Knock Resistance

[reubone]

I might have been missing something at first, but I found it confusing reading the initial post and log since I didn't see any mention of what vehicle we were talking about. From reading other people's comments, I think I have figured out that this is a Ford Focus ST. Is that correct? Also, posting the log along with your current tune file is the BEST way to make sure that you get relevant answers to your question.

Since I cannot see the current tune file to look up values you may be hitting in your limiters, etc here are my $0.02

1. Your AFR commanded vs actual under WOT is off, and is running richer than commanded. Have you attempted to use the Speed Density Calculator yet to correct your VE across the Mapped Points? Rich AFRs in Direct Injection cars can create higher than desired cylinder pressure, which can lead to knock. Also, too many people ignore tuning the Speed Density values on Ecoboosts, which would be like Ignoring MAF tuning on an LS3. Yes, on the surface it appears more complicated than MAF frequency tuning, but HPTuners gave us this awesome scanner and awesome tools to be able to calculate the coefficients needed to properly adjust our VE Mapped Points.

2. Under LSPI Reduction on the Torque Management tab, you may want to make sure that your limits are set high enough for the amount of boost you are trying to achieve. I know it says that it is the "Load Limit", so most people draw the conclusion that this is the Airload value they are referencing (where I see a max of around 2.20 Airload in your log), but from my observations over the years I believe this to actually be a Pressure Ratio limit (Manifold Absolute Pressure / Ambient Barometric Pressure), in which case I see you hitting values closer to 2.40 in your log. Then be sure your Combustion Max table and others related to that limiting are also in check.

3. Looking at your Spark Source in the log around some of your higher KR events (-3.0 or worse in the first pull of the log) you are hitting your Cylinder Pressure Limit (See #1 about Speed Density tuning recommendation to get your WOT AFR closer to commanded)

Thank you for your interest. The vehicle in question can most of the time be derived from the description at the top right of the scanner window. In this case it is a 2020 mustang ecoboost. It is true that the commanded ant actual lambda do not match up. I had made a previous post trying to address this situation. Note that the commanded lambda wonders around a bit while actual is tracking exactly what is directed in the tune file. I'm not totally sure why the commanded is waving up and down but as long as my actual lambda is tracking what I dictate in the tune file I'm ok with that. My trims are never more than 8 off at max and on 6% off at wot. I don't think a lambda of .81-.82 is rich enough to force detonation but I could be wrong. Doesn't seem likely when the factory tune consistently delivered .75-.73 at times. I am also aware of the LSPI tables and what they do. This post was asking about knock resistance trickery not exactly tune manipulation. Cylinder pressure limit was reached for a split second before knock took timing back below that limit. This knock issue is what Im trying to solve. Some on here have more boost and timing with less knock so If they had a solution Im all ears.

[Stevekreger]

i got a 17 2.0 fusion running e85. stock everything except bigger intercooler .84 lambda 20 deg advance no knock. 93 oct doesn't really help much.