Gen 3 coyote a10 Tuning help

[203jgj]

Hello,

I'm new to tuning and working through my first custom 93 octane tune on a 2022 Mustang GT (Gen 3 Coyote, 10R80). I'm using HP Tuners MPVI3 with VCM Suite, and I?m running into a few persistent issues that I could use help resolving. I'd love to become more versed in the tuning space so i can teach others as well so any knowledge given is appreciated. The logs include idle, casual driving and moderate pulls. 93 MAF base.hptdrive log 93 62225.hpl

Current Modifications:

JLT 120mm Cold Air Intake

Catless Longtube Headers

Full Catback Exhaust

Issues I'm Facing:

Knock Advance at 34%+ Load:
No matter the RPM or speed, I?m consistently seeing knock advance (0.3?0.5?) across all 8 cylinders beginning at around 34% absolute load (SAE). It becomes more pronounced as load increases. Fuel trims look reasonable, and commanded EQ is rich, but the knock remains.

Idle Dip When Coming to a Stop:
When decelerating to a stop rpm begins to dip in AUTO mode below 800 rpms to about 500 occasionally

I've worked through spark, fuel, MAF, and borderline knock adjustments, and enabled MAF adaptation. Despite this, the knock persists above 34% load, and the idle issue remains unresolved.

I?m attaching the latest tune and logs for review. Any help or suggestions would be hugely appreciated. Still learning, so if I missed something basic or overlooked a setting, feel free to call it out or edit the tune yourself and send it back, id appreciate i you explain the changes being made.

Thanks in advance!

[engineermike]

What you're seeing there is actually knock advance. If you've been reducing borderline timing, then you're going the wrong way.

You need to add spark timing and air load to any log where you're working with timing. The absolute load SAE channel is not the same thing.

I wasn't able to open your hpt file due to a checksum error. I'm using vcmeditor 5.0.4 which I believe is up to date.

[203jgj]

It was recommended by hp tuners for me to use the beta version of editor and scanner when creating my tune, should i switch over to the latest stable version instead?

[engineermike]

Up to you. I used to use beta because that’s all that would open the Whipple files. I use both now, but I don’t know if that’s why your file wouldn’t open.

[203jgj]

I believe if you try again on the beta version of the app the tune file should open, i got the same error a moment ago when trying to open the tune file on the stable version. Additionally if this does not work let me know please so i can begin reading the cars file on the stable version instead and potentially contact HPT if necessary.

[engineermike]

It opens for me in Beta. I looked at it a bit and there are a large number of changes made, many of which for no apparent reason. A good rule for tuning is that if you don't know what something does, leave it stock. I could go through and critique each one and tell you what to put back stock and what to leave, but really you just need to start over and just make changes you have good reason to make. For instance, we know the stock file is pretty good, but you changed a few parts. The parts you changed that affect the calibration are the headers and lack of cats, and the "cold air" intake. Honestly, I'd put the stock airbox back in it. Then you're left tuning for just the cats and headers.

[Pistol_91]

That isnt knock buddy. Its advancing timing. Negative knock retard is good. Positive is bad. Theres a hint, look at the knock per cyl you're logging. It even shows +Adv -Ret. They're all positive, they're all advancing. You aren't getting knock...
Get rid of all the SAE channels. Replace Absolute load for Air Load. Air load correlates exactly with what is in the tune, absolute load is just a percentage.

[203jgj]

Understood, changed the absolute load for air load and now have a better understanding of knock retard and the difference between adv+ and ret-. Thank you, when logging prior on my Palm beach tune i noticed knock retard and knock adv/ret would never move from 0 degrees. Any advice on what i should be aiming for when trying to retrieve this same result?

[engineermike]

You’ll get a lot of opinions on this but the bottom line is you need to understand what mbt, borderline, and cyl pressure timing is for and how the logic calculates each and selects which to use. But basically the stock tables work really well on 87 octane but on 91 or 93 it can take too long for knock advance to feed in. If you’ve increased octane you can add a few degrees to the borderline tables. And if you’re like me, you might limit the knock advance so it doesn’t run into knock all the time.

