CL Mythbusters - GForce Performance Chip - Club Lexus Forums
The link above will tell you everything you need to know. If you don't follow it, here's what I wrote before I found that thread:
I wouldn't touch that thing. that is a resistor in a fancy case. I could do the same thing with a 5$ bill and a trip to my local hardware store. Actually I could do it for free, as I have a few resistors, wires and electrical tape in my garage...
It has a 2 wire connection that works in either direction... that's one dead giveaway. And all it connects to is the MAF. If it connects to the IAT, it's the same principle.
If you know anything about ECU's and how they work, or about what the MAF does, you'll know that there is only one thing that making a connection there can do, and that is:
change the reading that the ECU receives from the MAF. You are artificially making the ECU see more air than it is expecting to see, which forces the ECU to respond by increasing the fuel supply.
That can do a couple things:
True, it MAY improve power by giving more fuel, but more likely it sends the vehicle into an over-rich state, triggering an engine code, and possibly putting the car into limp mode.
At the same time your car will smoke more, clog the 02 sensors, and clog the catalytic converters.
The rating of the resistor in that case, and the tolerances of the engine's ECU will determine if the ECU can handle the added resistance and artificial signal from the MAF.
It's a dangerous product.