Open

Open

* Disclaimer - Improper changes to your vehicle control strategy may result in engine failure ***

Jon Hebbeln & Jason Carberry

Introduction

Getting to know the Ford Focus RS

Here we will go over a few of the basic details and terminologies that are specific to Ford before we begin tuning on a COBB Accessport equipped Ford Ecoboost vehicle.

• 3D Breakpoint Setup– The Ford ECU uses a new style of 2D axes in select 3D tables. In these tables both the X and Y axis have "paired" data. On tables that would require it, we have broken these out for editing in separate folders. The axes are generally index based and may require manipulation to both the index and/or the data to properly display graphs or to utilize greater breakpoint resolution.  Our v300 OTS maps should have good base settings which can be modified further if need be.  More details on this can be found in section L.
  
  

• Boost Control – The RS does not directly target boost in stock form but rather a target engine torque. Engine torque is calculated based on numerous variables such as: pedal position, air flow mass, knock, OAR, and RPM.  The general strategy of the RS is to convert and crosscheck mainly torque, load, and airflow, choosing the lowest value, and then clipping the engine output at that value.  Raising WGDC directly with out modifying other limiters will have little to no impact other than to cause undesirable PID activity and oscillations.   
  
  

• Fuel Control – The RS operates in a constant closed-loop state, constantly utilizing the A/F values in its tables and making closed loop adjustments via the feedback from the factory wide-band O2 sensor. 
  
  

• Ignition Control – The Ford RS consists of four primary methods to control spark: MBT, Borderline, Cylinder Pressure, and Pre-Ignition. The ECU also allows full dynamic advance and retard based on octane learning and knock sensor feedback. There are up to 16 primary tables for each method, along with accompanying compensations. The majority of heavy load operation will take place in the borderline timing tables, however this can be clipped by any other timing table from the other categories if they are lower.  Watching the Spark Source and HDFX monitors will give you a good idea of which set of tables are being utilized at any given time.   
  
  

• MAP Based – These vehicles use a MAP based airflow system. This is also known as Speed Density.
  
  

• Throttle Closures – The primary method of controlling torque on the RS is done with the assistance of the drive-by-wire throttle system.  The factory tune allows the throttle to close to less than 20* (of the 82* max) which can result in extremely consistent torque delivery. There are two main offenders that will result in throttle closures: Load and Boost. We recommend adjusting these limits higher to take full control of the throttle. The most common throttle closures will happen at peak torque when TIP Actual is likely surpassing TIP Desired.  Adjusting the WG Canister Pressure Desired (FF) (OEM) table is the best way to help reduce throttle closures.  All throttle closures are not necessarily bad.  If you are hitting your load and torque targets and the transitions are smooth throttle closure can be an ideal means of hitting peak torque quickly while also maintaining a safe torque value. 
  
  

• Throttle Closure Safety Limits –  The OEM calibration has precautions in place to close the throttle if ECT or EOT achieve certain temperatures.  The v300 and higher maps have these limits lowered to a more conservative level to bring thermal management issues into perspective before they become critical.  v300 maps will start to limit throttle when ECT is greater than 230*F/110*C and/or EOT is greater than 270*F/132*C.  A DTC will also trip when these limits are triggered to assist in diagnostics.       

  
  
  

Commonly Used Acronyms

Preparing to calibrate the vehicle

Before anything make sure you go over our Pre-Tuning Guide

For information on using our software check out these areas for specific articles

Vehicle Specific Questions

Step 1 – What is the mechanical configuration of the vehicle?

The first step in tuning these vehicles is choosing a COBB Tuning Off-The-Shelf (OTS) calibration that most closely matches the mechanical components and modifications of the vehicle to be tuned.  Refer to our map notes and apply the map that most closely matches your vehicle's mechanical configuration.

Step 2 – What fuel is the vehicle using?

Please note that COBB Tuning offers select performance calibrations for three different fuels: 93 octane (98 RON), 91 octane (95 RON). ACN91 octane from Arizona, California, or Nevada is compatible with our 91 octane calibrations.  All calibrations are made with fuel that contains 10% ethanol.  If you are using 94 octane with 0% ethanol we recommend running the 91 octane calibration.  If your fuel does not meet the standard of the available COBB maps you will need to adjust the calibration accordingly. Take a moment to compare and contrast timing, boost, and ignition tables from each type of calibration. Higher octane fuels support more ignition timing, higher boost levels, and leaner air to fuel mixtures compared to lower octane. Using a map designed for high-octane with low-octane fuels may result in engine damage.

