As this is an area that is confusing to many, I took the liberty of combining/editing the most recent discussions between Murfie and others in a Word document. If it is useful, great. If you think it is worth zero, then file it into the trash.
MURFIES EXPLANATION OF TABLES AND ARRAYS.doc
2012 Mustang GT with S/C
4Runner with S/C
Turbo/NOS Hayabusa - 320RWHP
I didn't have the best understanding of how you drew your lines on that diagram. I was able to get the points populated obviously, they're just the plotted IVO/EVC values of all the Mapped Points.Originally Posted by murfie
I still think I'm missing a large part of this. Maybe this next statement will underline it. Why would "blending" the optimal stability table in way you suggested be any different than the way I had it in the above post? How would having a distance of 5 (at 2000), 2 (at 3500), be any different that having a distance of 0 in those cells (Since all those distances get you to Mapped Point 0)?Same with using 1.5 instead of .5? This might just be an issue of semantics (i.e. you just so happen to be using different distances than I would, to achieve the same result, and get to the same Mapped Point).
Thanks again, for helping me through this.
Last edited by AKDMB; 08-23-2017 at 05:46 PM.
I drew the lines in paint, just for easier visualization.
The ECU would need to interpolate to get from 6 at 1000 and 0 at 2000. At some point (~1850 rpm) that Interpolated value would be 1 giving you the MP at that index. It could make no difference if that MP is on the line, but if it's far off of it your cams may move to a less than desired position during this transition.
Last edited by murfie; 08-23-2017 at 06:36 PM.
I file away useful info from this forum every chance I get, just in case. The link to the Ghost Cam guide expired and I'm glad I had that saved.
Ohhhhh, that makes perfect sense, I should have caught that. In this portion of the tune the interpolation between the cells really does matter. Thanks again man.
Last edited by AKDMB; 08-23-2017 at 07:50 PM.
I just wanted to add some info to my points plot. Basically the two major things you want to keep in mind are the stroke that happen when valves are closed and cylinder pressure is raising. One is decided by intake restriction and the other is exhaust restriction. I also wanted to show how far away the borderline overlap is from the points actually being used.
MPs cam idle.PNG
would there be any value in copying speed density values from MP8 (similar IVO,EVC angles to CAM tune MP13) to MP13 speed density tables to make the speed density numbers happy when idling in cam mode? And any other values associated with MP8 for that matter such as torque and invtorque?
Last edited by GapRider; 08-30-2017 at 06:41 PM.
2019 C7 Stingray M7 - long tube headers, 6.30/6.22 226/238 cam, supporting stuff, DOD and VVT delete.
Stock everything else
Murfie,
What is the best way to lock down one map point when in WOT only so it doesn't jump around from say 14,21,25? Example, looking at the roush tune, map 25 is enabled but is not specified in any distance table or snap to line but yet it is used when at WOT. So when in WOT condition, how do you control what maps are used because I do not see this in HP Tuners software or maybe I am just missing something
Roush map config.jpg
Roush map config002.jpg
I think there are tables missing in the 15+. Specifically index array tables for drivability and OP modes. They may not even be their own tables but modifiers to the existing fuel economy array. I think people are getting around it by increasing fuel economy enable max load [ECM] 38202 ] above possible values seen so the fuel economy array is never disabled, since thats the one we do have access to. I've also seen this done to the drivability table so it is never enabled. You would also have to increase OP enable tables, following the same logic. From there you could modify the fuel economy arry and distances to target select MPs.
Yeah, there are defiantly tables missing. I still dont understand why there is a best driveability table but no map point config table for it, and there is defiantly no table for WOT conditions. I did what you said and maxed out values for the fuel economy table and it still went into map 25 at the beginning of the pull, then went to map 22 which is another map not specified in the fuel economy table. I will try and disable maps 22-25 and see if I can get it to follow the fuel economy tables that way.
Not sure what you mean for no table for WOT conditions. WOT is almost certainly in Optimal Power mode (though sometimes it may be unused and is using the best driveability table if cal'd off), and thus isn't necessarily using a set mapped point, but a moving target IVO/EVC from those tables. You can however enable the OP position at the current time to be an available mapped point in the Mapped Points Configuration. What you usually see to "lock" it to a given point at WOT is to have the Optimum Power point enabled (always the last point in the mapped point array), and then optimum power snap to point enabled. On 11-14 Coyote I believe this was done (on the couple cals I looked at), on 15+ using a set mapped point isnt used from what I've seen, so you'll have a blend of various points, typically ones "fencing" the region off, which I'll go into below. There isn't anything missing on the couple 15+ cals I've looked at that prevents you from doing this. There are no index tables for OP because it runs direct cam positions from the tables 38158 and 38156. Best Drivability also doesn't have an index table because it uses the Fuel Economy index tables. This hasn't changed 11-14 to 15+, there's just simply more points now for the IMRC.
