Logging Calculated MPG PID..... 12-City/23-Highway
10-30-2009, 08:16 PM
#1
Logging Calculated MPG PID..... 12-City/23-Highway
I ran across a thread on EFI live that had a MPG PID so i decided to log it.. Well the results are rather interesting... 12MPG avg less than 45MPH and 23MPG avg greater than 45mph... From the thread the PID is supposed to be pretty accurate, DC_Justin said it matched his Instant MPG display on his SSS... Btw my truck normally gets < 10MPG because i live less than 1 mile from work and all i ever drive is < 35MPH. I adjusted the filter to display only MPH less than 35 and it was 9.3 MPG... You gotta love big loose Torque Converters....
Here is the log of less than 45 MPH
Here is the log of Greater than 45 MPH
As you can see i created a MAP that resembles the Main Spark table, that way i could see how the load was affecting the MPH...
Attached is my calc_pids.txt file so you can use the PID yourself. HPTuner guys here is the equation, I am not sure how user calculated PIDs work on HPTuners...
MPG = {SAE.VSS.mph}/({GM.INJFLOW.lbpm} * {GM.IBPW1} * {SAE.RPM} * 4 / 6250 )
Make sure to log Injector base pulse width - bank 1 {GM.INJPW1} and Calculated Injector Flow Rate {GM.INJFLOW}
Here is the log of less than 45 MPH
Here is the log of Greater than 45 MPH
As you can see i created a MAP that resembles the Main Spark table, that way i could see how the load was affecting the MPH...
Attached is my calc_pids.txt file so you can use the PID yourself. HPTuner guys here is the equation, I am not sure how user calculated PIDs work on HPTuners...
MPG = {SAE.VSS.mph}/({GM.INJFLOW.lbpm} * {GM.IBPW1} * {SAE.RPM} * 4 / 6250 )
Make sure to log Injector base pulse width - bank 1 {GM.INJPW1} and Calculated Injector Flow Rate {GM.INJFLOW}
Last edited by BlackGMC; 10-30-2009 at 09:25 PM.
10-30-2009, 09:51 PM
#2
Corey, interesting. That 12 mpg isn't so great, but I'm diggin the 23.
Thanks for helpin those of us w/. HPT w/. a way to get the info ourselves. 
I'm not that advanced yet w/. my HPT, but hope to later implement this. 
Thanks for helpin those of us w/. HPT w/. a way to get the info ourselves. I'm not that advanced yet w/. my HPT, but hope to later implement this.
Last edited by fastnblu; 11-01-2009 at 06:45 AM. Reason: I'm not advance w/. tuning, but wanna add later after I get better.
10-31-2009, 11:54 AM
#6
This works pretty good, as long as your moving. It doesn't take into account the losses in MPG when your stopped and fuel is being burned and your not going anywhere. I tried to get some one to help me come up with a calculated PID that adds fuel consumed and miles traveled then divides the two to get TRUE average MPG, but nobody could do it. 
You probable saw my post in the EFILIVE forum about this.
You probable saw my post in the EFILIVE forum about this.
Last edited by kbracing96; 10-31-2009 at 09:52 PM.
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10-31-2009, 07:53 PM
#8
go to your EFI Live folder and open User Configuration folder then file Calc Pids. At the very bottom add this line:
MPG = {SAE.VSS.mph}/({GM.INJFLOW.lbpm} * {GM.IBPW1} * {SAE.RPM} * 4 / 6250 )
then save it.
You can see it on Corey's file above. If you've never changed yours before then you can just save his. His also has pids set up so you can tune with your trims. which i've done and works like a charm. Great for when you don't have a wideband.
MPG = {SAE.VSS.mph}/({GM.INJFLOW.lbpm} * {GM.IBPW1} * {SAE.RPM} * 4 / 6250 )
then save it.
You can see it on Corey's file above. If you've never changed yours before then you can just save his. His also has pids set up so you can tune with your trims. which i've done and works like a charm. Great for when you don't have a wideband.
11-02-2009, 07:41 AM
#9
We took a 260 mile road trip this last weekend and I pulled off 22MPG!!!! This was without the PID, this was doing it the old fashion way of mileage divided by gallons... This was cruising between 65-75MPH... I was really really surprised!