a rest for today.
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Offline 1manband

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Re: port mapping (easy way)
« Reply #29 on: October 27, 2015, 08:01:24 pm »
small snip of graph........
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