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Thread: Focus ST - Desired Torque Drops

  1. #1
    Tuner Blown383's Avatar
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    Focus ST - Desired Torque Drops

    Hey everyone. I've got something interesting going on with my Focus ST. I have the Driver Demand tables set up to 350 lb-ft at 100% Accelerator Pedal. At right about 3300-3400 RPM, Desired Brake Torque and ETC Desired Torque both drop from 350 to 284 lb-ft and scheduled and indicated torque both drop causing Desired Load to drop. I have been searching for a solution to this problem and so far the only thing "around" it I've seen is to hack the engine torque/torque inverse tables to keep Desired Load from dropping. Even with the hacked tables, Desired Torque still drops. I have posted a log of without the torque changes and with the torque changes. I know the log shows the throttle closing but that was due to hitting a load limiter which I later moved up. Any insight into this would be great. Thank you.

    15FocusST11.hpt
    ST DD Drop.hpl
    ST Torque Changes.hpl
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

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    Tuner Blown383's Avatar
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    I've been looking through the tune but still nothing obvious jumps out at me. Any help would be awesome.
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

  3. #3
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    Possibily its falling back to the launch DD table for some reason. You do get a partial throttle limit before and after the reduction in TQ. Accelerator pedal is reading .9 and not 1. make sure a floor mat isn't blocking the pedal from reaching WOT.

    look at your transmission gear ratios.

    ST gear ratios.PNG

    I guess that is overall ratio.

    focus ST gear ratios.PNG
    Last edited by murfie; 02-03-2017 at 12:02 AM.

  4. #4
    Tuner Blown383's Avatar
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    I did increase that on a revision but it still dropped. The ratio tables are stock. I'm really stumped on this one.
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

  5. #5
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    Try decreasing the launch table.

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    clip/add mode switch. have you tried disabling this?

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    I'll try decreasing the launch table tonight. It had no effect when I increased it. I did disable the CLIP/ADD function at one time but I reenabled it for safety purposes. I'll also try that again tonight. I wonder if this is related to 5 Popcorn/Combustion Stability or if there is another limiter that isn't mapped out in the tables. It always seems to drop right at 3300rpm-ish. I've added meth to the car. Here is the most recent log I saved. If I got WOT above 3300rpm it reverts to 284/286 lbs-ft. Under 3300rpm, it starts out at 350 then drops.

    ST Meth Final 2.hpl
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

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    anyone think it could be a hard limiter due to the wastegate being maxed out? yeah im not sure it was the clip/adder either

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    I don't think the wastegate is maxed out. At least not in the last log posted and the non torque changes log. DC is at .87 and drops along with the torque at the same RPM. I am still seeing comb. limit and other limit up until it cuts the torque. I think using the limits to control the boost is whats causing it. You want TQ values, TB, waste gate, or some parameter that is ment to control boost. When the ECU hits a limit table its going to infer something is wrong. That's the only time it was designed to use those tables. It will also correct it the best way it can using IPC.

    Im also seeing lots of LTFT at low throttle. Could be a vaccum/ boost leak.

  10. #10
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    Alright, after playing with the car some more, there has to be another limit that isn't mapped out yet. I believe my torque drop is related to the "5 popcorn" limit early in the run. If I begin a pull higher in the RPM, it defaults to the lower torque value. The launch table has no effect on the Focus ST as far as I can see. At my elevation, the wastegate maxes out on the stock tune, at a higher RPM of course. There are no vacuum or boost leaks. I would correct the fuel trims if I could get a better grasp of the VE system. I did notice the torque drop every single time the "5 popcorn" limit goes away. It leads me to believe there is something I am not seeing.
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

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    Alright, I set the CLIP/ADD to 0 to disable it. With it disabled, I see the throttle closing when I roll onto the throttle in 4th. There has to be a limit I am not seeing. When ETC Desired torque drops, TIP desired drops, making the throttle close. Any help with this would be awesome. Thanks.

    15FocusST6a.hpt
    FocusDDDrop3.hpl
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

  12. #12
    I suspect your Torque Model changes are the root of your problems. Your tables aren't very smooth when moving through the mapped points.
    Your change seems to happen around ~3500 RPM as the cam position sweeps.

    Two main things I notice, one that I think is why you have this drop, and the other is more a question of why you did it.


    So, I highlighted the smoothness changes here. First to note, with as much as you're logging, the update rate on the mapped points is probably a hair too slow to get a good picture of how fast they're changing in this RPM region.
    But what you're telling the engine is in parked cam position, to make 383.5 lb.ft, you need 2.22 load @3k RPM. But at points 6 and 13, which have some overlap, You need 2.51 and 2.61 load @ 3k RPM. This is a huge difference at this RPM, almost 2.35 lb/min of airflow. It's also backwards of what I'd expect. Cam position 6 should need less load to make that torque than position 0. Thats why we target it at Optimum Power, we can make more power at that RPM with less airflow.

