engine and drivetrain Finally Did A Little Dyno Tune Today

[jimk]

Those advance values are pretty much what I settled on.  Reason being with EFI there is better atomization and fuel evaporation.  It's the fuel vapor/air mixture that burns and with carbs it takes a little longer for the combustion to complete so more advance.  Compare the Tii values to the carb values and the same similarity exists.

[Colin]

Those advance values are pretty much what I settled on.  Reason being with EFI there is better atomization and fuel evaporation.  It's the fuel vapor/air mixture that burns and with carbs it takes a little longer for the combustion to complete so more advance.  Compare the Tii values to the carb values and the same similarity exists.

 

I also noticed you are running quite a bit of advance at idle.  I was quite surprised to see that.  Maybe I need some dyno time, too...

[Grover]

Colin. To be clear, when on the dyno we did almost nothing other than hard acceleration tuning. Most of the lower portions of the map were done by me over the past few months, and then Rob and I did some around town driving (with him driving and me working the laptop) to get a couple of other niggling issues dialed in. Each and every portion of the map is not "dyno" tuned. Regarding the advance at idle, I've tinkered with it quite a bit, and this is the best I've been able to get it to idle. With ITBs the idle KPA is higher than when I was using a common plenum, and I've had to raise idle rpm by a little bit. Right now it's idling around 1050 or so at high 40s kpa. and remarkably smooth. In contrast, with the common plenum, I used to find the best idle around 100rpm lower and if I recall correctly kpa was in the low 40s.

[Colin]

I have incorporated many of the findings from your dyno session into my spark map and will upload them, retune, and report back with my findings.

[jimk]

For ya'alls study and enjoyment, ignition advance.

http://www.nrteam.org/tech/68

[Colin]

So I updated my spark table to something much closer to what Grover has and it seems to work quite well.  The high advance at the lower loads makes the engine smoother.