The next generation M3 is still at least 3 years from its debut, but it's never too early for speculation, particularly about its powerplant. While the current E9x M3 is powered by the marvelous high-revving V8 engine (S65), it's been widely speculated that that the next generation M3 will return to using a 6-cylinder engine. Emissions regulations have forced the move, much like the new upcoming F10 M5 getting the more efficient S63 V8 Twin-turbo engine instead of continuing to use the iconic V10.
So far so good. However, according to our good source with close ties to BMW M, BMW has not settled on exactly which engine layout the company will use for the F30/F32 M3. Rather, the guys at BMW M are currently testing no less than four different engines
at the moment, using four separate E9x M3 prototypes. They are as follows:
1. S65 V8 Biturbo Engine
This one comes as the biggest suprise to us. Most of us are sad thinking about current M3's glorious S65 engine (which just won an International Engine of the Year Award) going away. However, according to this rumor, it may be far from gone. BMW M has allegedly reworked the engine internals, lowered the redline slightly, and -- sit tight -- added a bi-turbo. Maximum output would be only a tad higher than in the current S65, but with much more torque and much lower fuel consumption.
This engine would be suitable for a possible Z4 M and X3 M as well. As great as this sounds, we'd be highly surprised to see this engine in the F3x M3. As an aside, we've been told that the first X3 M prototype is currently being built!
2. Modified N54 Engine
We have heard rumors about a modified N54 or N55 engine as a possible choice and always considered it the 'natural choice' for the new M3. The biggest advantage of this solution would be relatively low production costs. But, the question is whether this engine will be powerful enough, and there's no easy way to increase its displacement. In other words, BMW may decide against a modified N54/55 engine for the new M3 fairly soon.
3. Modified S63 Engine
Think AMG's way of shoehorning here. It's apparently possible to fit the upcoming F10 M5's S63 monster V8 twin-turbo engine into the next M3. But, BMW isn't AMG and thus hesitant to follow the one-engine-for-all-cars trend, despite the possible cost savings coming with larger scales of use. Another downside is that this engine would not fit in the Z4 at all, and hardly at all in the X3.
4. V6 Engine Based on the S63
BMW is said to currently favor this engine - a V6 based on the S63 V8 turbo motor, with an yet undisclosed amount of turbos. This engine makes for better weight distribution and is also small enough to be fitted into the Z4 and the X3.
Only downside is (and it's a big one): How does BMW make a credible switch to a V6 engine without upsetting BMW fans and owners for abandoning the inline-6 philosophy. Former M CEO Dr. Segler did say that BMW does not subscribe to dogmas, but we're not sure he had this in mind.
It's obviously difficult to substantiate any of this info at the moment, and BMW may never confirm whether some or all of these options were/are being tested. But, some say speculation and discussing possibilities of an upcoming model is half the fun, so have it!