At this point, he thinks he can mount one set of batteries in the rear and the other set in the front with none in the middle.
My understanding of the plan for the 944 (which has a tunnel for the drive shaft in its torque tube) was to basically duplicate the stock Volt configuration, with central tunnel and rear seat sections of the "T" pack. The 911 doesn't have much of a tunnel, so it makes sense to change to rear and front packs.
So the weight distribution may not be much different than a stock 911 which has nearly 60% of the weight on the rear.
However, the total weight will probably be higher. The front torsion bars are easily adjusted for height. Adjusting the rear torsion bars is more difficult. There are adjustable trailing arms available which would make the rear adjustment easier.
I agree that the total weight will probably go up (it always does in long-range EV conversions). With a front battery pack replacing the fuel tank, perhaps the net increase will occur mostly on the front axle, reducing the 911's significant rear weight bias (and minimizing the spring adjustment challenge).
Front pack placement should be interesting:
- the stock fuel tank location is entirely ahead of the front axle and below the trunk floor; it is awkwardly shaped (not a problem for the fuel tank which is just shaped to fill the space, even moulding around the spare tire), and
- the trunk (from the firewall to the front, including over the tank) has a very high floor due to the bizarre structure and brake master cylinder location of the 911 (and presumably a design to make a flat-floor trunk over the tank and spare).
Do you go too far forward in the awkward space, or too high in the trunk space... and perhaps gain a trunk in the rear?
Then there's this one...
A Tesla battery pack mutes this classic Porsche 911’s flat-six engine
... which fills the entire front trunk and tank/spare space. I can save you ten minutes of the video attached to that article - just jump to 2:28 for a view of the front pack (of Tesla Roadster modules), which is the only technical content of this typical two-guys-chatting promotional video.
The bigger rear tires are still desirable, even in a stock 911... although there are limits to that, as the usual "fix" for the oversteer which made 911's (and Chevrolet Corvairs) dangerous is a high roll stiffness bias to the front, which leads to lifting the inside front tire in hard turns, making the car into a three-wheeler (which needs sufficient front tire size to make this work).