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Thread: Intro to Nissan/Infiniti tuning with HP Tuners

  1. #1

    Intro to Nissan/Infiniti tuning with HP Tuners

    This guide offers useful hints and suggestions for tuning Nissan and Infiniti vehicles. Its aim is to explain the functionality of Nissan/Infiniti-specific parameters rather than be a full tuning guide.

    Airflow Parameters

    Characteristic Coefficients



    Some of the sensors relating to air/pressure measurement rely on a linear first-order differential equation to come up with their transfer functions. Instead of a table to define different voltage inputs and their corresponding values, they will set a constant characteristic coefficient to define the curve. By applying Laplace Transform you can come up with the final defining equation.

    WOT Fill Up Efficiency IAT Compensation Coefficient



    This table defines volumetric efficiency calculation compensation values for a given intake air temperature range while at wide open throttle. To obtain the output volumetric efficiency, take the calculated volumetric efficiency and multiply it by this value (the volumetric efficiency shown in the scanner already has this adjustment applied). Adjusting this table has a direct effect on any table that uses volumetric efficiency in its cell lookups.

    Throttle Estimated Torque Switch



    Nissan has a couple throttle models. The most common one that is turned on from the factory centers around a torque demand (these tables explained later on in the guide). This is the master switch that controls whether or not this logic is used. By turning this off, the ECM will ignore the throttle related torque tables and give you a close to linear APP to TP relationship.

    Open Area to Target Throttle Open Degree Conversion



    As part of its airflow calculations, the ECM estimates the actual opening area of the throttle body based on the current throttle angle. Normally it is only advised to change this table with changes in throttle body sizes.

    VVEL (Variable Valve Event and Lift) Tables



    Nissan's VVEL system is used to control the valve duration and lift. It works in conjunction with the variable valve timing system. The duration measurement begins at the point the valve opens to the point of maximum lift. While the ECM itself sets the valve duration, it's the VVEL control module that will control the stepper motor that determines the desired shaft angle. It's important to note here that increasing or decreasing the valve duration will also increase/decrease the valve lift respectively. If the vehicle you are tuning is equipped with VVEL, the tuning of these tables is simple, increase the value for more duration/lift, decrease for less. You are provided with Min/Max limit maps, normal driving conditions maps and a WOT map to adjust VVEL duration/lift. For the other tables, it is not recommended that they be adjusted unless the VVEL system hardware is physically adjusted.

    Fuel Parameters

    Cranking Injector Pulse Width



    There are 6 main tables that control cranking injector pulse. Cranking Enrichment and Cranking Injector Pulse Width 1-5 all influence the final cranking injector pulse width. It is unknown at this time at what point each map is used, so it?s recommended that you increase/decrease these (Cranking IPW 1-5) at equivalent percentages.

    Injector Flow Rate Multiplier



    One of the constants that the ECM uses in order to calculate output injector pulse width is the injector flow rate multiplier, which has units of seconds per kilogram. The concept behind what this does is simple, increasing its value increases the pulse width output, while decreasing its value decreases the pulse width output. It's only recommended to change this value for a change in injector size. If you do have a change in injector size, a good value to start at would be to decrease the multiplier at an equivalent percentage to the injector size change.

    Period Control



    One of the more interesting things about Nissan is their oxygen sensor feedback logic. Part of the feedback system utilizes period-based feedback. This system uses a sine wave and oscillates around a stoichiometric equilibrium point. More information can be found by reading this paper: https://ieeexplore.ieee.org/document/5531230

    Open Loop Target Lambda



    This table is straightforward, when the vehicle is in open loop this is the lambda value that the ECM will attempt to target. Tuning tip: If you are unfamiliar or unaccustomed to looking at lambda values, by clicking the lambda symbol in the upper right-hand corner you can toggle between assumed stoichiometric values. Alternatively, you can right click on the table to toggle between units.

    Spark Parameters

    Trimming Adjustment



    The trimming adjustment map is going to be your main map that you use for timing adjustments. You may have seen this labelled before as Main Timing, Combustion Duration, etc. While increasing/decreasing the values of this map respectively increase/decrease the timing value, there isn't necessarily a 1:1 correlation between degrees in this map and timing changes, especially for VVEL equipped vehicles. The final timing adjustments are made based on VVEL and knock sensor feedback. In the event of knock detection, for select cells in the upper RPM/Load range the ECM will begin to blend the low detonation and high detonation tables. Non-VVEL vehicles have a much greater degree of control over the timing using this map.

    There are separately labelled timing maps for both low/high detonation. During testing it was found that these timing maps aren't active all the time, and the exact activation mode is still unknown.
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  2. #2
    Knock Threshold



    If the knock sensor feedback minus the noise floor is greater than this value, then knock is detected. This table is used to filter out "false knock" due to engine/accessory/etc. noise. Raising these values tells the ECM to filter out more "noise", however in doing so you may be filtering out real knock.

    Torque Model Parameters

    Estimated Indicated Torque



    The estimated torque map is an ECM estimation of the final output torque at a given engine load and rpm. If the "Transmission Type" switch is set to Automatic, the ECM then sends this value to the TCM to estimate an output transmission line pressure.

