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Discussion Starter #1
I had a dig and couldn't find a thread that covered this so thought it'd be helpful to have one...

One of the most common basic first steps for GT-R owners tends to be a Power FC. Once mapped it's all good, but the modifiying/improving bug continues to nibble... Sooo, which of the following will mean a car running a Power FC needs to be remapped?

1) Upgrading standard AFMs to Z32s
2) Upgrading standard AFMs to Nismo/Mines AFMs
3) A higher capacity fuel pump and/or uprated fuel pressure regulator
4) Atmospheric blow-off valves
5) Fitting an induction kit
6) Fitting a decat, free-flow exhaust/elbows/downpipes
7) New boost controller
8) New turbos (changing from standard to steelies)
9) Bottom end rebuild

Feel free to either answer or add more to the list :)
 

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Definitely (2) as the AFM's aren't listed. For (1) you can select Z32 AFM from menu. Maybe for (6) depends how rich you ran beforehand, definitely (7) if you are turning boost up significantly, likewise for (8).

(9) you will probably need to do if you don't do any of the above! Or maybe after doing all the above! :D
 

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My opinion, is basically if anything that changes the way air is metered, or the volumetric efficiency changes then a remap will be needed.

1) Yes
2) Yes
3) No if fuel pressure is still the same
4) No
5) Yes efficiency change
6) Yes efficiency change
7) Yes if running more boost
8) Again if the turbos are essentially the same remap will only be needed if running more boost . If type is changed efficiency will change remap will be needed
9) Only if capacity or compression ratio is changed
 

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Discussion Starter #7
Re. number 3 - if you change the pump but retain the same fuel pressure regulator at the same setting does the fuel rail pressure change? I guess what I'm asking is whether or not the fuel pressure regulator steps down the pressure as a percentage of the unregulated pressure, or steps it down to a fixed pressure level, irrespective of the pressure that the rest of the fuel system is at (assuming it's at least high enough)?
 

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I think fuel pressure is fuel pressure, doesn't matter what pump is pushing it. It's the pressure, and the injectors that determines fueling.

I fitted an atmospheric BOV and didn't have to change a thing on the map. I get big overfuelling on overrun and upshifting but that just makes for big flames and pops on the 1-2 and 2-3 shift. May not be so good for the car, but appeals to the boy-racer inside me too much to bother futzing with the fuel map to compensate.
 
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