M70 V12 in a 635?

[ted13b]

Just wondering if anyone has attempted it...it just seems the 6 is screaming for a V12!

[MWrench]

Yup I tried it, way to much work for an engine that weighs nearly 600 lbs fully dressed out and the max N/A power you can get is around 400 HP.

And way to much $$$$$, CSI engines are around 380 HP and to re-build into anything more would require sleeving the block or a turbo! Looking at well over $20K for anything that would compete with a stock LS2.

Here is one that I had sitting in a mock-up tub.
http://www.mwrench.com/m6v8/v12install/v12install-Pages/Image5.html

Compare with a LS6
http://www.mwrench.com/m6v8/LS6/LS6-Pages/Image23.html

[Rob Levinson]

You mean something like this?

http://www.robertlevinson.com/images/12in6_1Big.jpg

http://www.robertlevinson.com/images/12in6_2Big.jpg

This car was an engineering prototype that BMW AG was playing with. The car has E30 M3-style fender flares and the entire engine bay is significantly modified. Clearly, for whatever reasons, BMW decided not to pursue production.

- Rob

[MWrench]

HI Rob, rumor has it that this was only a test bead for the M70 engine. There is at least 1 completed E24 witha M73 engine that I know of in the USA. No body mods. The engine will fit nicely without ANY change to the body with the exception of enlarging the first part of the tunnel for the bell housing and that can be done with a BIG hammer.

Sure would like a set of those fender flairs if they were steel!!! always loved the E30 M3 look!

[Rob Levinson]

I used to have a more "official" story that went with those pics, but lost it in a PC failure a couple of years ago.

If I recall correctly, it was more than just a method of testing the V12... it was an experiment in a "super M6", which never happened. The basic E24 chassis had been in production since the late '70s, and was indeed long in the tooth (can you believe it made it to 1990?). The E31 8-series was the conceptual replacement that would eventually get the V12 that was denied the E24. That widebody E24 in the pics may even have been a very early test mule for a variety of E31 components. Without more of an insider's view, however, that's just conjecture on my part.

The V12 was, of course, primarily developed in the mid-1980s for the 7-series' flagship model to compete with the V8 and forthcoming V12 from Mercedes. The original plan was to put it in the E23, but with the chassis change to E32 looming, the best the E23 ever got was the turbocharged M30 6-cylinder, the 745i. Unfortunately, the reign of the "German small block", the big 6-cylinder, was destined to end. With the German rivals offering V8s, and even the upstart Japanese luxury brands offering their own V8s, it was a tough sell for BMW to continue with a "lowly" I6 in their uber-sedans.

- Rob

[ted13b]

Well, it seemed like a good idea! Is that LS6 in a 6 series?

[MWrench]

Yes, It is a '87 M6, has 170K on the clock and by the time I would have had the stock S38 re-built (has 3 low holes), I would have more then a new LS6 and new T56 6 speed into it. If I were to re-build the S38 to come somewhere near the 400 HP of the LS6, I would have 3X into it. Of course that would not be the case if I wasn't doing all the work myself, it might have been more equal. With the LS6, I have the potential for 500 HP with very little change or cost adders.

[ted13b]

How does it fit? Oil pan interference, headers, steering column, exhaust? When will you have it done?