MAF Scaling on B58 Engine (BootMod3)

Having recently completed the EFI Tuning Fundamentals and Practical Reflash courses I carried out some WOT data logging on my Stock B58 engine. The total fuel trims remain almost constant at +2 for all the logging sessions using BootMod3 (I was expecting more fluctuations in the STFTs but thought this may be due to the closed loop fueling via the stock wideband sensor for all engine loads). From the course content I understand a total fuel trim of +2 is good and MAF scaling would be required however, due to the descriptions of the tables I'm unsure where I would start to scale the MAF if I may any induction changes in the future and the total fuel trim deviate from the ideal range.

As you can see from the attached image I have found two tables that I think are the tables that would be required to scale the MAF but I'm unsure which table I would change to complete this exercise. Any help and advice on this would be greatly appreciated.

Any help would be greatly appreciated.

Post a log, STFT should be around 1 when you log.

This is adjusted from the Fuel Scalar table (Fuel/Scalar/Fuel Scalar) - mainly adjusted for running ethanol or meth/PI injection.

If your STFT is not 1 then you will need to adjust.

What are you trying to do?

BMW B58s are more torque based for tuning.

Hence you need to look at torque limiters, torque requests, then load and boost tables.

The AFR tables will need some adjustments as well.

Hi Shane,

Thanks for the response.

Please find a datalog via the link: https://www.bootmod3.net/log?id=643ce553c090c6393f6c4079

I noticed that there is also a table where the fuel ethanol content can be changed. In the UK all 95 RON petrol contains up to 10% ethanol so ive changed this from 5 to 10% for my 95 RON map.

My STFT is around 1 and my LTFT is also at 1. I watched the EFI tuning fundamentals course and noted that if total fuel trims are greater than +/- 5 then the MAF should be scaled. I know my total trims are within this acceptable limit but I was just curious that if I made induction changes in the future and the total trims increased, what table would I change to scale the MAF.

Thanks for the info, I will bear this in mind as I become more familiar with all the tables.

I made some changes to the Lambda Target Bank 1 table after watching the Understanding AFR course but had some questions when in came to filling in the gaps and smoothing the table (but I will open another thread for that).

I would revert the change you made.

I am not sure which table you adjusted but the fuel scalar is the main table to adjust for ethanol content and adjusting STFT.

For Lambda, there are two main tables as well as some conditions on other fuel tables that you need to change for them to work.

Look at the table descriptions which will help you understand what it is for as well as bm3 recommendation on how to set them.

If all fails send me a tune request (BM3ShahsMachineShop) and I'll take a look.

Hi Shane,

This is the table that I changed.

I noticed that there is lambda bank 1 and bank 2... I assume the bank 2 table isn't used?

Thanks for the info and the tuner request offer.

You can adjust that table (ethanol content), log STFT and see if it changes, if it don't use the fuel scalar table.

That table is on B58s, my b48 don't have that one.

I typically adjust both lambda bank 1 & 2 to the same values. Note there are other tables you need to adjust to ensure the dme use the lambda bank 1&2 tables.

Thanks Shane