Originally Posted by MrFatbooty
I honestly have no idea what amount of room is available in the RL engine bay. But allow me to indulge in some hypothetical reasoning for a moment.
The XC90 initially came out an inline-6, and all wheel drive. A transversely mounted inline-6 is even wider than a V8 placed in the same position.
Let's assume that the difference in width between an awd and fwd transmission is about the same as the difference in width between an I6 and a V8. So, a V8 with awd would be about the same width as an I6 with fwd.
The XC90 is based on the S80 platform, and the S80 was available with the same I6 with fwd. The S80 is about the same size as the RL. So, it seems reasonable enough that Honda should be able to design a V8 and awd transmission that is sufficiently compact to fit in the existing RL body.
Let's look at a couple pictures. First, the S80 with fwd I6.
Now, the RL with awd V6.
Looks to me like all that plastic in the RL is hiding a bunch of empty space into which Honda could shoehorn a suitably compact V8. :dunno:
The major assumption you're making here is that the difference in width between the blocks is similar to difference in width between the transmission housings. I really don't have any idea if this is true or not. But, even if it is, space is not your only constraint. I would bet the driveshaft to the rear couldn't go in the same place if you put in a V8, because the transmission will shift to the side. Which then might affect where the exhaust travels, or where the fuel tank is laid out or the structure of the rear axle. You change one thing and suddenly a gazillion things need to change as well. And each of these things will need its own solution to the constraints of the current frame. And you end up with a car that really wasn't meant to work that way. Or is really heavy, or is expensive to make. Add on that Honda doesn't have a V8 in its lineup anyway, so that needs to be developed. I think Acura made the right move here, salvaging what they can with the current generation, and hopefully moving towards a V8 for the next design cycle.