VCT VVT Tuning 2014 6.2 Raptor

[G_Force]

I am presently tuning a 2014 Raptor 6.2(6) and know how to tune the spark and fuel, but the VCT/VVT tuning is a mystery to me!
I can't seem to find anything that truly explains how Ford VCT actually works regarding tuning. I've successfully tuned many GM and Dodge VVT equipped engines, but I can't figure out how to advance or retard the overhead cams at any RPM or Load level.

In "Mapped Points", what does "Snap to Point" and "Snap to Line" mean? There is nothing that relates RPM and load to Mapped Points 0 - 4. Apparently, based on "Mapped Points Config," MP 5 - 14 are not used, as they are not enabled.

The "Intake Valve Opening" table and the "Exhaust Valve Closing" table should agree, since these engines have only one camshaft per head, to operate both intake and exhaust valves. Intake Valve MP 10 has 34 deg, but the Exhaust valve has 43 deg for the same MP 10, so that looks like a mistake from the factory. But other than that, if these numbers show MP 0 = 0 deg, MP 1 = 13, MP 2 = 23, and MP 3 = 33 deg , and they are all positive, does that mean the cam is advanced or retarded by that amount?

What do the "Distance Tables" do? They are based on RPM and Load, but the numbers vary from 0 - 4.00. When these values are higher, approaching 4.00, what should I understand about what the higher value means? What would happen if these values (of 4.0) were raised higher to 5.0 or 6.0 max? What would that do?

[ECM] 38158 - Optimum Power - Intake Valve Opening Angle vs. RPM
[ECM] 38156 - Optimum Power - Exhaust Valve Opening Angle vs. RPM
Both of these tables should agree and they do. They both have the same data: 500 - 3500 RPM shows 0 degs, 4500 RPM = 8.0, 5500 RPM = 12.0, and 6000 RPM = 18.0 (again not clear if this means adv or ret). I hope that doesn't mean that by 6000 RPM the cam is actually supposed to advance the cam by 12 degrees. If anything, the cam should be retarding in the upper RPM band to reap the best power at that point!

Thanks for any assistance provided!

[engineermike]

Each mapped point represents a fully calibrated engine at a single static cam timing. That way, you can run at any speed and load at any cam timing and the engine is already fully calibrated to run there.

Snap to point and snap to line are like in CAD. If cam timing is "close enough" to a mapped point, snap to point will only use calibration data from that single mapped point rather than averaging all weighted based on distance. Snap to line draws a line between two points and if it's close to that line then it will just average data from the two points rather than all of them.

Example, assume your mapped points are MP0: 0,0 and MP1: 13,13 and your actual measured cam timing is 11/10. With snap to point, it will use only MP1 for all the speed density, spark, and torque data. If you have a snap line from 0 to 1, then it will only use data from MP0 and MP1, but it will weight MP1 much heavier. With no snap at all, it will do a weighted average of all points.

Cam timing lower/negative is advance and higher/positive is retard.

Distance tables are used to command cam timing. If you're in fuel economy mode, then look up your speed and load on the fuel economy distance table and pluck the number off the table. Then look under "mapped points" at the table just called "fuel economy". This is what some call the index array and it's used to cross the number you just looked up on the distance table to a mapped point.

[G_Force]

Thank you. Very well stated! I have done CAD work before, so I do understand the association with respect to Snap to Point and Snap to Line.

The Distance Tables now make sense to me, thanks to your explanation!

Regarding the cam timing, I find that ALL Intake or Exhaust Valve Opening Angle timing numbers anywhere range from 0 -> 43.0 degs. There are no values that are negative. Mapped Point 0 = 0 degs, MP 1 = 13.0, etc. It looks to me like the cam phaser centers the cam centerline in the middle of its movement, but I do not know that for a fact! Dodge cam phasers works that way, but GM cam phasers start at one end of its travel where it is most advanced (by cam specs) and then retards the cam more as the numbers (all positive) increase in the tables. Therefore, I wonder if I could set MP 0 (now at 0) to something like -4 to get a bit more low-end torque? But, under the definitions for Intake and Exhaust Camshafts, the Base Intake Valve Opening & Closing events are set to 0 degs and same for the Exhaust Camshaft. So by this definition of these initial base values, and by the way HPT provides guidance (in the lower right corner of the screen) with values allowed from 0 -> 720 degs, it looks to me like negative values are not allowed!

14 F150 6.2 Raptor - Stock.hpt

[Pistol_91]

Im a visual learner so here you go
distance.png

[engineermike]

Im a visual learner so here you go
distance.png

Yes, that's exactly how it works.

[engineermike]

In Fords, generally 0 is considered the neutral/disabled/lock position. Ford has used both mid-lock and end-lock design phasers. On the exhaust all I've seen is the lock/neutral/disabled state is fully advanced, giving minimum overlap. On the intake they used mid-lock and full-retard lock, depending on year and engine. The Gen2 3 coyote and Predator were mid-lock, and Gen1 and 4 are full-retard lock IIRC. Ecoboost is full retard lock on the intake as well. If all your values are positive then it sounds like yours is full-advance lock. I don't think putting in negative values will get it any more advanced than 0 since 0 should be full advance already.

