Do I Need Z32 Afm? Hitman Says No!

[Drivebai]

Hey All,

Just a question.

I'm about to get my car tuned by hitman and he adivsed that i don't need to change my AFM to Z32 one as i would reach peak power before the standard AFM max's out.

Mods are

Full exhaust, FMIC, profec II, nismo fuel pump, 555cc injectors, PFC, GCG hiflow turbo. i'm hoping for around 240-250 rwkw.. i have z32 afm but hitman advised the car will run better without it.

After doing a search i read that standard afm will max out around 220rwkw.

Should i put the z32 in? will the car run better across the rev range with z32 afm or is it mainly for peak power?

Hitman says i don't need it.. but if the car will run better overall then i want to put it in..

What do you guys think?

Thanks

[r33_racer]

sounds like it doesnt matter what we think....make a deal with him that if he cant tune it to the 260rwkws without the z32 then he has to retune it for free when its been put on.

But im pretty sure its a necessity for that power level

[Cubes]

The std afm will max out just over 200rwkw.

At that point the afm will no longer tell the ecu how much more air is entering the motor.

You can tune it by simply dialing in the correct afr at the maxed out load point however there's 2 draw backs.

1. Example.

~200rwkw is made on 8psi and 16psi makes 260rwkw.

The std AFM max's out at 8psi and 200rwkw.

The load point used when the afm is maxed out will have to have a heap of fuel thrown in to it and a little ign timing pulled as the ecu won't know more air is entering the motor after 8psi/~200rwkw.

1. What this means is from 8psi/200rwkw until just before 16psi/260rwkw the afr's and ign. timing aren't going to be optimal. 'Possibly' resulting in a car that feels a little lazy should boost not flick through this boost range quickly.

8psi to 16psi.. I think you won't have anything to really worry about as it 'should' flick straight to 16psi or so once it has at 8psi on board.

A car with a suitable afm may have its boost build feel just that little bit snappier as it will have the correct ign and afr's to get the most power to the ground during this boost build time.

2. Those cold nights when the air is dense. As the afm is maxed out and unable to tell the ecu the air is denser (more air entering the motor) its still going to be dialing in the same amount of fuel as if the air was less dense. As a result the car will run leaner. The tuner would have to setup the afr's just that tad bit richer to allow for this.

Should i put the z32 in? will the car run better across the rev range with z32 afm or is it mainly for peak power?

So to answer your question in short.. The Z32 will aid reliability and aid turbo spool/boost transition as your able to get the ign. and fuel spot on.

HOWEVER... 260rwkw isn't too far away from where the std afm max's out so it may be that the afr's and ign are pretty damn close anyway so the gains will be basically nothing. If it were close to 300rwkw, I'd think thats too much of a jump.

Ask Hitman or grab another tuners opinion on what I have said.. They tunes the things every day so they will know first hand.

[Jimbo2000]

hmmm interesting thread

i would have definately said yes..

but then again hitman has quite a reputation so i dont know what to say

i'll just post a stupid pic instead

[hanyou]

sounds like it doesnt matter what we think....make a deal with him that if he cant tune it to the 260rwkws without the z32 then he has to retune it for free when its been put on.

But im pretty sure its a necessity for that power level

i think thats a good idea. if your going on his opinion make the deal free retune with the z32 if it doesnt meet the expectation.

[Drivebai]

Thanks heaps for the response guys.

I doubt he'll give me a free tune.. he's not saying i can't put it in.. he said it's up to me, but he says i don't need it.

Thanks cubes.. i understand what you are saying.

So if the Z32 will provide more reliability then i think i will go with it.. seeing as i've already bought it anyway.. haha He said my car will run smoother with standard afm.

[Guilt-Toy]

I know people who have had 300rwkw with standard AFM.

If you got it when why not..

[Drivebai]

Yeah i guess if i got it already..

Been to hitman before, so i'm very happy with his work, but it's just odd that alot of people on the forum have had to replace it during their setup, i guess each car is different.

[Trooper]

I had mine tuned at CRD a little while back at 210rwkw with stock AFM which i was told was "maxed out" along with the injectors.

I have now upgraded to larger injectors, new turbo and z32 as these were the main things limiting.

Compared with the cost of getting the car to the stage where AFM needs upgrading it seems a relatively cheap item. (think i paid a few hundred from nengun)

[SS8_Gohan]

what's so good about these Z32 afm's?

does it refer to the 300zx model? is it the factory afm's from these cars? and if so, why is a part from an old model so sought after and why wasn't it standard on the newer nissans??

