Jump to content
SAU Community

Recommended Posts

Hey anyone made a custom AFM??

Am thinking of using a Q45 (90mm 3.5") internals and plumbing it into a 4"pipe.

The reason you might say, to slow the air speed through the meter which will give a greater scope. Undoubtly 4" is not much of an increase, but i can also bolt it straight to the 4" turbo inlet and use a 4" filter. I was maxed out at 20psi (260rwkw) so maybe this may help a little.

Plus it is custom and i like tinkering. hehehe

Link to comment
https://www.sau.com.au/forums/topic/160559-custom-afm/
Share on other sites

your telling me you maxed out a q45 afm at 20psi and only made 260rwkw that doesnt sound right.. more info please

Ah good question.

Had low comp pistons and rb25 head, =extra low comp setup. It was somwhere around the low 7's cr.

When you think about it, 20psi is great for an AFM on rb30 setup, but it was the comp that was killing me, saying that it was an ignition monster, just wanted more and more. Could've thrown 30psi in there and it would've been happy.

However i have high comp standard rb30 pistons in there now so comp is a little more respectful, though would love to make over 300rwkw. So we just see.

Mate its a good experiment just to see how it all goes. plus "Custom" love custom!!!

Link to comment
https://www.sau.com.au/forums/topic/160559-custom-afm/#findComment-2983997
Share on other sites

Hey anyone made a custom AFM??

Am thinking of using a Q45 (90mm 3.5") internals and plumbing it into a 4"pipe.

The reason you might say, to slow the air speed through the meter which will give a greater scope. Undoubtly 4" is not much of an increase, but i can also bolt it straight to the 4" turbo inlet and use a 4" filter. I was maxed out at 20psi (260rwkw) so maybe this may help a little.

Plus it is custom and i like tinkering. hehehe

My understanding is that if you change the internal diameter of the pipe in which the air flow meter resides you change the calibration of the meter.

Link to comment
https://www.sau.com.au/forums/topic/160559-custom-afm/#findComment-2984524
Share on other sites

My understanding is that if you change the internal diameter of the pipe in which the air flow meter resides you change the calibration of the meter.

thats more than likely trua and something that has already been discussed in the Forced induction section.

the modifictaion to the AFM would require you to create a boxed section one the side of the inlet pipe and im assuming that it would require it to be on a straight section too to ensure the flow is even through the meter.

be some fiddly work to get the mounting threads welded on to keep the unit flat inside your box.

Link to comment
https://www.sau.com.au/forums/topic/160559-custom-afm/#findComment-2984602
Share on other sites

Yah calibrated, true, but basically whats the difference in calibration when you tune the car for the new calibration?? Yah am running a Power FC, so its all good. The only time you'd be worried about "calibration" so to speak is when you are using the standard comp.

Basically this way you are kinda tricking (real lamens terms) the computer there is less air going through the AFM, the just adjust the mixtures to suit, not rocket science.

Yah tricky making a box?? well really all you need to do is to get a bit of pipe, machine or file a basic flat, make a base plate, weld that on, then by cutting some ally plate say 20mmhigh x what ever the standard width is, then just weld it all up. Screw the AFM unit in and just silicon on a top if you can't be bothered tapping and screwing the top.

Piece of piss(if your a welder/fabricator)

Was thinking of it last night in bed for about an hour. Should hopefully have started it and maybe some pics by monday.

Link to comment
https://www.sau.com.au/forums/topic/160559-custom-afm/#findComment-2985319
Share on other sites

Yah calibrated, true, but basically whats the difference in calibration when you tune the car for the new calibration?? Yah am running a Power FC, so its all good. The only time you'd be worried about "calibration" so to speak is when you are using the standard comp.

Basically this way you are kinda tricking (real lamens terms) the computer there is less air going through the AFM, the just adjust the mixtures to suit, not rocket science.

Yah tricky making a box?? well really all you need to do is to get a bit of pipe, machine or file a basic flat, make a base plate, weld that on, then by cutting some ally plate say 20mmhigh x what ever the standard width is, then just weld it all up. Screw the AFM unit in and just silicon on a top if you can't be bothered tapping and screwing the top.

