WOT timing - EB 3.5

[metroplex]

So what exact limiters are you modifying, and what are you doing to those modifiers? I looked at the 2014 GT 5.0 vs the 2014 GT 5.0 with Roush TVS and it seems like they reduced the amount of spark advance in the temperature adders, and re-scaled the BKT tables for load while increasing the spark by a few degrees. We have pretty much the same spark tables.

At WOT, the spark is essentially the same from 4000-6000 RPM. The way the SHO's transmission/final drive is set up and the engine's powerband, it basically hits 6000 RPM for the 1-2 (and I try to target 6k RPM for the shifts), and then never drops below 4500 RPM after the shifts. The load stays the same, about 1.7-1.8, making it simple to identify in the BKT cells. I experimented with higher shift RPMs but it seems like the car loses momentum and the turbochargers are just pumping around heat.

My MBT's are pretty much set to 30-35+ degrees of advance in those cells. I don't normally see any knock retard with 1 heat range colder plugs. Borderline maxes out around 9-11 degrees of advance in those cells. I tried adding up to 6*-7* of timing to the BKT, and almost all of it was pulled as knock retard.

[tbrtuning]

The knock sensors are very responsive on the newer Fords so it is very possible that you are actually at the knock threshold. Log knock sensor voltages and look for spikes where you feel that you should be getting higher timing but it starts to limit it. I really want to find a local Ecoboost to experiment with but haven't found one yet. I keep lurking around the Ecoboost forum learning.

It isn't the approach that I like the best but I've seen many people run a low borderline and let sensors add a lot and they seem to hit very similar timing pull to pull because the sensors respond so quickly it pretty much always ends up detecting knock and pulling timing at the same point.

[metroplex]

I am monitoring knock, it's not causing the limit. There would be 0 knock retard (zero) during a WOT run if I keep the BKT stock with the ITV22 plugs. When I add spark to the BKT, whatever I added was pulled as knock retard. There's no PID for knock sensor voltage, only knock retard. The SHO is global knock retard, not individual cylinder. Only some of the newer EcoBoost engines have individual cylinder monitoring (mostly the 4-bangers).

I can also see if the sensors are adding spark (negative knock retard) and it never adds it during a WOT run. I will see it add some spark during non-WOT operations.

[posenheimer]

Have you moved your Preignition Limit and cylinder pressure limit spark tables up out of the way, 63.5 in all the cells?

[metroplex]

I didn't make them all 63.5, but even the factory settings would allow enough ceiling for the WOT spark to be higher than 9-11 degrees. For example, preignition limit for 1.4-1.8 load at 4000+ RPM stock is 20-23 degrees. Pressure limit in the same region is 25-28 degrees.

[murfie]

Have you increased the IPC spark maximum? do you even have that table on the SHO?

[metroplex]

Yes, that is increased. I maxed out the Preignition Limit and Cylinder Pressure Limit spark tables (63.5*) and there's no change to my final spark. When I am logging spark, I logged 4 values:

Spark Advance
Spark Advance (SAE)
Borderline Knock
Max Brake Torque (I think this is the 4th one)

The Borderline Knock spark data corresponds to my tables including the extra spark I added (about 16*-18* total). However, the Spark Advance and Spark Advance (SAE) show only 9-11* at WOT.

[murfie]

all sources are normal?

I thought base usually meant spark was being pulled by either lambda, iat, or ect hitting a negative value after muliplier.

[metroplex]

Spark Source is Base at WOT. I've seen it switch to Borderline at one point but I think it was at partial throttle or similar conditions.
If it is pulled by lambda, IAT, or ECT, I've not seen it show up in the logs. I checked the correction tables and nothing comes up as obvious. My ECT and IAT aren't too high. As for lambda, I don't recall which table I checked, but I think I actually even increased spark advance for lambda.

[murfie]

You did not increase this spark advance by making a negative number larger did you?

[metroplex]

In the BKT, I did not have any negative numbers. The SHO has only positives, unlike Mustang/F150. But I made it more positive in the BKTs to no effect other than for me to see BK increase without an impact on final spark advance

[murfie]

I meant spark advance for lambda that you increased.

[metroplex]

I only touched 2 cells on that table but made positive values greater. Any advice on what that table should look like? Looking at it holistically, it shouldn't be limiting my final spark advance.

[murfie]

Part of it depends on your changes to the WOT lambda. another part is cruising in CL it tried to maintain Lambda 1. Stock if it goes slightly rich it removes a small amount of spark and if it goes slightly lean it starts adding a fair amount of spark. Id probably zero out the lean lambda values. I think this is there to help advance spark quicker for DFCO, but could be used if you are getting lean tip outs and knock. The third part would be for really rich tip ins. That kinda depends on what you did with your spark tip in modifier. Its mainly just another option to help if you are getting knock on tip ins.

[murfie]

i was thinking you preignition adder vs lambda was increased.

[metroplex]

I looked over the tables and nothing jumps out at me as being out of place.

[murfie]

what are your ECT getting up to?

[metroplex]

Nothing over 200F, and IAT is 30F-40F
This was the track as well.

The IAT2/MCT is 90F at the street, and over 120F at the track but the final spark advance is the same at WOT between these 2 scenarios (in other words, I don't think IAT2 played a role in this final spark calc).

[murfie]

Are your actual lambda values pretty stable or are they fluctuating up and down from what you are commanding?

[metroplex]

Solid as a rock until 5800+ RPM, which it then dips down a few points (I discussed this in another thread). No rhyme or reason as to why it does this, but usually STFT dips down to 0% or negative when this happens. I suspect it is because the turbos ran out of efficiency. But basically commanded lambda = actual lambda up until 5800+ RPM, and then the delta is by 0.02 at most above 5800 RPM.