setting ignition curves without dyno

[Bruce Plecan]

-----Original Message-----
From: Clarence L.Snyder <clare.snyder.on.ca at ibm.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Friday, November 13, 1998 11:42 PM
Subject: Re: setting ignition curves without dyno
snips and clips

>Bruce Plecan wrote:
>> >>Dynos are great for getting the cam events right. Well more
>>prescisely  they are great for doing everything but timing, and final
>>mixtures.  They are worth every penny for doing anything other >>then
timing, and final mixtures.  So if your buying dyno time for >>doing just
those two items, you're not getting your money's worth >>in MHO...
>> >Why do you say this?? what is the BEST way in your opinion to >> >get
the right timing down and final mixture??
>> Actual testing.  Bolt everything together, put it in the car, and tune
>>it.  The only way to load the motor as the motor will be run is after
>>the installation.  Record the weather conditions, and make sure >>your
corrections for IAT/Bar (as/is used are correct) even.  Engine >>dyno stuff
is great for a starting point but, remember everything >>you do is being
optimized for only that use (running on that dyno).
>>    Yes, I get picky S---, about tune-up, that's just the way I am.  I've
>> done numerous (NA)engines at 100HP/L that went 100,000 miles with min
wear,
>> ie, dress the valves+seats-rings-bearings, and go another 100,000....
>> >
>> >Rick
>> >
>A programmed rolling road is still "the best" as it is a controlled,
>repeatable,"real world" situation. For those not aquainted with the
>concept, it is a chassis dyno with a calibrated inertial component >as well
as the restrictive or friction component. The ONLY way to >test for
emmissions compliance, as well.
>Too bad they are so expensive, not to mention rare. You can >actually
program them for, say, a full throttle accelleration run up an >8% grade
with a 1 ton trailer behind your truck, with a 5 mph >headwind - assuming
you know your co-efficient of drag and frontal >area. Setting mixtures and t
iming in this environment is the next >thing to heaven, as EVERY statistical
change is relevent.
>You are testing installed performance parameters under controlled,
>simulated conditions.
>Too bad I don't know where there is one for public use.

Sorry, I got lost I was talking to the DIYers, and practical applications.
The dyno if it was so perfect, the major coporations would not need to do
any road tests then.  Or then, why are there soo many updated chips for oem
stuff.  Cause things VARY, what looks
good on paper when executed may be different.  While the engineers look for
computer modeling to answer everything, I still
haven't seen that happen.  Even lab. testing like with a abc trick
dyno only answer the questions for that car.  Then they try to make
it flexible enough to cover all bases..
  I also think tuning in bad weather is good since you learn more
about corrections.
  I while I find the loaded dyno interesting, it's to me it still no better
than real world testing.
Cheers
Bruce
>