I think this thread could use some explanation on Ford VCT modes, what enables them, and their purpose, as well as some background on some of the tables. Descriptions could use updating, and will be as I get around to it.
Ford VCT Control
Managed by what is known as "HDFX" which stands for High Degree of Freedom eXecutive.
Why do I need it?
Life was simple when you had a single independent cam, or dual equal cams, because your cam essentially lived in a "1D" space of intake valve timing vs exhaust valve timing. You were on a set line, only one dimension of space.
Twin-independent cams however present a unique challenge. Now you can vary both cams independently, which means you can also vary your overlap centerline and overlap magnitude. Now your cam lives on a plane. HDFX is designed to account for this. Other OEMs use completely different strategies for this from what I've seen, but honestly I think after going through a few of them that Ford's has the best versatility.
As well, as you guys are probably aware, charge motion valves like IMRC add another dimension to this whole equation, technically meaning you're now in a 3D type space, blending between two sets of HDFX 2D pairs based on IMRC position as well. Life is not easy as you add more variables!
I love Murphy's graph above, and I've actually created a similar one I'll reference here to help explain things.
RcFZ9cq.png
Now onto the different modes of HDFX. I should add, on older vehicles this only scheduled cams, on newer vehicles (2015+) it can schedule any actuator that would effect cylinder flow (i.e. IMRC, IMCC, EGR, etc). You'll start to see this popup on the newest vehicles, so keep that in mind as well. The idea behind the modes will be the same, just change my references to cams below to your given actuator.
Optimal Stability (OS)
The goal of this mode is to represent the cam position that has the most stable operation. This basically means smoothest running in a way. Low variance from cycle to cycle, least likely to misfire, etc.
Optimal Stability is the targeted mode if your Desired Load is BELOW a given threshold. Below this given load, your target will be optimal stability.
Typically this will be one set point, but in the car I used above (a '14 Coyote), at high RPM it actually adds in some intake valve advance. There's usually a line defined in snap to line if so. More about that later.
Emissions Reduction (ER)
The goal of emissions reduction mode is in the name. Its designed to allow you to target a given cam position on cold starts. I dont think we typically map out the entry conditions, but they're based on coolant temp at startup and catalyst temperature, and a maximum load limit. Basically low catalyst temperature, cold starts. These are usually the situations that cars actually produce the most emissions because the catalyst is inactive. The goal of the ER mode is thus to put the cams in a position to allow the car to heat up the catalyst quicker so that emissions are reduced. Emissions Reduction will override Optimal Stability, Best Driveability, and Fuel Economy if its conditions are met.
Fuel Economy (FE)
Fuel economy is usually the mode you're most often in driving your vehicle. The goal is in the name as well, to optimize fuel economy. I.e. you're trying to make the most power per drop of fuel. This can be achieved in several different ways, but typically there's quite a few things being balanced. Combustion stability (no point if it runs like crap), pumping losses (i.e. lost power due to the act of pumping air into the cylinder. Higher manifold pressure = lower pumping losses typically), actual torque output, emissions output, etc. So for a given mode, your given desired load (amount of fresh air in the cylinder), we target this cam position that still keeps the engine running while minimizing pumping losses, maximizes power production, while meeting emissions.
Best Drivability (BD/FED)
Best Drivability is also known as "Fuel Economy Drive" mode. Above a certain load point, your cam switches to this mode, typically once you start to have less vacuum available. The goal is to improve driveability in these scenarios.
Best Drivability shares its mapped points with Fuel Economy. Above Optimal Stability max load, below Fuel Economy Max Load, you're running from the Best FE tables. Above the Best FE tables, below the Best Drivability, your mode is still "Best Drivability" but you're using a blend of the two tables. Above min Best Drivability load you're using Best Drivability table entirely.
Optimum Power (OP)
The goal of optimum power is also in its name. The idea is above a certain pedal position and load desired, forgo fuel economy in search for maximum horsepower period. I.e. we're no longer running to make the most horsepower per drop, just most horsepower period! Optimum Power is unique in that it defines its own constantly moving "mapped point" if desired. If enabled, it gets its own set of everything just like other points, but its constantly moving. You may not necessarily be at 100% Optimum Power mapped point though in Optimum Power mode due to reason we'll go into later, but its of note that it can be mapped separately. If you look at how it lays out in the 2D plane, it makes sense for this to be true as its often away from the other points (though there is usually a fence of points around the optimum power region).
