I recently started tuning my car's ECU for an efficient and more powerful boost profile. After doing a little research, I decided to peek at one of the tuned files in the subforums here (namely the mbox 91 oct stage 1 bin). I was looking at the KFMIRL values and was comparing them to my stock ones and something just didn't make sense to me. In the stage 1 mbox bin, all of the values for '0%' (from 400 rpm to 7000 rpm) are above zero. This seems odd to me because wouldn't it mean that there is always going to be load requested, even if you are at idle or off of the gas? Could this be a potential wear issue for the turbo to have load requested at all times, or does it not matter since it is such a small amount (around 7 or 8 for each rpm increment).

Please, school me if my thinking on the matter is wrong. I know a lot of work was put into that mbox file, but values other than 0 for 0% just don't make sense to me.

Well, today, while testing non-zero values for the 0% row, I noticed that I had about 2hg less vacuum (about 20.5 when normal for me is 22 or 23) than normal and that I could also hear my turbo trying to spool while the SAI was on while warming up (foot off of the pedal). I'm going to reset those values to 0 and see if those two things go back to how they were.

Am I right in thinking that KFMIRL is used to dictate what load to give at a certain RPM and pedal position, and then LDRXN sets a limit on the maximum allowed load for a given RPM? It seems like if you mess with KFMIRL too much and set values too high for partial pedal position then you are not going to get the fuel you need to support the boost it is providing. Is this where you would need to dial in the fuel to compensate for the added boost at a partial pedal position?

Yes, I've read (and loved) the wiki many times, but I was looking for a more in-depth description than what was provided in there. The info in there is incredibly helpful, but I was trying to get a better feel for how the map works so I could file it away neatly in my brain. For now, through experimenting with various values, I have figured out what values are working best for myself and my car.

Thank you for the help, I'm sure I'll have some better questions as things progress.

Yes


No.  KFMIRL does not need adjusting for upto 1.2 bar boost. The max load requested here is 190, which is roughly 1.2 bar.  Your MAF and injector calibration control the fuelling, KFMIRL has nothing to do with it.  My car runs 22psi currently.  To do this, I increased the requested load to 210 at  the 100 percecent requested torque.  For requested torque of 50% and above, i increased the requested torque by the same percentage.  For example, 100% requested torque was 190, now is 210.  That's roughly a 10% increase.  If 50% requested torque was 90 load, then it should be increased by 10% to 99.   

This ensures you have a smooth linear throttle and boost response.  You should ONLY touch KFMIRL if you need more than 1.2 bar of boost, otherwise leave it.  Use LDRXN to cap the boost/load. 

The MAF will compensate for any extra boost with added fuel - unless you go off the scale.

Rick

Don't guess. Log.