Most Power Through An Afm In Standard Rb25 Location

[Harey]

Hi All,

I currently have a Z32 AFM in the standard location (in the intake, in front of the turbo) with 3" metal piping and a pod filter.

I cannot seem to make more than 280rwkw no matter if I run more boost etc on 98 fuel. I am being told to move the AFM to the cooler piping and then either keep the 3" metal intake or upgrade to a 4" intake.

What is the most power have people made leaving the AFM in the intake system of the turbo?

[Crans]

Plenty of people making over 300rwkw with a z32 in standard location.

Do you see the max afm voltage rise as you turn up the boost?

May be an exhaust restriction

[paulr33]

yeah quite a few have made over 300rwkw no problems

apexi rate a single Z32 legit VG30 AFM at 350kw and ash we saw peaked 360kw with a single Z32 as well

how are you working out the AFM is limiting your ability?

does it reach 5v - are you seeing anything else

or simply you can't make any more power and guessing what the cause is?

if you are reaching 300rwkw at peaking 5v something is not right

if its a legit z32 AFM from a VG30 and everything is correct you should not peak 5v at that power level

[HEKT1K]

280 no dramas here, through a genuine z32 afm in factory location (and with factory airbox to boot)... I'll do a few WOT blasts when i get a chance and post up the AFM voltage if you like

[Harey]

Thanks guys. The AFM is not maxxing out voltage wise, I mean airflow wise. Surely it is a restriction in the intake and also means you can only run a 3" intake. So that intake system must have a power limit.

So sounds fine up to 300rwkw but I havent heard of many above this. Doesnt sound like the immediate issue then.

[SimonR32]

Thanks guys. The AFM is not maxxing out voltage wise, I mean airflow wise. Surely it is a restriction in the intake and also means you can only run a 3" intake. So that intake system must have a power limit.

So sounds fine up to 300rwkw but I havent heard of many above this. Doesnt sound like the immediate issue then.

No it's not the issue

[Harey]

No it's not the issue

From someone who has relocated the AFM to the cooler piping and running a 4" intake Thats what I want too.

Also doesnt mean it wont gain power either.

[paulr33]

i would expert 0rwkw gain by going to a larger intake pipe

if you are forced to upgrade to 4" intake then what about your intercooler pipework and throttle body

surely these must be upgrade as well to justify the 4" intake?

imho i wouldnt expect any point as i dont think you would be maxing out 3" of pipework

[luvpsi]

i would expert 0rwkw gain by going to a larger intake pipe

if you are forced to upgrade to 4" intake then what about your intercooler pipework and throttle body

surely these must be upgrade as well to justify the 4" intake?

imho i wouldnt expect any point as i dont think you would be maxing out 3" of pipework

i think he means intake pipe to the turbo not all of his intercooler piping that could still stay at 3'' and change the intake to the turbo to 4''.

when you think about it the turbo compresses the air so it will fit in the 3'' piping

[Harey]

Standard piping is 2.5".

I think the hot pipe is fine at 2.5" but yeah there is probably merit in a 3" cold pipe (after intercooler).

[sinistaGTR]

what mods etc...there could be a lot more variables here than an afm that will not have any affect getting past 280kw

[R31Nismoid]

I made 270rwkw on 98 with 17psi.

I made 369rwkw on 104 with 24psi

This was with the piping, same size as the AFM. Used an 3" -- 4" pipe to accomodate the GT30 4" intake.

A Z32 in a factory-ish position is not a restriction. If it was a restriction and now allowing the air in, it would never have made 24psi without giving issues.

AFM infront of the turbo, is not a restriction that's worth worrying about. Z32's flow enough for the majority of street setups, and have done so time over.

There are also people here with GT35's (4" intake also) who've made over 300rwkw with a Z32 as well. Check the dyno results threads and see.

The fact you run more boost without anymore power is indicative of two things.

1. Exhaust restriction or Intercooler restriction.

2. Turbo is on its limit.

Both are possible, #2 cannot be discounted until you rule out the #1 items.

[femno]

How about details of the setup?

Im guessing a 3076 from the thread you created not long ago about intake pipes.

In this case youre not really that far off the bat power wise. They all make 280 give or take 10 for dyno, exhaust and intake combos.

[tm_r33]

my first thought was exhaust cant flow any more power. but as ash mentioned cooler core could pose a restriction as well.

what turbo and what size rear?

[R31Nismoid]

I think he has a Hypergear turbo?

[Harey]

I have a Hypergear turbo ATR43G3 with 0.82 rear but with standard nissan comp cover, metal 3" intake, Z32 AFM, 800cc injectors, trust return flow intercooler, just jap 1 piece dump pipe, Catco 3" cat and fujitsubo catback exhaust.

The top 2 sheets are with the exact turbo on Tao's car, bottom two are mine. Note mine is pretty close to Tao's on that boost level. If I crank the boost up to 20psi it just drops off to the same 15ish psi, same with 22psi. Makes a bit more midrange with the increased boost but no more top end.

Only difference in setups is that Tao had his AFM relocated to the cooler piping, hence my query.

[R31Nismoid]

Different motors. Variance of 15rwkw. OK result in my book. You'll never get an identical result mate. Variance is to be expected as these aren't production controlled race motors.

Although i take it the "red" lines on the scanned graphs is you making the other results on?

In some instances they are mapped quite wrongly mate. EG: 1st graph vs 1st scanned graph - Nm is wrong.

4300rpm are identical (both are @ 475). However your mapping is different? (i realise one goes on to make more, but that aint the point)

One thing I've noticed: "GAIN" settings on a Dynapack. Yours have nothing, Hypergear ones have it populated.

Could be some correction factor being applied for whatever reason.

I CBF'd looking @ the other graphs as i've already noticed a few discrepancies. Something for you to keep looking with though.

[tm_r33]

15 kw could be the difference between cat convertors on each car. or bearing and ring condition. or plenty of other things.

drop the exhaust at the cat and do a run perhaps.

check if theres a pressure drop across the cooler core also.

ATR43G3 means nothing to me. what is a comparable garret turbo? or hks or similar?

.82 rear should not be holding u back i would not of thought but i dont know the other specs of said turbo.

if your turbo is getting towards the end of its efficent flow range then this could also prevent kw's climbing as psi is increased.

in the same way that a factory turbo at 15 psi will be shit compared to say a gt30 at 15 psi

[Harey]

Ignore the red hand drawn plot that is a different turbo that I was comparing.

The ATR43G3 is roughly equivalent to a 3076 in size.

It would be the front side that could be running out of efficiency, I am running a bored out standard compressor cover. Trent did say it was the most power he has had on his dyno with a standard compressor cover on the front of the turbo.

Interesting point about the cat.

[Harey]

Also did some exhaust troubleshooting:

yellow is full exhaust

light blue is with dump/front pipe and cat (catback exhaust removed)

dark blue is with only dump/front pipe (cat and catback exhaust removed)

I wish we continued the dark blue run, but it was mainly to see if we could improve response. Either way doesnt seem to be a big difference.