setting ignition curves without dyno

[Bruce Plecan]

-----Original Message-----
From: Chris Conlon <synchris at ricochet.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Friday, November 13, 1998 2:31 AM
Subject: RE: setting ignition curves without dyno


>Bruce wrote:
>
>> On the subject of dynos, and timing, I, used to do this full time, and
>> the dyno steady state stuff was always too advanced.  Also that was
>> almost 30 years ago.  While todays stuff is much better, I'd still verify
>> it was right by testing any of it when the engine was actually installed.
>>
>> I have never seen anything better for figuring out 60' times then
>> actually doing 60' runs..
>
>I guess what you're saying is, more or less don't bother, since
>I'd have to test it on the street anyway. Well, I guess I can
>accept that. It'd be nice to know how it works in theory anyway,
>even if that info is not useful in practice.

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...
>
>> >How about watching EGT closely?
>>
>> EGT peaks at Stoic.  EGT show you how close you are to the thermal
>> limits of you engine.  You can have a 1550dF EGT, and be three states
>
>But how do timing changes effect EGT, if you keep all else
>constant? It'd never work if things are changing all over
>the place, but what if you were only changing the timing?

Advancing usually increases EGT.  But, if the mixture is wrong
can do other things.  ie too lean too much timing, and the cylinder
misses, and EGT drops.
Bruce
>
>   Chris C.
>