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Help me Increase my Air Charge Max!
Posted: Sat Jun 13, 2026 7:00 pm
by m_kluch
I've been trying to raise my airc_max for the past couple of weeks and can't for the life of me figure out what's keeping it down below my target air charge numbers set in the boost section. I've raised some tables that I thought could be limiting me but don't understand what some of them do.
Mods are:
P600 turbo
XDI HPFP and 1400cc injectors
DW300c pump
PRL intake w/Race maf
MAP exhaust
Perrin Intercooler
Here are a couple of 4th gear WOT logs and my calibration. Any help would be greatly appreciated.
Re: Help me Increase my Air Charge Max!
Posted: Tue Jun 16, 2026 12:08 pm
by FK8_Hoonigan
Your hitting your defined AirC Limits
Doing what its supposed to.
Re: Help me Increase my Air Charge Max!
Posted: Tue Jun 16, 2026 10:25 pm
by Caustic Gnostic
I see the airc_max limiting the air charge in your logs. The limit in the table is 239%->233% but the airc_max goes from 222%-216% for some reason and the actual air charge follows the airc_max values. I have seen very similar instances in my own logs and I think they may be related to the KFMIOP and KFMIRL tables relationship to each other.
Those two tables should make sense relative to each other, for example in your KFMIOP table 170% AIRC at 7240 RPM equates to 82.2% of max torque. However in your KFMIRL table 82.2% torque at 7240 RPM requires 264% AIRC (instead of 170%). I don't know for sure if this was intentional on your part or just an accident from increasing column values to get more AIRC, but I think your issue may get better if you go back to the tables that hondata created for the 250% mod. If it still does not go away from that, my next guess would be that the limit is due to knock window tables seeing some type of noise at higher RPM and limiting the airc_max because of it.
Re: Help me Increase my Air Charge Max!
Posted: Thu Jun 18, 2026 4:15 am
by m_kluch
Caustic Gnostic wrote: Tue Jun 16, 2026 10:25 pm
I see the airc_max limiting the air charge in your logs. The limit in the table is 239%->233% but the airc_max goes from 222%-216% for some reason and the actual air charge follows the airc_max values. I have seen very similar instances in my own logs and I think they may be related to the KFMIOP and KFMIRL tables relationship to each other.
Those two tables should make sense relative to each other, for example in your KFMIOP table 170% AIRC at 7240 RPM equates to 82.2% of max torque. However in your KFMIRL table 82.2% torque at 7240 RPM requires 264% AIRC (instead of 170%). I don't know for sure if this was intentional on your part or just an accident from increasing column values to get more AIRC, but I think your issue may get better if you go back to the tables that hondata created for the 250% mod. If it still does not go away from that, my next guess would be that the limit is due to knock window tables seeing some type of noise at higher RPM and limiting the airc_max because of it.
Thank you for the feedback. Yes, I intentionally increased values in those tables to try to solve the issue. I tried going back to the stock values in these tables and the “air charge max” got even smaller. 210% at 7000rpm. I may just leave it alone for now. My fuel pressure can’t hold command past 6300 rpm anyways when I’m above E30….
Re: Help me Increase my Air Charge Max!
Posted: Thu Jun 18, 2026 4:19 am
by m_kluch
FK8_Hoonigan wrote: Tue Jun 16, 2026 12:08 pm
Your hitting your defined AirC Limits
Doing what its supposed to.
My defined AirC limits are set under the Boost section. They are higher than what I’m achieving when going WOT. Boost pressure is following Boost pressure command but the air charge is not reaching my desired limits. There is a “airc_max” in the sensors display that’s limiting my boost.
Re: Help me Increase my Air Charge Max!
Posted: Fri Jun 19, 2026 9:23 am
by jeffx
As Caustic Gnostic pointed out, your KFMIRL/KFMIOP tables are not in agreement. Correct that first and then see if you still have the issue.