Sounds like Haldex!!

[Mr.G]

Been reading up on the TTRS. Taken from VWVortex this info surely sounds like haldex to me:

The Audi TT RS features quattro permanent all-wheel drive as standard equipment. Its heart lies at the rear axle: an electronically controlled, hydraulic multi-plate clutch. If a situation calls for it, the clutch redirects a majority of the torque input from the front wheels to the rear wheels.

Within milliseconds, a powerful electrical pump in conjunction with an accumulator presses together the clutch’s plates via hydraulic pressure. Additions to the quattro powertrain include a constant velocity joint before the propeller shaft and a compact rear-axle differential – both are heavy-duty components.

Maybe the TTRS and RS3 if it ever happens might share the same engines and drivetrain as in Haldex systems.

Any thoughts??

G

 

[jojo]

Sounds like Haldex to me, it would be a lot of £££'s to re-engineer the chassis to have a different 4WD system installed just for an RS model.

 

[Mr.G]

So the question begs.....

340hp Through the front wheels primarily? As some have said haldex is FauxWheelDrive??

G

 

[jojo]

So the question begs.....

340hp Through the front wheels primarily? As some have said haldex is FauxWheelDrive??

G

I'm sure a few tweaks here and there to the Haldex controller will make it behave or respond differently to our S3 setup, it's not like the Haldex can't take the power or anything, few on here have BT power already in their S3's.

 

[Mr.G]

Very true. Wish i had that sort of power.

G

 

[ChriS3]

So the question begs.....

340hp Through the front wheels primarily? As some have said haldex is FauxWheelDrive??

G

Depends on many things. The Haldex ECU is primarily linked to the ESP sensors, and the accellerator pedal. It will engage the rears when the wheels slip or when you boot it. Done right, the Haldex clutch will be locked up before the engine starts to make power. As it's done on accellerator depression speed, it can keep it in fwd when cruising on motorways. You could also program the Haldex to be in permenant 4wd, as HPA's version does http://hpamotorsports.com/haldex.htm, although that would benefit from being deactivated under braking to make it better for road use.

 

[TheSpaceCowboy]

I thought the haldex was based off the rotational difference in speed between the two axles? I remember reading a response from Haldex themselves that said the haldex is actually putting some power to the back most of the time be it even 5% mostly to help prevent wear and lower heat on drivetrain components.

From Haldex themselves:
We need slip over the coupling in order to be able to transfer torque.
That slip (rotational speed difference between the front and rear axle) is created by different tyre rolling radius (front to rear) and drive slip between the tyre and road. The rolling raduis difference can be created by differently worn tyres (or different dimensions, something that should be avoided) and different load. In most cars, the front axle has a greater load than the rear axle, which causes the roll radius of the front tire to be smaller than the one for the rear tyres (given the same nominal size). This gives us the possibility to transfer torque to the rear axle also when no slip occurrs on the front tyres.

 

[ChriS3]

I thought the haldex was based off the rotational difference in speed between the two axles?

It is - otherwise known as wheelspin. The accelerator sensor was put to more use in the performance Haldex for the S3, but not really noticable in standard application.

The latest version, Gen IV, also has the option of in-built electronic LSD. It's a fair bit more advanced than what we had in Gen I.

Also from Haldex - Signals from the ABS and ESP systems and the engine control are vital for performance. For enhanced performance, signals from a steering wheel sensor, yaw sensor, lateral acceleration sensor can be used if available.

 

[TheSpaceCowboy]

Wheelspin isnt rotational difference? If youve got a set of wheels on the back with a large radius and a set on the front with a small radius thats a rotational difference but the wheels arent slipping?
Which links in with what Haldex said regarding the typical power transfer of 10% - 15% on a uniform surface at a cruising speed.

Officially I think the Gen 1 doesnt use the steering angle sensor on VW group cars but thats purely from my brainbox of memories!