at the bottom of each thread, so they use the "quote" button instead...
This tends to bring about quite a bit of repetition...
By way of an example:
I'm going to pretend to post the intro to the Needles Spreadsheet!
(Here goes!)
Welcome to Needles.ods (Version 024 - 2016/07/03)
The Carburetter Needle comparison and analysis spreadsheet
This spreadsheet is probably the most comprehensive tool available for analysing
or assisting in the choice of SU and Zenith-Stromberg CD carburetter needles.
This is a LibreOffice (.ods) document which should also open in OpenOffice.
Requests to convert this to a “different” format will be futile as the above
software is both easy to obtain and is totally free of charge. The author uses
LibreOffice v3.4 which is highly recommended for all systems that will run it.
For Windows7 and earlier, LibreOffice v3.4 can be downloaded from this link:
LibO_3.4.5rc2_Win_x86_install_multi.exe
For early Macs with the "Power PC" chip using OSX 10.4 and later:
LibO_3.4.5rc2_MacOS_PPC_install_en-US.dmg
For later Macs with the "Intel" chip using OSX 10.4 and later:
LibO_3.4.5rc2_MacOS_x86_install_en-US.dmg
For most other OS's, the latest (untested) version can be downloaded from:
http://www.libreoffice.org/download
General Information:
Before starting, there are some LibreOffice settings that need to be checked or
amended in order to get the best out of this spreadsheet. Please see “How to
optimise LibreOffice Calc” towards the end of this page. Because of variations
in the software, some of these instructions may not be 100% correct.
Unlike other existing utilities of this type, Needles.ods will calculate the
annular area in the jet, i.e. the effective jet area. What this means is that
valid comparisons can be made between needles from different jet size ranges.
For example: A needle for a 90 thou jet can be compared with one for a 100 thou
jet, or a 125 thou jet. (One “thou” is one thousandth of an inch i.e. 0.001”).
If a change is needed from one jet size to another in the same carburetter, this
spreadsheet will assist in finding a needle with very similar fuelling.
Comparisons can even be made between SU needles and Stromberg ones! The author
has investigated using SU needles in Stromberg carbs, and vice-versa. In some
cases, this is entirely possible with only simple modifications being required.
The mounting collar on most of the fixed SU needles is a nominal 0.125”, whereas
the collar on the fixed Strombergs is 0.135”.
Throughout the spreadsheet, diameters are expressed in “tenths of a thou” as
this standardises the way in which the values are quoted in the official needle
charts. A diameter quoted as .099” will be listed as 990, and a diameter quoted
as .0895” will be quoted as 895 . All areas are shown in square thou.
Each jet type has its own data tab which contains the needle chart. These are
provided as being approximate only, as some have been manually keyed and as such
are possibly subject to omissions and data input errors. The needles are listed
conventionally in columns, with the needle name or profile ID being at the top.
The “Basic” tab can be used to make a quick comparison of up to 6 needles of any
type. Simply select the tab names, eg “F100”, and the needle names, eg “RC”, in
the cells at the top of the table. Details of the diameters will be provided
and the chart will show the exposed jet area for each index point.
On the “Advanced” tab, there is the facility to compare two needles from any of
the data tabs in much more detail. Details of the index diameters will be
displayed along with the exposed jet area and a percentage comparison for each
index point. Several fine-tuning modifications and features are also supported.
The name of the “test” needle and the “AVE” (average) needle are also valid
needle names and so can be input in place of an official needle profile. The
lines on the charts will serve as a good visual comparison between the needles.
Changing the “Working Range Index” value on any of the tabs will grey out the
section of the needle which is never lifted out of the jet. This part of the
needle can be ignored as it does not affect the fuel metering.
Charting effective areas is more realistic than comparing the diameters alone.
Consider the two fixed 90 thou needles A5 and W3. The first index values are
890 and 880 respectively and a simple diameter percentage will tell us that W3
is 99% the diameter of A5 at this point. Although only 1% less in diameter, the
needle W3 will allow nearly twice as much fuel from the jet in reality.
Data tabs have comprehensive search facilities. Either of the main needles from
“Advanced” can be directly imported, as can a "Jet Converter" needle. There is
also space for a user-defined “test” needle which can be of any sensible values.
The mode is set in cell "D1" - Select from: "TEST", “NDL1”, “NDL2” or “CONV”.
The spreadsheet will suggest up to 5 needles which are a statistical close match
and the needles suggested can be fine tuned using the “Priority Index” and
“Tolerance” features. A match will always be sought at the “Working Range” of
the needle, but if a match is also required towards the idle end, selecting a
lower “Priority Index” will achieve this. If too many or not enough needles are
found, this can probably be rectified by changing the “Tolerance” value which is
a +/- percentage value and uses annular areas as a comparator. The table will
show each needle in the chart as a percentage of the “test” needle for both the
“Priority Index” and the “Working Range”, in rows 27 and 28 respectively.
The best match needle's column will be highlighted for easy identification.
The suggested needles can then be displayed using tab “Basic” by changing the
“Show Suggested” setting to “Yes” and selecting the correct needle type with the
“... From Tab” setting. If the chart is too cluttered with all of the suggested
needles showing, selected needles can be hidden using the “Show/Hide” pull down.