Step 3 – What type of air intake is on the vehicle?

These vehicles utilize manifold absolute pressure (MAP) sensors located pre and post throttle body to measure the mass of air entering the engine. Filter configuration does not necessarily require tuning but heavily contaminated air filters of both OEM and aftermarket construction were found to reduce power output at moderate to high engine speeds. Frequent air filter cleaning and/or replacement is recommended for best performance and engine protection.

Getting Started

Whether you're starting from a stock calibration or a Cobb OTS map, you will want to get a baseline of current engine operation in order to decide your next steps, tuning-wise.  The following list will provide you with information on which tables are active under various pedal position and load conditions.

Good Parameters To Log - Focus RS

• Accel. Pedal Pos. – Accelerator pedal position (this is direct pedal input before translations).

• Actual AFR – Wideband front oxygen sensor reading converted from Lambda to AFR..

• Airflow Mass – The calculated airflow through the engine and is used for almost all flow based tables.

• Boost Pressure – Manifold pressure (relative). This is MAP minus Barometric pressure.

• Charge Air Temp. – (CAT) Charge air temperature as measured post throttle body.  It is combined with the MAP sensor on the intake manifold.  

• Coolant Temperature – Engine coolant temperature.

• Engine Speed – Engine speed in revolutions per minute (RPM).

• ETC Angle Actual – Electronic throttle control actual angle.

• Fuel Rail Pressure Actual – The fuel pressure as measured in the fuel rail.

• Ignition Timing Corr. Cyl (1-4) – Individual cylinder timing correction in degrees (+/-). 

• Ignition Timing Cyl (1-4) – This is the final actual ignition timing after all correction and adjustments in degrees before TDC.

• Load Actual – This is actual calculated engine load value (absolute).

• WGDC Actual – This is the final wastegate solenoid duty cycle after PID system compensations.

• STFT – Short term fuel trims displayed in percent.

• LTFT – Long term fuel trims displayed in percent.

Good Parameters To Log - Raptor 

• Accel. Pedal Pos. (Translated) – Accelerator pedal position after drive mode & Dynamic Pedal Control translations

• Actual AFR (Average) – Wideband front oxygen sensor readings converted from Lambda to AFR, averaged between Bank1 and Bank2.

• Airflow Limit Source – The currently active load/airflow limiting source; reference the monitor guide to understand the translations this monitor and the tables currently in use.

• Boost Pressure – Manifold pressure (relative). This is MAP minus Barometric pressure.

• Charge Air Temp. – (CAT) Charge air temperature as measured post throttle body.  It is combined with the MAP sensor on the intake manifold.  

• Coolant Temperature – Engine coolant temperature.

• DFI/PFI Split Actual - The proportional split of fuel delivery between the direct fuel injection (DFI) system and the port fuel injection (PFI) system; 0% = all DFI, 100% = all PFI.

• Engine Speed – Engine speed in revolutions per minute (RPM).

• ETC Angle Actual – Electronic throttle control actual angle.

• Fuel Rail Pressure Actual – The fuel pressure as measured in the fuel rail (high pressure system).

• Fuel Source - The currently active fueling mode; reference the monitor guide to understand the translations between this monitor and the tables currently in use.

• HDFX Weight Table 01-15 - The proportional weights of all different HDFX modes; HDFX modes will be referenced by speed density tables, ignition timing tables, and load limiting tables.

• Ignition Timing Corr. Cyl (1-6) – Individual cylinder timing correction in degrees (+/-). 

• Ignition Timing Cyl (1-6) – This is the final actual ignition timing after all correction and adjustments in degrees before TDC.

• Knock Octane Modifier  - This is the global octane learning system that is used on the Raptor; very similar to OAR, but inverse.  +1 indicates maximum timing advance and maximum load limits, -1 indicates minimum timing advance and minimum load limits.

• Load Actual – This is actual calculated engine load value (absolute).

• Load Desired (TQ Control) - This is the current load limit.

