[protovack]

It is useful to be specific about language here.

- Throttle map: the variability in the relationship between how much you press the pedal, and how much fuel gets delivered to the engine, over the course of the RPM range.
- Throttle response: the subjective feeling of how well your input is transmitted to the rear wheels. Can be good, or bad, depending on your sensation of mechanical and electrical delay between your pedal input and the rear wheels turning.

The gas pedal sends an electric signal to the fuel system that can vary in intensity. The more voltage, the more fuel is sprayed. Roughly.
Throttle controllers such as Vitesse simply boost the voltage sent, more fuel is injected, and RPMs come up faster. As far as I know, and correct me if I'm wrong, aftermarket throttle controllers have nothing to do with throttle mapping. All they do is boost voltage and hence, you will get the OEM throttle map for whatever drive mode you are in, just "boosted" to higher voltage and thus the engine will respond more to a given pedal press. Thus, they don't write in the ECU and don't void your warranty.

I've never used one, personally, so I don't know exactly what they feel like. One of the questions I have is, does it eliminate that "dead space" to very quick pedal presses? Like if you just mash the throttle and let off, typically the signal never gets to the engine. I believe that is intentional in the design and not necessarily a bad thing. Power application should always be smooth and gradual to maintain chassis balance.

Track mode has the most linear, 1:1 throttle mapping of any mode. You press 20%, you get 20% throttle, you press 60% you get 60% throttle. Which is far better for track driving, and really, any driving where you need to modulate the throttle with a high degree of detail. Invariably, though, some will assume there is "dead space", but it's not. That's just what pressing through 5, 10, 20, 30% throttle feels like.

Sport and Tour mode are artificially boosted in the beginning of the pedal travel--you press 5%, you get 20% throttle. This is to make the car feel "zippier" around town and also just to make it so you don't have to press the throttle 20-30% every time you pull away from a stop (reduces foot fatigue for daily drivers). People are very accustomed to these non-linear throttle maps. It's a trick almost all auto manufacturers use to make their vehicles feel faster. My last subaru forester was a bad offender. It jumped off the line at the slightest throttle input. They did this to hide the fact that the engine was completely anemic and under-powered for the platform. It feels really fast on the test drive, but a month later when you load it up with the family and gear and get out on the highway, you discover how slow it really is.

Throttle mapping is different from poor throttle response, which is often caused by a combination of electronic and mechanical delay between you pressing the pedal to the transmission actually turning the drive shaft. It's much worse with the A8 due to the torque converter, and the TCM having to decide how to downshift before it goes. Getting a throttle controller really won't change that at all. It may give the illusion that its helping, though, because the increased voltage will get the engine going a bit quicker.

Observe that M6 owners don't seem to report this problem very often, and the major difference is that they don't have a torque converter and a TCM. My LTG M6 has very good, near instant throttle response. It is, however, very artificially boosted in the beginning of pedal travel, just like the A8 cars in tour and sport mode. If there's one thing I wish I had, it is the 1LEs track mode throttle map, which is modifiable via tuning.