Consider this example: A dyno session has suggested that an engine needs the
idle end of one needle, say “BC”, and the full power end of say “KU”. On the
F100 tab in the “test” needle, the diameters for indeces 1-6 can be keyed for
“BC” then the diameters for indeces 7-14 can be keyed for “KU”.
The “test” needle will therefore contain:
990,950,910,880,850,825 from “BC”,
then
812,783,756,729,700,673,645 and 618 from “KU”.
For this example, if the “Priority Index” is set half way down the effective
part of the needle at index 6 and the “Tolerance” is set to (+/-)2.75%, the
spreadsheet will suggest four needles. These are RK, ZA, SM and DF.
As detailed above, tab “Basic” can be used to review the results and it will be
seen that the spreadsheet's first choice of “RK” is visually a very close match.
The bias of match can be fine tuned by adjusting the “Priority Index” and
“Tolerance” values.
Alternatively, a data tab can be used to find a swing type needle which is
similar to a fixed type of the same size. On tab "Advanced", select an existing
profile in either "Needle 1" or "Needle 2". On the appropriate data tab, select
the mode in cell "D1", as "NDL1" or "NDL2" and the profile will be imported.
For example, using the diameters from F100/OA7 in the data tab for S100 will
find the needle “BCD” which is a 100% match.
The “Adjust Jet” feature is available for “Needle 2” on the right hand side of
the main table on tab “Advanced”. This will show the effect of lowering or
raising the jet for “Needle 2” relative to “Needle 1”. Matching the idle index
annular area of “Needle 2” to that of “Needle 1” will generate much more
realistic results as the profiles will be aligned as they would be in actual use.
Alternatively, use the feature to predict the amount of adjustment that will be
required in order to obtain the same fuel mixture at idle when changing needles.
Adjustment of the jet by up to the equivalent of one index point can be emulated,
ie 1/8". For example, to wind the jet half an index down, enter 50% using the
pull-down menu, or type "50". Multiples of 5% are valid.
Using percentages allows the spreadsheet to handle the fact that various thread
TPI values have been used by the carb manufacturers on their adjuster mechanisms.
For early SU carbs using 26 TPI adjustment threads:
Each index = 1/8" = 3.25 turns or 19.5 adjustment nut flats
ie each 5% will be equal to about one flat.
For later SU carbs using 40 TPI adjustment threads:
Each index = 1/8" = 5 turns or 30 adjustment nut flats
ie each 5% will be equal to exactly 1.5 flats.
The spreadsheet will automatically calculate the revised diameters of an
“Adjust Jet” needle in the “Result” column. This will facilitate locating a
standard needle to replace an adjusted one.
On an appropriate data tab, set cell “D1” to “NDL2” and this will automatically
import the revised values. Review the results on tab “Basic”, as above.
Some tuners use the “filing a flat down the needle” method of making a richer
needle out of one known to be too lean. The “Filed A/F” feature will show the
results from this technique. “Filed A/F” also available for "Needle 2" on the
“Advanced” tab but the “Adjust Jet” feature must be set to 0% for it to work.
Simply enter the amount filed off the needle at each index point into the
appropriate cells. The values must be entered in tenths of a thou (0.0001”).
The spreadsheet will calculate the area of the part that has been filed off and
will adjust the area displayed for that index to reflect this.
In reality it will be almost impossible to measure the needle at exactly the
correct index points and to arrive at the same values as the official needle
tables. This is the reason why the reduction figure at each index is used by
the spreadsheet as this should be close enough to provide a worthwhile
calculation. Bear in mind that the initial couple of thou will produce a very
small area increase as only the “tangent” point of the circle is being removed.
Once an appreciable sized flat becomes apparent, the area removed will increase
much faster for a given amount of height removed.
The spreadsheet could also be used to intelligently work out how much to file
off a needle in order to achieve a certain percentage area increase. Inputting
the same profile in both “Needle 1” and “Needle 2” will give a good idea as to
what the before and after results will be.
The spreadsheet will automatically calculate the round equivalent of a
“Filed A/F” needle in the “Result” column. This will facilitate locating a
standard needle to replace a modified one.
On an appropriate data tab, set cell “D1” to “NDL2” and this will automatically
import the revised values. Review the results on tab “Basic”, as above.
Owners of vehicles equipped with HIF type SU carbs and some types of 2” SU carb
may have a choice of jet size available to them. The spreadsheet will allow
advanced users to find a similar fuelling needle from different jet-size ranges.
The “Jet Converter” feature at the bottom left side of tab “Advanced” will
re-calculate the equivalent sizes for either needle on the main table, even if
“Needle 2” has been filed or had the jet position modified. If it is not
possible to generate the required area with a smaller jet a '!' is displayed.
On an appropriate data tab, set cell “D1” to “CONV” and this will automatically
import the revised values. Review the results on tab “Basic”, as above.
The “Comments” tab contains a “Lookup” facility which can be used to find
details of comments, needle names and needle part numbers. A comprehensive
database of part numbers for both SU and Stromberg has been provided.
Between rows 21 and 900 inclusive, the “Comments” tab also allows users to save
an individual comment for each needle. The general format for this is:
Column A – NeedleType/NeedleName
(eg “F90/AN” - A forward slash inbetween and no spaces)
Column B – The comment for the needle named in Column A.
