advantages/disadvatages of Flat 12 vs V12?

The Flat-12 has a lower center of gravity that helps with handling. However, when Ferrari made the Boxer and Testarossa it put the transaxle under the engine which defeated that benefit...

 

Wasn't the flat 12 (boxer 12, not 180 degree 12) a more naturally balanced engine too?

 

They went away from the flat motor for packaging reasons. It requires a very wide car and still there are trade offs in suspension design. Plus as stated on top of a trans the CG is too high and in front of a trans the package is too long (it would be ok with me).

It took them years to decide to go to a conventional engine trans layout with the V8 in the 360/430 and everyone complains that car is too big. A 12 cyl car would be a couple of feet longer.

 

How did the Maserati Bora pull it off so well then? The v8 longitude engine/transmission mounting as opposed to transverse v8 design a la 308/328 that is. The Bora is a small car, and the engine is 4.9l.

 

The boxer engine configuration has a stronger bottom end since all the forces are directed laterally rather than downward. Downward motion puts strain on main caps and bolts.

 

I wouldn't put it this way -- the Flat-12 is only more compact in height. Having the heads so far apart on a Flat-12 really requires completely separate intake systems (i.e., not much sharing possible -- like a single intake manifold Packard ) and the width of the Flat-12 doesn't fit as well between the (front) wheels as the narrow angle V-12s.

 

Google "wikipedia flat engine". Lots of info on flat engines plus links to V-type and other configurations.

 

How did you find a girl that would ask such questions and have these discussions with you. Sounds like a great girl!

Jeff

 

the flat 12 took Ferrari to 3 World Constructor Championships in the 70s in F1, a great reliable motor, Ferrari abandoned the F12 later due to the width of the car needed and aerodynamic changes to the bodies which the F12 would not have worked as well

 

It seems every time anyone writes about the Boxer, the first thing up is the C of G. It's totally ignored with the Miura etc.

Whilst I agree the C of G could be lower were it not for the trans underneath, a flat engine does have the advantage that everything else is in line with the crank, not above it...valves, cams, con rods, pistons, heads, blocks...etc. Also, all the induction and exhaust system is also correspondingly lower.
This moves a heck of a lot of weight lower than with a V12. Having the two arranged as they are also lowers total weight due to sharing of surfaces.
All in all not a bad layout at all, though maybe not the 'best'.

Robert

 

I'm somewhat surprised that there haven't been others to incorporate a "Miura style" configuration (transverse 12 cylinder, gearbox/differential behind). It's a rather compact and low package. Considering it had one real iteration it worked pretty well.
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Flat 12 is the better design. What killed the flat 12 was the introduction of underbody ground effects. You can't have the same venturi effect with the flat motor. Other than that, the flat 12 is a brilliant design. It's wide but the 512 TR with its flat 12 AND SIDE MOUNTED RADIATORS is barely wider than a 36O with its front radiators. If you want to know how well the flat 12 works, look no further than the legendary 917 Porsche with its flat 12.

 

most piston aircraft have a flat design also (horizontally opposed).

 

I am curious though, IIRC the F50 and Enzo are not THAT long. Wouldn't a 12 cyl mid engined car have similar dimensions?

 

Both cars are dedicated to their drive trains and both suffer from serviceability issues. Not a big deal in the top of the line car with so few made. During the entire run of the TR, Ferrari recieved criticisim for the design being too radical, so the 550 was very conservative. Ferrari recieves a great deal of criticisim for the 360 and 430 being too big. I bet the replacement is made smaller. A standard offering V12 with conventional drivetrain layout would suit me but Ferrari is mindful of the criticisim even if it does not appear to hurt sales. They might make one as a standard product but I would be surprised and that is based on their comments. They were always wringing their hands over wierd stuff but people cycle out of there pretty fast so who knows?

 

Piston enging aircraft manufactures use that design primarily for its simplicity in manufacturing, and its simple cooling.

 

i was thinking the same thing! LMAO!

where do these women hide?

 

What's the difference?

 

One other advantage of a flat engine (like the BMW motorcycle engine) is that the air under the piston in the crankcase helps push the other piston up, thus you have no crankcase pressure (unless you have leaky rings).

Many other engine designs compress this air as the piston goes down. This causes oil leaks and also is simply wasting power.
Pete

 

The 360/430 are big cars, they package a mid-engined V8 longitudinally with two seats and no luggage space to speak of. In dimensions and profile they are almost the same as the 2+2 Mondial that has much more room and a boot. Okay they are completely different animals separated by years of development and are aimed at a different market segment. Nevertheless it's an interesting comparison.
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There was a vivid discussussion on this topic some time ago.
Look what Wikepedia has to say.


A boxer engine should be flat, should always have individual cranktaps for each cylinder, and each pair of adjacent pistons should move in opposite directions.

So in any case, Ferrari flat V12 engines can never be seen as boxer engines, since their V12 cylinder engines are build as two 6 cylinder in-line-engines sharing two conrods per cranktap.