Tuning Ghettodyne partial throttle
Thread Starter
0.0 BAR
Joined: Jun 2003
Posts: 9
Tuning Ghettodyne partial throttle
Hey I'm having J. Davis chip and set me up for dataloggin.. 
But my question is how do you guys tune part throttle if ECUControl doesn't allow datalogging wideband? My buddy has a wideband and I can see the realtime display but it's hard to adjust the maps doing that.. How are you guys tuning ghettodyne other than full throttle on the dyno? Or is that all that matters :P. Thanks!
But my question is how do you guys tune part throttle if ECUControl doesn't allow datalogging wideband? My buddy has a wideband and I can see the realtime display but it's hard to adjust the maps doing that.. How are you guys tuning ghettodyne other than full throttle on the dyno? Or is that all that matters :P. Thanks!
3.0 BAR
Joined: Apr 2003
Posts: 2,260
Re:Tuning Ghettodyne partial throttle
You have to realize that up until about 80% throttle, your ECU is in closed loop and is adjusting A/R by readings from the O2... sooo, that makes it hard to tune partial throttle whether you use a wideband or not.
hehe true tho.
3.0 BAR
Joined: Apr 2003
Posts: 2,260
Re:Tuning Ghettodyne partial throttle
Correct. In open loop, the ECU extrapolates the values in your table finding the best adverage for the RPM and MAP pressure that you happen to be sitting on. This due to the resolution of the map.
For instance, a PM6 has 15x17 cell maps. Visualize this 2D table with MAP values going across the top, and RPMs down the left side.. a la Ghettodyne.
It will go out to the value between the two closest MAP values, then go down between the twp closest RPM values, and average the 4 values around that spot. And adjust the injector pulse width for that split second to that value derived from that equation.
Since it's constantly trying to hit lamda (14.7:1) your A/F gauge probably bounces all over the place. Which is why it's hard to tune at partial throttle, even with a wideband.
For instance, a PM6 has 15x17 cell maps. Visualize this 2D table with MAP values going across the top, and RPMs down the left side.. a la Ghettodyne.
It will go out to the value between the two closest MAP values, then go down between the twp closest RPM values, and average the 4 values around that spot. And adjust the injector pulse width for that split second to that value derived from that equation.
Since it's constantly trying to hit lamda (14.7:1) your A/F gauge probably bounces all over the place. Which is why it's hard to tune at partial throttle, even with a wideband.
Thread Starter
0.0 BAR
Joined: Jun 2003
Posts: 9
Re:Tuning Ghettodyne partial throttle
but adjusting the whole fuel map overall with ghettodyne will change the values because you are changing the base numbers that it is creating the averages from.. I really just want to make sure using the boost maps from ghettodyne will be safe for partial throttle.. Thanks for the help!
