Updated engine in S4 and S5

[tailpipe]

Rumour Control at Audi has just informed me that Dr Winterkorn, CEO of the entire Volkswagen Group, is not happy with the lack of economy in Audi's new supercharged 3.0 litre TFSI in the S4 and S5. It is not proving to be substantially better in this department than previous V8. So Audi's engineers have been ordered to develop a fix ASAP. The revised engine will offer more or less the same performance, but with dramatically improved consumption. Expect it to debut in A4-based models for 2011 model year cars.

[RXBG]

well woop de dooo. gotta meet co2 emissions goals.

[kju]

lol S4 engine fail ^^

[andreadebi]

maybe different gearing could solve partially and a better quattro transmission with less lack of power

[ChicagoAudi]

Forced induction engines, while under boost will consume considerable amounts of fuel. There is no reason for the Audi supercharged 3.0 l V6 to be any difference. If anything, the excess fuel consume, points to an engine that may be too good.

Typically, Otto engines have stoichiometric ratio of approximately 14.7:1; therefore, while under forced induction, as more air is admitted into the cylinder, the more fuel must be injected. Forced induction engines achieve reduced fuel consumption when not operating under boost, i.e., positive intake manifold, conditions. The increased fuel-air quantities in the cylinder resemble that of a larger, normally aspirated engine.

The forced induction engine also has higher parasitic losses associated with the supercharging apparatus, as the supercharger will consume horsepower as part of its operation.

Fuel consumption testing is fairly rigorous; however, the EU and EPA test methodologies do not necessarily map well with real-world driving conditions and driving habits. For example, the EU cycle includes very slow acceleration conditions that would limit the time the engine would be under boost; therefore, fuel economy would be artificially inflated than what would happen under the foot of the enthusiastic driver! Psychologically, the smooth boost delivery of the supercharger, and the immediacy of the throttle response, could have drivers accelerating more aggressively which would negatively impact fuel economy. Turbocharged engine, however, suffer from some lag, and this provides additional information to the driver, to back away from more application of the throttle during most driving conditions.