I love all you M/Fs!

Awesomely configured: the front-mid-engine/front-wheel-drive Saab Sonnet I…and friend

In yesterday’s Hooniverse Asks question about our favorite French cars, several folks mentioned the Renault 5 (Le Car in the States), along with Citroën’s SM and Traction Avant. All three are examples of the fairly rare breed of car that combines a longitudinally mounted front engine with a driven set of front wheels positioned fully ahead of the motor. This is commonly abbreviated M/F, for “mid engine/front drive.”

In all three of these cars, the transaxle is actually forward of the block (although some M/F cars shove the tranny under the engine). Think in terms of an air-cooled VW with the engine and transaxle pushed up to the front of the car, but not reversed. Or a 2-stroke Saab with the drivetrain rotated 180 degrees (which is basically what Saab did on the original Sonnet 1). Or a Cord 810…exactly as it is.
The Cord 810 powertrain. (The fan points toward the front of the car.)

There are some valid engineering reasons why there are very few M/F cars. The layout either a) makes the distance from the front wheels to the firewall very long, which affects maneuverability and economy, or b) causes the engine to protrude into the passenger compartment, hurting ergonomics and making engine maintenance an unholy form of torture. The Renault 5 went the latter route, probably because as a French car unholy torture was already a foregone conclusion.
M/F diagram from Wikipedia

On the other hand, there’s a lot to recommend the configuration. It allows a lot of mass to stay low, behind the front axle, and close to the vehicle centerline. The symmetrical nature of the M/F layout normally translates to equal-length half-shafts, which explains M/F cars’ widespread immunity to that typical front-wheel-drive bugaboo, torque steer. It provides much better traction than a F/R car, but since the weight is not fully over the front wheels, the improvement in handling over a F/F layout is offset by a slight theoretical decrease in traction, depending on how far behind the wheels the engine really is.
Image from fuoriserie.org

As someone who actually likes front-wheel drive, I would love to get some seat time in a well-designed, true M/F car. I can hear many of you already screaming at your computer monitor, “But it’s still wrong wheel drive! Just drive the rear wheels!” If you’re a RWD fan, that’s great. But just don’t be surprised if you’re stuck in the mire during an off-road rally and see an old Quatrelle go whizzing by, flinging clods of mucky earth from its extremely forward-mounted front wheels.

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  1. dukeisduke Avatar

    I've always thought the woman in the Sonnet I picture was hot. She looks kinda like Alyssa Milano, only without the tattoos.

  2. dukeisduke Avatar

    All those copper lines on the Cord transaxle – isn't that a pre-selector gearbox (a Wilson)?

    1. tonyola Avatar

      The Cord used a four-speed transmission with a pre-selector built by Bendix. Apparently quite troublesome.

  3. tonyola Avatar

    The old Cord L-29 also was M/F. However, it had a heavy straight-8 engine that was so far back that it made the car rear-heavy – not helpful in front wheel drive. Traction problems were always a complaint on the L-29, particularly on hills where the front wheels would actually slip because of the weight transfer to the rear. This was one of the reasons why the later 810 used a V8 engine.
    <img src="http://files.conceptcarz.com/img/Cord/30-Cord_L-29_Phtn_DV-07_MB_01.jpg&quot; width=400>

    1. Smells_Homeless Avatar

      Ah, but beauty begets forgiveness.

  4. engineerd Avatar

    Tune in tomorrow when we'll explore the wonders of RF — rear engine front drive — and Buckminster Fuller.

    1. Peter Tanshanomi Avatar

      Sorry, but that story's been canceled: the contributor researching it ended up in a ditch.

      1. engineerd Avatar

        Dammat! I was looking for some rear steer fun!

  5. Juliet C. Avatar

    I had no idea a Renault 4 could look so hot. I always thought they were ugly. Maybe it's just the angle.

    1. Paul_y Avatar

      Everything looks cooler in rally trim.

  6. Joe Dunlap Avatar

    Have we all forgotten the Renault R-16? That wonderfully wierd M/F set up? 3 lug wheels? A longer wheelbase on one side than the other? Or the piece de resistance, the camshaft driven A/C compressor? Changing the rear (front?) two plugs under the overhanging firewall was a near orgasmic experience.

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