Originally Posted by swizzle
Easy. An AWD platform has 4 shafts driving the wheels. Undo the front shafts and you have solely RWD. A part-time AWD that engages as needed can be RWD if RWD is the default for the "off" position.
For crossovers, the engine being ahead of the front wheels is a distinct packaging advantage.
The Toyoburu GT86 is essentially an AWD Impreza with the front shafts removed.
Well, on paper it seems easy but:
A classic RWD layout has the engine behind (or on the front axle), directly driving the rear differential form the gear box. FWD comes with traverse (which makes zero sense for RWD) and longitudinal variants (only Audi today); Traverse would add a transfer case for RWD only, so add weight and unnecessary complication, plus drive train losses, so I think that makes little sense again (there is a reason no one does it), so it leaves the longitudinal option; This is easier for AWD, but leaves the engine in front of the axle (so driveshaft can go directly form the front differential to the front wheels), which worsens weight distributions and gives a large front overhang (see Audi), and again makes little sense for RWD. RWD/AWD platforms usually have a short driveshaft going next to the gear box driving teh front wheels 8as the engine is positioned behind teh axle), which, for FWD only applications, again adds weights and gives you all the packaging disadvantages of RWD);
Ofcourse, all these versions are doable form an engineering point of view, but at least one of the 3 versions is seriously compromised. This is why I am interested what Ford will present (unless it means on of the versions is electric only, with an electric engine driving the axle usually unused in the 2wd/ICE application (and probably also making it AWD as a hybrid)
The GT86 has the engine behind the axle, unlike the Imprezza, which has it (like Audis) in front of it, so it#s a bit more than 2 drive shafts deleted. Technically speaking (even if engineering wise it probably started there), I think it can't be said it#s the same platform, give n by the definition of what is a platform (usually a fixed distance between front axle and a pillar base/firewall), as this (shared) front structure/crash unit is usually the most expensive part to develop.