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at light loads, between TTP 4-8. These loads are the equivalent of barely cracking open the throttle plates. The trade off zone falls somewhere between 40-45 mph. Beyond 45 mph in 4th gear, all cells used are outside of the zone of modification, and the timing remains unaltered, (OEM values ranging between 38-44' BTDC). It is important to note whenever the engine loads are increased even slightly, e.g., throttling up to moderately accelerate, the operational cells immediately jump well to the right of the re-tuned cells. Under any spirited driving, the operational cells utilized are always the base-tuned OEM cells. A small cluster of cells, TTP values 4-8 at rpms of 1600-2000, are the most problematic. These cell locations translate to light cruising around 40 mph. My modification lowers the timing in this zone to 25-30' BTDC [vs. OEM 40' BTDC] in order to provide a smooth transition. However, those cells can also be used for long periods of time under light load cruising of 35-40 mph. Likewise, in 5th gear, at 40 mph, under very light load of TTP 4, the timing can be as low 20' BTDC (versus an OEM value of 34' BTDC). But this condition is almost coasting with the engine loafing around 2000 rpm under minimum load. Except for the above note exceptions (rpm 1600-2000 / TTP 4-8), the modified cells are used only as a transition moving up or down from idle, or when the car is in a low speed driving mode, like a parking lot. I do not know what the consequence of pulling timing at such light loads for extended periods of time. But my instinct tells me that 25' degrees of advance under those conditions is negligible. Everything about the feel of the motor, and the sound of the exhaust indicate the engine is very happy with this timing.
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