A3/GTI VS S3/R engine differences

[Juntuned]

Other than the IS38 turbo upgrade on the S3/R engine and the accompanying tune, and the obvious AWD differences where applicable, is it essentially the same engine?

Strictly comparing the A3/GTI version to the S3/R version. Comparing the very latest version of the engine only, not the other aspects of the car.

Engine internals, valvetrain?.... what are the other differences besides the turbo?

[Spinnetti]

"essentially" the same. Bigger turbo, and a number of internal differences. Plenty of people pump up the A3 motor to the same power as S3, but due to the differences the S3 should have more headroom and/or better reliability at higher power levels. Somewhere in the googleverse is a list of all the differences.

[AlexQS]

Is it true that IS20 turbo being a smaller than IS38, that IS20 can spool-up quicker?

[AudieMurphy]

Yes, Look at dyno graphs for comparison, for example on APRs website. Smaller turbo in general will mean faster spool which results in torque down low. The IS38 "basically" shifts the dyno graph to the right by 500 to 1000 rpm.

[normcaldwell]

Other than the IS38 turbo upgrade on the S3/R engine and the accompanying tune, and the obvious AWD differences where applicable, is it essentially the same engine?

Strictly comparing the A3/GTI version to the S3/R version. Comparing the very latest version of the engine only, not the other aspects of the car.

Engine internals, valvetrain?.... what are the other differences besides the turbo?

Here's info I've picked up over the years:

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

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.

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