• LTFT – Long term fuel trims displayed in percent.

• Power Demand Status - Indicates whether or not the power demand threshold conditions have been met; relates to fueling and load limiting.  0 = not active, 1 = active.

• STFT – Short term fuel trims displayed in percent.

• Spark Source - The currently active spark mode; reference the monitor guide to understand the translations between this monitor and the tables currently in use.

• TIP Actual Absolute - Actual throttle inlet pressure (pre-throttle body), in absolute pressure.

• TIP Desired Absolute - Target throttle inlet pressure (pre-throttle body), in absolute pressure.

• Turbo PID I-Term - The integral component of the PID boost error system.  This is added to the feed-forward wastegate position base table values.

• Wastegate Position – This is the final commanded wastegate position for the wastegate actuators after PID system compensations.

Calibration Refinement (Using a Load-Based Chassis Dynamometer) Using OEM Strategies

A: Perform Initial Testing at Low Load / Low Boost

After choosing the most appropriate starting point calibration, prepare to test and refine the calibration on a load-based chassis dynamometer. When creating a custom tune, it is best to begin testing under low load and boost conditions.  This can be done many ways but the quickest is by lowering values from the "TIP Desired Max. (Ceiling) Non 5-Way" table since this table can be tuned in realtime. This will lower the maximum allowed throttle inlet pressure. Testing done at lower boost will allow you to assess the calibration without putting the motor under potentially dangerous conditions. Start the tuning process by loading this "low boost" starting point calibration onto the vehicle.

B: Simplified Overview of Torque/Load/Airflow/Boost Control Strategy

Here you will find a very generalized overview of how the control system works, more details are in the following sections.

Open

Each of these steps has a series of clips, compares, translations, etc... that all must be taken into account when trying to raise power output.  The ECU will always take the lowest value when comparing targets/requests within a subsystem before pushing it onto the next calculation.  For instance, If your Torque Maximum (CVC) is 350 and your Requested Torque is 375 it will compare the two, pick the lower one(350) and then send that out as TTL (Final) to be converted into load and output as Load Desired (TTL).  Load Desired (TTL) is then compared with Load Limit (LSPI) and Load Max Achievable and the lowest of those values is sent out as Load Desired (Tq Control). Load Desired (TQ Control) is then fed into a complex SD calculation to find an Inferred Manifold Target Pressure, so on and so forth.  This is all detailed in Flow Charts below.  

C: Raising Torque & Load 

The Focus RS ECU is primarily torque, load, and airflow based.  It uses a complex lookup routine to crosscheck several variables based on conditions to achieve its target torque. Boost levels will be dynamic based on environmental conditions such as barometric pressure, ambient temperature, charge air temperature, etc... 

The RS relies heavily on clipping values based on the lowest input.  For example when trying to decide what the TTL (Final) will be the ECU will cross check the outputs of different torque tables and choose the lowest value to pass off to be converted into load, that load value will be cross checked with other load values such as LSPI Load Limits or Max Load at WOT and again the lowest will be chosen to be sent off as Load desired which gets converted ultimately into a TIP desired.  It is very convoluted but when all the tables are calibrated correctly the torque delivery is very consistent.  It is highly recommended to learn the OEM logic.  See the flow chart below for a more in depth overview of how the requested torque and load systems feed into one another from APP Input to Load Desired output.              

Open

D: Boost Control

Boost targeting is as equally complex as the torque and load strategies used above.  It generally takes the Load Desired TQ Control output calculated from the torque and load targets and runs that through an equation to come up with an Inferred Manifold Pressure Target.  

The Inferred Manifold Pressure Target uses six variables in the calculation (shown below) and ultimately becomes your TIP Desired Absolute after a few limit and crosschecks.

Open

Use the flow chart below to help illustrate this process in further detail:

Open

Notes on Boost Control

E: Throttle Closures (TIP Desired vs. TIP Actual)

Ford Focus RS uses Electronic Throttle Control (ETC) aggressively to regulate torque.  When tuned properly this system can be used to make torque delivery extremely consistent.  And eliminate large torque overshoot(overboost) which overtime will bend rods and cause catastrophic engine failure.  Generally, throttle closures happen when TIP Actual Absolute surpasses TIP Desired Absolute.  Tip Actual Absolute calculation is detailed above via the intricate system of load and torque calculations.  Generally raising Requested Torque will raise load, which will raise boost, however you may come into certain situations, particularly with parts our OTS maps were not designed for, where TIP Actual far surpasses TIP Desired, or vice versa, and large throttle closures occur over a broad RPM range.  The factory calibrations relies very heavily on throttle closures to regulate torque. Our v300 and up OTS maps alleviate a large majority of the closures but still rely on it for initial torque control as boost hits.