[dead32]

so what sorta kw are we talking when a std rb20 afm maxs out at? or is it boost related?

[Cubes]

You could have a car running 400rwkw on the std afm.

It just means from the point of where it max's out until that 400rwkw its going to bog and feel lazy as its going to be pretty damn rich. It will still make the power without problems and be reliable providing the tuner plays safe with afr's.

[Trooper]

what's so good about these Z32 afm's?

does it refer to the 300zx model? is it the factory afm's from these cars? and if so, why is a part from an old model so sought after and why wasn't it standard on the newer nissans??

It can just measure a higher flow rate than the standard ones

The Q45 is even larger.

[Cubes]

so what sorta kw are we talking when a std rb20 afm maxs out at? or is it boost related?

Its dyno pending. Mine max'd out along with the injectors at ~180rwkw.

Not boost related. Airflow related.

[danoz]

dude if you want to make safe high rwhp just put in a z32 afm or you run the risk of blowin shit up so dont be a tight arse if you want horses you gotta feed them and feed them safely

[R31Nismoid]

As cubes has stated... it doesnt need to be done.

But it will cost you daily driving performance/economy as the tune will be set for a "maxed" afm... With the values required to go beyond that. from the point where it maxes out, to the point where you hit the end of the maps load points... the middle area on mid-high throttle isnt going to be the best.

If you want the BEST performance, upgrade the AFM's.

If you want OK performance cause you want to save $350, then dont change the AFM.

but for $350, i'd go the BEST performance over OK performance

[cameron]

You could have a car running 400rwkw on the std afm.

It just means from the point of where it max's out until that 400rwkw its going to bog and feel lazy as its going to be pretty damn rich. It will still make the power without problems and be reliable providing the tuner plays safe with afr's.

Cubes its running a power FC not a standard ECU hence no R&R

I've seen 400rwhp on stock afm aswel, but it had a chiped standard ecu and afrs were fine. Altho we upgraded it to a Q45 and PFC and it made 440rwhp much better curve through mid range were the "stock one would of been maxed"

Theirs ways of bending the afm curve, but thats a ruff fix at its best.

Go for the upgrade...

[paulr33]

think of a maxed airflow meter the same as a map sensor style tune

once max boost hits, "load" doesn't increase anymore so its not a major problem

[Cubes]

Thats it Pauline.

Cubes its running a power FC not a standard ECU hence no R&R

I've seen 400rwhp on stock afm aswel, but it had a chiped standard ecu and afrs were fine. Altho we upgraded it to a Q45 and PFC and it made 440rwhp much better curve through mid range were the "stock one would of been maxed"

Theirs ways of bending the afm curve, but thats a ruff fix at its best.

Go for the upgrade...

I'm not talking R&R..

Have a quick read of my above post and R31nizmoids regarding what occurs when an afm is max'd out and you wish to make more power when the afm keeps telling the ecu its still flowing 5.115v's worth of air.

Tuning requires one to richen up that last load point the max'd afm lands on to all buggery, this means from the point where the afm max's out until the peak power afr's and ign. timing will not be optimal as it will use the same set of ign and fuel values from lets say 200rwkw to 250rwkw. What happens when afr's are rich and its running bugger all ign. timing?

You can't bend the afm curve/output in respect to the voltage it reads at a given airflow. That is set in stone within the afm its self. You can however adjust which load point a given voltage output uses. But this doesn't achieve anything UNLESS your maxing out your load values before maxing out the afm.

I've done a few calcs with this based on the pfc's airflow curve's.

It appears the Q45 is pretty much a perfect match for the rb25's map reference (load point) values. You hit 5.115v on the q45 and your at load point 20. The Z32 is a different kettle of fish it maxes out load points before reaching 5.115v, so manipulation of either the map reference or airflow curve is required. Either one is acceptable as they both essentially do the same thing.

[WazR32GTSt]

what i don't understand is this...

if you go to a tuner, especially one who has a reputation and one you trust (like you have said), and he says to leave the standard AFM, then why question it?

i mean are you a mechanic? are you trained in tuning?

cars are variable at best, so at the end of the day if you can't trust what your tuner says, then change tuner. don't believe everything you read on SAU - some is excellent info and is based on years of experience and expertise, but some is simply "armchair tuning" and they just spit out what they read in a thread a few months back.

note: i'm not saying the z32 AFM isn't useful here, i have no idea whether or not its useful, i'm asking why one can't trust their tuner, but will still hand over a thousand for an ECU and tune... ?