Chris Lakian

superswiss

To spool the turbo quicker off the line. It puts the idle rpm close to where the turbo starts building boost once you step on the throttle, for virtually no lag off the line.

RickNY

But why when in Park?

Glisse

Firstly, the car can only be in S mode because the driver chose put it there, either via using the transmission shifter or cycling through the MMI modes. It will never start in S mode. So it idles in Park at higher RPM because that's how the driver set the engine/transmission map.

And the car is using a B-cycle engine, with variable valve timing depending on whether it is in B-cycle or Otto cycle. When in D mode, the car will run in B-cycle whenever it can depending on engine load and RPM. In B-cycle, it makes more torque below boost, and so runs a lower idle speed. It will transition from B-cycle to Otto cycle at specified engined speeds and loads. In S mode, IMO (Audi do not publish any specifics other than in their patents) the engine is never in B-cycle, so it has less torque below boost, therefore idles closer to boost (1370rpm) to avoid a torque hole.

Chris Lakian

Wow cool. i had no idea the car had two engine profiles.
thank you for the explanation.

no to sound like to big of a noob. but is there anyway to get another 40 horses or so out of this car without voiding the warranty.

i just cant hold back....

thanks
c

jondin2000

What a Fuken mess they made with this car transmission setup

mplsbrian

There is not. If you modify the powertrain in any way from its factory design, those components of your New Vehicle Limited Warranty are voided. You can definitely install reversible mods e.g. piggyback tuning units, and then remove them when you take your vehicle in for repairs or service with hopes that scans of the car and/or visual inspection do not reveal them, but from a legal standpoint you did in fact void the New Vehicle Limited Warranty the moment you installed them and would be guilty of committing fraud by seeking and potentially obtaining warranty service on something that has been voided. Getting caught for this sort of thing is not something you hear about often but that doesn't make it any more legal.

I happen to think it's pretty brilliant. I get 31mpg on the highway but still put down 354hp/369tq to four wheels via a full time mechanical AWD system. That's extremely impressive, and represents a 3mpg improvement with a power bump and torque available wayyyyy lower than the previous S4.

danktastic1

idk how you get 31mpg..

when i BABY this car, i get 26-27mpg at best

India Whiskey Charlie

Same here and I have yet to see 20 mpg overall average.

Glisse

Depends where you live. Not in North America, as per mplsbrian's reply. But your car sounds new, it will open up more at around 1k miles.