[Diy_efi] Tuning Ignition Advance...

[Michael Richards]

Hi guys,

I live in an area where there are only 3 shops/people who tune ECUs. I 
normally start with a very conservative ignition map, about 0.75-1 
degree off stock timing for every PSI of boost. Once complete I ramp up 
ignition with det cans to within a few degrees of peak torque. 
Obviously I stay away from pinging. So from experience I have a good 
feel for how much advance to use. I normally tune on the street but 
rent a dyno for the higher horsepower cars.

Now there is another tuner in my area and he has a dyno. I've re-tuned 
a number of his setups. I've frequently seen situations where a 9:1 
engine with a big turbo is fuelled on the rich side but the ignition 
advance is really really low. I'm talking 7-8 degrees of advance at 10 
PSI. 

One engine I'm re-tuning right now is a 4G64 in an Eclipse. My instinct 
says it should be running about 15-18 degrees at 4000 RPM but I haven't 
started inching it up there yet. 7-8 seems completely wrong.

I'm wondering what you guys think about the ignition tuning. I've 
always felt a "conservative map" was one with timing a few degrees off 
MBT and fuel around 11.2:1 or so around peak torque. Now 10.2:1 and 10 
degrees off on the timing sounds silly to me.

-Michael
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