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# Motec m800 fuel interpolation?

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Hello,

I have tried to interpolate the fuel table in the motec m800, but i have found out that i cant interpolate between 2 cells if i want to interpolate i have to do it for the whole row or column. what also i have found that if u press backspace you will lock the cell but even so the interpolation values will be set inbetween the first and last cell, which it will not benefit in anyway as you cant really tune the last cell for example, on load 40 rpm 6300 where is the cutoff, so is there by any chance that i can interpolate the value of for examplw the first cell and a middle cell (on the same load) without caculating the value of the last cell?

Thanks

Yep -- data table interpolation (other than full row/column) wasn't available on MoTeC software before the M1 series. You'll just have to do it by hand. The basic formula for linear interpolation for a value of X such that X0 < X < X1 is this:

Value ( X ) = Value (X0) + (Value(X1) - Value(X0)) * (X - X0) / (X1 - X0)

For example, let's say X0=1000 RPM and X1 = 2000 RPM, and the value at these RPMs were 8 @1000 RPM and 12 @2000 RPM

The Value at 1200 RPM would be:

Value(1200) = 8 + (12-8) * (1200-1000) / (2000 - 1000) = 8 + (4 * 200/1000) = 8.8

and the Value at 1500 RPM would be

Value(1500) = 8 + (4 * 500/1000) = 10.0

As David said, the Mx00 series ECU's only have row or column interpolation in the tables. This has been changed in the M1 to allow for a lot more flexibility in the area that is interpolated/smoothed.