2008 Audi A4 Avant: Engine Notes

same pipe is on the tiguan and other less sporty models. not sure if it makes any difference in performance, but a lot of the GTI guys swap that pipe over.

I think VW has it dead on with piping in the engine note to the cabin. I love to hear it and feel it is kind of a let down when I can't. Not sure how much I would like it with other notes but with the GTI keep it coming.

Anyone else think the 1.8T had a better sound than the 2.0T?

And Audi is supposed to be luxury, which typically means a cabin free of extraneous noise. If you like extra engine noise, get rid of the cats, resonator, and muffler, chip the ECU to allow lots of overboost and mild overrevving, pull out the sound deadening material in the engine bay including any ugly plastic cladding, and maybe throw a CAI in there for shits and giggles.

The engine in the '09 A4 is not the same engine as the one in the GTI. It shares some with the previous 2.0T, but it's been significantly upgraded, which might explain the different noises.

GTI -- enthusiast's car.
A4 -- luxury car.
I want to hear the GTI working. A4 drivers probably want to be more coddled.

"GTI -- enthusiast's car.
A4 -- luxury car.
I want to hear the GTI working. A4 drivers probably want to be more coddled."

Agreed ^^

The 2.0T in the A4 is indeed a different engine than the 2.0T in the GTI. The one in the A4 offers variable lift on the exhaust valves, along with better fuel economy and more power.

However, both the older 2.0T in our '07 A4 and the new one in the '09 I had for a couple of days sound and feel very "agricultural." Nowhere near as smooth feeling or sounding as most typical V6 engines found in competitors.

However, the trade-off is significantly better fuel economy.

sgude, that's the catch--the A4 isn't notably quieter than the GTI. It just doesn't sound nearly as good.

In fact, I'd say the opposite is true. The A4 engine sounds like its working harder.

Pardon my ignorance, but does the 2.0T in the GTI offer any variable valve timing at all? And where does one find that information? I've had trouble googling that successfully in the past.

crowb - How best to replace a legendary engine? Simple; build another legend!

Volkswagen faced the challenge of designing a successor to its renowned 1.8-liter turbo very simply—it built a completely new four-cylinder engine, the 2.0L Turbo FSI, and made it superior in every respect. Its unique combination of technologies not only delivers more power and more torque, it’s done more cleanly than and just as economically as the 1.8L Turbo.

Even though it’s a much stronger engine than the 1.8L Turbo, the 2.0L Turbo FSI yields comparable EPA mileage estimates: 24 city/32 highway mpg compared to the 1.8T’s EPA rating of 24 city/31 highway mpg. The new 2.0T also scores considerably higher than the 1.8L Turbo in the EPA’s Air Pollution index, earning a 6 out of 10 (and a 7 in ULEV II state configuration) for its reduced tailpipe emissions. This best-of-all-world’s balancing act is made possible primarily by the 2.0T’s singular mix of turbocharging and direct gasoline injection.

The 2.0L FSI Turbo is not just a bumped-up version of the 1.8T. Refinements from top to bottom include strengthened components in the valvetrain and a more robust crankshaft, resulting in a free-revving power curve entirely absent of turbo lag or flat spots. Its maximum output of 200 horsepower is available at 5500 rpm and holds steady until 6000 rpm, but the essential sporty character of the 2.0L FSI Turbo is better reflected in the broad and muscular torque curve. The 207 lb-ft of crank twist is available almost from idle, rocketing quickly to its peak at just 1800 rpm and then offering a gratifying plateau of power until it begins to taper off at 4700 rpm.

The result is quick response for the cut and thrust of urban traffic, an abundance of elastic mid-range yank for effortless passing, and a freely accessible top end for sustained acceleration. When it’s under the hood of the new 2006 Jetta GLI, this translates to 0-60 mph sprints of just 7.1 seconds for the 6-speed manual model and 7.0 seconds for the 6-speed automatic. The 2.0L is just as rewarding in the larger, mid-size Passat sedan, taking it to 60 mph in 6.9 second with the 6-speed manual and 7.4 seconds with the 6-speed Tiptronic® automatic.

