Haltech IG5 - Manual (Page 39)

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The third character in the ignition timing Map name specifies the Rpm at which
maximum advance occurs (ie.. how quickly advance changes with engine speed). This
character is a letter of the alphabet. Option A has full advance in by 1500 Rpm. Option
B has full advance in by 2000 Rpm. Option C at 2500, etc. up to J for 6000 Rpm.
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The fourth and fifth characters in the ignition timing Map name specifies the maximum
advance at atmospheric pressure. Cruise or light load advance is added to this value,
while retard on boost for turbocharged or supercharged engines is subtracted from it.
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The sixth character in the ignition timing Map name specifies the extra ignition advance
to use at light loads such as highway cruise. This is equivalent to the vacuum advance
on a distributor. If this character is A, there is no extra advance under light load. Each
successive letter of the alphabet after A adds 3 degrees of ignition advance to the full
load advance under light load, up to the letter H. (H = 21°)
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If the engine is turbocharged or supercharged then the seventh and eighth characters
specify the ignition retard the engine is to get under boost. This value is subtracted from
the atmospheric pressure advance value. If the engine is not turbocharged or
supercharged, then leave the name only six characters in length.
A description of each parameter is displayed on the Library Maps page to save you referring to
this manual.
As mentioned above, it is suggested that the timing be checked before starting the engine. If the
ECU successfully locks the timing at 10° then you should load a library map that will get the
engine started. Try be conservative. You should not be looking to gain the last few percent in
performance immediately. If you know the factory settings for idle, vacuum and full load
advance for your engine you can use those values to load an extremely effective Library Map.
5.4.1 On the Dyno
Whether the vehicle is on a chassis dyno, or the engine on an engine dyno, the principles of
programming the Haltech IG5 are the same. The quick map feature mentioned previously is a
great starting point and should allow the motor to start and run.
Take the engine rpm up to 1000 and apply partial load and adjust the 1000 rpm range. Now
keep an eye on the dyno readings and adjust the ignition curve appropriately to achieve
maximum gains. Continue, adding more load, up to the full load settings. Repeat this for the
rest of the ranges.
Full load tuning should be approached with caution. An engine at full load that is over advanced
may begin to detonate and destroy pistons and crankshafts. Before loading the engine, decrease
the heights of the right most bars so that they are lower than the line projected by drawing a
straight line from the idle and free-rev settings and through the part-load settings.