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you can't recalibrate the sensor, your options are

1) change to another airflow meter, R33 GTST, Z32, Nismo AFM etc

2) remove the GTR afm sensor and place it in a larger shell, so a 80mm shell, instead of a 65mm shell

- this would still require lots of re-tuning work, as the sensor wouldn't be in the same linear fashion and it wouldnt know its a larger MAF shell

3) tune around the maxing afm. once the afm maxes out, it cant show anymore air increase, this is the same as a map sensor when it hits target boost

there is no harm done, just a comprimise in the tuning and you run out of load points

1 is prefered, cheaper, easier and more effective

2 is backyard and not recommended, lots of tuning rework and manual fiddling

3 is ok but no tuner would recommend it

just sell your GTR afm's and go for R33 GTST (cheaper than nismo's / Z32s) and will support tons of power

they are larger in size and can be found for fairly cheap price

Couldn't disagree more that it acts the same as a map sensor when it maxes out. If the boost goes higher or spikes, or you get cooler weather, then the maxed AFM cant do anything, which will result in leaning out, wheras a map will still work as intended

it can be done i had a guy quote me $250 each to recal my gtr afm to nismo ones so?

your correct it can be done... to a few afm's too.

Edited by URAS

i just dont see the point of recalibrating the GTR afm's for such a high price

surely it would be better off to sell them and buy nismo's or Gtst ones

if the tuner was stupid enough to tune with maxing AFMs

then you have no choice but to dump in heaps of fuel to account for all varying loads beyond that point

so whilst it would still work, its not exactly a great idea. the only difference between a maxing AFM

and a map sensor setup as adriano pointed out, is the map sensor has a bit of insurance outside the scope

both give you less load points however...

well itsnot a high price to recailibrate really your looking at $500 to get you stock ones done to the same spec as nismo or z32 but nismo ones cost nearly $1000 now and z32 will cost $600 for decent pair with plug and you still have to change the plug and get new piping to fit them so i recon fo $500 recal you stock ones is a great idea?

But as Paul already suggested, why not upgrade to the rb20/rb25 item? They're both cheap as chips, and the physical size of the pipe is larger than the rb26 ones, making them a better and also cheaper option :(

There is a slight difference between series 1 and series 2 r33 items though, you want to get the series 1 (or r32 rb20) as it has the same plug as the rb26

If you're running a PowerFC, the VC maps are actually included already, so no messy/costly tuning!!

Recalibrate an AFM, I don't think so. I have seen some dodgy stuff, like a resistor in series with the AFM so it reads lower voltage. Some guys call that recalibrating. There is some OK stuff too, like using a Z32 hot wire inside the GTR AFM body, which helps a bit, but not much. By far the best and cheapest method in a GTR is using the RB20/25DET AFM, lots of guys with GTST's upgrade to Z32 or Q45 AFM's so there are plenty of RB20/25DET AFM's floating around.

Cheers

Gary

There is some OK stuff too, like using a Z32 hot wire inside the GTR AFM body, which helps a bit, but not much.

This is what a Nismo AFM is...it has Z32 internals fitted to the STD AFM body.

I dont think they are z32 internals in 65mm body, as then they wouldn't have the same voltage curve as the z32. I did some sums a while back using the voltage curves/airflow, and it certainly appeard that r32 gtr and z32 used the same sensor but the bigger housing gave it the extra resolution.

Ye they are not 'identical' so a Z32 from all reports, however they are very similar.

well itsnot a high price to recailibrate really your looking at $500 to get you stock ones done to the same spec as nismo or z32 but nismo ones cost nearly $1000 now and z32 will cost $600 for decent pair with plug and you still have to change the plug and get new piping to fit them so i recon fo $500 recal you stock ones is a great idea?

$500 for a 2nd hand set of AFMs? :P

See that is the key point - your paying $500 and then it could fail 6 months down the track. Then what do you do? The poor man pays twice.

Soon as your $500 AFM's die, you need to buy another 2nd hand set @ $150-$200, then calibrate them - $500.

And repeat the process each time they fail. And given my experience with 15yr old AFM's, its a fairly likely opportunity.

Guess what... suddenly Nismo's are cheaper you'll get 10yrs out of them at least.

Last thing you want is a AFM playing up and having to diagnose that.

  • 2 weeks later...
Ye they are not 'identical' so a Z32 from all reports, however they are very similar.

$500 for a 2nd hand set of AFMs? :sick:

See that is the key point - your paying $500 and then it could fail 6 months down the track. Then what do you do? The poor man pays twice.

Soon as your $500 AFM's die, you need to buy another 2nd hand set @ $150-$200, then calibrate them - $500.

And repeat the process each time they fail. And given my experience with 15yr old AFM's, its a fairly likely opportunity.

Guess what... suddenly Nismo's are cheaper you'll get 10yrs out of them at least.

Last thing you want is a AFM playing up and having to diagnose that.

but you already have stock afm thats the point you dont have to buy any just get stock ones calib? and stock gtr afm you can get them for $150 a pair usually all thats wrong withthem is the dry solder that takes 10 min to fix, i dont think i could justify $800 each for nismo ones or $300 each for z32 then another $150-$200 for the larger piping needed aswell as wiring.

Considering the amount of AFM related troubles i see and hear about... im happy spending the extra $$$ rather than toying with a 10yr+ old AFM.

Sometimes its the solder, sometimes they are just not fixable.

Troubleshooting with an intermittent AFM is nothing but a pain in the ass... i guess you have to go through it to appreciate spending the $$ for peace of mind.

Never again will i buy a 2nd hand AFM.

+1 for tweaking your stockers

I had one of mine fail and after I cleaned them up and re soldered them my tuner asked if I had upgraded them as they had such low voltage readings.

AFM's arnt realy that complex, if you destroy a stock gtr one its not like its a fortune to replace

cheers

already been threw it all b4 runing like crap and not revving past 3k :( went out and bought some second hand ones and few months was good then same issue but then found the DIY topic on the solder and all been good for a long time :) and now i got a set of tweaked ones and std and both work perfect :) good for rwc just pop the std ecu in and std afm saves alot of hastle with chnging piping then plug changing and i recon i paid $80 for the second set of gtr afm to.

but i am a tight arse lol if i dont have to pay extra for something i wont :) if i had the money yeh i would have got the nismo ones straight up but the yen is to rich for us poor buggers an the gtr makes us poorer, maybe i should sell it and buy a scooter na ill keep living like a uni student and live of noodles its more fun :)

Edited by Travis Trayhern

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