How to tune your Mustang using HP Tuners - Modular Fords

  • How to tune your Mustang using HP Tuners

    HP Tuners has been a leader in providing software for GM custom tuning. So much so that when they began supporting a few Ford vehicles no one really noticed. The initial Ford release was missing a few parameters that I personally feel should have been included, but HP Tuners did listen to the community and has updated their software to include the missing parameters. HPT now has a quality product for tuning your 2005-2010 Ford Mustang! Follow along as I give you a crash course on how to tune your own Mustang with basic bolt-ons.

    Our project car is a 2005 Mustang GT with a 5 speed manual transmission. For mods, it has a C&L Street intake, 3:73 gears from FRPP, Charge Motion Control Valve (CMCV) deleted, American Racing 1 5/8" headers with catless H pipe, and a Magnaflow axle back to finish off the exhaust. To get the most from the tune, we are going to be using 93 octane pump gas. This is a pretty routine tune that isn't overly complex to setup and dial in.

    The first step in tuning your own Mustang with HP Tuners is to make sure you have downloaded and installed the latest beta release of the software. To get access to the beta you should email HP Tuners tech support email and they will add it to your customer area so that you can download it.

    Once you have the software download and installed, plug your HP Tuners MVPI interface into the OBD-II diagnostic port and turn the key to the "on" position. Take a read of the stock tune and then license it so you are able to edit it. Save the stock file some place, making sure to label it as such so you don't accidently modify it. It is important to keep this file safe in case you decide to put the vehicle back to stock. Make a copy of the file, and name the copied file something intuitive so you will know what it is.

    With the copy of the stock tune opened, it is time to start making some changes to account for the modifications done to the vehicle. Out of all of the mods that we have made, the one requiring the most parameter changes is the CMCV delete plates. The PCM uses different tables for several critical calculations depending on whether or not the CMCV plates are open or closed. The speed density calculation used to infer the manifold pressure (MAP) is affected. The VCT as wells as the spark calculation, are impacted by our CMCV delete plates. There is a switch in Engine > Airflow > General > IMRC that is the master enable / disable control for the CMCV. Changing this to disabled tells the PCM that they have been deleted. The only problem is that the PCM defaults to using the parameters for the CMCV being closed. This is easily solved by copying the data from the open CMCV parameters to the closed CMCV parameters.

    Navigate to Engine > Airflow > General > Speed Density. Copy the contents of MAP at Zero Airmass (Open) and paste the values into MAP at Zero Airmass (Closed) as shown.


    In the same section, find MAP per Airmass (Open) and copy the values. Then paste the values in MAP per Airmass (Closed) as shown.


    These two changes will now correct the inferred MAP reading so that it is calculated properly. Next Navigate to Engine > Airflow > General > MAF. Open the table Load with failed MAF (IMRC Open) and copy the contents of the table. Open Load with failed MAF and paste the values as shown.


    The Load with failed MAF tables are very important to the fuel calculation. The PCM uses the tables to anticipate fueling 2 events into the future (yes, it is complex) as well as during a MAF failure. While dialing in the tune it is important to monitor throttle position, calculated load, and engine speed so that you can populate this table with accurate data.

    The Variable Camshaft controls are also impacted by the removal of the CMCV. There are two pairs of tables that are used in the VCT calculation. They are found under Engine > Airflow > General > Variable Camshaft. Angle (IMRC Open) Torque and Angle (IMRC Closed) Torque are the pair of tables used if the switch Table Select is set to Torque. Likewise Angle (IMRC Open) Torque and Angle (IMRC Closed) Angle is used if the Table Select switch is set to Load. This particular calculation is set to use the Load based tables, but your calibration may be different depending on what Ford vehicle you are tuning. To avoid confusion, I suggest copying the values from both the IMRC Open tables to the appropriate IMRC Closed tables.

