Z32 Afm????

[DJ984]

I know this has most likely been talked about 1000 times but i need some info...

I understand that this allows you to suck more air as they are designed to suck more air than the RB20 AFM...????

What is the purpose of the upgrade... I wanna get 200KW @ the rears.... shopuld i be doing this upgrade to acheive this goal... someone give me info pleez.... loatsa DETAILED info...

cheers guys,

Dave.

[JimX]

Well my first reaction was going to be to tell you to search, but I tried searching myself and there's too much other Z32-related stuff to make it easy to find anything. So I'll try to sum it up in here, and hopefully other people searching in future will be able to find it too. Also hopefully I'm not too far off the mark, anyone with corrections please let me know! (heh, as if you wouldn't let me know I'm wrong anyway)

Your AFM outputs between 0 and 5 volts, depending on the amount of airflow. On an RB25 AFM, it reads 0.5 volts or so at idle, and 5 volts at some pre-assigned amount of airflow, which usually works out to around 210rwkw. It's less on the RB20 AFM I presume.

When the amount of airflow causes the AFM to hit 5 volts, it is said to have "maxed out" and won't go any higher. Your ECU usually interprets this as a message to dump as much fuel as possible in to avoid leaning out.

A Z32/VG30 AFM has a finer resolution, and caters for more airflow. So at 5 volts, it's not 210rwkw, but say around 260rwkw. So the point of upgrading to a Z32 AFM isn't for more power, but for more tuneability for the ECU to be able to read the fairly large gap between 210 and 260rwkw. If running off the old AFM the ECU would just be dumping fuel in and you'd get a really bad power curve and waste a lot of fuel.

If your goal is only 200rwkw, you might want to consider the much cheaper RB25 AFM instead. It's the same physical size as the Z32 AFM, but will support a bit more than your power goal. The R33/Z32 AFMs are bigger than the R32 AFM, but that's not the main point of the upgrade.

[jtir]

I am thinking the opposite, the smaller RB20 AFM would have smaller resolution as it can map out finer airflow amounts. The larger Z32 unit would have coarse/larger resolution, as it needs to map out airflow for a greater range?

[JimX]

I've been told all over the place that Z32=higher resolution AND higher airflow capacity. But I get what you're saying. If I've been misinformed then you should use the AFM with the closest limits to your wanted power goals.

Whatever the case I'd be getting an R33 AFM for only 200rwkw, just to save around $200.

[DJ984]

Save around $200... now that's good thinking!

Ok, well thanks heaps... that clears a heap up for me....

[Sydneykid]

Hi guys, I have never seen any differences in airflow resolution between RB20DET AFM's and RB25DET AFM's.

[Chris32]

I agree with Sydneykid, from all the cars I have seen RB20/RB25 AFM seem to do pretty much the same thing? And its the Z32 offers the greater resolution

Don't know about more flow, they are pretty well the same size aren't they? I know SR/CA AFM's are tiny compared to the RB AFM's, but all of the RB AFM's, apart from GTR's which seem smaller, are the same size from what I have seen?

[browny]

I thought they were all about 80mm.

I think maybe that some of the terms used to describe the characteristics are often misused and interchanged which causes confusion.

My understanding is that:

Resolution is the minimum measurable interval

Range is the difference between minimum and maximum readings.

So the Z32 AFM can measure a greater range of airflows and give a useful output.

The resolution on the other hand will be determined by the electronic trickery in the AFM. The ECU may even limit the resolution depending on how sensitive it is and how it interprets the input signal.

[Sydneykid]

Hi guys, AFM diameters follow;

R32/33 GTR = 65 mm (X 2)

R32/33 GTST = 80 mm (X 1)

Z32 = 80 mm (X 1)

Q45 = 90 mm (X 1)

It is a simple logic really, I explain it like this;

Z32 AFM - 3.0 litre at 6,000 rpm & 1 bar = 4 volts

RB25DET AFM - 2.5 litre at 6,000 rpm & 1 bar = 4 volts

Thus Z32 AFM (3.0 litre) needs 16% more airflow to read 4 volts on a 2.5 litre at the same boost and RPM. Or you can look at it the other way around. The Z32 AFM will only show 3.4 volts when a RB25DET AFM would show 4 volts.

Since they both max out at around 5 volts, you can have 16% more airflow before a Z32 AFM will max out compared to a RB25DET AFM.

Rough maths, but not far from the real world experiences.

Hope that helps

[Cubes]

I've ran a RB25DET AFM on my RB20DET. Power etc was exactly the same.

[lwells]

Hmmm. Time to resurrect an old thread.

Is there any point to upgrading the AFMs on an R32 GT-R from stock items to Z32 or Q45 items? Do they make any difference on their own, or only in conjunction with other mods?

Edit: Just to be clear, it would obviously be in conjunction with a PFC, but basically no other mods except maybe exhaust.

Cheers,

Lucien.

[Sydneykid]

Hmmm. Time to resurrect an old thread.

Is there any point to upgrading the AFMs on an R32 GT-R from stock items to Z32 or Q45 items? Do they make any difference on their own, or only in conjunction with other mods?

Edit: Just to be clear, it would obviously be in conjunction with a PFC, but basically no  other mods except maybe exhaust.

Cheers,

Lucien.

Basically Lucien, it would be a waist of time and money until you get to the limit of resolution of the standard GTR (65 mm) AFM's. And that's a bit over 300 rwkw, which you won't get any where near with just a PFC and an exhaust.

[lwells]

SK: Thanks for the straight-down-the-line answer, appreciated

LW.

[jager]

What car does the Q45 come from?

call me dumb haven't heard of it?

is it better than th z32 in a r33 gtst

[Jimbo2000]

i THINK its from some 4x4, patrol or something,

definately open to correction though

[Sydneykid]

Q45 Infinity V8, its 90 mm, Z32 and GTSt's are 80 mm and GTR's are 65 mm.

[Jimbo2000]

infinity.

thanks SK

what is an infinity again? :Oops:

[Sydneykid]

www.infiniti.com