Forum » General Tuning Discussion » Master fuel setup RB25 on base map

Master fuel setup RB25 on base map

General Tuning Discussion

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The base RB map for the Link G4 has this in the notes:

"This map is to be used as base for tuning only. DO NOT

use this map without having it tuned for the specific

requirements of your engine.

Details of our test vehicle are as follows:

R32 Skyline

RB20DET engine, stock internals

GTR 440cc/min injectors with 6 x 4R7 ballasts

Walbro fuel pump

T3/T04E turbocharger, external wastegate

custom intake manifold

98 Octane fuel

1.3Bar of boost

electronic boost control has not been setup."

The Master Fuel is set to 7 ms.

I'm using an RB30 with R33 Rb25DET VVT head which is using the standard purple 370cc injectors. Having only experience with the PowerFC, does the master fuel trim need to be changed to suit?

The only info I can find on the 370cc injectors is the Invalid Injection Time = 0.64ms.

I believe you are supposed to set your master fuel in a way that you have 50% ve numbers in the middle of the map.

hope that helped. Im new with Link and will be tuning one shortly.

The master fuel number is used to gain reasonable resolution in the fuel map numbers. It needs to be selected based on the size of the injectors and the amount of fuel flow the engine needs. With small stock injectors you're typically going to need a larger master fuel number in the order of 8-12 ms. For large injectors (1000 cc for example) the number is likely to be much smaller (5-7 ms perhaps).

The aim is to choose a master fuel value that will have the peak numbers in your fuel table reaching around 80-90%. Watch this webinar that details it thoroughly -