how do ecu's work?
 

newbie question: okay, i know if you mod intake exhaust than you need to upgrade your ecu to get more fuel. my question is do you just buy a new ecu and replace it or do you send the tuner your ecu and they send you back it reprogrammed? on the m2 website it seems like the reprogram it for you, but i always see people selling their m2 ecu. i know for the power fc you program it but what about the rest. thanks.

anybody? is this question too stupid?

Well, if you follow the links in the newbie sticky or visit any of vendors, you would find the answers you're looking for.

The M2 and Pettit add custom chips to the stock ecu to increase fuel and boost levels. "Standalone" ecus such as PowerFC, Haltek, AEM replace the ecu entirely. There is also the "piggyback" class of chips such as PMS that work in conjunction with the stock ecu to add fuel and change timing with increased boost.

If you are not going past basic upgrades and just want a safe and simple plug in, go with the M2 or Pettit. However, you will still have to deal with basic drivability issues such as 3k rpm hesitation and general jerkiness that the old 8-bit ecu can't smooth out.

The more sophisticated standalone ecus have the potential to drive smoother and handle more upgrades but have to be tuned to be effective (or safe).

people sell their reprogrammed ecu when they finally decide to get a standalone.