Jump to content
SAU Community

RB26 airflow meter upgrade Rb20 or 25??

[[d a n n y]]
 Share

Recommended Posts

paulr33 Grand Master

paulr33

Posted
Posted

rb20 and rb25 afm are same size and same calibration.

Rule of thumb for Air Flow meters RWKW & Engine BHP

------ ---- OD ---- RWKW ---- RWKW ---- BHP ------ BHP

No of AFM's ---- ------- 1 -------- 2 -------- 1 -------- 2

RB26 ------ 65 ------ 149 ------ 299 ------ 271 ------ 474

RB20/25 --- 80 ------ 226 ------ 453 ------ 376 ------ 683

Z32 ------- 80 ------ 255 ------ 511 ------ 415 ------ 763

Q45 ------- 90 ------ 302 ------ 605 ------ 479 ------ 890

pnblight Mentor

pnblight

Posted
Posted

OK the rb20/25afms are a good upgrade for the gtr rb26 with a pfc as the afms will plug straight into existing harness and can be selected from a menu in the setting of the pfc ,the only thing is, it normally requires some customising of the pipe work to the turbos from the afms (the same as would be required for the z32) and the best advantage over nismo units is price and less restriction to flow (80mm over 62mm) PLUS i remend de-screening them as the mash covers about 33% of the cross sectional area of the afm and the turbulence would be significant (just make sure you run good filters).

PS. if you are aiming over 540rwhp i would go the Z32 as my rb20/25 were reading 5.03volts(5.13 is max out) at around the 529rwhp mark, my z32 now read in the low 4volt range for the same hp.

cheers

BoOsTeD_RB26 Experienced

BoOsTeD_RB26

Posted
Posted

Aftermarket piping is beneficial however it isnt required so to speak. If you dont have the funds they do sqeeze into the factory rubber piping. I did this with mine!

Piping is expensive. The Greddy suction kit is $1,100 odd delivered from nengun!

I have removed the rear screen on my afms. Not the front as I've heard conflicting rumours.

RedDrifter Experienced

RedDrifter

Posted
Posted
rb20 and rb25 afm are same size and same calibration.

Rule of thumb for Air Flow meters RWKW & Engine BHP

------ ---- OD ---- RWKW ---- RWKW ---- BHP ------ BHP

No of AFM's ---- ------- 1 -------- 2 -------- 1 -------- 2

RB26 ------ 65 ------ 149 ------ 299 ------ 271 ------ 474

RB20/25 --- 80 ------ 226 ------ 453 ------ 376 ------ 683

Z32 ------- 80 ------ 255 ------ 511 ------ 415 ------ 763

Q45 ------- 90 ------ 302 ------ 605 ------ 479 ------ 890

How accurate are these figues?

Need to get a resonable guess to get me started as i am soon upgradeing my RB20 afm to z32 using the stock ecu.

7heavn Experienced

7heavn

Posted
Posted

rb20/25 afm's are the same . I have rb25 afm's on my GTR if you have custom pods then they will probably not bolt up to the 80mm afm's like I found with my blitz pods. I just bought two gts-t pod adapters and mounted new filters . The rubber turbo intake pipes just squeeze over the back of the 80mm afm's help to heat them up they slip on easier. Have a look in my gallery have a pic of the my engine bay with rb25 afm's .

pnblight Mentor

pnblight

Posted
Posted

in my opinion if your looking to replace the std afms it means you are looking over 400rwhp as i believe that about where the std afms start to run out of head room, and that be so you are starting to look at serious power levels.

So concider this while people go full on with big exhausts and plenums and coolers to etc etc why would you run a resistive intake where the air has to be drone in (not pumped etc)

so the choice of good filters and intake piping and large not resistive afms are very important as this is the first link in the chain

(as what air you are trying to pump through the rest of the system must pass through here first and must do so under no pressure only by the vacuvm of the turbo intake)

eg why put a ~2"x2(ID)grilled afm on the intake and a twin 3" exhaust or 4"intercooler

the grill takes up about 33% of the cross sectional area of the afm and serve no purpose but to add resistion to air flow(i believe the only reason the grills are there is to stop objects touch the afm elements).So if you run good filters and dont go putting tools or fingers into them the grill is redundant.

my 2c

GTR-Ben Proficient

GTR-Ben

Posted
Posted

I made a post a while ago about running the AFM inline as well as increasing the ID of the pipe the AFM is installed into to allow more power before maxing out etc.. I got no responce..

I will be trying this on my own setup though. The AFM probe is simply O-ringed into the pipe. I think if I run a single GTS-T 80mm AFM inside a 4" pipe, this will have the same flow as 2 x 3" pipes, saving a lot of space :(

e.g a 80mm GTS-T afm in a 4" pipe should in theory allow 453rwkw. I'm not sure how this would effect the resolution however. I was hoping an expert could shed some light..

Seems like a lot easier and cheaper way to do things if it works. I know of a few cars running AFM's inline on the pressure side of the piping. Normally after the Intercooler.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Kapr
      RB20DE NEO smallbox clutch.

      By Kapr · Posted

      For once a good news  It needed to be adjusted by that one nut and it is ok  At least something was easy But thank you very much for help. But a small issue is now(gearbox) that when the car is stationary you can hear "clinking" from gearbox so some of the bearing is 100% not that happy... It goes away once you push clutch so it is 100% gearbox. Just if you know...what that bearing could be? It sounding like "spun bearing" but it is louder.
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      Yeah, that's fine**. But the numbers you came up with are just wrong. Try it for yourself. Put in any voltage from the possible range and see what result you get. You get nonsense. ** When I say "fine", I mean, it's still shit. The very simple linear formula (slope & intercept) is shit for a sensor with a non-linear response. This is the curve, from your data above. Look at the CURVE! It's only really linear between about 30 and 90 °C. And if you used only that range to define a curve, it would be great. But you would go more and more wrong as you went to higher temps. And that is why the slope & intercept found when you use 50 and 150 as the end points is so bad halfway between those points. The real curve is a long way below the linear curve which just zips straight between the end points, like this one. You could probably use the same slope and a lower intercept, to move that straight line down, and spread the error out. But you would 5-10°C off in a lot of places. You'd need to say what temperature range you really wanted to be most right - say, 100 to 130, and plop the line closest to teh real curve in that region, which would make it quite wrong down at the lower temperatures. Let me just say that HPTuners are not being realistic in only allowing for a simple linear curve. 
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      I feel I should re-iterate. The above picture is the only option available in the software and the blurb from HP Tuners I quoted earlier is the only way to add data to it and that's the description they offer as to how to figure it out. The only fields available is the blank box after (Input/ ) and the box right before = Output. Those are the only numbers that can be entered.
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      No, your formula is arse backwards. Mine is totally different to yours, and is the one I said was bang on at 50 and 150. I'll put your data into Excel (actually it already is, chart it and fit a linear fit to it, aiming to make it evenly wrong across the whole span. But not now. Other things to do first.
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
×
×
  • Create New...