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GT-R: 2013+ Low Octane Dealership Fix (explained)


The 2012 and 2013 GTR is the most powerful stock GTR thus far.  Nissan pumped up the power on these cars with some minor mechanical changes including larger turbo inlets but the majority of the new power comes from MORE boost and MORE ignition timing compared to earlier model GTRs.

The problem with this tuning approach is that power depends entirely upon fuel quality.  Anyone with a stock 2013 car who happens to reside in California and because of state laws can't use race gas to supplement their 91 octane, will find out in short order that power is intermittent because the car pings constantly, reducing power, and sometimes going into a no boost "limp" mode.

This "limp mode" issues is so prevalent in California and other areas with crappy fuel that Nissan Issued a factory "fix" ECU reflash that retunes the car for lower octane.

Here at COBB we tune a lot of GTRs and have run into this dealer flash and wanted to share with you the Nissan fix.

First as you might expect, nissan reduced primary ignition.  This means less torque for any given load but hopefully less knock will increase consistency on terrible CA 91.

Here is the stock primary ignition table:

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Here is the primary ignition table from the new low octane Nissan mapping.

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You can see the changes noted in yellow.  Yellow indicates a reduction in values.

In addition to the timing tables Nissan also altered several intake air temperature induced timing adjustment tables.  Logically, they increased timing reduction in the presence of high intake temperatures.  For example: the changes in air temp compensations would result in something like a -2 deg. timing correction once the 113 F IAT threshold was met, whereas with the previous factory calibration, you would have to hit 134 F IAT before any IAT correction is applied (-1 correction at that point).

Of course.....  why would you stay stock and worry about nissan's terrible factory tune and updates?  The forthcoming new DBA COBB off the shelf mapping has special calibrations for CA 91, 91, 93, and 100 octane.... no compromises and ultimate in consistency with COBB mapping..... free to download soon.

Best regards
Tim Bailey - COBB GTR calibrator.

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