A dynamic unibody?

Okay I think this question is far enough separate from my turbo/awd question to warrant a new thread. Again, mods, if this gets too speculative, please kick it to IMHO for me.

What are the major obstacles to designing a unibody structrue that could support a transversal OR lateral mounted engine? Same said floorplan would then allow for a FWD or RWD vehicle to be manufactured from the same basic design. On top of that, it’d be a small matter to make this design work for AWD, FW dominant OR RW dominant.

With a setup like this, a car company could have a truly universal floorpan that they could use to create… oh, a FWD I4 economy car, a turbo I4 ‘sporty’ car, a turbo AWD I4 ‘boy race’ car, a V6 FWD luxury car, a V6 RWD touring car, a V8 RWD ‘muscle’ car, or a V8 AWD ‘exotic’ car, with any combination between.

With some tweaking, you could also make for a coupe, sedan, wagon, convertable, roadster, or hatchback.

What are the obvious obstacles or pitfalls of such a ‘modular’ design?

As far as I can see, you’d need a longer engine bay, but not necessarily wider than a normal engine bay for a V8 RWD vehicle, like the Fox-body Mustang. A I4 or small V6 would fit easily, transversally, into a Fox-body engine bay from my just eyeballing the bay.

You’d have to have a driveshaft hump in the car, but then, most cars already have a hump like that for rigidity and the exhaust. Okay then, where would the exhaust go on a RWD version? Most cars also have a channel near the sides of the vehicle also, and a side-exhaust on a muscle car is tres cool, so that doesn’t seem to be a problem here.

This question has been bothering me for months. Why DON’T we see cars that are offered FWD or RWD, with a lateral or transversal engine? Kinda like the old K-car from Chrysler. Heck, they even made a mini-van from that design!

I can see weight distribution and suspension as being two problems, but I’d think those would be easily solved, too. Heck, I dunno.

What’s the deal?


Okay I’ve been thinking. The differential hump for the RWD would take up a good deal of trunk space if it were to be beefy and a low slung vehicle. Much like in an F-body, I suppose. Okay so where does the gas tank go, then? In a FWD vehicle it could go where the differential would go, but where in a RWD?

Geez. I’ve been sitting here picking nits with my idea for so long I won’t even bother to list them. I suppose THAT’s why they don’t do it.


Either behind the axle or between the driveshaft and framerail (or whatever protrusion acts as such in a unibody)