RaudiA7

I would think that naturally, the 6 speed would have more hp, since an automatic transmission is less efficient and the torque converter loses some power, etc. just out of curiosity, why are both engines rated the same? Is the hp the same, but something is lost through the transmission before it reaches the wheels?

April

HP is usually rated at the crank.

Sleestack

Engines are typically rated at the crank to sell... but, yes, hp at the wheel is what matters.

Singletrack

I assume you're reffering to the acceleration difference which is simply the inability of the automatic to shift as efficiently as a manual (driven by a professional).

The torque rating on the auto tranny is also lower than the manual, but that shouldn't really play a role unless you chip the car. The stock HP and torque ratings are identical.

-st

Singletrack

So the question is does an auto at the wheels have less HP than a manual?

Sleestack

I don't think that is true... unless there is something really special about Audis.

Silver 2.7tt

it's true what you are saying; actual horsepower to the wheel should be more efficient for the 6 speed(although recent automatic are closing that gap in efficiency). But Audi like all others only publish number on the output at the crankshaft before any power is absorbed by the drivetrain or even the weight of the brakes, wheels, and tires. Upsizing your tires and wheels if thus increasing the weight would also lower the actual output.

However, A6 box is surprising efficient as far as producing accelerating numbers. Only .6 sec hehind despite gaining almost 200Ibs and higher gear ratios.

Singletrack

Then explain it to me so I understand : )

Sleestack

The same car mated with an automatic transmission will suffer 17%-25% power loss at the wheel, while a manual transmission loses about 10%-15%. I caould be a little off on those percentages, but I'm pretty sure its pretty close.

Singletrack

Seeing as the tip is quite a bit heavier and is just a whee bit slower.

-st