WG Canister Pressure Desired (FF) (OEM) will be your main table to adjust when it comes to closing the gap between TIP Actual and TIP Desired.  It is the main variable in the x-axis of the WGDC Base table.  More info for these two tables is found to the right →.  

Here is a basic rule to follow when adjusting canister pressure to help offset a TIP Error in TIP Actual & Tip Desired differential:

• TIP Actual < TIP Desired (Positive Turbo TIP Error (Desired-Actual))

  • Decrease WG Canister Pressure Desired (FF) (OEM)

• TIP Actual > TIP Desired (Negative Turbo TIP Error (Desired-Actual)

  • Increase WG Canister Pressure Desired  (FF) (OEM)

• Notes

  • Disabling the PID Control while trying to dial in Canister Pressure and overall WGDC will help keep things consistent.

    •  This can be done by taking the following steps:

      • Set PID P-Term Gain Multiplier table to 0

      • Set PID D-Term Gain Multiplier table to 0

      • Set the PID I-Term Max. & PID I-Term Min. tables to 0

      • Don't forget to revert these settings when you are satisfied.

  • The PID KAM Learned Values table can be referenced after the car has been driven for some time and those values can then be ported into your main WG Canister Pressure Desired (FF) (OEM) Table to even further refine boost control overtime. 

  • Rescaling the X-Axis of the WG Canister Pressure Desired (FF) (OEM) can further enhance control of boost, particularly during spool and initial boost onset.  See our v300 or higher OTS maps for a good example.

  • Turbo Turbine Flow Estimated is based off of the sum of Air Flow Mass and Fuel Flow Mass changes in lambda can have an impact on the x-axis of the WG Canister Pressure Desired (FF) (OEM) Table.  See our v300 or higher OTS maps for a decent place to start for target lambda. 

To reiterate, some throttle closures are not necessarily bad and play a vital roll in torque management.  As long as the closures are not interfering with smooth torque delivery at your target torque they should not need to be changed.

• WG Canister Pressure Desired (FF) (OEM)

  • X-Axis - Turbo Turbine Flow Estimated (lb/min)

    • This axis is an estimate of the sum of Air Mass and Fuel Mass

    • Monitor Name:  Turbo Turbine Flow Estimated 

  • Y-Axis - Turbo MFRACT Desired (Mass Fraction)

    • This axis is a desired ratio of exhaust mass flow through the turbine.  An MFRACT of .75 would be desiring 75% of exhaust mass flow to pass through the turbine and 25% to bypass the turbine via the wastegate.

    • Monitor Name: Turbo MFRACT Desired 

  • Table Output Monitor Name: Turbo PID WG CP FF Base

  • Location: Boost Control Tables → Wastegate → Wastegate Dynamics → Proportional  

Open

• WGDC Base

  • X-Axis - Turbo PID WGDC Base X 

    • This axis is calculated using the following formula: (Turbo PID WG CP  FF Base + Barometric Pressure - Compressor Inlet Pressure + Turbo PID I-Term + Turbo PID P-Term + Turbo PID D-Term) ).  

    • Monitor Name: Turbo PID WGDC Base X   

  • Y-Axis - Turbo PID WGDC Base Y

    • This axis is calculated using the following formula: (Compressor Outlet Abs. Pressure - Compressor Inlet Abs. Pressure) 

    • Monitor Name: Turbo PID WGDC Base X

  • Table Output Monitor Name: Turbo PID WGDC Base  

  • Location: Boost Control Tables → Wastegate → Wastegate Base Tables 

F:  General Overview of Boost Control Work Flow

Here is a generalized breakdown of how to approach raising TIP Desired Absolute by manipulating limits, targets, and requests from various torque/load/airflow based systems.   

