Hi all :
Please ignore my previous request for SU needle charts. A little web
surfing today turned up more than I ever wanted to know about the subject,
on the Team.Net server (of all places <g>).
If anyone else is interested in maximum performance from their SU carbs on
a somewhat modified engine, check out
http://www.team.net/www/morgan/tech/tuning.html and download the
SUNEEDLE.EXE program (if you have a PC capable of running a DOS program).
It has needle charts for almost 500 different needles, along with tools to
select and compare needles. I've only scratched the surface, but there is
all kinds of interesting information available. For instance, the 'lean'
needles listed by Moss for the TR3/A are only leaner over a small band of
low power (cruise) settings. They are actually richer through the higher
power bands than the 'normal' needle !
BTW, after downloading SUNEEDLE.EXE, you should move it to a directory of
it's own before executing it. It is a self-extracting archive of 11
different files including 5 different DOS programs. You will want to read
HAYSTACK.MAN which is a plain ASCII text file, using WordPad or whatever.
Also, the web page mentions using an exhaust analyzer. You can make a
suitable substitute by mounting a common 1 or 2 wire O2 sensor from a
modern car in the exhaust, and using a DVM to read the output voltage. The
output voltage ranges from 0.000 (very lean) to around 0.900 (very rich)
and is really only accurate around 0.500 volts (which is the 14.7 AFR, 1.0
lambda, stoichiometric mixture required for catalytic converters, etc.)
This is exactly the same information displayed by all of the moderately
priced (under $500 US) exhaust analyzers.
Randall
59 TR3A daily driver - somewhat modified ...
Randall Young wrote:
> Would some kind soul with the charts for SU H6 and HS6 needles please
share
> the measurements with me ? I have what I believe to be a mixture of
unmarked
> needles, and I'd like to sort them ...
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