[TMcQ150]

I have a bunch of DMRs that I have been reading in my logs. I think some of these readings are bogus but does anyone know how the DMRs are calculated and what is and is not reliable? I am going to list a hand full and see if anyone can enlighten me. I know what a lot of these are but I don't know the unit of measure or what contributes to it.

if you guys can tell me anything about these I would be appreciative, even if its just the unit of measure

ACTUAL AXLE TORQUE
ACTUAL BASE ENGINE TORQUE
ACTUAL AIRFLOW BY ETC
FUEL RAIL PRESSURE ACTUAL
MBT SPARK
BORDERLINE SPARK
PREIGNITION SPARK
KNK SENSOR SPARK ADDER
INJECTOR PULSEWIDTH
EFFECTIVE THROTTLE AREA
ETC MANIFOLD VACUUM

here is a pic so you can see what they are reading and can maybe help me figure them out

 

[mass-hole]

fuel rail pressure actual I assume the actual(as opposed to desired) pressure after the hpfp

mbt spark could be the calculated spark timing if the pcm is using the mbt tables. The truck may run in mbt(maximum brake torque) at light loads.

boarderline spark may be the calculated timing if the pcm is using the boarderline tables. This what it uses if it cant get to mbt spark timing due to lack of octane.

preignition, same as above but for when knock is detected.

Knk sensor timing adder almost sounds like Knock retard that we all talk about. Basically the real time spark adjustment

Injector pulsewidth is probably the time the injectors are open?

effect throttle area is probably a calculated flow are of the throttle body based on the angle. There are tables in the tune that tell the pcm the area.

 

[TMcQ150]

Dude thank you so much for the info, it has been so hard trying to find out about some of this stuff. I am finally about to get on the dyno at a local shop on Friday. The guy did a buddy of mines car a couple weeks ago and i was told hes real knowledgable and specializes in tuning fords, tho mostly mustangs, so I am hoping I can get some more clarification. I will share what I find just to get it out there if someone else has been trying to figure it out. Really appreciate the response tho

 

[mass-hole]

Dude thank you so much for the info, it has been so hard trying to find out about some of this stuff. I am finally about to get on the dyno at a local shop on Friday. The guy did a buddy of mines car a couple weeks ago and i was told hes real knowledgable and specializes in tuning fords, tho mostly mustangs, so I am hoping I can get some more clarification. I will share what I find just to get it out there if someone else has been trying to figure it out. Really appreciate the response tho

I mean, honestly, most of those DMR's are probably not super useful except for maybe the Boarderline and fuel rail pressure actual. You might use the boarderline one to tweak the timing tables if it is actually what I think it is.

In the time I spent logging and tuning my truck I never found that the timing was ever that far off. It seems like Ford pretty much nailed the timing tables and any minor errors are corrected for with OAR and KR. I don't think there is a whole lot of opportunity in the timing short of the tables needing to be expanded due to you running more air load than the tables have in them.

 

[TMcQ150]

@mass-hole I don't think there is any chance that I try and tune anything myself anytime soon. I am just trying to understand all the info I have access to now in order to maybe spot a small problem before it becomes a big problem or identify weak points to know what to avoid and when I need to stop pushing the limits.

the octane adjust ratio is one I have seen come up a good bit, what is that pid telling me? I started watching it and it has mostly been at -.96 but it did go to -.92 for a bit today. I know it adjusts based on the fuel but I don't understand the reading or what is beneficial

 

[mass-hole]

@mass-hole I don't think there is any chance that I try and tune anything myself anytime soon. I am just trying to understand all the info I have access to now in order to maybe spot a small problem before it becomes a big problem or identify weak points to know what to avoid and when I need to stop pushing the limits.

the octane adjust ratio is one I have seen come up a good bit, what is that pid telling me? I started watching it and it has mostly been at -.96 but it did go to -.92 for a bit today. I know it adjusts based on the fuel but I don't understand the reading or what is beneficial

OAR is an indication of the fuels relative ability to resist knock. Its relative because a tuner could go in and make your boarderline spark tables really aggressive and your OAR could shift toward positive.

If that happened, the positive OAR doesnt mean you are running less timing than when it was a -1, it just means that the OAR is having to not add as much timing as it was because the boarderline tables are already doing it.

Oar can advance or retard timing a certain amount. Its a multiplier. On my 2014 it allows up to 5* of timing adjustment in either direction. A OAR of -0.5 would be adding 2.5* on my truck.

The only downside to OAR’s lower than -1 is that it could cause the pcm to limit air load depending on what the tuner does with the lspi tables

 

[TMcQ150]

After seeing the dyno results I can't help but notice that the torque I got was almost dead on what the ACTUAL BASE ENGINE TORQUE is if that dmr reads in Newton meters and you convert it to ft lbs. But would the dyno reading be representative of my engine torque? I thought it would tell me the torque at the wheels? Is this a coincidence?