Custom Build , self tuned ...weird data.

[CrazyCanadian]

Thanks For your answer ,
My 91 tune is good now, making 250 whp with no knock and no lean spot. I'm quite happy for that .

I began to tune with methanol and obviously, got weird data again , probably cause I'm better at building things than tuning them ...

So as my first post says , my meth injection is controlled by a microsquirt, I have 2 650cc injectors.
I began to change the AFR target and compensate with the meth to reach the desired AFR of around 10.6 (I think thats OK for an AFR on meth...).

Then I read that the proper way to do it is to reduce MAF from around 3V to the end and compensate with the Aux fuel witch I did ...
I did many pulls , raising the RPM by little each time to try to dial the Aux fuel table in the minisquirt. In the last couple of pulls I got something that I hope ill get an answer for, I command lambda of 0.73(10.59 AFR) and suddenly, the command AFR goes to 14.7 during the pulls ... this shouldn't be affected by the maf as the AFR as WOT is dependent of the LOAD and RPM right ?
My MAP is a 3.5 bar (bosch) which can read up to 43 psi and since I got to 47.7 psi in that pull, could this cause to throw the desired AFR to 14.7 ?

P.S. my actual AFR is lean, and I know it, I'm raising bit by bit and raising or lowering my aux fuel after each pull.
P.S.2 I got wheel spin on the last pulls , I would be surprised if that would make my command AFR to go lean... but I thought I should mention it.
91US_95EU +METH v1.00.vtune

Full-3MPSBL-Logging - 2023-06-18 15.54.48.csv

When the water meth turned on, manifold pressure increased... Overboost fuel cut limit kicked in, but the throttle overboost throttle reduction didn't..

Also how's the Megasquirt tuning set up for the water meth.. are you using any wideband feed back to it? Or do you have any limiters set up in that software.. it's possible that it reduced the water meth flow due to something like that going on causing your lean issue..

[dominic_pderoy]

Hey thanks for the reply!

I did lots of work on the tune since last posted.
I still get the commanded afr to go to stoch, that's what I want to eliminate?!?. But the actual afr is not that far off (compared to before) now.

The microsquirt runs on Maf and has a maf curve , the table used is mafload. I put a constant everywhere in the table and I adjust the maf curve to get the desired afr (that's the best way I have found so far to make it work with the car).
I have a bosch 4.9 that goes to the megasquirt , but use it only to keep an eye on the afr when adjusting something, it's not running in close loop.
I activate the meth pump with the microsquirt above 3000 rpm so it's ready and priming the system and when it's time , the Injectors pulse. I still get some knock when above 30C outside , so ill need to push more meth ...

I'll post a log when I'm happy with what I have done.
It may take a while, I have less time now.

[CrazyCanadian]

A traditional set up running a MAP sensor might better account for the increased manifold pressure you are getting when injection happens...