Piece of piss(if your a welder/fabricator)

Was thinking of it last night in bed for about an hour. Should hopefully have started it and maybe some pics by monday.

only reason if that would be tricky is if the underside of the circuit board isnt flat

Link to comment
https://www.sau.com.au/forums/topic/160559-custom-afm/#findComment-2985336
Share on other sites

  • 2 months later...
Yah calibrated, true, but basically whats the difference in calibration when you tune the car for the new calibration?? Yah am running a Power FC, so its all good. The only time you'd be worried about "calibration" so to speak is when you are using the standard comp.

Basically this way you are kinda tricking (real lamens terms) the computer there is less air going through the AFM, the just adjust the mixtures to suit, not rocket science.

Yah tricky making a box?? well really all you need to do is to get a bit of pipe, machine or file a basic flat, make a base plate, weld that on, then by cutting some ally plate say 20mmhigh x what ever the standard width is, then just weld it all up. Screw the AFM unit in and just silicon on a top if you can't be bothered tapping and screwing the top.

Piece of piss(if your a welder/fabricator)

Was thinking of it last night in bed for about an hour. Should hopefully have started it and maybe some pics by monday.

Might be a bit of science in it, the afm reads the airflow and outputs in a logarithmic curve, then the computer outputs that in a linear curve using a conversion table, by increasing the diameter you may throw the curve well out of whack. How's it all going anyway? im curious to know

Link to comment
https://www.sau.com.au/forums/topic/160559-custom-afm/#findComment-3135213
Share on other sites

  • 3 weeks later...
  • 3 weeks later...

Hi, I don't know much about air flow meters but i need one for my 95 series 2 gtst skyline.

Can anyone advise me on what one to get and where to get it from?

Cheers.

You will get a better response in the Forced Induction section.

stick with STD or if you have a Power FC and are chasing power try a Z32..

Search in FI if you are unsure about this

Link to comment
https://www.sau.com.au/forums/topic/160559-custom-afm/#findComment-3203032
Share on other sites

  • 1 month later...

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


  • Similar Content

  • Latest Posts

    • Means something is not set up right, tune/calibration related.  
    • Finally replaced the previous temporary mesh indicator surrounds (temporary was the last 10+ years 😂) with a 3D printed GTR style version for the front indicators. I think it looks a lot nicer than the old setup and at least the indicators now point in the correct direction rather than angled off. Needed a little bit of tweaking to deal with the intercooler piping but got there in the end. Old and new photos below. 
    • It's weird to me that you say this because I'm pretty sure locals with relatively standard standalone tunes (boost/barometric compensated alpha-N) still have driveability issues when they pop intercooler hoses. Maybe with enough data I can just train some kind of model that spits out an expected grams/cyl given every sensor input except MAF like what FCA did with their Pentastar 3.6 ECU logic. Basically stock everything. The main motivation honestly is to have a sensor that can be a decent baseline source of truth. In scenarios you're describing obviously it won't work every time but it seems to me the number of corner cases that exist in MAF load is maybe not as severe and difficult to manage vs ITB alpha-N with some MAP/barometric compensation.
    • What are your plans for your blow off valves? Purely plumb back? How soft will the spring in them be? AFM can be tricky to get super smooth and nice, especially depending on the rest of the system, and then can be very easily upset if something slightly changes. IE, even if you run recirc blow off valves, you could still see issues getting it to behave at certain load points as turbos might start to spool, but you release the throttle but it's not enough pressure to crack the bov open to recirc, and you can end up with reversion which can cause double metering, and hence dumping of fuel into the system, and stalling the engine.   If you're going to run a map sensor for closed loop boost control from the ECU, what makes you want to keep the AFM?    
    • It's not bad, it's just not flexible. And say if you have any leaks between the MAF and plenum, well then your load axis goes out the window. Here's a real world scenario, I blew off an intercooler hose last track day, as the clamp decided to Bluetooth itself somewhere. Still continued to do 2 laps and drive it to the pub for a couple of beers then home. Good luck doing that with a MAF setup 
×
×
  • Create New...