[G_Force]

Im a visual learner so here you go
distance.png

This is good! That's what I kind of thought how it works. Thanks!

[G_Force]

In Fords, generally 0 is considered the neutral/disabled/lock position. Ford has used both mid-lock and end-lock design phasers. On the exhaust all I've seen is the lock/neutral/disabled state is fully advanced, giving minimum overlap. On the intake they used mid-lock and full-retard lock, depending on year and engine. The Gen2 3 coyote and Predator were mid-lock, and Gen1 and 4 are full-retard lock IIRC. Ecoboost is full retard lock on the intake as well. If all your values are positive then it sounds like yours is full-advance lock. I don't think putting in negative values will get it any more advanced than 0 since 0 should be full advance already.

Thanks for the added detail. I forgot to mention that this 6.2L V8 has a SOHC valvetrain setup, so the cam phaser affects both intake and exhaust valves the same. So I would agree that trying to use a negative (cam angle) value just doesn't seem like it would work. Instead of adjusting the cam tables for Intake and Exhaust openings, it looks like the best place to adjust the cam phasing would be in the "Distance" tables. In the Raptor tune, there are basically only "Best Drivability" and "Best Fuel Economy" tables in which someone could advance or retard the cam at different RPM and Load levels. The "Emissions Reduction" and "Optimum Stability" tables are populated with zeros.

VCT Optimal Stability Max Desired Load vs RPM.jpg
One more question about this table under Optimal Stability (lower right corner of Variable Camshaft), which establishes the Maximum Load for O/S. Is the table saying that if the engine is running under 5000 RPM there is no O/S Max Load limitations? And if greater than 5000 RPM and if the Load is greater than 0.16 that Optimal Stability reverts, to possibly Optimum Power??

Thanks again!

[Pistol_91]

Log VCT Schedule on your scanner. You will see how each distance table works at which times and load vs rpm. O/S is used usually idle or off the throttle.

[G_Force]

Thank you, all!

[engineermike]

it looks like the best place to adjust the cam phasing would be in the "Distance" tables. In the Raptor tune, there are basically only "Best Drivability" and "Best Fuel Economy" tables in which someone could advance or retard the cam at different RPM and Load levels. The "Emissions Reduction" and "Optimum Stability" tables are populated with zeros.

It depends on what VCT mode is at the time. It uses Emissions during cold start and Stability at coastdown and idle. Fuel economy is used when cruising and drivability is used at heavier loads less than Optimum Power. The zero's just send it to (I think) MP0 if you follow the same logic flow you did earlier.

One more question about this table under Optimal Stability (lower right corner of Variable Camshaft), which establishes the Maximum Load for O/S. Is the table saying that if the engine is running under 5000 RPM there is no O/S Max Load limitations? And if greater than 5000 RPM and if the Load is greater than 0.16 that Optimal Stability reverts, to possibly Optimum Power??

I made an attempt to run the engine on one distance table 100% of the time to simplify tuning. I was unsuccessful. I can get it to avoid Optimum Power and Drivability, but I could not make it use Fuel Economy at idle. I believe there is some combination of *and* and *or* logic statements that include pedal position in addition to the table you posted above. At any rate, it's going to use Optimum Stability whether you want it to or not.

[G_Force]

Yes, I do understand the VCT Schedule Mode better now, but not fully. I went for a test drive today and found (like you said) during decel and idle, Optimum Stability was used. During normal driving it would be in Fuel Economy or Best Fuel Economy mode. But at WOT, it was in "Fuel Economy Drive"!! What the heck is that? No Optimum Power mode! It was getting the correct fuel enrichment, just like it was configured in the Power Enrich tab, "WOT Lambda". And the cam phasing for IVO and EVC angles matched what is specified in the Optimum Power tables per RPM level, so it behaved as it should in Optimum Power mode. Max Load was 0.85 @ 4600 RPM (probably peak Tq), as we are just over a Mile High here in Denver, CO.

Very interesting that you were able to simplify the engine operation by getting it to run successfully on one Distance Table. Did it affect the fuel economy or the performance?

[SiriusC1024]

https://forum.hptuners.com/showthread.php?108530-F-250-6-2
https://forum.hptuners.com/showthread.php?105734-6-2l-tuning-help
https://forum.hptuners.com/showthrea...2l-tuning-help

[Pistol_91]

But at WOT, it was in "Fuel Economy Drive"!! What the heck is that? No Optimum Power mode! Max Load was 0.85 @ 4600 RPM (probably peak Tq), as we are just over a Mile High here in Denver, CO.

Looks to be disabled.

op.png

[SiriusC1024]

Yep, and the settings linked above will correct it.

[SiriusC1024]

Sorry, I double pasted the bottom two links. Meant to include this:
https://forum.hptuners.com/showthrea...wap-and-tuning