    The spark calculation adds in timing when the IMRC are opened so we need to make some adjustments in the Engine > Spark > Advance > IMRC Spark. Open Base and copy the values then open Borderline Knock in the Main Spark section and select the entire table. Right click and select Paste Special, Add. Your Borderline Knock table should look like this:


    This will add in the ignition timing that is normally added in whenever the CMCV plates are opened. For good measure, go back into the Base table and zero the entire table out. The Base MBT table under IMRC Spark should be copied and added to the Main Spark > MBT Spark table the same way. I recommend setting the Base MBT table to all zeros as well.

    The last changes that should be made are found Under Engine > Spark > Advance > Variable Cam Spark. There are four more tables that needs to be adjusted here. Copy the Base (IMRC Open) table and paste it into the Base (IMRC Closed) table. Next copy the Base MBT (IMRC Open) table and paste it into the Base MBT (IMRC Closed) table.

    With the changes made for the CMCV delete plates completed its time to correct for the 3:73 gears. Under Speedometer > General change the Final Drive Ratio to 3.73. The PCM also needs to know to use this value instead of the value stored in the VID block. Set Use VID to Disabled as shown.


    While in the Speedometer section if you want to change the top speed limiter, click the Limiter tab and set VSS Limit ETC to where ever you want it to be set or just raise to way up to 255 MPH to remove it.

    The headers from American Racing relocate the upstream O2 sensors further away from the engine. Because of this the readings from the sensors are delayed. The PCM will eventually learn this delay, but we can go ahead and make an adjustment for it. Under Engine > Fuel > Open & Closed Loop > 02 Transport Delay Learn there is a table called Transport Delay. Open it up and select the entire table. In the toolbar, enter 1.15 and click the X icon to multiply the entire table. This increases the values in the table by 15%.


    Another change I generally make is to the 02 sensor heaters. I generally turn up the heater duty cycle a bit to keep the O2s nice and warm. HPTuners software is currently missing the function for controlling this. In the future I am sure it will be added in.

    Since our American Racing H-pipe is catless, the rear 02 sensors need to be disabled to prevent a check engine light for catalyst efficiency codes. Go to Engine > General and set O2 Rear Config to 0. This will take care of the missing catalytic converters. Since the Cats are gone, the logic to add fuel in to cool them off can also be disabled. Under Engine > Fuel > General > COT set Cat Temp Control, Flange Temp Control, and O2 Sens Temp Control to Disabled.

    The C&L Street Air Intake system is an excellent modification that adds quite a few ponies, but it also requires tune adjustments in order for our project car to run properly. This intake completely replaces the factory airbox and inlet tube. The Mass Air Flow (MAF) sensor is housed in the factory inlet. Now that it has all been replaced with a larger inlet, the MAF transfer function is now inaccurate. Since the MAF sensor is only direct means the PCM has for measuring airflow, it is critical that the MAF transfer function is adjusted to account for it.

    Whenever possible it is best to use a known good MAF transfer function for the specific cold air kit being tuned. Some cold air kit manufacturers will supply you with this data. Use it if available, but remember the wise phrase "trust but verify". It is possible to create a transfer function from scratch but that is a topic for another article. Navigate to Engine > Airflow > MAF. Select MAF Airflow vs. Voltage. The transfer function is pretty self explanatory. For each voltage listed there is a corresponding airflow value. In the image below I've modified the transfer function for the C&L intake using a known good transfer function.


    Now that all of the changes have been made to account for the modifications on our Mustang, the other areas of the tune that can increase our power output are going to be adjusted. Head over to the Engine > Airflow > Electronic Throttle > Max Throttle Limits section. Select Max Throttle Angle vs RPM and select the entire right hand column then enter 82 degrees in the toolbar and click the "=" icon to set the max throttle angle to 82 degrees at all RPMs as shown.

