yeap....this is what im talking about....this guy on the 240 forums posted that it works good for him....so i dont know....got to do more research....nx2thousand said:What he's talking about is called the MAF hack, a very popular proceedure when turboing the ka24de. The theory is that you take the ratio of your injector size to the inside diameter of your MAF senesor and then replace the maf tube with one that equals the ratio of your new larger injectors.
I am very curious to see if it really works and if anyone has tried it on our sr20's. Could cut about $450-500 off the price of going turbo for some guys.
iNGEN said:Ok....Big breath....
We all have "hotwire" MAFs. What that means is the MAF sensor doesn't actually sense anything. There is an alloy filament (the 'wire') in the MAF that is kept at a fixed temperature (the 'hot') by passing an electric current through it. The filament gets hot due to electrical resistance. The filament is exposed to an air column. As the temperature of the filament drops from exposure the sensor increases voltage to the filament to maintain its temperature (it isn't much different than an incandescent light bulb).
Since only mass can absorb heat, and the filament's temperature is fixed; then simply measuring the volume of air passing over the filament at a given voltage gives a status point. Do this at only 2 points (2 voltages/flows) and you have the ratios you need to determine the flowrate at any given voltage, or visa-versa.
The MAF "sensor" doesn't actually sense anything having to do with flow. The signal we use is actually the drain signal from the heating up of the hotwire.
If you change what proportion of the air column contacts the hotwire you change the flow volume per unit temperature/pressure (thats electrical pressure; ie: volts). So yes, this will work. However, the ratio of injector size to MAF diameter is not what must remain constant. What should remain constant is the ratio of injector size compared to the ratio of hotwire frontal area to MAF port diameter.
Did I just confuse the **** out what should have been simple?
You could wire resistors into the drain line to accomplish the same thing.