Audi R8, Audi RS4: Dyno test comparison

Automobile Magazine has done a great dyno test comparison between the Audi RS4 and the Audi R8. A must read for all Audi lovers!

Our Four Seasons Audi RS4 has a lot of fans around the office. While it's a great all-around car, it's the 8,250-rpm, 420-hp, 4.2-liter engine that really gets our attention. The V-8's power delivery is so linear that it feels like an electric motor, except of course no electric motor could ever sound this good. I once described its staccato exhaust note as sounding like a thunder cloud. Assistant editor Sam Smith said it sounded "like an angry, drunken bear being shot from a cannon." One of us is obviously a big fan of hallucinogenics.

Anyway, Audi's new R8 shares the RS4's engine, albeit with a couple of small changes. First, it has different intake and exhaust paths due to its mid-engine layout. Then, its dry-sump lubrication system allows the engine to be mounted lower in the chassis, permitting the use of a smaller, and lighter, flywheel.

The lightened flywheel is evident as soon as you turn the key. The R8's V-8 revs much more quickly than the RS4's. So quickly, in fact, that it seems the flywheel must be made of helium. Teensy little prods of the throttle result in huge surges of revs, with sharp barks of anger shooting out of the short exhaust pipes.

2007 Audi RS4 Dyno
In gear under load, the R8 sounds frenetic, evil, and pissed off. By comparison, the RS4 sounds happy, refined, and non-threatening. Never thought you'd hear those words about an RS4, did you? The R8 sounds that good.