Rusty911
A2OC Donor
Yes, that's right. The gearbox in the TT drives the front wheels just like a front wheel only drive car. The difference is that it has a additional output shaft that goes through a transfer box to the Haldex clutch. The clutch controls how much power goes to the rear wheels so for most of the time its more or less like a front wheel drive car. When the front wheels loose grip, the ECU engages the Haldex clutch and directs power to the rear wheels but it can be only a maximum of 50% as the front wheel drive is permanently connected. The problem with the standard set up is that it takes up to 4 revolutions to fully engage the Haldex. As this happens after the front wheels have lost grip, there is a noticeable delay before the rear kicks in. A common mod for Haldex cars which I have on my Mk1 TT is to reprogram the Haldex ECU to engage the rear drive on the throttle. When applying power, the rear drive engages straight away and so before the front grip is lost. This means you can power out of corners and have the back of the car push you round the bend with a little bit of controllable oversteer if you want. That completely transforms how the car drives.
regards
Andrew
That's fasinating, thank you: I'd not heard of that particular upgrade.
I wonder, have you done the DEFCON mod or the offset rear bushes / caster increase?
I'm not normally into modding, but to turn the TT back into the car is was originally designed to be (more driver orientated) does appeal.