    The above change will allow the throttle to be fully open at any RPM. That change alone is not enough to make the electronic throttle feel like a standard cable operated throttle body. The factory tune also limits the rate at which the throttle body opens up. To eliminate this rate limiting go to Engine > Torque Management > ETC Torque Management and select Tip-In Torque Rate Max. Select the entire table then enter 73,756.21 into the toolbar and then click the "=" to set the entire table to the maximum value as shown.


    In the Engine > Airflow > Electronic Throttle > Misc set IPC ROM Switch and IPC ROM Enable both to disabled. These two changes will prevent the IPC from shutting the throttle down from a calculated torque error caused by our modifications. The Independant Plausibility Check (IPC) is a system for checking the electronic throttle operation and in the event that the engine is delivering more torque than it thinks it should, the IPC will step in put the vehicle in limp mode with a throttle shut. Disabling the IPC is a quick fix to prevent limp mode from happening but disabling it means there is nothing to keep the throttle from shutting down in the event of a real failure (Remember Toyota?). The correct method to calibrate the electronic throttle is a lengthy processes and it isn't covered in this article.

    To give our project Mustang a little better throttle feel, I recommend lowering the Pedal Pos WOT Start scalar found under Engine > Airflow > Electronic Throttle > Pedal. This parameter is the pedal position at which the transition to wide open throttle (WOT) starts. Alternately the Driver Demand Engine table can be adjusted to increase the part pedal feel, if needed though lowering the Pedal Pos WOT Start to around 200 as shown really improves the feel.

    To optimize the airfuel ratio at WOT go to Engine > Fuel > Open & Closed Loop > Base Fuel and select Fuel Base. This table controls the commanded lambda when the engine is operating in open loop. Ford uses lambda instead of airfuel ratio to describe the fuel mixture. A lambda value of 1 represents the stoichiometric point of the fuel, generally being 14.64:1 AFR. The factory values in this table are .82 lambda in the high higher RPMs. That equates to being a 12:1 AFR being commanded, even before the temperature model that we disabled earlier steps in to fatten things up even more. I recommend setting all the cells with .82 lambda in them to .85 lambda. This changes the commanded airfuel ratio to 12.44:1 at WOT which is still a little rich but due to the huge variations in fuel quality and ethanol content I feel its best to stay a little on the rich side. My Fuel Base table is shown below.


    This factory tune for this Mustang was setup to run on 87 octane. To take advantage of the increased octane the timing calculation needs to be adjusted. Ford is just nice enough to include the MBT timing values for this engine. MBT stands for Maximum Brake Torque and it is basically the timing that will deliver the most torque. If you run an engine at a certain RPM and airflow, increasing the ignition timing will increase the torque to a point. That point is the MBT timing value for that RPM and airflow. Increasing the timing further will cause a decrease in torque. Since Ford gives us this data there is no reason not to use it as a guide for what we can get away with.

    Take a look at the MBT Spark table found under Engine > Spark > Main Spark and you will see that this engine likes around 31 degrees at WOT for making the best power assuming there is no detonation from not having enough octane. Using this information you can adjust the Borderline Knock table found just above it. The Borderline Knock table is the desired ignition timing that is octane limited. Open it up and you can see just how conservative the timing is compared to the MBT timing. I've modified the Borderline Knock table below since our Mustang is running 93 octane.


    Ford uses a series of calculations to determine the final spark value that PCM uses. The Borderline Spark table is modified by several parameters that take into account things such as engine coolant temperature (ECT) and air charge temperature (ACT). Similiarly the MBT table gets modified in the same way. The final value of both calculations are compared and the lowest value gets used. There are other parameters that can clip the ignition timing as well. One such table is the Combustion Pressure Limit table found under Engine > Spark > Advance > Miscellaneous. Open this table and set every cell to 63.5 degrees to eliminate it from clipping the spark.

    The Spark Correction Lambda Spark table is one of the tables that gets added to the Borderline Knock table. This table is used to raise the timing based on how rich the fuel mixture is. I recommend setting the all of the areas that are richer than 1.0 lambda to 0 as shown so that the timing calculation is easier to understand.


