afm help

[jmco]

hi new to the forum my car is away having a full rollcage fitted at the mo just geting a few bits sorted , i would like to get rid of the afm i will be fitting a full management system in november time but any ideas of how to get rid of it now.

[Prof]

unless you\'ve got a standalone or a piggyback ecu that allows elimination of the AFM, then the car won\'t run without it.

[m1tch]

I know the Power FC can run without it, but like Prof says, you will need a differnt engine managment unit to run without it, might be an idea to change the AFM to a larger unit for better flow.

Welcome onto the forum though ask lots of questions and remember to post some photos up

[jmco]

thanks , you say a bigger afm witch one can be used ?

[Prof]

to be honest, the stock ECU is quite sensitive to the voltage output from the AFM - even if it\'s off a fraction of a volt it will adversely affect fueling.
 
I did a little experimentation with the airflow replacement map in the emanage - which suggests a replacement AFM isn\'t going to gain you much.
 
The stock AFM will read down to 0 volts - which is about 12 psi boost (around 320 BHP) , and will flow enough air to go to over 400 BHP.
 
In terms of choices that you could use - the flapper AFM from the MX5 and older FC\'s is a worse choice - the standard cone AFM is actually pretty good.  You could go to a Cosmo 13B/20B AFM - which was also used on a piston engine Mazda - but don\'t know which one, sorry - that is slightly bigger but the gains would be minimal and the map would be off - so needs tuning.
 
An other option may be to swap it out for a MAF type sensor - but you need some sort of controller as the voltage outputs are completely different.