Comments for the “test” needle for each needle type are input on the individual
data tabs themselves. They are automatically copied to the “Comments” tab and
no attempt should be made to edit their entries on the “Comments” tab.
When migrating from one version of Needles.ods to another, it is possible to
import the comments tab from a previous version. Please see “How to import the
Comments tab”, further down this page.
Limitations:
Like most utilities, this one has its limitations, and being an editable
spreadsheet is one of them. The spreadsheet is generally protected against
typing in areas which should not be typed in. Areas where user input is allowed
are shown with a pale yellow background. In most cases, invalid user input will
be prevented but this is not guaranteed.
Useful information is provided when some cells are clicked but sometimes this
will not display correctly. Clicking the same cell again should cure this.
Sometimes the help may be intrusive, press the “ESC” key to clear it.
It is not possible to easily import either the test needles for each needle
type, or their associated comments.
IMPORTANT WARNING:
“Copying and Pasting” should be avoided unless the user is able to select
“Numbers Only” when pasting the clipboard contents into the spreadsheet. See
under “Edit/Paste Special” or similar. Ignoring this advice will probably ruin
the spreadsheet formatting and cause terminal damage. The only exception to this
is when copying the “Comments” tab as detailed below.
How to optimise LibreOffice Calc:
(Only available on the spreadsheet version of this page)
Click here for Part 1 (Disable Autoinput)
Click here for Part 2 (Disable Spelling/Grammar Check etc)
Click here for Part 3 (Disable Cursor Movement)
How to import the Comments tab:
(Only available on the spreadsheet version of this page)
Click here for Part 1 (Preparation)
Click here for Part 2 (Copying)
Click here for Part 3 (Pasting)
Click here for Part 4 (Finish off)
Warning:
The software used to operate this spreadsheet is “Open Source” and free. It is
maintained entirely by a community of volunteers and whilst every effort is made
by the numerous programmers to issue a stable product, a small number of “bugs”
may exist which can cause unexpected results, or even data loss.
USERS MUST ALWAYS KEEP AT LEAST ONE BACKUP COPY OF ALL IMPORTANT DOCUMENTS.
Disclaimer:
The author will not be held responsible for any unfortunate events which may
occur as a result of using this facility. It should be used with caution as
some of the needle data has been keyed manually and possibly contains errors,
although every attempt has been made to keep these to a minimum. Cross-reference
to an official needle chart is strongly recommended prior to making any
modifications based on the results from this spreadsheet. The arithmetic and
calculations in general should be correct, but again, this cannot be guaranteed.
This spreadsheet has been created primarily as a technical challenge for the
author, but also as a useful tool for his personal use. The author hopes that
it will also be of benefit to other engine tuners, subject to the above.
E & OE – Use it “as is” and at your own risk!
Updates may become available. Suggestions are welcome for discussion!
Please also feel free to report data corrections required in the needle charts.
Contact: ian(_UNDERSCORE_)robert(.DOT.)hamilton(@AT@)hotmail(.DOT.)co(.DOT.)uk
If you would like to contribute some “beer money” towards this project,
then PayPal donations are welcome using the above email address.
See also:
Ratios.ods
The A-Series Gearbox comparison and analysis spreadsheet
Acknowledgements:
Many thanks go to Mark Forster for hosting this work on his excellent website:
mk1-performance-conversions.co.uk
Copyright © 2016 Ian Hamilton. All Rights Reserved.
n.e.body wrote:Hey, thanks, that's really interesting...ianh1968 wrote: Welcome to Needles.ods (Version 024 - 2016/07/03)
The Carburetter Needle comparison and analysis spreadsheet
This spreadsheet is probably the most comprehensive tool available for analysing
or assisting in the choice of SU and Zenith-Stromberg CD carburetter needles.
This is a LibreOffice (.ods) document which should also open in OpenOffice.
Requests to convert this to a “different” format will be futile as the above
software is both easy to obtain and is totally free of charge. The author uses
LibreOffice v3.4 which is highly recommended for all systems that will run it.
For Windows7 and earlier, LibreOffice v3.4 can be downloaded from this link:
LibO_3.4.5rc2_Win_x86_install_multi.exe
For early Macs with the "Power PC" chip using OSX 10.4 and later:
LibO_3.4.5rc2_MacOS_PPC_install_en-US.dmg
For later Macs with the "Intel" chip using OSX 10.4 and later:
LibO_3.4.5rc2_MacOS_x86_install_en-US.dmg
For most other OS's, the latest (untested) version can be downloaded from:
http://www.libreoffice.org/download
General Information:
Before starting, there are some LibreOffice settings that need to be checked or
amended in order to get the best out of this spreadsheet. Please see “How to
optimise LibreOffice Calc” towards the end of this page. Because of variations
in the software, some of these instructions may not be 100% correct.
Unlike other existing utilities of this type, Needles.ods will calculate the
annular area in the jet, i.e. the effective jet area. What this means is that
valid comparisons can be made between needles from different jet size ranges.
For example: A needle for a 90 thou jet can be compared with one for a 100 thou
jet, or a 125 thou jet. (One “thou” is one thousandth of an inch i.e. 0.001”).
