Afm Mod When Maxed Out (has Any One Done This) Rb25

[RB SANDY]

You cut the sensor out of the std rb25 AFM and you put the sensor in to a 3in pipe because the std one is 2.5in so this means that less air will go past the sensor,has anyone done this before.

[dontfeelcold]

Similar to what Autospeed did except they used a seperate bypass pipe then the digital fuel adjuster to get the A/F mixtures correct.

In theory it should work the same way, just don't damage the AFM hotwires!

[mad082]

as above, you would need some sort of piggyback or full ecu to adjust the afrs.

[R31Nismoid]

You cut the sensor out of the std rb25 AFM and you put the sensor in to a 3in pipe because the std one is 2.5in so this means that less air will go past the sensor

umm... no it doesnt

have you looked at an AFM before?

You'll see that changing the diameter wont affect it at all as the AFM wire is in the middle of the AFM itself.

The amount of air going isnt going to change

[mad082]

the ratio of air going past the sensor to the air going into the turbo will be different.

[RPR33]

I think it would, wouldn’t the wire measure the air and then calculate that by 2.5'' pipe

so if the pipe was 3'' the air would measure the same but there would be more air in the 3'' pipe then the 2.5'' pipe.??

I'm just guessing..

[mad082]

area of a 2.5" pipe = 31.6cm2

area of a 3" pipe = 45.5cm2

the bigger pipe will flow more air, but since the sensor only reads what goes though the little hole it sits in, then calculates how much air that is for the designated size of the pipe, when you put it into a bigger pipe it throws the calculations out and you end up with leaner mixtures.

[BHDave]

Someone did it a while back. Can't remember if it was successful.

[WazR32GTSt]

as has been said, the AFM wire will indeed sense less amount of air, but all this will do will make the car run leaner as it will add less fuel. without tuning it would be useless. and given you'd have to tune, it makes sense to go z32 if you are going the whole hogg

btw.. nissan AFMs use a hot wire with variable resistances, right?

[RPR33]

I agree z32!!

[oops]

course z32, and of course a tune would be required. the question is will it work? go the diy afm upgrade

anyone tried it? when would it max out (rwkw) compared to stock 32 33 or z32 afm's?

i know im interested

[mad082]

would this diy just make it a home made z32 afm?

[Ronin 09]

DIY or not is it worth running the risk of leaning out your motor to save $300...??

you'll still have to incur the tuning costs either way anyway

[mad082]

but since you generally have to run some form of either piggyback or full ecu to run a z32, i don't think that leaning out would be an issue since you have to get it tuned for the afm either way.

personally i'd just get an ecu that uses a map sensor.

[batesr33]

buy a z32 or q45.... dont start hacking at afms left right n centre..

[r32gt_rb20]

just know about this a while ago....

found a webpage that did this...and in the same time...upgraded his injectors...

so i think there wouldnt be any problem if u cut off the AFM and fit it in a bigger pipe and in the same time fit in a bigger injectors....and tune it back to optimal settings....

i just dont see a problem with this MOD...

plus...u can save some cash....for budget drifters....

Edited November 29, 2006 by r32gt_rb20

[GeeTR]

Bah, pack of gurls! =)

There’s a risk, but in reality if you seal the sensor to the pipe well ( careful not to use any noxious adhesives that will eat the PCB) and tune it properly, ( piggy back, FC) it would be well impressive to get it working.

Perfect for the budget conscious.

That said, for $300 there’s no way i would risk my motor

M