Is it my imagination or do iPods charge faster using a car charger?
The answer to this question is that "it depends" and it is actually quite possible that your car charger is charging your devices faster than the AC charger you use at home. In both cases, there is significant power available at the source to do the charging relative to the number of watts being used to charge the device. That is, both the AC wall outlet and the cigarette lighter socket are both going to have "hundreds" of WATTS available if not more whereas the device being charged is only going to be consuming maybe "tens" of WATTs at the most during peak charging rates.

Therefore what makes the difference is the amount of power being OUTPUT by the particular charger itself....you just need to check the ratings of the charger and see how much power than can each OUTPUT. The output power is simply VOLTS times AMPS for the DC power that your device is likely to be using.

Some wall chargers that are very inexpensive have very small power supplies in them and only put out a limited amount of charging current at the rated charging voltage for your device. Others may be quite a bit beefier and will be output up to or above the maximum the device will take. Similarly for the car adapter.

Given that the DC source from the car is directly available and a very low cost regulator can be used to generate a regulated charging voltage without having to convert using a switching power supply from an AC line, it seems more than likely that you have a car charger that charges quicker than your home unit. Also, it is possible that the device accepts a variable input DC voltage and can take the 9V to 12V range from the car directly. In this case, it is quite possible that the car charger will end up delivering significantly more charging power than the AC charger.