If a change is needed from one jet size to another in the same carburetter, this
spreadsheet will assist in finding a needle with very similar fuelling.
Comparisons can even be made between SU needles and Stromberg ones! The author
has investigated using SU needles in Stromberg carbs, and vice-versa. In some
cases, this is entirely possible with only simple modifications being required.
The mounting collar on most of the fixed SU needles is a nominal 0.125”, whereas
the collar on the fixed Strombergs is 0.135”.
Throughout the spreadsheet, diameters are expressed in “tenths of a thou” as
this standardises the way in which the values are quoted in the official needle
charts. A diameter quoted as .099” will be listed as 990, and a diameter quoted
as .0895” will be quoted as 895 . All areas are shown in square thou.
Each jet type has its own data tab which contains the needle chart. These are
provided as being approximate only, as some have been manually keyed and as such
are possibly subject to omissions and data input errors. The needles are listed
conventionally in columns, with the needle name or profile ID being at the top.
The “Basic” tab can be used to make a quick comparison of up to 6 needles of any
type. Simply select the tab names, eg “F100”, and the needle names, eg “RC”, in
the cells at the top of the table. Details of the diameters will be provided
and the chart will show the exposed jet area for each index point.
On the “Advanced” tab, there is the facility to compare two needles from any of
the data tabs in much more detail. Details of the index diameters will be
displayed along with the exposed jet area and a percentage comparison for each
index point. Several fine-tuning modifications and features are also supported.
The name of the “test” needle and the “AVE” (average) needle are also valid
needle names and so can be input in place of an official needle profile. The
lines on the charts will serve as a good visual comparison between the needles.
Changing the “Working Range Index” value on any of the tabs will grey out the
section of the needle which is never lifted out of the jet. This part of the
needle can be ignored as it does not affect the fuel metering.
Charting effective areas is more realistic than comparing the diameters alone.
Consider the two fixed 90 thou needles A5 and W3. The first index values are
890 and 880 respectively and a simple diameter percentage will tell us that W3
is 99% the diameter of A5 at this point. Although only 1% less in diameter, the
needle W3 will allow nearly twice as much fuel from the jet in reality.
Data tabs have comprehensive search facilities. Either of the main needles from
“Advanced” can be directly imported, as can a "Jet Converter" needle. There is
also space for a user-defined “test” needle which can be of any sensible values.
The mode is set in cell "D1" - Select from: "TEST", “NDL1”, “NDL2” or “CONV”.
The spreadsheet will suggest up to 5 needles which are a statistical close match
and the needles suggested can be fine tuned using the “Priority Index” and
“Tolerance” features. A match will always be sought at the “Working Range” of
the needle, but if a match is also required towards the idle end, selecting a
lower “Priority Index” will achieve this. If too many or not enough needles are
found, this can probably be rectified by changing the “Tolerance” value which is
a +/- percentage value and uses annular areas as a comparator. The table will
show each needle in the chart as a percentage of the “test” needle for both the
“Priority Index” and the “Working Range”, in rows 27 and 28 respectively.
The best match needle's column will be highlighted for easy identification.
The suggested needles can then be displayed using tab “Basic” by changing the
“Show Suggested” setting to “Yes” and selecting the correct needle type with the
“... From Tab” setting. If the chart is too cluttered with all of the suggested
needles showing, selected needles can be hidden using the “Show/Hide” pull down.
Consider this example: A dyno session has suggested that an engine needs the
idle end of one needle, say “BC”, and the full power end of say “KU”. On the
F100 tab in the “test” needle, the diameters for indeces 1-6 can be keyed for
“BC” then the diameters for indeces 7-14 can be keyed for “KU”.
The “test” needle will therefore contain:
990,950,910,880,850,825 from “BC”,
then
812,783,756,729,700,673,645 and 618 from “KU”.
For this example, if the “Priority Index” is set half way down the effective
part of the needle at index 6 and the “Tolerance” is set to (+/-)2.75%, the
spreadsheet will suggest four needles. These are RK, ZA, SM and DF.
As detailed above, tab “Basic” can be used to review the results and it will be
seen that the spreadsheet's first choice of “RK” is visually a very close match.
The bias of match can be fine tuned by adjusting the “Priority Index” and
“Tolerance” values.
Alternatively, a data tab can be used to find a swing type needle which is
similar to a fixed type of the same size. On tab "Advanced", select an existing
profile in either "Needle 1" or "Needle 2". On the appropriate data tab, select
the mode in cell "D1", as "NDL1" or "NDL2" and the profile will be imported.
For example, using the diameters from F100/OA7 in the data tab for S100 will
find the needle “BCD” which is a 100% match.
The “Adjust Jet” feature is available for “Needle 2” on the right hand side of
the main table on tab “Advanced”. This will show the effect of lowering or
raising the jet for “Needle 2” relative to “Needle 1”. Matching the idle index
annular area of “Needle 2” to that of “Needle 1” will generate much more
realistic results as the profiles will be aligned as they would be in actual use.
Alternatively, use the feature to predict the amount of adjustment that will be
required in order to obtain the same fuel mixture at idle when changing needles.
Adjustment of the jet by up to the equivalent of one index point can be emulated,
ie 1/8". For example, to wind the jet half an index down, enter 50% using the
pull-down menu, or type "50". Multiples of 5% are valid.
