Motor Clubman and Special Builder
TEST
By ROLAND DUTT |
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The
Lotus XI Series 1 IN the 1100 cc sports racing
class, few cars have retained the popularity and success of the
Lotus Xl’s in their various forms. Although the basic design is now
far from new, a Lotus XI is still something to be reckoned with in its
class and certainly can be considered a very potent piece of machinery
for the club driver. Consequently a magazine with the title Motor
Clubman could not be without a description of the handling of
such a car. As a result, this month’s track test is a little different
from usual — instead of dealing with a specific car on a particular
circuit, it covers the impressions gained of two cars and a number of
circuits. Sometimes under racing conditions. The two
Lotus’s (or should this be Loti?) concerned were the XI Series 1 and
the XI Series 2 and both types are too well known for it to be
necessary to give their specifications in any great detail, in any case
the various combinations of carburetters, gearboxes, and degree of
tune of the engine available make this almost impossible. However, I
think the two cars tested can be considered typical of their type. Both
cars incidentally although in tip-top condition had covered quite a few
racing miles. The Series
1 was fitted with a 1098 cc Coventry Climax engine, stage two tuned but
with a high compression head. In case you don’t know, stage three
tuning incorporates larger diameter big-end bolts and in the interest of
safety, a 5 bearing camshaft. Gearbox was a BMC A30 with special close ratio gears. Continuing in the wording of the typical
classified advertisement, DeDion, discs and wire wheels. The familiar
all-enveloping body, which really is as aerodynamic as it looks, gives
the car a compact and purposeful appearance. The cockpit is roomy and
comfortable for the average driver. If you are on the long side and have
to sit on the floor with the minimum cushion, there is about 2 inches of
adjustment available to enable the steering wheel to clear your knees.
This is achieved by is undoing one clamp bolt and lengthening the
steering column. A detachable headrest is fitted -- probably quite
effective on the original design which had a wraparound windscreen on the
driver’s side only but with full width windscreens it looks rather
cumbersome, does not appear to serve any real purpose and tends
to obscure rear vision, The
propshaft tunnel which is a stressed part of the structure comes fairly
high on the left of the driver and acts as a support without restricting
arm movement. Due to the perfect position of the pedals one can heel and
toe with the greatest of ease, this with the close ratio gearbox makes
changing down a joy. Ones’ first impression of the Series 1 is the outstanding acceleration for 1100 cc’s particularly at the lower end of the scale. Getting away from the starting line even from a bad position, it is possible to gain several places before the first corner. In spite of the car’s good power/weight ratio from a standing start wheel spin can be kept to a minimum. The
roadholding in general is good by most standards, but compared with the
heavier IX or the later Series 2, I would not say it was exceptional. On
a medium slow bend one tends to broadside with opposite lock, which of
course gives a bit of wheelspin coming out of the corner, with a consequent
waste of time. However, on faster bends, the car behaves very much
better, diving into the corner with the well known Lotus understeer and
the minimum of drift. Control through the corner is maintained almost
entirely on the throttle, nevertheless it must be said that the general
handling characteristics of the car are deceptive. It is particularly
sensitive to the slightest error or ham-handedness and at high speed it
is very easy to overdo it. In other words the car is by no means as safe
as it feels, as I know from experience. This of course is to be expected
when realises the extreme lightness of the vehicle. The
steering characteristics can be altered by quite a considerable amount
to suit the individual driver’s requirements. Apart from the usual
variations of the tyre pressures, the degree of understeer can be varied
by adding or removing washers at the top of the front suspension units.
On the straight the car is fairly
stable and can be driven “hands off” at quite high speeds, but as
the maximum approached, particularly if there are any slight undulations
on the surface, it shows a tendency to snake. This is very slight, but
one can’t help getting the impression that even the slightest
relaxation of effort on the driver’s part, and things could very
easily get out of hand. I put this tendency down to the front
suspension, being of the spilt axle type. This particular car appeared
to have rather hard rear suspension, which had no adverse effect on the
roadholding, but did not give the driver a very smooth ride. Braking is
extremely good and only the most violent braking produced a slight wheel
patter, at the front end. After one particular race when the car had
been driven very hard and the brakes had consequently become really hot,
it was noticed that grease was melting and throwing from the front-hubs,
due to the heat generated by the brakes. Incidentally
on the Series 1 there are no air ducts to the front brakes and the
fitting of wire wheels does not materially assist cooling of the discs
as the wheels themselves are almost entirely enclosed by the body. Under
racing conditions as distinct from tests when one has not the time (or
inclination) to look for faults, the general impression gained is that
the car handles well, but does require a certain amount of concentration
from the driver. The revs
build up with remarkable rapidity and one goes up to the permitted 6000
rpm through the gears with incredible ease. Changing from third into top
at peak revs, when really pressing on, brings about a certain amount of
clutch slip before the drive becomes solid. This is accompanied by a
strong smell of burning clutch lining. Provided that you are just that
little bit inside the limit, the car goes round corners literally on
rails, and particularly noticeable is the almost complete lack of roll
for a sports car. It does however take sometime before one is
sufficiently familiar with the car to know exactly what that
all-important limit of the car’s cornering ability really is. In the
early stages, the driver finds himself taking fast curves well below the
car’s capabilities. Of course, as can be expected under such
conditions and with such a high cornering speed, the limit is met very
suddenly with practically no preliminary warning. It is therefore
advisable to really get to know the car and build up slowly to this very
critical point. It is an
ideal car in every way for the beginner and a good introduction to high
speed motoring. At the same time it is a car to be treated with respect
and one that does not permit liberties to be taken. The
Lotus XI Series 2 The Series
2 can be considered the logical development of the 1 and in the course
of this development, the various faults of the 1 have been eradicated.
