RB20 AFM's onto a GTR

[Parag0n]

Hi all,

I've heard different tales of when the GTR AFM's bottom out, some say 280rwkw others 350rwkw, does anyone know an accurate figure?

Anyway, I'm looking at putting on RB20 AFM's as I am told that two of these on a GTR can support approximately 350rwkw? Is this correct.

If so do you need an adapter of sorts or any other complications?

Thanks, Gary.

[600hp]

my tuner says that at around 300 awkw they start to be less accurate because of the element.

got z32 on mine because they use a different element than the rb20 ment to be more accurate when fine tuning.

[T0nyGTSt]

I suggest you need to bend the ear of several competant tuners...

In Syd. it would be Peter at Advan, Jim/Theo at CRD, John/Ben UAS, Ben/Eric at Bel.

You'll get opinions but that's what you'd expect.

T.

[Sydneykid]

Hi, I have posted this table a few times, but just in case you missed it.

Rule of thumb for Air Flow meters RWKW & Engine BHP

------ ---- OD ---- RWKW ---- RWKW ---- BHP ------ BHP

No of AFM's ---- ------- 1 -------- 2 -------- 1 -------- 2

RB26 ------ 65 ------ 149 ------ 299 ------ 271 ------ 474

RB20/25 --- 80 ------ 226 ------ 453 ------ 376 ------ 683

Z32 ------- 80 ------ 255 ------ 511 ------ 415 ------ 763

Q45 ------- 90 ------ 302 ------ 605 ------ 479 ------ 890

Please note that this is only an indication, every engine is different and tuning makes a big difference. For example, I have seen a GTR equiped with twin Q45 AFM's make 1100 bhp.

RB20/25 and Z32 AFM's are all 80 mm OD, that's outside diameter, not ID that's inside diameter. There is no real difference between an RB20 and an RB25 AFM. On the other hand the Z32 AFM is calibrated differently, so at the airflow the RB20/25 AFM shows max voltage, ~5 volts the Z32 afm is only showing ~4 volts. This means when the airlfow gets higher the Z32 can still show voltage increases to the ECU.

Q45 (Infinity) AFM's are 90 mm (OD), so they have the same calibration advantage but they are also larger in diameter for less restriction.

Hope that helps