MPG L/100Km gauge?

tbitz · Post by **tbitz** » Sun Aug 06, 2006 12:14 pm

Just wondering if anyone has created a gauge to read MPG or L/100Km with MegaTune?

I know the main problem is that setups with MegaSquirt don't have a speed sensor.

But everyone does have RPM info. There could be a configurable variable that takes wheel diameter, tranny gearing, pinion, etc.. and calculates speed for one gear based on RPM info. Then it is just a matter of some math. (Pulse widths, open time, RPM, gear factor).

By having an "accumulation variable" one could have a "instantaneous" MPG readings or a trip MPG reading by making the accumulation time very long.

This would be nice when tuning for economy.

Tony

tbitz · Post by **tbitz** » Sun Aug 06, 2006 12:14 pm

Just wondering if anyone has created a gauge to read MPG or L/100Km with MegaTune? I know the main problem is that setups with MegaSquirt don't have a speed sensor. But everyone does have RPM info. There could be a configurable variable that takes wheel diameter, tranny gearing, pinion, etc.. and calculates speed for one gear based on RPM info. Then it is just a matter of some math. (Pulse widths, open time, RPM, gear factor). By having an "accumulation variable" one could have a "instantaneous" MPG readings or a trip MPG reading by making the accumulation time very long. This would be nice when tuning for economy. Tony
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=134946#134946 -------------------- m2f --------------------

Posted by email.

tbitz · Post by **tbitz** » Sun Aug 06, 2006 12:14 pm

Just wondering if anyone has created a gauge to read MPG or L/100Km with MegaTune? I know the main problem is that setups with MegaSquirt don't have a speed sensor. But everyone does have RPM info. There could be a configurable variable that takes wheel diameter, tranny gearing, pinion, etc.. and calculates speed for one gear based on RPM info. Then it is just a matter of some math. (Pulse widths, open time, RPM, gear factor). By having an "accumulation variable" one could have a "instantaneous" MPG readings or a trip MPG reading by making the accumulation time very long. This would be nice when tuning for economy. Tony
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=134946#134946 -------------------- m2f --------------------

Posted by email.

tbitz · Post by **tbitz** » Sun Aug 06, 2006 12:14 pm

Just wondering if anyone has created a gauge to read MPG or L/100Km with MegaTune? I know the main problem is that setups with MegaSquirt don't have a speed sensor. But everyone does have RPM info. There could be a configurable variable that takes wheel diameter, tranny gearing, pinion, etc.. and calculates speed for one gear based on RPM info. Then it is just a matter of some math. (Pulse widths, open time, RPM, gear factor). By having an "accumulation variable" one could have a "instantaneous" MPG readings or a trip MPG reading by making the accumulation time very long. This would be nice when tuning for economy. Tony
-------------------- m2f -------------------- This post is at: http://www.msefi.com/viewtopic.php?p=134946#134946 -------------------- m2f --------------------

Posted by email.

LT401Vette · Post by **LT401Vette** » Sun Aug 06, 2006 12:56 pm

Check in the msns-extra.ini ini file if you are on extra code.

They have all the calculations for it in there, it is based on speed sensor input though.

tbitz · Post by **tbitz** » Sun Aug 06, 2006 6:19 pm

Thanks. I didn't know this existed.

Looking at the msns-extra.ini file it seems fairly easy to modify the equations to use a scaled RPM number instead of the Speed Sensor in the calculation.

I'll see if I can come up with something that works.

Tony