I am a noob, and i was reading up on the afc hack. it seems all we want to do is lower the voltage signal from the MAP to the ECU. do we really need an AFC to do only this? is there some way to wire up something inline (a resistor causes voltage drop ) to drop the voltage?

 

yes you can use a voltage divider circuit or other voltage controlling circuits. the problem is then it is not dependent on RPM, it is just constant. both this method and the hack suck anyway. run uberdata.

 

I am looking for something cheaper than AFC hack....

Anyway, doesn't the afc hack lower the voltage by a constant percentage, because with the 450cc injectors, you set it to -40% accross the board. So finding a circuit to drop the map signal voltage by 40% would essentially do the same right? the afc hack is not rpm specific as far as i know.

 

to make a long story short, the AFC hack IS the cheaper alternative.
AEM EMS, Hondata, Uberdata

once i find someone who can chip my ECU for me, i'm gettin' me uberdata.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XSNRGS-R &raquo;</TD></TR><TR><TD CLASS="quote">I am looking for something cheaper than AFC hack....</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ndogg &raquo;</TD></TR><TR><TD CLASS="quote">run uberdata.</TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XSNRGS-R &raquo;</TD></TR><TR><TD CLASS="quote">I am looking for something cheaper than AFC hack....

Anyway, doesn't the afc hack lower the voltage by a constant percentage, because with the 450cc injectors, you set it to -40% accross the board. So finding a circuit to drop the map signal voltage by 40% would essentially do the same right? the afc hack is not rpm specific as far as i know.</TD></TR></TABLE>

yes it is rpm specific.. you can control how much at 2k rpms or at 6k rpms..

 

Voltage dividers are NOT a good way to lower MAP sensor voltage. The varying resistance of the MAP sensor - varies as the manifold pressure changes - skews the voltage the MAP sensor would see from a voltage divider circuit.

Here's a method I came up with using an adjustable voltage regulator... things would be greatly simplified if you just used an LM7803, though, as it is calibrated for 3 volt output. If you want to be able to vary the voltage level around a bit, use the adjustale regulator and circuit described.

http://www.carolinahondas.com/...=1924

Now, all that being said, there is a reason why manipulation of MAP sensor voltage (AFC hack, Cybernation's RSX turbo kit, etc) to fool a stock ECU into working with boost isn't a great idea. With a speed density system, you alter ignition as much as you do fuel, and -40% deflection is a lot of ignition deflection. Read up on it here:

https://honda-tech.com/zerothread?id=841443

None of this covers the need to tune the fuel a little - how do you do that with a flat -40% cut? If you're savvy you can piece together everything needed to chip your ECU and run Turboedit (OBD0) or Uberdata (OBD1) for under $100 and have full standalone capabilities.

You seem to be a bright guy who can figure out what's going on under the hood of your car - most people here can't, or can't think the system through. The fact you ask a question like you have demonstrates that. Why don't you hop over to http://www.pgmfi.org and see how that interests you... there's not much conscious though on HT, only ravenous consumerism.