    Keeping the engine cool will keep power output at the maximum, so turning the electric fans on a little sooner is not a bad idea. The parameters for this can be found under System > Fans. I dropped the enable temperatures down some as shown below.


    Although our Mustang does not have the engine modifications that justify the need to raise the factory rev limiter settings, there is reason to make a couple of changes. From the factory the engine speed is limited via the electronic throttle first. It takes a split second for the throttle to reopen if you accidently hit the factory rev limiter at the drag strip. Eliminating this throttle based limiter and using the traditional fuel cut limiter could be worth some ET. To do so, find RPM Limit ETC under Engine > Fuel > Cutoff > RPM Limiters and set it to higher than the RPM Limit Cutoff. If you need to raise the fuel cut limiter, RPM Limit Cutoff is where you would make this change.


    Before flashing this tune in, navigate to the DTC list found under Engine Diag > DTC's. Scroll the list until you find P0605 and set the Error Mode to "3 - No Error Reported". This will prevent the PCM from setting the P0605 code which is caused by the custom tune having the incorrect checksum value.


    Finally, plug the HP Tuners cable back up to the OBD-II port and flash in the custom tune. Fire up the VCM scanner and datalog to ensure everything looks good. In a follow up article I will explain in detail how to use the VCM scanner to datalog and make changes to the tune based on the logs.

    I hope this article is helpful to anyone interested in tuning their own Mustang with HP Tuners. If you have any questions on Mustang tuning or need help, feel free to contact me via Brooks Speed

    -Eric Brooks

    *Edited 6/5/2013
    Fixed broken pic links 5.23.2016 eschaider
    Comments 13 Comments
    1. bad92stang's Avatar
      bad92stang -
      Great write up Eric
    1. Eric Brooks's Avatar
      Eric Brooks -
      Thanks
    1. Buschur Racing's Avatar
      Buschur Racing -
      Yes, excellent write up! Thank you.
    1. Eric Brooks's Avatar
      Eric Brooks -
      I'm working on another already. Going to be much more technical.
    1. guilloe's Avatar
      guilloe -
      Thanks, one like that for SCT tunning.
    1. Eric Brooks's Avatar
      Eric Brooks -
      Quote Originally Posted by guilloe View Post
      Thanks, one like that for SCT tunning.
      Easy enough. Same type combo?
    1. m993v's Avatar
      m993v -
      Do they feel no need to support 1996-2004 FORD'S (MUSTANGS?????) This product seems to be a excellent tuning tool would very much like to see 96-04 fords supported. Maybe it's just me but that would be a investment for HP Tuners!!!!
    1. cjadams2's Avatar
      cjadams2 -
      I'd get it for my 96 cobra. Maybe we've got a petition going!!
    1. MF/Ken's Avatar
      MF/Ken -
      HP Tuners has generally been pretty slow with adding additional support for Fords. I don't expect the pace to change any time soon, people have been asking them for years to add more support.
    1. Eric Brooks's Avatar
      Eric Brooks -
      Quote Originally Posted by MF/Ken View Post
      HP Tuners has generally been pretty slow with adding additional support for Fords. I don't expect the pace to change any time soon, people have been asking them for years to add more support.
      It's about to change!
    1. Alfie's Avatar
      Alfie -
      Quote Originally Posted by Eric Brooks View Post
      It's about to change!
      Coo. I have that and haven't Been really happy so far. I been using sniper tuning along with live link. Need to get on the SCT train tho. LOL.
    1. MadScientist06's Avatar
      MadScientist06 -
      Eric what about for one of these cars with some cams
    1. carmonch's Avatar
      carmonch -
      Hello Eric.

      are there any change to do at the PCM program if ported heads are instaled ?
      and 2th question:

      what numbers do you recommend for the MAF parametters if it is being used the C&L Raice intake ?
      thaks , i ike your post very much.
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