What makes a tuner a tuner?

[moyam]

I have heard alot of "Take it to a tuner". What makes a tuner a tuner? What does it mean to "tune a car". Where can I find more info on car tuning and how to dio it.

[littledan]

i think tuning would imply changing the fuel map and timing in order to maximize horsepower. this can be done in a bunch of different ways, probably the best would be to do it on a dyno so you can see the results. if your turbo then you can use an exhaust gas temp gauge to tune as well.