Dual Afm On Singelturbo Rb25det

[nicksamaniac]

Has anyone tried 2 afm on 1 circuit?

If 1 measures 2500mv,(random value) then 2 in series should measure 1250mv each? Would this be the general consensus?

Then adjust the afm percentage up to 200% so the ecu still see's its correct intake of air volume.

[GTSBoy]

It's very simple actually. The structure of the typical Nissan AFM is not designed to take internal pressure. They are also not intended to run at high temperatures (although they do run win a hot engine bay, the air flowing through them is supposed to be cooler - from outside the engine bay).

They will take a certain amount of internal pressure. How much is an pen question.

They will take a certain amount of extra temperature. Same as above.

The sensing elements in a hotwire AFM are 1) the temperature sensor to measure the T of the incoming air before it goes over the hot wire and 2) the hot wire itself. The AFM needs to know the T of the incoming air so that it can correct the mass flow calculated from the electrical current needed to keep the wire at a fixed temperature. Colder air coming in cools the wire more at the same mass flow rate. Hotter air cools the wire less, resulting in less current needed. These things should have a wide enough range to cope with boosted air, but I would definitely prefer to run it post intercooler. There's no need to make it suffer by hitting it with >100°C air from the turbo.

I think the main problem is the amount of oil that gets on the elements when you put them on the pressure side of the turbo. We get enough trouble with that sort of stuff in the clean inlet side, let alone with turbo seal oil and recirc crankcase gases getting onto them.

[1kr33steven]

Nick in answer to your questions they take so called hot air fine that is why you see them mostly installed on the cold side of the cooler my standard one holds 20psi no problem and has for some time now.

My afr's are fine surprisingly they were fine when I did this mod and had the stock ecu in there as I needed to drive it from my place to the shed next door to put it on the dyno before I could play with tuning.

If there is a n issue with boost use the ford ranger unit that can be put into any size pipe hot air and air density is kind of irrelevant unless you are running the standard ecu if you are tunning your fuel and ignition maps the shitty out-dated afm system is just a voltage signal giving you a reference/load input point of when it puts x fuel in in correlation to rpm ect

I am no pioneer with this set up it has been done for years nizpro to my knowledge were the first really to do this and it is a fairly standard mod for them I am sure a heap of other shops do it also,

NB they warrant there work you have to fix shit yourself so im sure its fairly well tested.

2nd NB if you are a full hectik kebab eating mofo you can even use an external bov with this lol even better a solid steel intake pipe to get mad dose hahaha sorry just taking piss now

[Super Drager]

On Z32's we use these :

http://www.selindesign.net/collections/frontpage/products/2nd-gen-dual-maf-translator







Edit: I'm a dumbass and didn't read the op date.

Edited October 29, 2014 by Super Drager