Transient Performance (TPM)
This is present on turbocharged vehicles, designed to maximize spool of the turbocharger. Typically it does this with blowthrough air. I.e. increase air in the exhaust. Exhaust mass drives the turbine, and thus you get better spool. Typically this will be positions with very high overlap magnitude, and the earliest overlap centerline (which increases EGT as the exhaust valve opens sooner). We haven't really mapped this out for many calibrations, as even on most of the Ecoboosts, it remains disabled. There are many many conditions for it, and if active, it trumps all other modes INCLUDING optimum power. The entry conditions are based on MFRACT Desired, Catalyst Temperature safety (from raw fuel exotherm plus raised EGT), blowthrough availability (i.e. high overlap might not actually cause blowthrough, so we need to actually have the ability to increase exhaust flow), fuel availability (more fuel needs to be injected as some of it will go through into the exhaust and never be combusted), etc.
Manual Launch
This mode is designed to be enabled when launching (defined simply as taking off from a stop) for manual transmission vehicles. You may see "Launch" tables in several areas, all designed to help a car get moving from a stopped position, which may have extra torque desired over normal briefly to help smooth taking off from a stop.
Startup
Present on some of the newer vehicles. This is a mode used during cranking and shortly after cranking to help the engine start the easiest. Due to VCT design, the base de-energized cam position may not be the best for starting the engine, so this mode exists. We don't currently have this mapped I believe.
Manual Mode
Used to help calibration. You can manually lock the cams to a certain position to help calibrate a given mapped point for example.
Computer Controlled Shut Down (CCSD)
Used for auto-start stop. Mapped to the point where the cam lives when it is de-energized.
Disabled
Mapped to de-energized point as well. This mode is used if cam position cannot be measured accurately, or cam/crank misalignment is detected to prevent PTV damage.
Okay so we know the different modes, what about the actual mapped point usage?
So at any given moment, you have a desired mode, and your target cam positions are based off of that mode. Often times we're moving from one point to another as we go up in revs/load, etc, to reach the goal. Because we have a wide, 2D range, points have to picked that we can actually map out all of the things that depend on it, and then we need a way to actually figure out our final values for all the various outputs (borderline, MBT, airflow, inferred MAP, etc).
This is done by looking at the "distance" tables for a given mode, (or maybe only one point for that mode if thats how it is), and then referencing this distance to the index table to see which point is targetted. In OP mode this is forgone, as we usually are sweeping the cams through some range that would take far too many points to map out and is quite different from the other points used during normal operation.
First, you'll notice certain modes are basically "1D". They move the cams along a given line, to precise mapped points at times and so on. Obviously mapped points are spaced along these lines, and the lines are even defined with "snap to line" segment definitions. As well, points that are expected to be targetted directly typically also have a "snap to point" setup. What does this actually mean for these points, and how are the "weights" determined?
Well, remember we don't live in a perfect world. The cams are targetted to the given position closed loop, but the actual position maybe a little off. Because of this, Ford uses an inverse distance weighting to ALL mapped points at a given moment (including the "moving" OP point). That way if your cam is off in la-la-land or in between two points, an accurate value for all the various things that depend on HDFX can be determined.
However, the inverse weighting algorithm might not be perfect for predicting this. We can be right next to a given point, but have weights from other points that maybe make no sense (why should I have 1% weight from this point 40* away?). This is where "snap to point" comes into play. If you're close enough on the 2D plane to a "snap to point" point, the weight of that point is prioritized, because you're close enough to it. You'll lock in to that given point. "Snap to Line" is a similar idea. Draw a line segment between those points (like I've done on my image above). Now if you're close enough to that line, the weights will actually switch to an interpolation BETWEEN those two points along the line instead of between all points.
Why would we want this? Well, it helps alot during cam transients for starts. If we're cruising along and on the right side FE line, with just some EVC retard, and suddenly you tip in quickly to one of the higher points in the drivability section. Your cam is going to move to try to catch your new point, and its going to go straight through unmapped territory. It may not make sense to care about the heavily advanced, retarded lines, instead knowing that most of that area is close enough to these lines or points, we can weigh those more heavily with this snap logic. As well, if you're just a little off (-1* IVO, 10* EVC), it makes more sense to just use the Mapped point for 0,10, then it does to weigh ALL 15 points or whatever that is defined.
As well, you'll often notice some points defined that don't have a "snap". Usually these aren't points the car ever actually targets directly via any mode, but they kind of "fence" in a region the cam may operate in, for example during OP mode. The idea here is to help improve all of our HDFX outputs (spark, airflow, etc) when we're in one of these areas by having a good mapping on the outside of where we expect it. That way, operation while "inside" this fence or near it is still very good. For example in my image posted, the points at -50,20;-50,0;-14,0 dont have snap to point defined, instead notice they kind of act like the "outside" of the optimum power zone. This way if the cams dont quite follow our OP line perfectly (and our weight wouldn't be 100% then in this mode because we got too far away to "snap" to it), we still have good operation because we're in that region that's fenced in. It also wouldnt make sense to have line segments for these, as we don't necessarily want to blend directly from one of the points to the other, as we're not travelling along a line.
