2010 Audi S4: Undisclosed Extra Horsepower?

It's great when sedans crack the 12 second quarter mile mark at 108mph or more. But when they weigh 4,000lbs and are rated at 333hp, something doesn't add up. In this case, the S4 seems to be making approximately 70 horsepower more than advertised. Consider the following test results:

Road & Track May 2010: 12.9 seconds @ 108.6 mph

Road & Track January 2010: 13.2 seconds @ 106.8 mph

Car & Driver October 2009: 13.4 seconds @ 106 mph

With very aggressive gearing and AWD like the Porsche Panamera this would be believable from a 333hp 2-ton sedan. But these times have been achieved with 6-speed manual cars. Looking back to the 420hp RS4 that was also around 4,000lbs, this matches pretty well. Audi isn't lying about the weight either. The Road & Track car weighed in at 4,010lbs. A really quick pig, if you will.

At 333hp, an all-wheel drive car needs to weigh around 3,300lbs to achieve those speeds. There is more parasitic loss with AWD vs. two-wheel drive powertrain layout. Is Audi purposefully underrating the car? Or does cool weather and a cool motor with direct injection make a lot more horsepower than if fully warmed up at normal operating temperatures?

This has happened in the past and perhaps forced induction motors are more susceptible to horsepower variations in temperature. If intentional, it's a nice benefit for the owners. But if the ratings creep up during the model run, what changes warrant it?

There is a 13.0 @ 107mph on dragtimes.com that is attributed to a private party. Hopefully this means these are not magazine "ringers" with aggressive tunes or smaller-than-stock supercharger pulleys creating more boost. Many including myself think Nissan did this with the pre-production GT-Rs that were much quicker than those sold in the showrooms. And of course, the Nurburgring times are questionable for any 3800+lbs, 480hp car. You can't defy physics. Audi isn't making any wild claims though. Except of course the low horsepower rating...

It's in Audi's best interest to disclose the horsepower variance. And I would love to see if the 7-speed DCT transmission can do better and if it has more aggressive gearing. Interestingly Audi lists the weight of the manual transmission car at 3847lbs, 77lbs less than the 7-speed. They are not fibbing that the weight is over 3800lbs, that's for sure.

Audi's supercharged S4 eclipses the previous generation RS4 and is beating the competition. If driving it is anything like my experience from A5 review from 1//17/10, it's awesome. Not bad from "only" 333hp, right? Oink oink!