Open

G: Tuning for appropriate Air to Fuel ratios (Lambda)

The ideal air to fuel ratio depends upon fuel quality. Higher octane fuels are more detonation resistant and therefore can be run at leaner air to fuel ratios. Leaner Air to Fuel ratios produce higher power but also create more heat. Excessive heat can lead to detonation. Lower octane fuels such as 91 octane (95 RON) are more prone to detonation and therefore generally require a richer air to fuel ratio. Rich air to fuel ratio combustion produces less heat and therefore less detonation. 

These vehicles utilize an internal wide-band oxygen sensor to monitor fuel mixtures. The sensor is located in the down pipe. The target values for the Air to Fuel mixture can be monitored using the following, Commanded EQ Ratio and Desired AFR (Power Demand). The currently measured air to fuel mixture can be seen using the Actual AFR or Actual AFR (SP) monitors. The adaptive adjustments made by the ECU are monitored using Short Term Fuel Trim and Long Term Fuel Trim. The adaptive adjustments run full time in a closed-loop PID system.

The primary means to adjust fueling during WOT conditions is with the Desired Fuel Target (Power Demand) table. This table is referenced by ECT and Engine Speed. The targets in this table are used by the ECU to set the desired AFR (Lambda). The threshold for utilizing this table is determined by Accelerator Pedal Position input and is named Power Demand Threshold (APP). Under this threshold the car will run in Closed-Loop and attempt to achieve the Fuel Scalar Stoich. Setpoint.

H: Tuning for appropriate Spark Advance

The Ford Ignition Timing Strategy

The timing strategy in this ECU is extremely complex and robust. We highly recommend using one of our OTS maps as a base when beginning to tune. Below you will find a general overview of the ignition timing strategy and how it can be manipulated to ease tuning. Most of these tables are referenced by Engine Speed and Load Actual. Logging these parameters will allow you to reference the specific regions of these tables that may need to be edited to produce optimized ignition timing.

The ignition timing strategy decision logic

1 = MBT Timing (MBT)

2 = Borderline Timing (BL)

4 = Pre-Ignition Timing (PRE)

 5 = Cylinder Pressure Timing (CYL)

The ignition timing strategy post-decision "sandwich" logic 

 Knock Sensor Dynamic Feedback

Ignition timing is also adjusted in response to detonation. The ECU can actively increase and reduce timing in response to detonation (or lack thereof). The ECU has the capability to make individual cylinder timing adjustments. This means that monitoring a single cylinder for timing correction will not result in a global picture of engine operations. Timing adjustments are logged with the "Ignition Timing Corr. Cyl 1-4" monitor. The amount of timing subtracted during knocking conditions can be adjusted with the "Knock Sensor Timing Decrement (Retard)" table. During non-knocking conditions, the ECU will attempt adjust timing in small increments up to the maximum value in the table "Knock Sensor Timing Max. (Advance)" or the delta of the Ignition Timing Ceiling and Ignition Timing Base tables; whichever is lower.

Ignition Timing Compensations

Ignition timing compensations exist for each timing method except for the Pre-Ignition Timing Limit (Ceiling). Be mindful of the total value of each group of compensations when developing a desired timing curve. Since the ECU chooses the lowest of these tables, various compensations could push one table higher than others and drastically change the base or ceiling chosen.

Ignition Timing General Guidelines

Generally speaking, higher ignition timing supports higher torque and greater power. However, ignition timing should be increased with great caution. Higher timing yields higher cylinder pressures and this is limited by fuel quality and mechanical limitations of the engine. Too much timing will produce negative knock corrections when fuel quality is limiting. When fuel quality is high, ignition timing should ONLY be added when its addition produces a substantive increase in torque and power. If increased timing does not increase torque the extra cylinder pressure is simply producing unnecessary stress on engine components.

I: Tuning Ti-VCT (Variable Camshaft Timing)

The VCT operation of this car is well optimized from the factory for the stock turbo. These tables may need to be altered considerably for larger turbocharger, or aftermarket engine components. Also note that changing VCT may require changes to the Speed Density Tables to ensure accurate calculations.  Altering VCT can also change how boost is controlled since the HDFX is changed based on the cam pairing . The SD tables used are based on HDFX and are used while calculating an Inferred Manifold Pressure Target.