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I have a 90mm GM DBW and I have the Throttle Area table just set up in a linear fashion. Im curious what impact this table has on the throttle function itself. I just want to be as accurate as I can.
If you consider the airflow through a throttle plate, it doesn't increase in a linear fashion and this is what the Throttle Area table defines. As per the help file, if you don't have this data then it's fine to just use a linear interpolation but this will affect the relationship between pedal position and throttle plate position. You can however also use the Throttle Pedal Translation table to change this relationship so it's not really a big concern. I'd use a linear interpolation and then just work on the translation table to get the feel you want.
Is there a way to solve for the throttle area % relative to servo %... aka throttle translation?
You can do this correctly using a flow bench, and controlling the throttle with the M1 to set the servo position.
For the GM throttle bodies used on the LS engines, I have found a flow vs. position information, I used this in one M1 controlled LS. It was very tricky especially at idle as the engine is only using like 1.3% throttle position.
I did another M1 / LS3 with linear throttle area vs. throttle position, and it was easier to do idle control, but I had to take quite a bit out of the throttle pedal translation to make it very driveable.
Thanks David! I’ll be using the M150 to control an 82mm Bosch GT3 TB (0 280 750 473).
Another question... while I am sure each TB is different... wouldn’t most similarly sized TB have close to the same Throttle area versus throttle blade opening (once you adjust for close as 0% and 90 degree as 100% open)? At least wouldn’t this be marginally better than using a linear representation. I realize the throttle plate surface area will vary but would think they would be closer than using linear.
Most throttle bodies with straight bores will match the MoTeC default provided. The LS throttles have a specially machined spherical shape, so mechanically the first 25% of throttle angle flows much less air -- making it more linear.
I believe this is where I got some of the flow information:
Thanks again... wondering if I am doing something wrong, when I play with the different "pre-loaded" servo calibrations in M1 Tune it does not change the Throttle Area calibrations.