ORIGINAL: rmh
ORIGINAL: Tired Old Man
That had to have been a long and painful process. Imagine what could have been done if you could have observed all the various the impacts of changes in timing as they occurred using a high output, remotely programmable ignition. The exhaust system is indeed an important part of the performance equation.
Not too bad -
I always used my ear and a tach
mostly my ear -
Often I would get asked - ''how can you tell it's running faster?
the sound - faster is a higher pitch (relatively)
I have perfect relative pitch (as opposed to perfect pitch) developed as a musican from the time I was a little kid.
Lots of musicans have developed this
Here is a little aid which demonstrates why there are so many timing setups: take some poster board an make up a crank throw of 1'' (simulate a 1'' stroke)
now make a con rod which is 2'' long and one which is three'' long
With a piece of graph paper -assemble either rod to the throw (using straight pins) and turn the throw 360.
measure and mark the top of the rod for every 20 degrees of rod revolution.
change rods and do the same thing again alongside this first set of marks on the graph paper -
Note that the markes are now spaced differently vertically , as the throw rotates
You can also use this to demonstrate a DeSax cylinder arrrangement whre the crank is offset to one side a little bit
The piston -during the last 20 degrees before and after top dead center will rise at a different rate per each degree of crank rotation
This makes a BIG difference in when you want the spark to occur
-It also enables the designer to INCREASE compression when using a a longer rod to stroke arrangement !
More power can now be made with less chance of preignition or detonation
(That's a bitoversimplified but basically true)
DA notes this setup in their advertising