Wednesday, 30 January 2008

Wrong Wheel Drive

In these days of the almost universal use of front wheel drive there’s a lot to be said for proper wheel drive. Packaging and cost considerations aside, the linearity of response and steering clarity is something you notice even just driving down to the shops. Trust me, I’ve been driving rear wheel drive vehicles exclusively for more than a year.

But I also remember my past experience of the downside of the combination of turbo-diesel muscle and front wheel drive.

Imagine you’re on the way to work, and are in a queue at a busy roundabout.

And its raining.

The sequence of events goes like this: :

Spot gap in busy roundabout

1.Endeavour to accelerate briskly off line into gap
2. Turbo lag means nothing happens
3. Lots of throttle then applied; gap disappearing fast
4. Turbo spools-up; 200+ lb/ft of torque heads for front wheels
5. Head snaps back; steering goes oddly stiff
6. A nano-second later, the front wheels give up the traction battle, and the inside wheel spins, compliant suspension bushes allow spinning wheel to flail around in wheel arch
7. The Bosch ‘Traction Control system spots the spinning wheel, and cuts throttle
8. Head snaps forward, the turbo spools down. Now 20 lb/ft at front wheels.

Progress so far: 6 ft.

9. Gap almost gone, and disaster looming fast.
10. Throttle pedal now mashed to floor; turbo spools again, front tyres vapourise under the onslaught
11. Repeat steps 3 to 10 until field of view completely taken up by Seddon Atkinson badge

And breath...

….for 14 milliseconds until engine reaches end of 1200rpm power ‘band’ then frantically search for 2nd gear


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