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"

THE 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.

It 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.

First, 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.

As 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.

Bearing 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.

With 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.  

The 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.

                                                          British test                      R&T test
          Timed top speed                            112.5                           132.06
          0-60 mph                                       10.9                                9.0
          ss ¼  mile                                       17.9                              16.0
          Axle ratio                                       4.22                                4.22
          Test weight                                    1355                              1360
          Frontal area (sq. ft., approx.)          14.0                              11.0

            Both 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 drag strips.

Acceleration, 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).

We 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.

In 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.

The 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.

Model      U.S. Price                               Remarks

“Sports”       $3253                    Ford 1172cc engine, solid rear axle, drum brakes

“Club”          $4301                   C-C engine stage I, solid rear axle, drum brakes

“Le Mans”    $5287                  C-C engine stage I, deDion rear axle, Girling disc brakes

 “Le Mans”   $5467                  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.