Road & Track, March 1957
Unusual side view "before and after" comparison shows instant accessibility of the Lotus, both front and rear
Road Test: LOTUS "ELEVEN"
LOTUS MARK XI,
with 1100 cc Coventry-Climax engine is now officially called the
“Eleven” and this test report brings forth some of the most
startling performance data ever published.
also provided our test department with one giant-size headache (on which
more later) and a truly fantastic array of performance figures
highlighted by an honest timed top speed of 132 mph, plus acceleration
from a standstill to 100 mph in 22 seconds.
let us state that the car shown here is not the actual car which we
tested, though it is identical in every detail except color. The test
car (finished in red) was owned and driven by Lotus distributor, Jay
Chamberlain, and ran exactly as it returned from Nassau including battle
scars from a “brush” with a course marker.
for the headache, there were actually several. The first problem was
where, or rather how, to seat the observer. Removal of the cockpit cover
would also entail dispensing with the driver’s windscreen with
attendant loss in performance as well as some discomfort at high speed.
Finally a compromise was made which placed the editor under the cover. After much twisting and squirming the editor /
observer’s head emerged alongside the driver’s left shoulder, in
line for easy reading of the instruments. We should say “instrument”
for it was impossible to fit a fifth-wheel to this vehicle and the
tachometer was used as a performance gauge (no speedometer is supplied).
It is no mysterious trick to get accurate test data with only a
tachometer and a surveyed 1/4 mile strip as “tools,” but the process is a little more
involved than normal procedure and by the time the tachometer was
calibrated and the “Zeros-to” tests were completed the editor was
very glad to be released.
in mind the above, the one-way timed run was made with no internal
observer and, as explained in the tabulated data section, the Tapley
meter readings were taken with the observer upright (in order to install
and read the meter) which necessitated removal of all the cowling
including the windscreen and headrest. Accordingly, the Tapley readings
in each gear are slightly reduced, especially in the higher gears as the
extra drag becomes more important.
Also, the total drag loss given in the data as only 68 lbs. would
actually be even less with the fairing installed. It is, therefore, not
possible to correlate drag data with the engine’s output and the
recorded top speed but rough figures put the drag coefficient (Cw
factor) at about .400. Using this factor and a frontal area of 11.1 sq.
ft. it can be shown that about 77 bhp was required to attain 132 mph.
respect to the timed top speed the driver reported that the tach reached
7100 rpm well before he entered the 1/4 mile and would go no higher, yet at Nassau he could touch 7400 rpm
on the lone straight, equivalent to very nearly 138 mph. Needless to say
the lower figure is still extremely good and especially in view of the
4.22 axle ratio which is not ideal for best possible top speed. The
optional 3.66 ratio would undoubtedly allow a timed top speed in the
vicinity of 145 mph, but most competition is done on “slow” circuits
for which builder Colin Chapman will supply further alternative ratios
of 5.125, 4.89, or 4.55 if so ordered.
dry weight is given as exactly 1000 lbs. and this figure includes oil
and water but no fuel. Except for the high speed run, all tests were
made with a gross vehicle weight of 1360 lbs. plus or minus 5 lbs.
because of fuel consumption. We made no fuel consumption checks but
Chamberlain reports that he used exactly 13 gallons in the 210 mile
Nassau Trophy Race—equivalent to 16.15 mpg. A British road test on an
identical machine except for wider spaced transmission ratios and a full
width Le Mans type windshield reports 35 mpg (U.S.) on the road and up
to 48 mpg when cruising leisurely. Incidentally, our test car beat all
the British test figures by a substantial margin.
cars had the “Stage II” tuned engine (83 bhp) and the British
figures look suspect to us, if for no other reason than the that our
standing start 1/4
mile time is 1.9 seconds quicker— there’s no question of error
in this test—a car either does it,
or it doesn’t. Possibly the engine of the overseas car wasn’t
tuned quite up to par, for the addition of a big windshield shouldn’t
make for much loss over the standing quarter. In any case we once got
15.8 seconds and Chamberlain says he has done better than that at local
naturally, is really fierce even at low speeds. Some care must be
exercised to avoid getting too much wheel-spin for the car tends to
snake when getting off the mark. A rev limit of 7500 rpm in each gear
was used but the tiny C-C engine will scream past 8000 rpm if you want
to risk it. The gearbox unit is very small and light; from an Austin A-30 but re-designed to give closer
ratios. It takes a real beating in competition and seems to be
trouble-free. Incidentally, the differential unit is also B.M.C. (Austin
A-30 or Morris Minor).
did not drive the car, but there is a small amount of understeer and
ample power available to force the rear end out and into an oversteering
attitude. The steering takes only 1.75 turns lock to lock but the
turning circle is not impressive at 42 feet.
front there is an Allard type swinging half-axle independent
suspension—with a difference. Colin Chapman has cleverly lowered the
pivot point (and roll center) to about 12” above the ground and in so
doing avoids the usual jack-knifing and front end side-skitter of
the older Allards. At the rear we find the tried and true de Dion system
and the entire suspension is fairly stiff. This and the high axis makes
for practically no roll at all, in a corner, but the ride is not
designed for a comfortable Sunday trip.
Lotus Eleven is not a dual-purpose sports car—it is designed win in
Class G and the price of $5467
delivered in the U.S.A. strikes us as being quite reasonable. However,
there are lower cost models, as given below.
Ford 1172cc engine, solid rear axle, drum brakes
C-C engine stage I, solid rear axle, drum brakes
C-C engine stage I, deDion rear axle, Girling disc brakes
Same except stage II
Same except stage II
Even the lowest priced model may not put a Lotus in every garage but it would certainly make an interesting racing class if enough of this type are brought over.
|(Website) editor's note: Chamberlain's Eleven was fitted with Weber carburetors for the Nassau races and these remained in place during the timed runs for this test. The resultant enhanced performance of this Eleven caused several R&T readers to write complaints to both Chamberlain and the magazine. The body damage noted in the test actually occurred while the car was being towed. Also, misleading captions for some of the photos have been omitted here.|
|HOME to www.lotuseleven.org|