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 914 - Part 1
No, mid-engine cars are not uncharted territory, at least not for Porsche. As a sports car manufacturer, it was actually founded with that very concept in mind, since the first model shown below had a mid-engine layout. This
is inherent in the very design of the rear-mounted engine, which, except in buses, naturally lacks a driveshaft. The engine, axle drive, and transmission are directly interconnected, regardless of whether they are mounted
transversely or, much more commonly, longitudinally. In the latter design, the engine's torque is transmitted to the transmission without being affected by the axle drive, and is then directed to the two rear wheels as it
returns.
Yes, there have even been vehicles in which the engine, transmission, and drive axle were permanently connected in exactly that order, but probably only in race cars. There is no such thing in the series. The driver simply
should have been moved too far forward. And what does that have to do with the rear-mounted engine? Quite simply, because the parts are interlocked, you can just rotate them 180° and suddenly the heaviest part, the
motor, is positioned between the axles.
That's actually the somewhat crude definition of a mid-engine layout. Whether it's in the front or the rear, if the engine is moved to the area between the axles, it is automatically referred to as a mid-engine. It's actually not
possible to place the engine exactly in the middle between the axles, except perhaps in a Hummer, which is so wide that the entire powertrain fits between the two front seats.
Of course, it's not quite that simple to convert a rear-engine car into a mid-engine one. The problems are still relatively easy to solve if it's just a matter of the direction of travel, because, of course, a rear-mounted or mid-
mounted engine would rev up at full throttle and drive backward. With a longitudinal engine, however, it is often possible to simply install the ring gear from the other side. The gearshift is almost always stiffer because it
has to be routed around the engine. For transverse engines, however, a different design solution is required for the transmission to the axle drive.
Perhaps that is also why transversely mounted mid-engines usually evolved from front-wheel-drive vehicles, in which the entire powertrain is simply moved to the rear. In some cases, even the front axle was carried over,
and its steering was deactivated. It is still retained at the front, and only the wheel bearings are secured by the drive shaft stubs. Of course, it’s even easier with a front-mounted engine and rear-wheel drive, which can be
moved backward when the cardan shaft is shortened.
None of that applies to the 914. So if there's one thing that's clear about this car from the outset, it's the fact that the engine, drive axle, and transmission are reversed. The former from the VW 411, which is currently under
development, and the latter from Porsche, since VW did not have a five-speed transmission at the time. It might not have been possible anyway, because the 914/6 was designed to offer a Porsche six-cylinder engine as
an option. As a result, the 914's transmission would likely have been more expensive to replace than the engine.
Even before that time, the mid-engine layout was already a revolution in motorsports. Since the beginning of the 20th century, race cars have had the engine in the front and rear-wheel drive. And that remains the case even
after World War II. While the Ferrari boasts an impressive twelve-cylinder engine, its suspension is that of a dwarf, namely, a rigid rear axle with leaf springs. Of course, Mercedes also had front-engine, rear-wheel-drive
models, but at some point, presumably in connection with the development of the rear-engine 130, 150, and 170 series they introduced the swing axle.
This means that manufacturers with front- or rear-wheel drive are confronting the racing scene with mid-engine solutions, for the first time massively with Ferdinand Porsche's Silver Arrow Type C from Auto Union. So,
around the time the VW-Porsche was being developed, the topic really started to heat up. Now it's not just manufacturers of expensive sports cars, such as Lamborghini with the Miura and, a little later, Ferrari with the 246,
are dealing with this issue.
Gradually, many manufacturers are also introducing more affordable models: Opel with a rear-mounted engine as the standard powertrain in the GT, and Fiat later with a transversely mounted rear engine in the X1/9.
However, the French were the pioneers of this development, more specifically, Matra, starting as early as 1962 with the famous DJET, whose development later led to the Bagheera and Murena. Another interesting aspect
here is the variety of engines, unprecedented in a production model at the time, ranging from Renault to Ford to Simca, though this was, of course, often due to production taking place on the brink of insolvency.
None of this applies to the 914, which is currently in production. It has 'strong parents' at that time. At VW, they don't yet fully realize just how tough times are going to be, and Porsche is desperately searching for a
successor to the outdated 912 as its entry-level model. So they meet up, and Karmann is also happy to be able to manufacture the body, after all, the larger Ghia model is a flop, and the end of the Beetle convertible is in
sight. So everything's fine, but only at first glance.
Why are mid-engine cars, like the 914, so popular? Because this design has undeniable advantages, as proven by its success in racing. First and foremost, there's the issue of aerodynamics. The front
hood doesn't have to be pulled over a high engine compartment; instead, it can rise gently and meet a windshield that's inclined at almost the same angle. When driving, you can sit lower, which
results in a lower center of gravity, yet you still have a good view.
