KEVIN97A4

Valid point about warranty. I see the Audi USA configurator lets one add sports suspension while keeping the 18 inch wheels on the A3. Any idea how that would compare ride wise to the S3 with 18s?

Spinnetti

From a performance standpoint yes, more or less the same, but there are some engine differences and of course the brakes and some engine/trans tuning differences no doubt. I got a used S3 cheap then downsized to 18" wheels, and if you can get a good deal, it'd be better to start from the S3 IMO.

CFLQTRO

I believe the S3 has a different head and valves than the A3,

Wife has a TTS and I used to have a Golf R with the same engine. People ask the same question about the difference between a GTI engine and a Golf R engine. One of the main differences there are the head and valves. There may be others.

norm4.2

Differences between S3/MK7 R EA888 and A3/MK7 GTI EA888 Engines

S3/MK7 R EA888 engine has the following changes and upgrades:

Cylinder head (made from a different alloy compared to other engines in this module because of higher thermal stress)

Exhaust valves (hollow, higher Ni content, nitrided)

Exhaust valve seat rings (improved temperature stability and wear resistance)

Exhaust camshaft (adapted valve timings)

Compression ratio 9.3:1 with different pistons

Piston cooling jets (higher flow rate)

High pressure injectors (even higher flow rate)

Exhaust turbocharger

Charge pressures of up to 17.4 PSI (1.2 bar)

High performance main radiator with 1-2 auxiliary radiators (depending on country specifications)

Additional acoustic modifications have been made in order to achieve a sporty sound - use of a sound actuator (for the occupant cell) and active exhaust flaps in the exhaust system


Additional Info

From page 9, S3 Sedan high-performance engine:

Significant upgrades compared to the already highly agile 2.0T engine and influenced from TFSI development in racing

Design changes for the new Audi S3 engine:

Pistons with new bolts and rings

Reinforced connecting rods

New mounts transfer the power to the crankshaft

Gray cast iron crankcase reinforced at the main bearing seats and the main bearing cover

New cylinder head made from lightweight aluminum-silicon alloy characterized by high strength and temperature resistance

New exhaust valves, valve seats and springs

New high-pressure injection valves

New turbocharger includes a self-adapting plastic seal between the compression wheel and housing, which improves efficiency

On top of that, the S3 runs a lower 9.3:1 (compared to 9.6:1 in the A3) compression ratio that's slightly better suited to higher boost applications.

On page 10, it specifically mentions the construction of each model's cylinder head is "Aluminum" and the S3 is "Aluminum-Silicon" - the E888 HAS had an aluminum cylinder head since the MK6.
The aluminum-silicon alloy version created for the MK7 R/S3 is unique and designed to tolerate higher thermal stress.


Turbo specs

S3/MK7 R 2.0T EA888 Gen 3

IHI IS38

6/6 Blade Billet Compressor Wheel & 8 Blade Turbine Wheel

45.2 mm Inducer / 58.0 mm Exducer - Compressor

47.4 mm Inducer / 54.7 mm Exducer - Turbine


A3/MK7 GTI 2.0T EA888 Gen 3

IHI IS20

6/6 Blade Billet Compressor Wheel & 8 Blade Turbine Wheel

42.5 mm Inducer / 54.0 mm Exducer - Compressor

46.8 mm Inducer / 50.4 mm Exducer - Turbine

Steve Kraut

I have been proven wrong. That is awesome information.

Spinnetti

Awesome, thanks! Glad I went S3!

sdbrousseau

Be really careful with trusting ECS part numbers....I have had them send me stuff that was supposed to work on my S3, but missed by a country mile.