In the original post, the dip from 6,000 to 6,250 rpm was around 25 lb/ft of torque. In the graph that Daniel just posted, the biggest dip is around 40 lb/ft or torque. I don't think that difference defines whether or not it is retarding the timing. That graph looks like a turbo'd vq35 with more boost... conventional camshaft sees torque fall off at high rpms where the vvel keeps pulling. If it is a high boost 3.5, it's retarding more degrees of timing to compensate for the high boost. If you run California's 91 octane vs the 93 octane the rest of the country gets, it will retard more. If your engine is heat soaked when you do the run it will retard the timing even though you've done 5 runs where it didn't retard the timing. Also, when you remap the ECU, if you advance timing aggressively, it's going to have to retard it based on the knock sensor and get choppy. If you map it conservitavely it won't need to retard and your graph will be smooth. Also, if you forget and leave traction control on during your dyno run, it would do the same thing. If you don't have enough weight on the rear end and it's spinning (a little), it would also make a wavy dyno curve. I still say, get the ODB output if it's available.
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