Hopefully this gives you guys a good answer to some of your questions, and some insight into how it works. We should have everything mapped for the vehicles we support to control the modes, minus emissions reduction and transient performance, which we know we need to add and are on the list of things to do!
Awesome!
Eastern and Central Europe American Muscle and Harley-Davidson tuning
www.hd-customs.pl
http://www.facebook.com/hdcustomspl
Thank you.
2012 Mustang GT with S/C
4Runner with S/C
Turbo/NOS Hayabusa - 320RWHP
Nice one ! Thanks
Thank you very much for your time and effort in explaining this! It is a big help for all of us here trying to understand this. I have learned a lot from this forum and will need to learn a lot more Guys like you, Murfie, and many others on here make things easier for guys like me to pick this all up and run with it. I was able to take my car to a dyno recently and made 800 RWHP but at 14psi. I should be able to get more HP at this PSI so I am trying to learn more about maps and other functions here to see if more power can be generated while keeping things simple and safe. Anyhow, thanks again for your help and keep up the good work!
In my case, I have an S550 twin turbo which I am self tuning for fun. I have a boss intake so I am using a lot of the strategy from the 2017 Roush tune which only uses the IMPC open maps (14-25). The part that was throwing me off was how the WOT pulls kept changing map weight positions for different pulls and also using maps not associated with these tables, but it seems things are very complicated with this S550 not having a spark OP mode versus an S197 that does and more time will be needed to figure this all out. I am trying pinpoint out a method to keep the car in one map at WOT similar to the OP map on an S197 for spark timing reasons as the cams are already following the OP cam tables. Do you have a tune that can be shared for an S550 that does just that? maybe take the roush tune and modify it to test?
So basically the best/easiest way to make it stay in one MP at WOT is to modify your OP cam angles at all RPMS to match the MP value or values referenced in the high load area of your drivability distance table.
On the 2015+ that would mean keep the IVO and EVO at 0 at all RPMs to stay in MP 14. Make IVO 0 and EVO 20 at all RPMs to stay in MP 21.
R8Bill is still getting weight from MP 25 even though its not a snap to point or snap to line. I didnt see it before but he also is getting a lot of weight from MP24 so it must just be using those MPs as they are enabled and probably are the only points close to use to achieve the OP angles.
Seems like roush made it harder on them self's disabling mp25 as a snap to point.
Last edited by murfie; 12-13-2017 at 10:04 AM.
Yeah, but obviously you'd sacrifice OP here. The way to get closest is using the OP Point and snapping to it, but of course a lot of the cars dont have the OP points mapped out in any of the tables so you have to do all of that yourself.
Roush has more info and good calibrators. Why they chose to do something a certain way is only known to them, but its generally safe to say they have good reasons for what they do.
But yeah, he gets weight from the nearest points, and without snap to point enabled on them, he's going to get blending from all of the points. And even with snap to point, if he's not close enough at that moment, it won't "snap" in. I believe there are parameters that can control the distance it will snap to something, but I'd have to double check. It may be useful for some of you guys who want to snap to the OP point during OP.
Steve, so are you saying on an S550 you can make OP mode work for spark by adjusting the tables? Do you have an example of this? I have tried to turn on OP for snap to point and line but still nothing.
in 2015 OP mode in some calibrations you can do OP for spark in some not. Works for cams. But you don't need to force it to use OP mode in spark, just adjust tables you have in WOT.
Eastern and Central Europe American Muscle and Harley-Davidson tuning
www.hd-customs.pl
http://www.facebook.com/hdcustomspl
Could the "Snap" distance be the bend table? All 1's Based on RPM. Not sure how far 1 is or how much you can increase or decrease that table.
There's an overall distance for snap that is separate, I forgot to mention bend.
The idea of the bend table is to reduce the weighting of OP point when enabled but youre not close to it at certain conditions. I.e. say you're on the fuel economy schedule, but maybe not snapped in, this reduces the weight of OP which is off somewhere else. It multiplies the OP distance directly acting on the OP weight. You could theoretically calibrate it higher, but you risk weighing the OP point more heavily than you should when operating in another condition (especially transients).
You should be able to get it to use an OP table during OP conditions by:
1) Enabling the OP Mapped Point
2) Enabling Snap to Point for OP
3) Ensure your OP Bend Distance is 1 / 100% in the RPM ranges you'd expect to be using OP in.
This should get you the heaviest weighting for the OP point posible, provided your cams are actually tracking OP (i.e. minimal cam error).
I dont think there's any other conditions I'm not thinking of right off hand.
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