The BMW 850 was an amazing car in many respects, but it was a bit heavy and never got the engine that it needed. Yes, the V12 was smooth, but they never made a true M version. Despite it's age, it still looks great and I think that rich people who buy things like Icon trucks and Singer Porsches would buy a similar product based on the 850. But what drivetrain to use?
Yep, keep it BMW and pull the twin-turbo from the M6. Plenty of power, and folks could take it to their local BMW dealer for regular service. Or if you are a sheik:
AWD and 600hp in an 850i would be pretty neat. Now, this is clearly a perfectly reasonable idea and my business plan is beyond reproach, so who's going to fund me?
But will you be able to repair the pixels? 
Keep the engine, update the engine management system, and put e36 M3 four valve heads on the V12 engine block.
Wrong drivetrain. Use the S65 V10, then I will be happy. And no AWD. I do love me some E31 though...there's a sea green metallic one with throwing starts on it in the BMW museum in Munich and is just beautiful.
I've seen like three 8 series in the past week. Seems like a fantastic car for a long road trip with your SO. I'd rock one.
Furious_E wrote:
I've seen like three 8 series in the past week. Seems like a fantastic car for a long road trip with your SO. I'd rock one.
Except when one of the ECM's craps the bed 200 miles into the trip and she leaves you for somebody in a reliable automobile.
stuart in mn wrote:
Keep the engine, update the engine management system, and put e36 M3 four valve heads on the V12 engine block.
Except you can't.
IIRC, the V12 used in that car is essentially 2 M20B25s from the E30s sandwiched together. To electric throttle servos, 2 ECUs, etc.
This was ours. Had it for ~6 months. Not terribly entertaining. Granted it was an 840, not 850, but it was late enough in the model run that it had the M62 motor (4.4L), which was the preferred V8. What would have been relatively straightforward would have been to swap in the S62, as found in the e39 M5, with its 6-speed. 400 hp and a manual would have made it a LOT more fun.
My 850i was fantastic. But I approve of your company and would like to knoe more about investing. Swap seams cheaper then keeping the DK motors functioning properly on the V12. 
Having driven the M6 and the X6 M recently (well, M2, M3, M4 and M5 too) I cannot find any issues with your business plan.
PS: X6 M has incredible brakes. And that's an understatement.
z31maniac wrote:
stuart in mn wrote:
Keep the engine, update the engine management system, and put e36 M3 four valve heads on the V12 engine block.
Except you can't.
IIRC, the V12 used in that car is essentially 2 M20B25s from the E30s sandwiched together. To electric throttle servos, 2 ECUs, etc.
Is the bore center the same? If that is okay, then everything else is just plumbing.
For reference, people have made DOHC big-block Mopars using Porsche 928 cylinder heads...
dyintorace wrote: 400 hp and a manual would have made it a LOT more fun.
The 850i is one of the few cars that C&D tested and said the manual transmission sucked the fun out of it, get the automatic.
crankwalk wrote:
Furious_E wrote:
I've seen like three 8 series in the past week. Seems like a fantastic car for a long road trip with your SO. I'd rock one.
Except when one of the ECM's craps the bed 200 miles into the trip and she leaves you for somebody in a reliable automobile.
Baseball is like being married to a German woman. You might love the game but the game doesn't always love you back.
I am thinking duel clutch paddle shift needs to be an option your new company should offer.
Upgrading the existing motor make us a "tuner" and not a "bespoke manufacturer" and limits how ridiculous our prices can be. We have also decided to include a retro 4-speed manual transmission and a paddle shift dual-clutch auto.
And an ejector seat option.
pinchvalve wrote:
Upgrading the existing motor make us a "tuner" and not a "bespoke manufacturer" and limits how ridiculous our prices can be. We have also decided to include a retro 4-speed manual transmission and a paddle shift dual-clutch auto.
And an ejector seat option.
The maintenance bill works as an ejector seat for the owner, no need to be redundant.
