Gtr Afm Upgrade

[cefiro]

I am throwing some steel wheeled turbos into my 260rs stagea and I am not aiming for more than 300rwkw (280-290 would be fine) however tuner recons the afm would be out of range, so got to get something else in there yeah I know the best route is prob Nismo but with the aus $$$ not going to happen, and the Z32 is a good option however I am tempted just to throw in the RB25's, how may people are out there running them in GTR they also plug straight up into the loom. I am also thinking how to mount onto std air box anyone just re drilled the holes into the airbox so they fit??? and just stretch the rubber going to the turbos over the 80mm, will that work????

[Tomek]

Standard AFM's will do just fine for 300kw.. My 0.2

[R.3.2.G.T.R]

also interested in this, from what i have read lots have ppl have been limited to around 270-280kw due to afm unable to cope but have also read tuners like ben@racepace simply tune around the limitation.. are rb25 afm same size body or larger?

[JonnoHR31]

larger, silvertop and 25 afm's are same diameter as z32, 80mm

[R31Nismoid]

Stock will be fine

Worst case, you can put any AFMs on, you just need adaptors to make em fit.

Better off buying new, simply because they are new. 2nd hand AFM's are a pain if they start failing, by the time you replace a couple you could have brought new ones lasting another 15 years

Or have connectors failing like i do making me think it was AFMs

So get the Nismo GTR Replacement AFM's IMO.

[Dearlove]

so do your injecters run out of steam b4 the afm's???

[Public Enemy]

R32 GTR Power FC supports RB25 MAF's. I was using these on my old twin setup.

[R31Nismoid]

so do your injecters run out of steam b4 the afm's???

around the same point i believe

[Dearlove]

oh ok, but i thought the afm's died round 16 psi and i dont think you'd be making 300rwkw at that?? im prob wrong tho

[R31Nismoid]

Its airflow driven - not PSI

[Dearlove]

Its airflow driven - not PSI

yeah, but the equivalent max air flow they can read is 16 psi?? i dont know, because if i try to go over ~16 pound it just pings??? so i dont do.

[R31Nismoid]

Thats tune related, not AFM... being you can tune past the AFM's limit

[nizmonut]

RB25 AFM, R33 are used on the vg25 and vg30 which you'll find in a maxima, a fwd cefiro, 300zx etc etc etc, two of these are three litre engines and have no issues with reading upto 600 hp aslong as you leave enough distance in piping between the afm and the turbo to stop turbulence.

the other trick is to grab the throttle body of a vt to vy commodore with the map sensor and do away with the afm all together

[cefiro]

ok thanks for the replys, Still in limbo as to what to do. be much cheaper to got eh rb25 and thats a bonus as well but do want reasonably tunability out of it which is my main concern.

[Tomek]

What my mechanic told me on this subject was that, the higher you go on stock AFM's the more difficult it will be to tune around them. Obviously there is a limit here but it wouldn't be 300kw, pretty sure Evocoop on this forum was running just under 330kw 19-21psi through stockers with ease.