Using percentages allows the spreadsheet to handle the fact that various thread
TPI values have been used by the carb manufacturers on their adjuster mechanisms.
For early SU carbs using 26 TPI adjustment threads:
Each index = 1/8" = 3.25 turns or 19.5 adjustment nut flats
ie each 5% will be equal to about one flat.
For later SU carbs using 40 TPI adjustment threads:
Each index = 1/8" = 5 turns or 30 adjustment nut flats
ie each 5% will be equal to exactly 1.5 flats.
The spreadsheet will automatically calculate the revised diameters of an
“Adjust Jet” needle in the “Result” column. This will facilitate locating a
standard needle to replace an adjusted one.
On an appropriate data tab, set cell “D1” to “NDL2” and this will automatically
import the revised values. Review the results on tab “Basic”, as above.
Some tuners use the “filing a flat down the needle” method of making a richer
needle out of one known to be too lean. The “Filed A/F” feature will show the
results from this technique. “Filed A/F” also available for "Needle 2" on the
“Advanced” tab but the “Adjust Jet” feature must be set to 0% for it to work.
Simply enter the amount filed off the needle at each index point into the
appropriate cells. The values must be entered in tenths of a thou (0.0001”).
The spreadsheet will calculate the area of the part that has been filed off and
will adjust the area displayed for that index to reflect this.
In reality it will be almost impossible to measure the needle at exactly the
correct index points and to arrive at the same values as the official needle
tables. This is the reason why the reduction figure at each index is used by
the spreadsheet as this should be close enough to provide a worthwhile
calculation. Bear in mind that the initial couple of thou will produce a very
small area increase as only the “tangent” point of the circle is being removed.
Once an appreciable sized flat becomes apparent, the area removed will increase
much faster for a given amount of height removed.
The spreadsheet could also be used to intelligently work out how much to file
off a needle in order to achieve a certain percentage area increase. Inputting
the same profile in both “Needle 1” and “Needle 2” will give a good idea as to
what the before and after results will be.
The spreadsheet will automatically calculate the round equivalent of a
“Filed A/F” needle in the “Result” column. This will facilitate locating a
standard needle to replace a modified one.
On an appropriate data tab, set cell “D1” to “NDL2” and this will automatically
import the revised values. Review the results on tab “Basic”, as above.
Owners of vehicles equipped with HIF type SU carbs and some types of 2” SU carb
may have a choice of jet size available to them. The spreadsheet will allow
advanced users to find a similar fuelling needle from different jet-size ranges.
The “Jet Converter” feature at the bottom left side of tab “Advanced” will
re-calculate the equivalent sizes for either needle on the main table, even if
“Needle 2” has been filed or had the jet position modified. If it is not
possible to generate the required area with a smaller jet a '!' is displayed.
On an appropriate data tab, set cell “D1” to “CONV” and this will automatically
import the revised values. Review the results on tab “Basic”, as above.
The “Comments” tab contains a “Lookup” facility which can be used to find
details of comments, needle names and needle part numbers. A comprehensive
database of part numbers for both SU and Stromberg has been provided.
Between rows 21 and 900 inclusive, the “Comments” tab also allows users to save
an individual comment for each needle. The general format for this is:
Column A – NeedleType/NeedleName
(eg “F90/AN” - A forward slash inbetween and no spaces)
Column B – The comment for the needle named in Column A.
Comments for the “test” needle for each needle type are input on the individual
data tabs themselves. They are automatically copied to the “Comments” tab and
no attempt should be made to edit their entries on the “Comments” tab.
When migrating from one version of Needles.ods to another, it is possible to
import the comments tab from a previous version. Please see “How to import the
Comments tab”, further down this page.
Limitations:
Like most utilities, this one has its limitations, and being an editable
spreadsheet is one of them. The spreadsheet is generally protected against
typing in areas which should not be typed in. Areas where user input is allowed
are shown with a pale yellow background. In most cases, invalid user input will
be prevented but this is not guaranteed.
Useful information is provided when some cells are clicked but sometimes this
will not display correctly. Clicking the same cell again should cure this.
Sometimes the help may be intrusive, press the “ESC” key to clear it.
It is not possible to easily import either the test needles for each needle
type, or their associated comments.
IMPORTANT WARNING:
“Copying and Pasting” should be avoided unless the user is able to select
“Numbers Only” when pasting the clipboard contents into the spreadsheet. See
under “Edit/Paste Special” or similar. Ignoring this advice will probably ruin
the spreadsheet formatting and cause terminal damage. The only exception to this
is when copying the “Comments” tab as detailed below.
How to optimise LibreOffice Calc:
(Only available on the spreadsheet version of this page)
Click here for Part 1 (Disable Autoinput)
Click here for Part 2 (Disable Spelling/Grammar Check etc)
Click here for Part 3 (Disable Cursor Movement)
How to import the Comments tab:
(Only available on the spreadsheet version of this page)
Click here for Part 1 (Preparation)
Click here for Part 2 (Copying)
Click here for Part 3 (Pasting)
Click here for Part 4 (Finish off)
Warning:
The software used to operate this spreadsheet is “Open Source” and free. It is
maintained entirely by a community of volunteers and whilst every effort is made
by the numerous programmers to issue a stable product, a small number of “bugs”
may exist which can cause unexpected results, or even data loss.
