[s-cars] Dyno time!

[mlp qwest]

Just one, sounds simple, but, "Know your dyno...."  From what I've seen on
the list, and various other sites, the "dyno" is a great device for
generating numbers, but... if what you are trying to do is compare your
results with other "dyno" numbers, you will want to try to establish some
bench mark basics.

Some thoughts and suggestions to annotate your results with:

1.  What final drive ratio is used to plot your chart?  How was/is that
number determined & how is it graphed for you?  My understanding (certainly
subject to criticism, I could be very wrong about this) is that while the
final drive ratio selected won't alter your "peak" rpm or torque values, it
will skew the graph of the results against your rpm (almost always the
x-axis) either right or left.  Think about it.  At the very least verify AND
note the gear or gears your runs are done in.  Your chart may plot out peak
figures at x rpm, for example the factory claims you should/can have peak
torque on a stock motor as early as 1950 rpm, but

2.  What does the dyno purport to give you for a result?  RAW bhp/torque
data or an SAE (temperature and altitude) corrected torque and horsepower
results?

3.  Can you get the operator to provide you with the raw data file(s)?  By
way of example, Dynajets work off of raw data, i.e. the program generates a
".pts" file that contains/logs (a) run time; (b) wheel hub rpm (from which
your x-axis is a computed figure based on the drive ratios entered); (c)
torque in ft/lbs; (d) torque "master"; (e) torque Slave; (f) Power HP SAE
Power "Corrected" Hp SAE; (g) Temp F°; (h) Barometric in Hg; (i) Relative
Humidity; (j) Vacuum/Boost and finally (k) Voltage, which in this case is a
value taken from a lamba O2 sensor that can then be converted to an Air/Fuel
level mixture at any give level of boost/rpm.

Run time & wheel hub are used to compute the "raw" rpm and bhp at a given
rpm number.  Temperature, barometric pressure (i.e. altitude) plus humidity
are used to compute a "standard" SAE corrected bhp figure.

4.  What other information can you acquire with the dyno run?  For example
the DynaJet will data log and plot (a) the intake manifold pressure against
rpm; and (b) if connected, a wide band O2 sensor out put.

There's probably a lot more things you might want to consider as well.  But
at the very least, try to see if you can't get the "raw" data file along
with the computed values and chart most people walk out of the dyno shop
looking at.

As the accountants all say, "Liars can figure, and figures therefore can
lie...."

Finally, you will need to apply to the list for the official Hap "NCFS" **
or alternatively,
OLBJBSB *** dyno sticker if you want to post your results

** NCFS -> Not Corrected for Snott
*** OLBJBD -> Official Levi Blue Jean Bar Stool But Dyno

Nest to last you will need to document each and every little tiny
modification, if any, to your car and the purported Octane (and how many
miles you have had that witches brew) in your tank for the ECU to try to
adjust to and take advantage of the run (Mance's old 100+ fill up comes to
mind at the 200? S-Car nationals comes to mind)

AND, finally last, you will have to stand everyone on the list a drink of
their choice, and answer all of their questions on just exactly where and
how you manipulated the accelerator etc., etc., when you made the pull.

HTH
Mike "more confused by numbers than ever, but hoping for enlightenment and
clarity" Pederson

~-----Original Message-----
~From: s-car-list-admin at audifans.com
~[mailto:s-car-list-admin at audifans.com]On Behalf Of riff944 at cox.net
~Sent: Monday, November 03, 2003 2:30 PM
~To: s-car-list at audifans.com
~Subject: [s-cars] Dyno time!
~
~
~Hi All-
~
~Looks like I will be putting my car on a 4wd dyno this weekend.
~There is an open house on 11/8 at KTR performance in Ayer, MA.
~Found out about this on (gasp!) Audiworld forums 2 pulls for only
~$65.  I have never had any of the car's I've owned dynoed, any
~special precautions I should be aware of?
~
~Cheers,
~Riff
~
~'95 S6
~
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