Why did the Audi engineers make the TT with a 80/20 split? All the other Audis' have 50/50 split with a torsen.

I'm pretty sure they could have made the TT with the 50/50 split with the haldex if they wanted to...even we as end consumers can get the 50/50 haldex unit, so why the 80/20?

Does the having the 50/50 split make it consume more gas? Less reliable?

Also, won't there be more drivetrain power loss with the 50/50 split?

 

Please, someone who knows answer these questions, I want to know too.

 

So 50/50 split is no real big deal. Haldex system IIRC is a wet clutch actuated system.... the constant 50/50 would have a lot more wear and tear on the internals. More wear and a bit less gas mileage as it's always engaged IMO. I'd love to have the 50/50 feel of my old A4s Quattro system but think my Haldex would be toast.... I could be wrong. I know Petervan is going with the 50/50 split but with his HP, that may be the ticket for him. If I were to upgrade, I'm loking at the Haldex Race unit thathas become increasingly popular as a mod recently.

 

I wonder what the torque split is for the HPA car

 

The transverse engine cars get a Haldex instead of Torsen primarily for packaging purposes-a Torsen diff is a bit bigger than a standard open diff, and the room in the transaxle is at a premium so even an open diff wouldn't fit.

The torque split is misleading-if you're driving on dry road with equally sized tires at a steady throttle, there is NO power, or torque, being transmitted to the rear wheels outside of residual drag in the Haldex clutch. When the front wheels start to turn faster than the rears, a series of piston pumps in the coupling will build pressure to cause the clutch pack to "lock up". This locking action is further controlled by the umm.. controller, which can vary the fluid path within the clutch to change certain characteristics.

The clutch pack is easily capable of transmitting everything the engine puts out, and will do so if you have no traction at the front wheels. However, the rear wheels can never spin faster than the front wheels.

The controller can limit maximum torque to the rear wheels, but more important is its ability to change the RATE at which the clutch engages. This is where the "race" controller differs from standard, sending a more aggressive "ramp-up" signal, especially when you slam the throttle down. You aren't really getting much more, if any peak torque-you just get it faster.