    This disjoint nature between your torque model is probably showing itself here as you rapidly transition from tables that claim to need a lot of airflow to ones that claim they need little is what it seems like to me. The torques that "jump", Engine Indicated, ETC Torque, and Scheduled Torque, are all calculated through those torque model tables, their sudden jump is because of the sudden jump in desired load. Desired Load ultimately comes from the Inverse Torque tables as your pedal demand torque goes through them. I highly suspect the huge transitions across your torque calculation tables are the cause of the sudden "snap" in both desired load and torque requests.

    As an aside,

    This change is suspect. If you didn't change the turbocharger, why did you change the surge line? This table controls the bypass valve, which you have controlled in an odd manner. Open time minimum of 30 seconds? Raising those values means at those higher boost levels you're making the valve open, possibly under boost if TIP actual and desired get within the open/close thresholds and you're under 20lb/min of air (which you would be at the lower RPMs).

    Just thought I'd mention that those are odd.

  13. #13
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    Bugasu, all the torque tables are stock. I have an aftermarket bypass valve now. I was experimenting with the surge table to see what it did, just never bothered to change it back. I learned that the minimum open time would keep the valve open at part throttle unless the hysteresis is exceeded. It would snap shut immediately with a good throttle transition. It stopped the constant purging. Here is the stock calibration.

    15FocusSTstock.hpt
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

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    I'm having the same issue, on a hunch I fiddled around to make commanded torque ride the max torque tables per gear under torque management > General > maximum torque. These tables end at 3400RPM, and at that point my ETC torque request drops to 287 and stays there no matter what else I do. I am showing no limits active.

    Several hours fiddling various limits and I can find nothing relevant to fix this... This is on a 2016...

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    Also, FWIW... I had a customer on my dyno with a 2014 on AP tuned elsewhere, and although I did not look at the tune the plot shows the exact same problem, a nonsense torque corner at 3400

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    Hitting this as well with a 2016 ST that I'm working with. I can get a great boost curve with nice response up until that 3400rpm territory. The the popcorn hits and throttle closes down to about 25%. Still looking for the cause.
    Jeff Chambers, Owner
    CRT Performance, LLC
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    Norwalk, OH 44857
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    If you look at his log file the 5popcorn does not coincide with the torque drop. I'm pretty sure the that is the LSPI, changing those tables does change where that goes in and out. I don't have the popcorn limit at all and I get the same drop at 3400...

    definitely something we don't see...

  18. #18
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    Yeah I can't figure it out. I hope Eric chimes in and helps us out. NCS, I haven't been able to get the 5 popcorn to go away. I have my LSPI tables raised up but it still goes popcorn. I figured there were tables similar to the F150 that are missing in the Focus calibrations.
    2007 Ford Mustang GT/CS: RGR 322 3v - JPC Intake - Vortech YSi-B - Magnum T56 XL - Built 8.8 - Full Suspension
    2008 Ford Shelby GT500: VMP Gen 2 - ATI 15% - SCJ TB - Full Bassani Exhaust - Full Suspension - Upper Pulley - Meth Injection - JLT 127mm

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    I'm not honestly sure what eliminated the popcorn, I cleared a bunch of stuff out just trying to make the thing ride the table set that suspiciously ends at 3400... I could backtrack and figure it out (in my mind it was the LSPI but there's a chance it was something else... I did raise it ridiculously....), but I do know from a couple other ecoboosts the popcorn limit isn't a deal-killer. At least in my experience it'll still command torque and make boost with it active. I assume it's just pulling timing, but it would be nice to have a solid explanation of what triggers it and what the specific results are. It's the great popcorn mystery.

    But first things first, this 285 mystery limit has got to go!
    Last edited by NCS; 03-29-2017 at 04:49 PM.

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    Quote Originally Posted by NCS View Post
    I'm not honestly sure what eliminated the popcorn, I cleared a bunch of stuff out just trying to make the thing ride the table set that suspiciously ends at 3400... I could backtrack and figure it out (in my mind it was the LSPI but there's a chance it was something else... I did raise it ridiculously....), but I do know from a couple other ecoboosts the popcorn limit isn't a deal-killer. At least in my experience it'll still command torque and make boost with it active. I assume it's just pulling timing, but it would be nice to have a solid explanation of what triggers it and what the specific results are. It's the great popcorn mystery.

    But first things first, this 285 mystery limit has got to go!
    Here, here!
    Jeff Chambers, Owner
    CRT Performance, LLC
    349 Cleveland Road
    Norwalk, OH 44857
    Ph: 419-668-4151
    Fx: 419-668-4643

    Performance Parts, Service and Dyno Tuning Specialists