[Diy_efi] Tuning Ignition Advance...

[Michael Richards]

Ok, I did the final tune today and thought I'd give an update as to 
what I did. The car was a 2003 eclipse with a 2.4l engine. I can't 
remember for sure if it was SOHC or DOHC but I think it was a single 
cam. The engine wasn't making a huge amount of power and was having EGT 
problems. The probe was mounted about 1" from the turbo at the 
collector. It's a cast turbonetics manifold for a Talon (I think) but 
it fit just fine.

Before I did any tuning it would hit 1600 EGT as soon as it was on 
boost and climb very rapidly to 1700 before I'd tell the owner to lift. 
The previous tuner had it mapped to dip in at about 10:1 AFR as soon as 
it saw 1 PSI and hold that up to 10 PSI.

Once finished I added about 10 degrees of timing. Peak torque occurred 
at about 4500 and took about 18 degrees. Below that I ran 17 at 3000, 
19 at 4000 and 20 at 5000 up to 22 degrees at redline. EGTs stayed at 
1625 during high speed 4th gear pulls. This is a little hotter than I'm 
used to and I did add some extra fuel. It's now running 11.2:1 where 
11.8 would have seen 75 more degrees of EGT at WOT. I have a feeling 
head work and/or cams would be of great benefit on this engine. I also 
leaned out the spool region (up to 5 PSI) a fair bit and this made a 
big difference in lag.

-Michael

> First I HAVE to say I'm no turbo expert. So take my advice w/ a grain
> of salt. Coming from a Mitsu background, I think you could run even a
> bit more timing than 15 deg. 18 degs sound more suitable to me. I
> think you could also enlean up to 12.0:1 but I'd rather stay safe and
> use 11.5:1 as a safety margin.
> BTW, what 4G64 is that? Does it still have its stock cast pistons or
> custom pistons? Is it a DOHC conversion? I'd say the DOHC engines can
> use a tad more spark advance as their combustion chamber design allows
> for that. And if it's a DOHC conversion, what's it static compression
> ratio now?

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