With all the tech and luxury included in Audi's S6, you would be forgiven for overlooking the sports car levels of performance available from the twin-turbo V-8 and rear biased Quattro all-wheel drive. When a friend of ours told us he was about to pull the trigger on some big performance modifications and offered to let us test the car afterward, we not only said yes, we also asked if we could follow along with some of the modifying process. Our friend has chosen to remain nameless as he may or may not live in a state where some of these modifications may be seen as questionable.
It started with a couple of simple requests: "I want an exhaust for a bit more sound; it needs to sound like a big V-8. I won't put up with any drown and I still want a quiet mode. I want it lowered a little, but I don't want to give up the factory ride quality or the ability to lift it up for driveways and speed bumps. Some wheels, something more aggressive, but also something that doesn't make me look like a teenager."
I completely understood the goal of the project and made a few suggestions. This is a typical build we see on cars of this caliber—just some wheels, a little drop, and a little more noise. So that's where we started.
Audi has worked with Akrapovic on the exhausts of its WEC prototype race cars for several years. A recent result of that partnership is a titanium cat-back system for the S6 and S7. It's available from your local dealership and can be bought, and presumably financed, along with a new car purchase. In this case, the exhaust came after the initial purchase of the car, but is still covered by the balance of the factory warranty. It's 17 pounds lighter than the factory exhaust, but let's be honest, that's insignificant on a 4,500-pound car; and it's fair to mention that the lowest point on the car behind the firewall is literally the least advantageous weight to remove.
But it sounds—amazing! That is what we are after—factory levels of fit and finish that still use the exhaust valves to change the sound and the volume with the push of a button. Does it add power? Believe it or not, it does that, too. We're seeing fewer and fewer cat-backs that show any measurable gain on the dyno, but this makes an additional 17 hp and 13 lb-ft of torque on the dyno. Will you feel those numbers on a car already putting down 395 hp at the wheels? Hard to say. The installation is straightforward, but be honest, if you own an S6, you aren't doing this in your driveway.
The S6 comes from the factory with Audi's adaptive air suspension. This is not the same as aftermarket air suspension kits, which have become the most popular way to ruin perfectly good vehicles. This is a set of components designed specifically for this application and utilizes magnetorheological dampers to work in conjunction with the air spring units and a computer, controlling ride and handling characteristics to tie both of those systems together. While most of you are familiar with H&R as a supplier of top-level suspension hardware ranging from sport springs to coilovers to antiroll bars, being at the top of the game also requires some attention to cars like the S6. The H&R ETS electronic lowering system is like an intercept system we've come to know from ECU tuning, except it works in conjunction with the suspension's computer system.
While it can't alter spring or damping rates, it does give the car a lower ride height, while still allowing the computer to change the ride height as required. It has a few adjustments on the control module itself, if you need to dial in the ride height to exact specifications. We installed it and it immediately worked with no adjustment required; that will probably be the case for 99 percent of users.
While several different aftermarket wheels were considered, the owner decided on a set of 21 by 9-inch Audi wheels from an RS7. He also decided on Pirelli P Zeros in 265/30-21, which is admittedly a fairly rare size. It is close to the factory dimensions being less than a quarter inch larger in diameter but a half inch wider in both section and tread width.
Lastly, it was decided that if the S6's owner goes in search of more power, the car would do well with a little more brake. Not so much about additional stopping power, but more about energy capacity for repeated use in canyon driving. While the aftermarket offers a variety of options, Audi's parts counter offers a carbon ceramic kit that not only adds the energy absorption and dissipation your after, but also a significant weight loss, probably a bigger and more meaningful reduction in mass than anything short of stripping the car's interior and all insulation. We don't have a total price on all the components; they have to be ordered piecemeal and I don't think the owner wanted to really think about the total bill—plausible deniability, etc. Let's assume they are in the neighborhood of a new VW Golf. But, if you think about buying brakes by the inch, the fronts, at 16.5 inches, may not be that bad of a deal; the rears are a still staggering 14.6 inches. The front calipers, while being "only" six pistons, are of an obscene size, truly megalophobia inducing when you see one off the car. The rears calipers appear to the same single-piston sliding model as on the rear of my GTI.
In the next update, we plan on getting actual test data on the newly enhanced S6. For right now, I can assure you that the sound alone of the Audi/Akropovic titanium exhaust has transformed the car. I have been a little down on aftermarket exhaust manufacturers lately. It seems like most have given up on making modern turbocharged engines sound good and have settled for loud. This is truly an exception. In Dynamic Mode, it is loud, really loud, Cars and Coffee ruining kinda loud. In Comfort Mode, it is still maybe a little louder than I would like on the outside. It doesn't burble and pop as much, but it no longer disappears into the background in the way it does on a pleasantly luxurious stock S6. With that said, if you bought an S6 just for the luxury element, you may have missed the point of the car.
As of yet, I haven't noticed a downside to lowering the car. The S6 uses multi-link suspension at both ends, which is far more forgiving to ride-height changes than the more common MacPhersen Strut. We also haven't lowered the car all that much. The difference in handling feels to be negligible, but we will see once we get to the test track. Our owner is already itching for more power. We will have to see what happens between now and testing. Until then, check out the video to listen how the new exhaust sounds.