We already know what you’re going to say: The 10 Best Engines judges were suckered by the same formula that worked 40 years ago for Detroit muscle cars.

Stick a big V-8 in a small-bodied car and watch the concoction go like hell.

It’s a good strategy, really. One that can make just about any big-displacement V-8 perform like a hero. Audi AG’s 4.2L V-8 actually isn’t all that big (only Volkswagen AG makes a smaller 8-cyl.), but it packs a mighty wallop.

The luxury-car-smooth DOHC V-8 comes across like a piledriver in the comparatively light S4 bodyshell. The available torque – a prodigious 302 lb.-ft. (409 Nm) peaking at a wieldy 3,500 rpm – flows as inexorably as lava from a roiling volcano, so one can forgive the high 7,000 rpm needed to attain maximum horsepower.

Big punch in small package from Audi 4.2L DOHC V-8.

But unlike its genuine muscle-car progenitors, this Audi V-8 isn’t just about the numbers, and its reportoire isn’t limited to overpowering a compact-car chassis. All the Best Engines judges commented on the subtlety of the S4 package. Unlike some contemporaries that seek to replicate the muscle car – notably General Motors Corp.’s Cadillac CTS-V that employs GM’s 5.7L OHV V-8 – Audi’s V-8 is fitted in the S4 with what seems to be an inordinate level of attention to package-specific development.

The engine’s exhaust tenor, for instance, is permitted to fully express itself only at the appropriate times; the idle burble is a wonderful mix of raw muscle and sophistication, while wide-open throttle tingles the spine. The rest of the time, the 4.2L V-8 minds its own business, something we can’t say of the raucous V-8 bellow always present in the CTS-V.

We also credit Audi engineers for the S4’s excellent handling balance. If you didn’t know there’s a V-8 shoehorned in this car, you probably wouldn’t know it from the driving. And the gear ratios of the 6-speed manual transmission allow the driver to perfectly channel the V-8’s power according to the kind of driving desired, the way a master strokes the head of a well-trained but not-entirely-trustworthy Rottweiler.

Despite its 5-valve-per-cylinder, variable-intake, all-aluminum refinement, Audi’s 4.2L V-8 is hand-grenade-with-the-pin-pulled exhilarating in the S4, an engine hoping you want the explosion to happen.

The beauty is, it never insists. If controlled chaos isn’t your fancy, go on your way content that you’ve got access to a technically intriguing, flawlessly refined, tidily dimensioned DOHC V-8 that also boasts, at 81 hp/L, specific output that bests almost any other V-8 in the market. That includes those passing themselves off as modern-day muscle-motors.

There isn’t an 8-cyl. engine available at the S4’s $45,650 base price that can match the sophistication and outright power of Audi’s magnificent 4.2L V-8.

AUDI
Audi AG 4.2L DOHC V-8
Engine type 4.2L 90-degree DOHC V-8
Displacement (cc) 4,163
Block/head material aluminum/aluminum
Bore x stroke (mm) 84.5 x 92
Horsepower (SAE net) 340 @ 7,000 rpm
Torque 302 lb.-ft. (409 Nm) @ 3,500 rpm
Specific output 81 hp/L
Compression ratio 11:1
Application tested Audi S4
Fuel economy
for tested vehicle
(EPA city/hwy. mpg)
14/20

bvisnic@primediabusiness.com