I just wanted to add to this convo about what a chip is doing to add performance...
The ECU has a programmed air/fuel ratio. often refered to as rich or lean. A rich running vehicle (like most stock engines) are wasting a little power. By leaning out the air/fuel ratio with less fuel the combustion in the cylinder becomes hotter, more heat means more energy, more energy applied to the piston means more horsepower. They can claim gas mileage gains because indeed you are burning less gas and creating more power.
heres the catch... "but whats the cost??" the cost of chips varies apon manufacture, as well as abilities the chip provides. Some just wire inline with the ecu to the fuel delivery system making adjustments to the ECU's output. Others wire into the ECU itself also offering heads up displays of EGT's, Tranny Temps, Oil pressure stuff like that.....
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what about the hiddin costs... what is this going to effect over time....
Back in the carburator days guys running hot rods just had to take a screw driver and lean out the fuel mixture to gain more power. worked great until they realized if you lean the mixture out to much and get the combustion fire to hot you'll actaully burn a hole in the top of your piston. (not good) luckily for them they had a screw to turn and adjust they could run it in or out accordingly and prevent any unnecessary damage. Where as with us newer EFI guys we're taking something a company has decided is a sufficienct air/fuel ratio and putting it into a computer chip to override what toyota's engineers determined as a safe fuel mixture for long term life of the vehicle. Now yes you do have emission standards that might have effected how rich the mixture was dialed in by toyota but, unless you have a way of knowing how hot your combustion is you wouldnt know if your damaging anything until your pulling your heads to check for a hole in your piston. just my knowledge of Computer chips (FYI we have alluminum topped pistons, the old hot rod guys alot of times had steel topped pistons and they managed to burn holes in them alluminum melts even faster!)
