AFM Advice - Z32 Alternatives

[gonzomagic]

Now, I know most peeps go for the Z32, and in the UK one of the resident mappers has used the Z32 in their set maps.

Since I am going to be mapping via Nistune,

In tersm of ease, the commonality of the z32 makes knowledge in its instalation fairly easy?

I have heard of the QXX afms.

Any other AFM's used in the SR20det setup?

[PL]

You can also use the R32/33 AFM's if you only have a mild SR. They're good to a bit over 200rwkw (measured on Dyno Dynamics). I tend to use these on the local SR20DE+T jobs.

I know people have also used the VQ45 AFM (larger dia) but the jury is still out as to whether they will actually read to a higher HP figure than Z32. I've heard that, although they're larger dia, they will still top out earlier than Z32. But that's all heresay - I haven't tried them out myself.

The Ford "Lightning" AFM seems to be popular in USA.

I'd just stick with Z32. Well proven. Grab a new one if you can. Used ones can be trouble. And new ones are not that expensive. Here in Oz they can be bought for under $AU300. You can buy them from regular parts suppliers in Bosch boxes. But they're the proper JECS AFM inside.

Watch out for the Chinese copies - they're rubbish!!!

PL

[gonzomagic]

You can also use the R32/33 AFM's if you only have a mild SR. They're good to a bit over 200rwkw (measured on Dyno Dynamics). I tend to use these on the local SR20DE+T jobs.

I know people have also used the VQ45 AFM (larger dia) but the jury is still out as to whether they will actually read to a higher HP figure than Z32. I've heard that, although they're larger dia, they will still top out earlier than Z32. But that's all heresay - I haven't tried them out myself.

The Ford "Lightning" AFM seems to be popular in USA.

I'd just stick with Z32. Well proven. Grab a new one if you can. Used ones can be trouble. And new ones are not that expensive. Here in Oz they can be bought for under $AU300. You can buy them from regular parts suppliers in Bosch boxes. But they're the proper JECS AFM inside.

Watch out for the Chinese copies - they're rubbish!!!

PL

Many thanks, yeah here in the UK used afm are £100 and new dare I say from Nissan are probabaly £300+.

Hence most people here thrive on the used ones.

I would fancy a new one if I could find a source, as I have seen the chinese copies on ebay. Also heard they are poo.

[PL]

If you get a used Z32 then make sure your remove (temporarily) the mesh from each end and clean the sensing elements with acetone and a fine modelling brush. Minimum.

My mate actually refurbs them for $25. He removes the whole electronic part from the housing, checks/reflows all the joints (the solder joints between the connector and the internal circuitry fail from vibration), cleans the sensing element under a microscope and re-seals the electronics back into the housing.

That's pretty much what you need to do to have them reliable. Else you could easily be tuning to a faulty AFM. Which is both frustrating and dangerous for your engine.

PL

[Zuikkis]

You can also use the R32/33 AFM's if you only have a mild SR. They're good to a bit over 200rwkw (measured on Dyno Dynamics). I tend to use these on the local SR20DE+T jobs.

I know people have also used the VQ45 AFM (larger dia) but the jury is still out as to whether they will actually read to a higher HP figure than Z32. I've heard that, although they're larger dia, they will still top out earlier than Z32. But that's all heresay - I haven't tried them out myself.

The Ford "Lightning" AFM seems to be popular in USA.

S14/S14a/S15 original AFM measures about 330hp (dyno proven), it's actually bit higher than R32/R33 gtst AFM. So IMHO it's pointless to change to gtst.. S13 SR20DET is another story, it is not much better than S13 CA18DET AFM.. Something like 240hp at best!

Q45 AFM is exactly the same as R32/R33 gtst AFM electrically, but because of the larger diameter, more air gets in.. So it measures perhaps 380hp, not more. Also because of the larger diameter, it is more likely to cause mixture problems at idle or deceleration.. I'd say avoid this AFM.

Ford Lightning AFM is very good for single turbo RB engines. It's also quite affordable, usually a new Ford AFM is cheaper than used Z32 AFM.. It doesn't work so well in smaller engines, because at idle there's so little air flow that the AFM barely measures it. In CA18DET it doesn't work at all really because CA18DET AFM vqmap starts at 1V and Ford AFM idles at 0.6V or so..

There's also one idea that I haven't yet tried, but should work. Nissan ECUs understand AFM voltage upto 5.1V, but the AFM output doesn't stop there! I have seen dyno graphs where RB25DET AFM voltage is reaching 7 Volts, way over 400hp there. So basicly you could add a resistor divider at the AFM output, to drop 7V to 5V or so, then use a modified vqmap.. This would give a much higher measuring range.

[PL]

Good point on the AFM voltage going beyong 5.1V. I've seen 8V out of a Z32 AFM on the bench!

PL

[tmh983]

i suspect that the only difference between an rb afm and a z32 afm is the configuration of resistors/amplifiers inside the device that give you the signal range that you need.

If i had a spare one that I could ruin, then i'd like to crack one open and see what makes them tick

[PL]

I reckon you'd be right there. But from memory it's all done on a thick-film-ceramic-hybrid with minimal discrete components as such.

PL

[Zuikkis]

i suspect that the only difference between an rb afm and a z32 afm is the configuration of resistors/amplifiers inside the device that give you the signal range that you need.

If i had a spare one that I could ruin, then i'd like to crack one open and see what makes them tick

I have several opened Z32 and RB afm's here.. I hate to ruin your fantasies, but the truth is that difference is in the hot wire resistors itself.. The electronics seem to be the same otherwise. I have successfully fixed a blown Z32 afm by transplanting electronics from RB afm.. And it worked as a Z32 afm afterwards.

If you have an AFM with broken screen, you can measure the resistor directly with multimeter. The thicker one is the one that is different. It's about 550ohm in Z32 AFM, and 300ohm in Q45 or RB afm.. The thinner resistor is about 20ohm in both AFM's.

[tmh983]

hmm, interesting.

Out of interest do you know what the two different elements are for? are they for low/high range measurement?

[PL]

I always thought one would be just for measuring air temperature and the other for air flow.

PL

[KillerB]

Agreed with PL

One resistive wire is for temperature compensation, the other is for flow measurement.

[Matt]

Thats correct. Uses the current ambient temperature to offset the temperature on the hot wire sensor (so that ambient temperature does not affect your load readings from the sensor)