A higher rear end—setting aside the issue of visibility for a moment, could be beneficial for aerodynamics, because you can let it slope down gently and use a small hump to create a sort of spoiler. The weight distribution
is unmatched; naturally, it exceeds the 50% mark on the side where the engine is located. However, the shorter the distance from the center between the axles, the less it does so. So the mid-engine layout comes much
closer to the ideal of as evenly distributed wheel loads as possible than the other designs.
In fact, a rear drive axle with a slightly higher load is desirable for better traction. Ferdinand Porsche gave a great deal of thought to front-to-rear weight distribution from very early on. He was particularly concerned about
how these factors might change as the race progressed. That was the era of premium gasoline, which was used in greater quantities than usual. In some Mercedes models, the fuel tanks were extended toward the rear.
Porsche, however, simply moved the driver even further forward so that the fuel tank could be positioned exactly between the driver and the engine.
| Comfortable suspension for a sports car |
Without the cardan shaft, the center tunnel is shallower, which, in the 914, for example, allows for a third person to sit in the middle. In addition, the engine will be lighter overall. Handling remains neutral even at higher
cornering speeds and is also easier to correct in this range. The 914 doesn't even have stabilizer bars, which allows for even higher speeds without overloading the outer wheels in a turn. And yet, the roll angle remains
within reasonable limits. What's surprising is the narrow tire width of 155 mm on the 914 and 185 mm on the 914/6.
In the event of a front-end collision, the non-deformable engine does not interfere here. Another advantage of the mid-engine layout, though it does come with a number of disadvantages. The drive system is actually best
located up front, perhaps, back when that was still an option, along with a spare tire. This creates a large, versatile interior or cargo area in the rear, something that would be impossible with a rear mid-engine layout.
However, Ferrari does have a Dino model that is a 2+2-seater, even though the engine is still located in front of the rear axle.
| In the Miura, the engine already makes the interior unbearably hot. |
Often there are even two luggage compartments, as in the 914, but they are not connected. On top of that, the rear one is also very flat and, unfortunately, affected by the engine and, above all, the heat from the exhaust
system. That might be helpful for sleeping bags on a trip through wintry Scandinavia, but otherwise it's very inconvenient. The engine, whether it's in the front or all the way in the back, is somehow quieter or may be better
insulated. It requires a great deal of work for the partition between the engine compartment and the passenger compartment.
Try servicing a mid-engine car sometime. Or to get to it if there's still luggage in the trunk. After all, quite often there's just one flap responsible for that. That's not the case with the 914, though, unfortunately, at the expense
of a very short engine compartment. It's hard to imagine having to adjust the valves on an inline engine, which was still common back then. However, with the 914, you have to embrace the suspension if you don't have a
lifting platform available.
It is by no means uncommon for mid-engine or rear-engine supercars to require the engine to be removed for certain maintenance tasks (e.g., the Testarossa). No, you’re spared all that with the VW-Porsche, and while the
VW engine’s quite rich sound isn’t particularly exciting from a sporty standpoint, it’s actually quite tolerable. However, any savings made on the propeller shaft are offset by the additional piping required at the front of liquid-
cooled engines. And with the radiator, air ducts, and spare tire, there's no luggage space left at all in the front (e.g., the Miura)
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None of that fazes the 914. On the contrary, if you move the front spare tire to the rear, you create a cargo area that might even live up to the 370-liter capacity listed for both cargo areas combined. However, because of its
fairly square shape and its height, it is not very suitable for storing suitcases. On top of that, you wouldn't want to burden a rear axle with a motor, axle drive, drive shafts, and transmission with a fuel tank as well. So it has to
go up front.
Of course, for safety reasons, it shouldn't be placed too far forward. With the 914, the decision was made to take a radical step that was unique among all other production Porsche and VW models: to position the fuel tank
entirely above the front footwell, extending all the way to the hood, with a bulkhead in front of it. However, with a volume of 62 liters, this results in a height that makes refueling from the side impossible. It would be hard to
imagine today that you have to open the front trunk to fill up the tank. A hole will be cut into the hood for the GT version at a later date.
Ein Fahrzeug mit Mittelmotor kassiert halt für diese besondere Lage des Antriebs praktische Nachteile. So wird durch den hohen Tank schon wieder etwas von dem Vorteil des niedrigen Schwerpunkts verspielt. Trotzdem
bleiben etwa 10 cm weniger Höhe als beim 911 und mit etwa 0,37 ein deutlich günstigerer Luftwiderstand. Der 914 ist also bei richtiger Auslegung mit gleichem Motor schneller als der 911. Da ist es schon verständlich,
dass man ihm nur den älteren Motor des 911 T zugesteht. Durch das Umdrehen der Antriebseinheit hat er bei 15 cm mehr Radstand auch 10 cm weniger Außenlänge.
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