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Tuner in Training
VVT tuning for Atlas engines
I’m trying to grasp how the VVT works on my 3.7L Colorado. The stock “High Baro” table (I suppose it should be more accurately referred to as “High MAP” table) which the ECM refers to at over 95kPA, has 9 degrees cam retard across the board in the high cylinder air mass areas, so it’s not really taking advantage of its ability to modify exhaust cam timing when I’ve really got the pedal on the floor. I changed the cam retard to 24 degrees across the entire RPM band in the high cylinder air mass areas as shown and the truck went from 7.3 seconds 0-60 to over 10 seconds. I also tried going to 15 degrees everywhere and the truck ran a little better but still not as good as stock. I believe that the mistake that I made was allowing full retard at low RPM. I am now planning to try the table shown in the last image. I will start with 0 degrees retard at low RPM to allow max cylinder pressure and increase with RPM to the full 24 degrees at high RPM.
Does anyone have any thoughts on this? Am I heading in the right direction or just way off? Thanks
Rob
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Tuner in Training
Didn't work. 0-60 time was 9.25 seconds. I also wound up with over 9 degress of KR (0-60 run is at 3:27 into the log). Here's a copy of the tune and log. Don't know what I'll try next.
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Advanced Tuner
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