It is a more robust and slightly heavier car but nevertheless is much
superior in performance to the Series 1. It is possible that it does not
possess quite such good initial acceleration as the Series 1. On some
circuits of the slower or twisty variety, some drivers prefer the S.U.
carb to the more usual Weber to improve the acceleration at lower revs.
Although wire wheels can be fitted to the Series 2, the majority have
light alloy disc type. This
particular car was fitted with an MGA close-ratio gearbox, which is
considerably more robust than the A30 BMC, but also a good deal heavier.
Gear changing could not be effected nearly so rapidly on this box,
neither was the spacing of the ratios all that could be desired. The
clutch was incredibly heavy and brake pedal pressure a good deal higher
than the Series 1. The handling of the car is quite outstanding, the
roadholding and cornering capabilities being beyond criticism. Experimenting
with tyre pressures, it was found that the best results were obtained
with a pressure difference of 4 lbs between front and rear, the front
being the higher. The steering has that firm feel and there is
practically no kickback from the road wheels. The bound and padded
light alloy steering wheel looks very small indeed, but on driving it
fits in well with everything else. This
feeling of firmness, coupled with the high gearing, gives a direct
response enabling the car to be placed accurately just where you want
it, in a corner. There is absolutely no necessity for any of the
dramatic wheel fighting, common to many of the smaller cars. One feels
almost relaxed even at quite high coming speeds. Going really fast
through a corner at racing speeds, the car remains accurately on the
chosen line, with an almost imperceptible amount of drift. Plenty of
throttle is required right through the corner —too much and of course
the front-end tends to break away—but even so, you receive a
reasonable amount of warning and a slight easing of the throttle and it
is instantly under control. The driver never has that odd moment of
doubt coming out of a corner when the outside grass verge comes rapidly
nearer and nearer. Under the most extreme conditions it is unlikely
that the back-end will break away. In fact I would say that when one is
familiar with the car, having set tyre pressures and steering geometry
to suit the driver, it is definitely the most ‘unspinable’ car I
have ever driven. Winding it
up on the straight towards the 8000 rpm mark (which incidentally is off
the power curve and not to be encouraged), far from showing any tendency
to snake, the car seems to sit down on the track even more than usual.
At these speeds there is a tendency for the rear of the bonnet to lift
due to the pressure of air trapped inside. Apart from
this, the aerodynamics (or to the uninitiated and old fashioned —
streamlining!) must be very efficient as there is no eddying in the
cockpit whatsoever and neither is the driver troubled by wind noise. In
spite of the very high pedal pressure, braking is really good even from
very high speeds, such as the straight at Aintree. Really hard and
vicious braking due to an incident at Melling Crossing, caused nothing
more unpleasant than smoke from the tyres, not even a twitch of the
steering wheel, but the driver had second thoughts about a safety
harness if only to keep him in the cockpit. On either
side of the radiator intake are small air ducts for the front brakes and
scoops on the undertray for the back. After several races on widely
differing circuits, I have never known the brakes to give trouble or
overheat. Incidentally on the disc wheeled car, changing the front
wheels interferes with the disc brakes and it is essential that a couple
of pumps are given to the pedal after the operation to restore fluid in
the calipers and brake-lines. I once forgot with disastrous results at
the first corner, due to complete lack of stopping power. The Series
2 is only slightly bigger than the 1, but manages to give an almost big
car feel as regards handling. It can be said that it possesses no vices
and provided that one remembers that the car is cornering a lot faster
than the driver realises, it is a remarkably stable car. To obtain the
best results, it is as well to know the proposed circuits and make the
necessary alterations to suit that circuit. After all it is only 1100
cc, a fact that the car encourages one to forget. Apart from the obvious
choosing of suitable back axle ratio, different carburetters are
sometimes more suitable for a particular circuit depending on just what
revs you really want the power. This car had the full stage 3
modifications
to the bottom-end and a high compression head, but had not been fitted
with the 5 bearing camshaft. Although the heavier valve springs
that go with this modification had been fitted, no trouble has been
experienced with camshaft bearings on the camshaft itself. One cannot
fail to be impressed with the roadholding, I once heard one Special
enthusiast proudly describing his car by saying it held the road like a
Lotus. If he meant an XI he certainly had something. Even under wet
conditions it still possesses that little extra.
I shall probably be unpopular for saying so but I
think it is a better car than the later type 17. |
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