Map/load bin question

[philhoward]

My Megajolt system was mapped on a rolling road at the end of the summer last year. Recently I had cause to look at the map, and I can see that the load parameters are calibrated from 0 - 255. My system works from a throttle position sensor which is calibrated from 0 -100. The result is that the Megajolt only seems to use the first 3 lines of the map.

I spoke to the garage who tuned it (Sanspeed in Bexleyheath who I've always been very happy with). They said that all systems will only use a part of the map - and it'll be a different part depending upon whether it's MAP sensor or a TPS. Turbo engines would also use a different part of the map apparently. This is because Megajolt and many other systems are quite basic. Use only two or three lines of the map is quite normal apparently.

I tried the map after it had been recalibrated to 0 -100, and to be honest it didn't seem to make much difference to performance, if anything, it was better on the Sanspeed map.

What do people think? Is it normal to use only 3 or 4 lines on a Megajolt map?

[brentp]

Hello Phil,

The intention of the Megajolt is to use all 10 bins of the load axis, calibrating the unit for the appropriate application. Consequently for TPS you would have 0 - 100%; for normally aspirated engines you would have 0 to 103 KPa, and boosted engines 0 to 255KPa.

Since the load axis is pre-calibrated for the MAP sensor, the TPS option has an extra calibration step to ensure idle and WOT correspond to 0 and 100% TPS.

Your map was made with roughly 1/3 of the available resolution, and it may run fine this way. In principal, increasing the resolution on the load axis *will not* make it run worse, providing it's spread out in a linear fashion.

Hope this helps!