    Load/Torque Conversion



    The load/torque conversion tables have a direct effect on transmission shift speed (for automatic transmission equipped vehicles in manual mode) and throttle response. Raising these values will increase the throttle request, while decreasing does the opposite. Tuning tip: Adjust these values in VERY small increments. Adjusting the values too high can throw the vehicle into a temporary limp mode with no throttle response at all. This table also has a linked table for which the values must align.

    Estimated Torque Compensation



    The estimated torque compensation table is a rough compensation value for the estimated indicated torque table based on a given gear ratio and engine speed. Tuning is straightforward, increasing the compensation value increases the estimated torque value, while decreasing does the opposite.

    Transmission Parameters

    Transmission Type



    The transmission type switch is used to tell the ECM which transmission the vehicle is equipped with (either automatic or manual). This can be used if you are attempting to write a calibration for a different transmission type, although it is highly recommended that you use a calibration that contains the correct value from the factory.
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  3. #3
    HPT Employee Mark@HPTuners's Avatar
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  4. #4
    Potential Tuner
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    I'm in the process understanding tuning VR30 Q50 3.0T 300hp version which is a detuned version except for turbo speed sensors and secondary intercooler pump. I plan on leaning it where I can and adding some timing but now I'm inquiring for two adjustments one increasing the boost as if it was a 400 hp version besides wastegate parameters would I have to change estimated torque and torque tables as well. I've looked at the boost tables and they seem to be populated with the 400hp boost amounts even though when I data log the car I don't reach the desired boost that is listed in table. Also the last the thing I would like to adjust is throttle estimated torque switch to off but in my file I don't seem to have that setting or maybe it is labeled differently? Appreciate any help pointing me in the right direction!

  5. #5

    Tire Size Adjustment

    Quote Originally Posted by Mark@HPTuners View Post
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    Hey there Evan, is there a way to change the oem tire size on the MPVI2? I've looked all over, but can only find the conversion calculator. I just purchased some 295 70r18's (up from 275 70r18) and need to change my gear ratio. Can you provide me with a little insight as to when this may be available??

    Thank man!

    Oh, it's for a 2011 Titan.

  6. #6

    Gear Ratio for Changes in Tire Size (I'm running 295 70r18's.)

    Quote Originally Posted by evan.s@hptuners View Post
    Knock Threshold



    If the knock sensor feedback minus the noise floor is greater than this value, then knock is detected. This table is used to filter out "false knock" due to engine/accessory/etc. noise. Raising these values tells the ECM to filter out more "noise", however in doing so you may be filtering out real knock.

    Torque Model Parameters

    Estimated Indicated Torque



    The estimated torque map is an ECM estimation of the final output torque at a given engine load and rpm. If the "Transmission Type" switch is set to Automatic, the ECM then sends this value to the TCM to estimate an output transmission line pressure.

    Load/Torque Conversion



    The load/torque conversion tables have a direct effect on transmission shift speed (for automatic transmission equipped vehicles in manual mode) and throttle response. Raising these values will increase the throttle request, while decreasing does the opposite. Tuning tip: Adjust these values in VERY small increments. Adjusting the values too high can throw the vehicle into a temporary limp mode with no throttle response at all. This table also has a linked table for which the values must align.

    Estimated Torque Compensation





    The estimated torque compensation table is a rough compensation value for the estimated indicated torque table based on a given gear ratio and engine speed. Tuning is straightforward, increasing the compensation value increases the estimated torque value, while decreasing does the opposite.

    Transmission Parameters

    Transmission Type



    The transmission type switch is used to tell the ECM which transmission the vehicle is equipped with (either automatic or manual). This can be used if you are attempting to write a calibration for a different transmission type, although it is highly recommended that you use a calibration that contains the correct value from the factory.
    Hey there Evan, is there a way to change the oem tire size on the MPVI2? I've looked all over, but can only find the conversion calculator. I just purchased some 295 70r18's (up from 275 70r18) and need to change my gear ratio. Can you provide me with a little insight as to when this may be available??

    Thank man!

    Oh, it's for a 2011 Titan.

  7. #7
    Potential Tuner
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    For Nissan's equipped with VTC, are you going to add vvt tables to control intake and exhaust camshafts?

  8. #8
    Quote Originally Posted by shopard View Post
    For Nissan's equipped with VTC, are you going to add vvt tables to control intake and exhaust camshafts?
    VTC tables should already be available. If you run across an OS where they are not, send in a support ticket and I'll add them ASAP

  9. #9
    For vehicles equipped with VVEL, they will not have exhaust cam tables, only VVEL and intake cam tables. For non-VVEL tables you are provided with both intake/exhaust tables

  10. #10
    Tuner in Training
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    Evan.s i have an issue with infiniti and i see another person with the same problem, i move everything in vvl, vvt and timing maps and I don?t get any gain or lose in the dyno, the fuel map have the rpm axle in the oposite way, but works perfect with the afr, limits rpm perfect but the most important maps (timing) doesn?t work