Built around Volkswagen’s time-tested arrangement of cast iron engine block and aluminum alloy cylinder head, the 2.0L Turbo FSI’s displacement (1984 cc) results from a larger 82.5 mm bore and longer 92.8 mm stroke (3.2 x 3.7 in.). Dual overhead camshafts drive four valves per cylinder; the hydraulic lifters are maintenance free. For critical heat dissipation the exhaust valves are sodium filled, and the intake valve seats are reinforced for durability. Other valvetrain upgrades include roller rocker fingers to reduce the land width of the camshaft and roller, and identical high-tension valve springs for both the intake and exhaust valves. The engine’s bottom end was also beefed up with stronger main bearing flanges and journals on the forged steel crankshaft, and dual balance shafts counteract vibrations and harmonics developed during the four-cylinder’s normal engine operation.

The secret to the 2.0T’s blend of increased performance and undiminished estimated fuel mileage lies in the optimized combustion process. Because gasoline is injected directly into each cylinder at extremely high pressures, the air/fuel mixture burns more cleanly and more efficiently. A primary advantage of direct injection is that combustion chamber temperatures are cooler than with conventional manifold injection, which allows the 2.0L turbo to run an aggressive 10.3:1 compression ratio without fear of detonation. And because the mix of fuel and air takes place within each cylinder, it’s less affected by outside forces than in a manifold injection system. Combustion therefore is very predictable, which means engine timing can be precisely monitored and adjusted for optimum economy or performance, depending upon the weight of the driver’s right foot. Also, because direct injection results in cooler exhaust temperatures than in manifold injection systems, engineers are allowed greater scope in the design and operation of the turbocharger.

The 2.0L turbo operates in two modes. Cold-start conditions initiate a dual-injection mode for rapid heating of the dual catalytic converters. A quantity of fuel is injected on the intake stroke around 300 degrees BTDC of ignition, and the fuel distributes itself homogenously because of the long gap before ignition. A second injection, around 60 degrees BTDC of ignition during the compression phase, forms a rich mixture around the spark plug, which allows a considerable degree of retarded timing without affecting the engine’s stability. Normal mode and stoichometric levels begin quickly, when the catalytic converters have reached operating temperature, usually within 30-40 seconds.

A range of internal modifications assist this clean-burning technology to enhance operating smoothness, including a special intake port design and piston crown shape to reduce detonation “knock.” Intake manifold airflow is controlled by tumble flaps, individual plates located within the intake manifold runners, that are actuated at specific engine speeds for best air/fuel mixtures. On the exhaust side, a divider in the exhaust manifold ensures a steady flow of gases to the turbocharger and also prevents gas pressure from expanding into the other cylinders.

The North American-spec 2.0L FSI Turbo engine should not be confused with the similar European-spec FSI powerplant, which features a third mode of engine operation, stratified charge combustion, to allow short periods of extremely lean burn. In such low-speed, light throttle conditions, the very slight amount of fuel added to the mixture can result in stoichometric ratios as high as 65:1 (the normal ratio for gasoline engines is 14.7:1) and periods of exceptional fuel mileage. Because of North America’s lower fuel quality (which would require special catalysts to handle the extra NOx emissions from our high-sulfur-content gasoline), this technology is not yet available outside of Europe. True stratified combustion will be integrated into this engine, and other VW (and Audi) FSI powerplants, when the high sulfur content of U.S. fuels is decreased in the next several years.

Even without ultra-lean-burn technology, the benefits of the 2.0L turbo are clearly evident. The EPA estimates that the combination of direct injection and forced induction, when compared to a conventional gasoline engine, delivers on average 15% more power and a 10% reduction in fuel consumption. Add the character of a genuine performance engine into the equation, and Volkswagen’s 2.0L Turbo FSI is an appealing blend of sportiness and clean-running economy.

leescott - we can assume thats a quote from somewhere?

The main sound difference may be due to the layout configuration. The A4 engine is longitudinally mounted with the air inlet on the passenger side and the intake manifold on the drivers side of the engine
The GTI's engine is transversely mounted with air inlet near the grill and the intake manifold next to the firewall.

doug, press info