Datalog Review/Air Charge Questions

[jmheath357]

Hello,

I have a 2025 FL5 with the TSP catted exhaust, PRL front pipe, and obviously the Flashpro with the 91 Octane basemap tune that I made some adjustments to the Lambda tables and torque request tables for 1st and 2nd gear in sport and +R modes. Can someone review these logs and see if you see anything that needs attention or suggestions? I'm including two 4th gear pulls. One thing I noticed is that the AFR seems to dip to around 11.5 when the target is about 12.0 at around 4,500RPM. I've seen this same behavior of that dip with the TSP Stage 1 tune as well as the Factory Settings tune even with the car completely stock. Also, I'm new to turbo charged engines and was curious if someone could explain the process for tuning air charge. Are the two main tables you use KFMIOP and KFMIRL? Do you focus on making adjustments in one table and then just mirroring that in the other and if so, which is the main table to tune with? I know they are supposed to be the inverse of each other but I don't quite get what that means as to me the standard definition of inverse numbers would be like 1/2 and 2/1 or 5 and -5 but the numbers in these tables don't line up like that or so it seems. If you make an adjustment of say 5% difference in a cell in one table, do you just make the same 5% change in the exact same cell in the other table? Any and all guidance on this would be greatly appreciated. Thanks!

[jeffx]

I never messed around with the torque model (KFMIRL/KFMIOP) on a stock turbo really because these tables didn't exist until well after I had upgraded the turbocharger in my car. I don't really think there's really much to be gained by messing with these if you're running a 91 octane tune on a stock turbocharger, though. It definitely helps once you're pushing a lot more air through the engine with a larger turbocharger though, and yes, the tables need to be basically inverse of each other.

On the KFMIRL table it's requested torque vs RPMs with the cell value in the table being the target AirC for requested torque (which is calculated from your throttle tables and the MDNORM). On the KFMIOP table, it's actual AirC on the x-axis vs RPM on the y-axis. The cell value is the torque request maximum. So there's a risk of an error condition if your 2 tables don't agree with each other.

Using the FL5 KFM table pair, let's say you have a torque request of 80% at 3500 rpms. According to the KFMIRL table, that works out to a target AirC of 206.3%. Now if you look at the KFMIOP table, the value at 206.3% airC and 3500 rpms should calculate out to ~80% torque so these tables are in agreement. So if you change the values in the KFMIRL table, you will need to change the KFMIOP table inversely so they remain in fairly close agreement.

Having said that, I have noticed it's not a perfect inversion on the factory KFM table pair so there's some (small) margin for tuning.

[jmheath357]

Thank you for that information, I appreciate it! I'm not really looking to make any gains by adjusting these settings as much as I was curious if this might be a good way to lessen the fuel pump demand as the duty does run in the upper 90's between about 3k-5krpm at WOT with the current map on the car. Once I move back to Texas later this year and have access to 93 octane again, I plan on getting a custom tune done. I would just like to make sure everything is running well enough for the time being until then and I enjoy learning about how and what adjustments to make if I see any small potential issues.

[jeffx]

I just had a quick look at your logs. Yes your fuel pump is spending a bit of time in the 90s around the torque peak, but your fuel rail pressure and lambdas are staying close enough to their commanded values that I'm not seeing a critical issue in these logs. Yes there is a brief moment around 4500rpm (which is right after VTEC engages and your intake cam phasing suddenly shifts) where it goes a bit richer than command - that's way better than going lean. You're always gonna have a momentary reaction there with that cam timing/lift stuff happening - but the AFR settles out quickly and goes back to tracking the commanded AFR nicely. I'm not seeing any knock retard issues or anything alarming.

If you really want to calm down the fuel pump in that area you can back off the torque request in the throttle maps and ramp it up more smoothly. You're only hitting 83% of requested torque anyway so maybe set a max target of like 480 in your throttle maps and then see how that affects your fuel pump.

Down the road if you're looking for more power and torque and you eventually decide to add CANFlex and/or a larger turbo you will definitely want to look at a fuel system upgrade for sure.

[jmheath357]

Thanks for taking a look at the logs, I appreciate it. I'll definitely give that a try and see how that works. I was actually looking at the factory settings map and the 91 octane maps and the KFMIRL and KFMIOP are the exact same so it seems like just adjusting the throttle tables should be a good place to start. Thanks for the advice!