sti maf in 4" pipe

[1quickchic]

anyone have any experience with this? or even the stock maf in the 4" pipe?

[steve99]

Some info here


But your going to have to scale it from scratch


https://www.ft86club.com/forums/showthread.php?t=106496

[1quickchic]

Thanks,I used that as a start on blow through, but on a 2.75 pipe it was hitting max voltage and could get it consistently reading. so I moved it to the front of the turbo which is in a 4" pipe and now, it straight wont start. its a sti maf, I haven't tried the stock maf yet as I don't got it anymore o_o

[steve99]

Originally Posted by 1quickchic

Thanks,I used that as a start on blow through, but on a 2.75 pipe it was hitting max voltage and could get it consistently reading. so I moved it to the front of the turbo which is in a 4" pipe and now, it straight wont start. its a sti maf, I haven't tried the stock maf yet as I don't got it anymore o_o

Check map sensor as well and you have correct map sensor scalaing in tune as well as maf sensor.



Unplug maf sensorconpletly and see if it starts in failsafe mode


If you have a maf extension harness check continuity

[1quickchic]

map has been rescaled to omni 3 bar settings, no extension harness, tried unplugging maf but think its to out of tune do to the port work. putting the maf back into the 2.75 pipe from the 4" as it did run, just not perfect, thoughts on using a resistor on the maf to ower overall reading? maybe got a bad maf as this was a used maf off ebay ...

[steve99]

Originally Posted by 1quickchic

map has been rescaled to omni 3 bar settings, no extension harness, tried unplugging maf but think its to out of tune do to the port work. putting the maf back into the 2.75 pipe from the 4" as it did run, just not perfect, thoughts on using a resistor on the maf to ower overall reading? maybe got a bad maf as this was a used maf off ebay ...

Resistor wont work


The maf is just a sensor that put out 0 to 5 v depending on the velocity of the air flowing past it. Iits a hot wire sensor compenssted for temperature. The ecu will only accept 0 to 5 v then interprets that as air flow. Bigger tube lower velocity for same air volume.




4" tube is is over double the cross section of the 2.75 so you likey going to need to double the values in the !af maf flow numbers in maf scale​ as a rough start poimt




Resistor will just screw up readings. Wont help your problem.

[Yobiwan]

Originally Posted by 1quickchic

Thanks,I used that as a start on blow through, but on a 2.75 pipe it was hitting max voltage and could get it consistently reading. so I moved it to the front of the turbo which is in a 4" pipe and now, it straight wont start. its a sti maf, I haven't tried the stock maf yet as I don't got it anymore o_o

I think if maf is located before turbo, BOV will screw reading.
MAF should be between BOV and Throttle body .
how about try new 3" pipe instead of 2.75 pipe . That will give slightly more room .

[tomm.brz]

What about....ecutek and none of this is a problem since you setup a hybrid SD with full SD after a certain load and you keep the maf in blow through configuration that measures charge temp instead of the useless intake temp pre turbo

OK sorry, joking... I leave