USERS MUST ALWAYS KEEP AT LEAST ONE BACKUP COPY OF ALL IMPORTANT DOCUMENTS.
Disclaimer:
The author will not be held responsible for any unfortunate events which may
occur as a result of using this facility. It should be used with caution as
some of the needle data has been keyed manually and possibly contains errors,
although every attempt has been made to keep these to a minimum. Cross-reference
to an official needle chart is strongly recommended prior to making any
modifications based on the results from this spreadsheet. The arithmetic and
calculations in general should be correct, but again, this cannot be guaranteed.
This spreadsheet has been created primarily as a technical challenge for the
author, but also as a useful tool for his personal use. The author hopes that
it will also be of benefit to other engine tuners, subject to the above.
E & OE – Use it “as is” and at your own risk!
Updates may become available. Suggestions are welcome for discussion!
Please also feel free to report data corrections required in the needle charts.
Contact: ian(_UNDERSCORE_)robert(.DOT.)hamilton(@AT@)hotmail(.DOT.)co(.DOT.)uk
If you would like to contribute some “beer money” towards this project,
then PayPal donations are welcome using the above email address.
See also:
Ratios.ods
The A-Series Gearbox comparison and analysis spreadsheet
Acknowledgements:
Many thanks go to Mark Forster for hosting this work on his excellent website:
mk1-performance-conversions.co.uk
Copyright © 2016 Ian Hamilton. All Rights Reserved.
etc etc etc...ianh1968 wrote:You're very welcome...n.e.body wrote:Hey, thanks, that's really interesting...ianh1968 wrote: Welcome to Needles.ods (Version 024 - 2016/07/03)
The Carburetter Needle comparison and analysis spreadsheet
This spreadsheet is probably the most comprehensive tool available for analysing
or assisting in the choice of SU and Zenith-Stromberg CD carburetter needles.
This is a LibreOffice (.ods) document which should also open in OpenOffice.
Requests to convert this to a “different” format will be futile as the above
software is both easy to obtain and is totally free of charge. The author uses
LibreOffice v3.4 which is highly recommended for all systems that will run it.
For Windows7 and earlier, LibreOffice v3.4 can be downloaded from this link:
LibO_3.4.5rc2_Win_x86_install_multi.exe
For early Macs with the "Power PC" chip using OSX 10.4 and later:
LibO_3.4.5rc2_MacOS_PPC_install_en-US.dmg
For later Macs with the "Intel" chip using OSX 10.4 and later:
LibO_3.4.5rc2_MacOS_x86_install_en-US.dmg
For most other OS's, the latest (untested) version can be downloaded from:
http://www.libreoffice.org/download
General Information:
Before starting, there are some LibreOffice settings that need to be checked or
amended in order to get the best out of this spreadsheet. Please see “How to
optimise LibreOffice Calc” towards the end of this page. Because of variations
in the software, some of these instructions may not be 100% correct.
Unlike other existing utilities of this type, Needles.ods will calculate the
annular area in the jet, i.e. the effective jet area. What this means is that
valid comparisons can be made between needles from different jet size ranges.
For example: A needle for a 90 thou jet can be compared with one for a 100 thou
jet, or a 125 thou jet. (One “thou” is one thousandth of an inch i.e. 0.001”).
If a change is needed from one jet size to another in the same carburetter, this
spreadsheet will assist in finding a needle with very similar fuelling.
Comparisons can even be made between SU needles and Stromberg ones! The author
has investigated using SU needles in Stromberg carbs, and vice-versa. In some
cases, this is entirely possible with only simple modifications being required.
The mounting collar on most of the fixed SU needles is a nominal 0.125”, whereas
the collar on the fixed Strombergs is 0.135”.
Throughout the spreadsheet, diameters are expressed in “tenths of a thou” as
this standardises the way in which the values are quoted in the official needle
charts. A diameter quoted as .099” will be listed as 990, and a diameter quoted
as .0895” will be quoted as 895 . All areas are shown in square thou.
Each jet type has its own data tab which contains the needle chart. These are
provided as being approximate only, as some have been manually keyed and as such
are possibly subject to omissions and data input errors. The needles are listed
conventionally in columns, with the needle name or profile ID being at the top.
The “Basic” tab can be used to make a quick comparison of up to 6 needles of any
type. Simply select the tab names, eg “F100”, and the needle names, eg “RC”, in
the cells at the top of the table. Details of the diameters will be provided
and the chart will show the exposed jet area for each index point.
On the “Advanced” tab, there is the facility to compare two needles from any of
the data tabs in much more detail. Details of the index diameters will be
displayed along with the exposed jet area and a percentage comparison for each
index point. Several fine-tuning modifications and features are also supported.
The name of the “test” needle and the “AVE” (average) needle are also valid
needle names and so can be input in place of an official needle profile. The
lines on the charts will serve as a good visual comparison between the needles.
Changing the “Working Range Index” value on any of the tabs will grey out the
section of the needle which is never lifted out of the jet. This part of the
needle can be ignored as it does not affect the fuel metering.
Charting effective areas is more realistic than comparing the diameters alone.
