[Finehouse]

I am new to hypermiling, this is my first post, and I haven't done any mods so far.

A few days ago, an idea came upon me to couple the engine of a Mercedes 240D onto the gearbox of my 2000 Civic EX. It seems ideal, they're both inline 4's, the Mercedes engine is powerful and runs with computer control, and might fit inside if turned 90 degrees to be mounted laterally.

It seemed like an even better idea when I compared the similar MPG's, despite the weight and final gear ratio differences (240D weighs in at 1.5 imperials tonnes with 4th gear at a ratio of one, and the EX is 1.25 tonnes with 5th gear at 0.7), so the Mercedes engine will require less effort to turn the wheels, and the wheels turn more per engine rotation.

The problem is that I'm not sure about this idea. Is the length difference between them too great to fit the OM616? Is it too wide to put in without ruining the cooling? What kind of extensive modifications would need to be made to the gearbox and engine mounts to allow it to be attached if the bay is large enough?

I know that this isn't the most sane idea, and might be impossible. If it works, it could push the miles per gallon into the 50's (sorry for thinking so small), but before we consider the resulting efficiency gains, I need to ask: Is this physically possible to do without completely changing the drive train of the Civic?

None of these questions are rhetorical, I'm genuinely asking if it's a feasible idea that could be done.

I'd also like to know if I put this in the right part of the forum.