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Hi, a question for those in the know....
My 32GTR has a PFC and I'm looking to fit NISMO AFM's to the car. What exactly needs to be done to get them working properly?. Does the whole map on the PFC need adjusted or is there a simpler way of getting them to run properly (or at least well enough to get it to a tuner) ??.

TT
 

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The airflow curves will need to be scaled so that the car will run properly. The relationship between airflow and AFM voltage is very different to standard, or any other option on the airflow settings.

I've just fitted and mapped some for my R33 GTR. How to get it running will depend on how it has been mapped for your current setup.
 

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You can select which AFM's you are running in 'settings' on the base map on PFC.
 

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In theory, if you increased the injector size over standard by the same amount as the Nismo AFM increases flow measurement range over standard, would it work.

I.e.:

0-5V = 0-250bhp --> 0-5V = 0-300bhp flow measurement (20%)

Voltage corresponds to a pulse width (via ECU) going to injectors determining duty cycle %.

So if 0-5V with 0-250bhp AFMs equates to 0-90% pulse with 440cc injectors,

would

0-5V with 0-300bhp AFMs equates to 0-90% pulse with 528cc injectors.

I'm unsure of the range for stock and Nismo AFMs, so I've assumed 250 and 300bhp respectively.

The alternative would be to alter fuel pressure. To obtain a 20% increase in injection capacity, increase fuel pressure by 44% (1.2^2).

Note this assumes a linear relationship between airflow curves for stock and Nismo AFMs!

This is just theory as well, don't take my word for it.
 

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R33_GTS-t, like i said, no need for all the maths.. just choose the AFM's u are running on hand commander and PFC will adjust to suit :)
 

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The curve on the Nismo AFM is more similar to the Z32 Afm according to the data sheet as supplied with mine when they were new

Nik
In theory could you take Z32-sized top-feed injectors, Z32 AFMs and Z32 ECU and wire them up so that the Z32 ECU only received the AFM inputs and crank signals and gave the injector outputs but left the stock ECU to cover the rest. It would result in a lower rev-limit though I guess. Probably other things I haven't considered too.;)
 

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Leggus, there is no option on the PFC for the nismo AFMs.

The shape of the airflow curve for the nismo AFMs is different to the options available in the PFC so increasing fuel pressure or injector pulse width by 20%, for example, would not work.

The airflow curve for the Z32 may be close to the nismo at higher airflows, but at lower airflows it is way out. The RB25 curve matches the shape of the nismo curve most closely (after the standard curve) but needs serious scaling to get it to work
 

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Am I correct in assuming that I could fit RB25 AFM's and select that option in the PFC and the car would run correctly without any other changes (i.e. boost, fuel, etc)? And this would be give me more room on the MAF when the upgraded turbo's come?
 

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On my R33 with standard turbos, standard AFM to turbo inlets, and HKS SPF filters I used the RB25 setting and scalings started at 200% (the maximum) at low voltages reducing to around 180% as airflow increases. This was to achieve roughly the commanded AFR as the measured AFR.

This may not be comparable to your setup though Pete, and some tuners may not use this AFM scaling technique in the same way that I do.

Is there a problem?
 

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no i dont think there is a problem, mine were set to VG30 and are all at 100% but i guess it has been mapped in the fuelling to take it all into account...

Just wanted to see if others had used the same method etc
 

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It may have been mapped into the INJ map (will be easy to tell if that's the case), or they could have scaled the 32 point fine airflow curve that you cannot access through the commander.

I know of other tuners that use the method you describe but I prefer to have my INJ table to represent measured AFR for ease of tweaking. For example if your commanded AFR is the same as your measured AFR you can make direct changes to the INJ table with the knowledge that it will be reflected in the measured AFR without the need for a correction factor.
 

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Did you figure out the Nismo scaling setting?

I'll be using the Z32 setting as a starter. If you figured out already, please post here.
 
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