Quote Originally Posted by Mirek View Post
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Rallycars are 4WD not because of dry asphalt but because of loose and dirty surface. .
From an historical perspective I can't agree and have read old magazines which were then current when first Saab and then Audi began using turbochargers---and Saab, where I am friend with and stay on visits with rally engine development guy---admittedly were going to turbochargers to make huge amounts of torque---that the main problem was putting down the massive amounts of torque with just 2 tires of a limited specific size...

The engine torque in turbo car regardless of surface drove the need for dividing the power up to 4 tires instead of just 2...Old group 4 --which the Saab 99 Turbo and Audi Quattro we homologated in---it had wheel and tire max size limits based on engine size x turbo factor (1.4 in early days if I recall correctly..Later 1,7 times engine cc later)

Who can forget the scenes of Vatanen in his Escort at Ilse of Man going thru a 90 degree corner so hard and leaving 2 very wide black marks all the way thru the corner? It still sends a shiver up the spine to see that..

In those days BDG Escort (2,0 liter) made 262 hp (10,000 rpm) and the first Quattros in Group 4 made 265hp...but the quattro made maybe 3x the torque and was spread over a big broad band.
THAT drove the need for 4wd---even on asphalt IN RALLY 9with the width restrictions and available tires in those days)

Different perspective but that's the talk from when this crazy trend was just beginning..and some of it I got directly from at least one person directly and intimately involved (and frustrated too! Saab was so small and the gearbox they could make was very delicate even for good n.a. power, and there was no "9 minutes gearbox swaps" for a Saab)