Australian consortium wanting to spend up to $750mill to acquire Holden plant

[Road_Warrior]

Originally Posted by malazn mafia

Not a car engineer by any stretch, but for many years I have always wondered why modern cars are monocoque chassis? Why couldn't we tear a leaf out of the history books and build a solid modular space frame or ladder chassis with front suspension and IRS bolted in as modules. The frame could utilise modern lightweight materials and be designed to absorb crash impacts. Installing an engine would be a case of fabricating a bunch of brackets and braces to secure to the frame. Then a standard ISO pattern or even a Lego-themed assembly could be used to attach whatever body style you want to this chassis. The frame could stay the same for eternity, with the IRS, front suspension and powertrain components being continually developed, and the wheelbase or track could be adjusted by manufacturing parts of the space frame or ladder chassis in different lengths. The body styles could be assembled overseas and interior options could be built up as modules running a simple CAT5 or even a power/data/earth configuration. With this setup, average joe doesn't need to buy a new car... He could upgrade his car which he has setup and modified with the latest body style or a different one as his needs change. Couldn't this all work or am I just crazy ?

Ok I'll bite. The only real benefit a Body-On-Frame (BOF) configuration has over monocoque or unitary is durability for load carrying applications. There's a reason all the car makers are still persisting with BOF for commercial vehicles - because they handle the abuse a lot better and support the variable needs of a commercial vehicle platform very well.

Passenger cars don't need this, because they're not lugging a tonne of bricks around in the tray or whatever, so monocoque is the way to go. Not only is a monocoque chassis lighter and cheaper to make, it can be designed to be just as flexible and almost as tough as a BOF platform.

Not only do they not need the weight and toughness factor, they also have to comply with rigid safety standards that commercial vehicles do not.

Look at the Falcon for example. Here is a RWD, front engine platform that supports 4 different engine types, plus an AWD SUV. Holden's Zeta platform is another. Supports 2 engines, a LWB, SWB and sort of supports a coupe.

A monocoque platform can be scaled just as you describe with the BOF system, but the product doesnt have to pay a weight penalty or need extra plant at the manufacturing end to build it (read: more dudes on the line or more expensive automation). You can continually evolve the expensive bits like suspension units and engines and leave the rest pretty much static, or whack on a new top hat if you want fresh sheetmetal - sort of what Ford did from BF to FG, just with a lot more work in some areas and less where they should have.