Consider the two fixed 90 thou needles A5 and W3. The first index values are
890 and 880 respectively and a simple diameter percentage will tell us that W3
is 99% the diameter of A5 at this point. Although only 1% less in diameter, the
needle W3 will allow nearly twice as much fuel from the jet in reality.
Data tabs have comprehensive search facilities. Either of the main needles from
“Advanced” can be directly imported, as can a "Jet Converter" needle. There is
also space for a user-defined “test” needle which can be of any sensible values.
The mode is set in cell "D1" - Select from: "TEST", “NDL1”, “NDL2” or “CONV”.
The spreadsheet will suggest up to 5 needles which are a statistical close match
and the needles suggested can be fine tuned using the “Priority Index” and
“Tolerance” features. A match will always be sought at the “Working Range” of
the needle, but if a match is also required towards the idle end, selecting a
lower “Priority Index” will achieve this. If too many or not enough needles are
found, this can probably be rectified by changing the “Tolerance” value which is
a +/- percentage value and uses annular areas as a comparator. The table will
show each needle in the chart as a percentage of the “test” needle for both the
“Priority Index” and the “Working Range”, in rows 27 and 28 respectively.
The best match needle's column will be highlighted for easy identification.
The suggested needles can then be displayed using tab “Basic” by changing the
“Show Suggested” setting to “Yes” and selecting the correct needle type with the
“... From Tab” setting. If the chart is too cluttered with all of the suggested
needles showing, selected needles can be hidden using the “Show/Hide” pull down.
Consider this example: A dyno session has suggested that an engine needs the
idle end of one needle, say “BC”, and the full power end of say “KU”. On the
F100 tab in the “test” needle, the diameters for indeces 1-6 can be keyed for
“BC” then the diameters for indeces 7-14 can be keyed for “KU”.
The “test” needle will therefore contain:
990,950,910,880,850,825 from “BC”,
then
812,783,756,729,700,673,645 and 618 from “KU”.
For this example, if the “Priority Index” is set half way down the effective
part of the needle at index 6 and the “Tolerance” is set to (+/-)2.75%, the
spreadsheet will suggest four needles. These are RK, ZA, SM and DF.
As detailed above, tab “Basic” can be used to review the results and it will be
seen that the spreadsheet's first choice of “RK” is visually a very close match.
The bias of match can be fine tuned by adjusting the “Priority Index” and
“Tolerance” values.
Alternatively, a data tab can be used to find a swing type needle which is
similar to a fixed type of the same size. On tab "Advanced", select an existing
profile in either "Needle 1" or "Needle 2". On the appropriate data tab, select
the mode in cell "D1", as "NDL1" or "NDL2" and the profile will be imported.
For example, using the diameters from F100/OA7 in the data tab for S100 will
find the needle “BCD” which is a 100% match.
The “Adjust Jet” feature is available for “Needle 2” on the right hand side of
the main table on tab “Advanced”. This will show the effect of lowering or
raising the jet for “Needle 2” relative to “Needle 1”. Matching the idle index
annular area of “Needle 2” to that of “Needle 1” will generate much more
realistic results as the profiles will be aligned as they would be in actual use.
Alternatively, use the feature to predict the amount of adjustment that will be
required in order to obtain the same fuel mixture at idle when changing needles.
Adjustment of the jet by up to the equivalent of one index point can be emulated,
ie 1/8". For example, to wind the jet half an index down, enter 50% using the
pull-down menu, or type "50". Multiples of 5% are valid.
Using percentages allows the spreadsheet to handle the fact that various thread
TPI values have been used by the carb manufacturers on their adjuster mechanisms.
For early SU carbs using 26 TPI adjustment threads:
Each index = 1/8" = 3.25 turns or 19.5 adjustment nut flats
ie each 5% will be equal to about one flat.
For later SU carbs using 40 TPI adjustment threads:
Each index = 1/8" = 5 turns or 30 adjustment nut flats
ie each 5% will be equal to exactly 1.5 flats.
The spreadsheet will automatically calculate the revised diameters of an
“Adjust Jet” needle in the “Result” column. This will facilitate locating a
standard needle to replace an adjusted one.
On an appropriate data tab, set cell “D1” to “NDL2” and this will automatically
import the revised values. Review the results on tab “Basic”, as above.
Some tuners use the “filing a flat down the needle” method of making a richer
needle out of one known to be too lean. The “Filed A/F” feature will show the
results from this technique. “Filed A/F” also available for "Needle 2" on the
“Advanced” tab but the “Adjust Jet” feature must be set to 0% for it to work.
Simply enter the amount filed off the needle at each index point into the
appropriate cells. The values must be entered in tenths of a thou (0.0001”).
The spreadsheet will calculate the area of the part that has been filed off and
will adjust the area displayed for that index to reflect this.
In reality it will be almost impossible to measure the needle at exactly the
correct index points and to arrive at the same values as the official needle
tables. This is the reason why the reduction figure at each index is used by
the spreadsheet as this should be close enough to provide a worthwhile
calculation. Bear in mind that the initial couple of thou will produce a very
small area increase as only the “tangent” point of the circle is being removed.
Once an appreciable sized flat becomes apparent, the area removed will increase
much faster for a given amount of height removed.
