Jim Gurief of Whiteline is one of Australia's leading aftermarket suspension experts. Here we talk to him about factory constant all-wheel-drive set-ups


Describe the handling of an unmodified constant all-wheel-drive vehicle - such as the Subaru Impreza WRX or Mitsubishi Lancer GSR.

It's important to clarify here that we're talking about front-wheel-drive cars with torque trimmed to the rear - not the other way around like in the Nissan Skyline GT-R. This really does make a big difference to handling.

With standard diffs, you'll find a constant AWD generally behaves like it would without the rear drive - it tends to understeer. However, turn-in at the limit is better - it has to be because there's torque going to the rear. The big thing, though, is the performance envelope is more open, because you've got additional drive.

Power understeer is the name of the game in a WRX. The newer model (MY01) is much better than the old one because Subaru raised the rear roll centre, making it more neutral. It also has a 25mm wider front track - which makes a hell of a difference. That was one of the greatest weaknesses of the earlier WRXs - the Lancer GSR always had the goods over it in the front track.

It's the 'praying mantis' scrabbling of the front tyres on corner exit that's the trademark of a WRX. A stock Lancer GSR (non Evolution model) doesn't really do that, though. It comes out of a corner much flatter because it doesn't really have the power. I think a standard GSR is a nicer car than a Rex. It turns-in better because of the wider front track, plus it doesn't lift and squat at the back as much as the WRX. Of course, increase the power and it will, though.

There's no question that - for the average punter - any all-wheel-drive system is a great thing. It flatters. I mean, ham-fisted people - like me - can get away with blue murder and still come out smiling. In front or rear-wheel-drive cars you need to be much more precise - but if you're having a bad day behind the wheel, you're going to have a real bad day.


Some AWD vehicles - such as the Mitsubishi Galant VR4 - also feature rear-wheel-steering. How does this affect handling?

The VR4's active rear steer is a nightmare. It transitions from understeer to oversteer very abruptly mid-corner. It says, "You're pushing the front, [so] I'll start steering from the back to make it more neutral." At that stage you're about to get on the power and full boost - so the next thing you know, the tail's hanging out. Then you go to correct it and it says, "Oh you're turning the front wheels back," and you can end up in this terrible fishtail cycle.

We don't like active rear steer at all - in any car. Front, rear or all-wheel-drive. It just adds an element of unpredictability.


So why would the factory chose to install it?

Because it makes it more foolproof for the average person.

 

Yeah. Personally, I have always wondered about the rear wheel steering. It basically confirms my thought that the more electronic driving aids you add, the less predictable the car becomes.