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Originally Posted by fireguy50
What RPM is the TTNOV calculated at, 2000RPM?
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Well, I calculate it at 2000 RPM for convenience, but it is a constant for each gear.
e.g. 2.73's, 3.35 1st gear ratio, 25.6" diameter tire.
MPH @ 1000RPM - 8.4MPH, 2000RPM - 16.8MPH, 3000RPM - 25.2MPH
N/V @ 2000RPM = 119, @ 2000RPM = 119, @3000RPM = 119
TTNOV is there so that the ECU can determine if the vehicle is in 1st gear (or not). If it is, FN1119 spark reduction is applied.
N/V in second gear is 69.
For this example above, you could set TTNOV at, say 100 & the FN1119 would thus pull timing in first, but not second.
If N > TTNOV * VSBAR (avg speed) then apply FN1119 - 'C', else 'C' = 0
Spark formula;
SAF = Y * ['S' + B - C + FN1133(ECT, LOAD)] +KPS1
Notice how 'C', the torque truncation spark table, FN1119, is subtracted from the calculated spark?
This table will be applied any time TTNOV is set low enough that when multiplied by the rolling average speed of the car, it is smaller than the engine RPM at that speed.