feralc

Audi says that the S versions are not longer the sport versions of the model but the bigger engine and they come out with an A8L with the same engine than the S8/RS7 but tuned to 420hp just like the S6/S7, I saw the car is BEAUTIFUL, and tuning this car could possibly give you the 560 HP the RS7 is capable of.
Plus the interior of the car was really sporty two tone color and everything and starting at 87k you can have a really nice one with 100k and the s8 starts at 110k, quite a difference after adding some options.
Maybe it will have different suspension or other sporty stuff but having basically three engines in the whole line, the 2.0t, 30t, 4.0t and just changing maping tunes is odd, the 3.0t is tuned to 333hp in the S4 and A8 but 310hp in the A6/A7 and after tuning it properly you get 90hp more, the same with the 4.0t 420hp in S6/S7, 520hp in S8 and 560 HP in RS6/RS7.
I am not taking in consideration the W12 or the v10.

itsasecret

There are many internal difference between the 4.0L 420hp and 4.0L 520hp version. Different pistons with a change in compression being one. The turbos are also different. Tuning is also part of the calculation but not the only thing done in the case of the 4.0L

feralc

what I read in April's car and driver is that the difference is more boost (15.9 psi vs 12.3 psi this is only software) revised valve timing and more efficient intake plumbing. Nothing about turbos and pistons.

itsasecret

I can assure you that there several different internal differences. Compression on the 420HP version is 10.1:1 the 520HP version is 9.3:1. This is done by a larger dish in the piston for the 520HP version. I can provide more differences if you would like.

JohnnyJ A6Q

So if the 420hp is 10.1 and the 520hp is 9.3 then the 560hp jumps back up past the 420hp with 10.5:1 compression ratio, then it should be safe to say that the 420hp with it's 10.1:1CR could be tuned and/or add larger turbos to surpass the power of the lower CR of the 520hp 4.0



2012 AUDI RS7 engine

Engine type V8 (90°)

Materials Light-alloy / Light-alloy

Valves per cyl 4

Distribution DOHC

Aspiration 2 turbo

Displacement (cm3) 3993

Bore x Stroke (mm) 84.5 x 89

Compression ratio 10.5

Horsepower (hp rpm) 560 from 5700 hp @ 6700

Specific output 140.25

Peak torque (mkg rpm) 516 @ 1750-5500

Torque by Liter (mkg) 17.88

itsasecret

Tuning does have a part in making the larger power output it is just one part of what was done to increase the power

raslam77

+1

If you tune an engine to said specs - You've also got to ensure the internal parts can reasonably and continuously handle the beating.