Phil refers to "the classic race-car longitudinal [engine] layout" of
the Europa. Can anyone tell me what are the advantages of that layout
over the transverse mid-engine Miura/Fiero/MR2/x1/9 configuration?
Well, it's *way* cool.
Other than that, it's mainly of interest to single-seat car builders.
Basically, it allows you to present the narrow side of the engine to
the wind, keeping down potential frontal area. Note that this is a
really big deal in today's open-wheel series; the type B Ilmor-Chevy,
for instance, was built with a more compact shape as one of its primary
design goals (along with reducing resistance inside the engine in order
to improve the amount of power that comes out the back end).
There are other advantages. You want to put the engine in the center
of the car, not skewed off to one side or another. You also want
equal length half-shafts so that the torque loadings on both wheels
are equal (as well as for geometric reasons). Consider the great
lengths that various FWD car builders have gone to in an attempt to
get rid of torque steer caused by unequal-length halfshafts.
On the other hand, I seem to recall that there's a power loss involved
in going from longitudinal rotation (as in a driveshaft) to transverse
rotation (as in a tire), so there are some theoretical advantages to
mounting the engine sideways. Can anyone remember the actual figures?
I faintly remember from college days hearing that there's about a 50%
reduction in the amount of wasted energy if you go transverse rather
than longitudinal (again, that means that if it costs you 3 hp to
turn a standard ring and pinion gear, it means it only costs you 2 hp
to turn a ring-to-ring, NOT that if you have a 200-bhp engine you can
make it a 300-bhp engine by turning it sideways :-). I think the extra
power from the more efficient transverse mounting isn't enough to offset
the gains made by using a centrally located engine with equal-length
halfshafts, while on the street it helps a company's CAFE rating to get
the maximum out of the engine's EPA figures. Then they add things to
the chassis to try to make up for the poor geometry and unequal weight
of the halfshafts and end up with cars that don't handle well AND get
poor gas mileage...
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