[203jgj]

Understood, definitely going to start fresh again. I have been considering throwing the stock air box on with a drop in filter but I'm having trouble separating from the JLT despite the horrible heat soak and extra steps it takes in tuning to try and account for my 120 degree IAT but I'm a fan of the intake noise unfortunately so id like to keep it. I have mini cats on my downstream O2 sensors so I'm not worried about a CEL, do i need to make any changes to optimize the extra scavenging from the headers and do you believe the rpm dip i am seeing is just bad MAF scaling in the low end?

[Pistol_91]

Any advice on what i should be aiming for when trying to retrieve this same result?

Well frankly there's a few different ways they could have retrieved what you were seeing on your device. Could be good, could be bad. No telling without digging into the tune file. Just because it was at 0 doesn't mean it was good. They could have completely disabled knock advance. They could have also disabled your knock sensors or made them less sensitive. Or their timing could have been spot on and it was perfect.
Like mike said there's so many ways you can go about tuning for timing. I personally like to leave a 1 or 2 degree cushion at WOT or about 2-4 at light throttle or part throttle. In case I get a tank of bad e85 since I don't test as much as I use to. I also change the rate slightly so it will advance a bit sooner rather than later.
The simplest thing to start with is just adding a degree or 2 to the borderline tables where it is advancing timing at. If it says -4 knock retard at 2500rpm at .8 load on mp 25, 75% and mp21, 25%. Then add 2 degrees to MP25 and 1 to MP21. Should be close to putting knock retard around -1 degree give or take. So, it will be adding 1 degree after the change. It will vary though, it won't be perfect. It may be too much, or too little, or the mapped points are blending even more than just 2 MPs.
Either way, its easy and can be done fairly quickly with fast results.

For headers you can change Transport Delay. Theres a write up on here how to. A lot of people never even touch it. I do.

JLT 120mm OPEN box intake correct? Where did you pull the data from? I personally have never pulled data for this intake because it never ran right. Just adjusted the stock curve until it worked. Don't recall having stalling issues except with a Lund tune.

[203jgj]

Regarding the JLT 120mm i actually pulled the MAF data from here, saw a few threads regarding the airflow vs period table for my intake, a few of which saying they got directly from JLT, averaged them out and did a little bit of smoothing. The car doesn't quite stall never has but its not far off, RPM's dip to around 500, takes half of a second to recover.

[engineermike]

The correct way to tune the MAF is to tweak the MAF transfer function until the fuel trims are very low, assuming your injector data is good.

On the knock retard, if the old tune never moved, then either the tuner disabled it (bad) or there is some other problem and FMEM is preventing it (also bad).

On the headers/scavenging, this subject can get pretty complicated. Yes, technically the LT headers will change the optimum cam timing. My guess is the exhaust cam should be advanced a bit to reduce blow-through/over-scavenging, but I don't have dyno testing to know specific numbers. You'd probably be safe running the exhaust cam around 10 in OP instead of 18 or 22, or put it on a dyno to get better numbers. Beyond that, there are lots of things that could be affected regarding air dilution of the exhaust that could throw off the WB02s but that's a much more complicated subject with no actionable answers I can provide without a lot of testing. Most just leave all that alone and it seems to work well enough.

[203jgj]

Okay heard, definitely going to mess with the MAF tuning some more after i log, I'm assuming PBD doesn't change anything regarding the headers considering they never asked if i had them or not so ill likely leave that. Additionally going to take some time to adjust timing today now that i have a chance to.

[veeefour]

No exhaust header will ever require you to adjust VCT - period. And this comes from days of dyno time - no street maf warriorring...

If you kept your engine stock the only bolt on part that will ever affect your VCT is intake manifold. If you introduce boost into equation this will not make any change either - it will just multiply. Now vct is asjusted for forced induction but this has nothing to do with max flow

[Nate_Nelson]

Here is MAF data I got from an email from JLT. I have the 120mm open box for my 2019 GT Mustang. CAI-FMG-18.xls Hope this helps.
I've always heard increase transport delay by 1.5x for long tube headers. Never had much issue with IAT on this intake or stalling. My car has ran great on it in the past. Unless idling IAT will increase but while moving mine are always low. Hope this helps someway!

[203jgj]

Thank you for the input, ill check this out later and possibly give it a try to update the thread if its any better than my current setup. Tune is running great as on now will be reposting the file again soon once i dial in a few more things.