The spreadsheet could also be used to intelligently work out how much to file
off a needle in order to achieve a certain percentage area increase. Inputting
the same profile in both “Needle 1” and “Needle 2” will give a good idea as to
what the before and after results will be.
The spreadsheet will automatically calculate the round equivalent of a
“Filed A/F” needle in the “Result” column. This will facilitate locating a
standard needle to replace a modified one.
On an appropriate data tab, set cell “D1” to “NDL2” and this will automatically
import the revised values. Review the results on tab “Basic”, as above.
Owners of vehicles equipped with HIF type SU carbs and some types of 2” SU carb
may have a choice of jet size available to them. The spreadsheet will allow
advanced users to find a similar fuelling needle from different jet-size ranges.
The “Jet Converter” feature at the bottom left side of tab “Advanced” will
re-calculate the equivalent sizes for either needle on the main table, even if
“Needle 2” has been filed or had the jet position modified. If it is not
possible to generate the required area with a smaller jet a '!' is displayed.
On an appropriate data tab, set cell “D1” to “CONV” and this will automatically
import the revised values. Review the results on tab “Basic”, as above.
The “Comments” tab contains a “Lookup” facility which can be used to find
details of comments, needle names and needle part numbers. A comprehensive
database of part numbers for both SU and Stromberg has been provided.
Between rows 21 and 900 inclusive, the “Comments” tab also allows users to save
an individual comment for each needle. The general format for this is:
Column A – NeedleType/NeedleName
(eg “F90/AN” - A forward slash inbetween and no spaces)
Column B – The comment for the needle named in Column A.
Comments for the “test” needle for each needle type are input on the individual
data tabs themselves. They are automatically copied to the “Comments” tab and
no attempt should be made to edit their entries on the “Comments” tab.
When migrating from one version of Needles.ods to another, it is possible to
import the comments tab from a previous version. Please see “How to import the
Comments tab”, further down this page.
Limitations:
Like most utilities, this one has its limitations, and being an editable
spreadsheet is one of them. The spreadsheet is generally protected against
typing in areas which should not be typed in. Areas where user input is allowed
are shown with a pale yellow background. In most cases, invalid user input will
be prevented but this is not guaranteed.
Useful information is provided when some cells are clicked but sometimes this
will not display correctly. Clicking the same cell again should cure this.
Sometimes the help may be intrusive, press the “ESC” key to clear it.
It is not possible to easily import either the test needles for each needle
type, or their associated comments.
IMPORTANT WARNING:
“Copying and Pasting” should be avoided unless the user is able to select
“Numbers Only” when pasting the clipboard contents into the spreadsheet. See
under “Edit/Paste Special” or similar. Ignoring this advice will probably ruin
the spreadsheet formatting and cause terminal damage. The only exception to this
is when copying the “Comments” tab as detailed below.
How to optimise LibreOffice Calc:
(Only available on the spreadsheet version of this page)
Click here for Part 1 (Disable Autoinput)
Click here for Part 2 (Disable Spelling/Grammar Check etc)
Click here for Part 3 (Disable Cursor Movement)
How to import the Comments tab:
(Only available on the spreadsheet version of this page)
Click here for Part 1 (Preparation)
Click here for Part 2 (Copying)
Click here for Part 3 (Pasting)
Click here for Part 4 (Finish off)
Warning:
The software used to operate this spreadsheet is “Open Source” and free. It is
maintained entirely by a community of volunteers and whilst every effort is made
by the numerous programmers to issue a stable product, a small number of “bugs”
may exist which can cause unexpected results, or even data loss.
USERS MUST ALWAYS KEEP AT LEAST ONE BACKUP COPY OF ALL IMPORTANT DOCUMENTS.
Disclaimer:
The author will not be held responsible for any unfortunate events which may
occur as a result of using this facility. It should be used with caution as
some of the needle data has been keyed manually and possibly contains errors,
although every attempt has been made to keep these to a minimum. Cross-reference
to an official needle chart is strongly recommended prior to making any
modifications based on the results from this spreadsheet. The arithmetic and
calculations in general should be correct, but again, this cannot be guaranteed.
This spreadsheet has been created primarily as a technical challenge for the
author, but also as a useful tool for his personal use. The author hopes that
it will also be of benefit to other engine tuners, subject to the above.
E & OE – Use it “as is” and at your own risk!
Updates may become available. Suggestions are welcome for discussion!
Please also feel free to report data corrections required in the needle charts.
Contact: ian(_UNDERSCORE_)robert(.DOT.)hamilton(@AT@)hotmail(.DOT.)co(.DOT.)uk
If you would like to contribute some “beer money” towards this project,
then PayPal donations are welcome using the above email address.
See also:
Ratios.ods
The A-Series Gearbox comparison and analysis spreadsheet
Acknowledgements:
Many thanks go to Mark Forster for hosting this work on his excellent website:
mk1-performance-conversions.co.uk
Copyright © 2016 Ian Hamilton. All Rights Reserved.
Polite Request: If you are replying directly to a post where no-one else has beaten you to it,
please don't use the "quote" facility, use the "postreply" button instead. I'm sure that you
will agree, it does tend to get a bit boring/tedious reading the same old stuff over and over
again, as has been demonstrated above.
In case you missed it, the first, second and third times, here it is:
http://mk1-performance-conversions.co.u ... l_carb.htm
Ian
