If a new car ever created greater excitement around our office than the new Jaguar XK-E, we can’t remember it. And to sum up this car in the third sentence of a report may be unusual for us, but it is easy to do. ‘‘The car comes up to, and exceeds, all our great expectations.” The car itself was fully described in our May issue, but, briefly, it has a 96-in.wheelbase monocoque chassis, a 3.8-liter double-over-head-camshaft 6-cyl engine developing 265 bhp, and a curb weight of just over 2700 lb. Two body types are available, a coupe and a roadster— the latter being actually a true convertible, also available with a very neat removable hardtop.
This report is a compendium of experiences involving three people, four cars and two countries. However, we must say that the longest time at the wheel (by one driver) was only two hours and in this respect we were at a disadvantage, as cars were made available to the British Press early in March. Our test data, therefore, are limited to a top speed of 100 mph and the fuel consumption range, given as 15 to 21 mpg, must be considered tentative.
This story originally appeared in the September 1961 issue of Road & Track.
As is well known, the genuine top speed of the showroom-stock Jaguar XK-E is 150 mph. Actually, this speed has been slightly exceeded and, though the fastback coupe looks more aerodynamic than the roadster, there appears to be very little difference in drag, or concomitant top speed. In this connection, our coasting tests from 80 mph were made in a roadster and reference to the performance graph will show that lowering the top shortens the coasting times and distances.
The standard axle ratio specified for the XK-E is 3.31:1. In our opinion this is a perfect choice, completely satisfactory and ideal for 99% of all owners, or prospective purchasers. This ratio gives almost exactly 150 mph at 6000 rpm, with an allowance for tire expansion. However, ratios of 2.94, 3.07 and 3.54 are available and it will be interesting to see what can be done in a speed run with the lowest ratio; we would expect something close to 180 mph under favorable circumstances. The axle ratio in our test car, however, gives a somewhat misleading comparison with the older, heavier XK-150-S. Similar gearing in the two cars should result in a striking performance difference.
While such speeds are largely academic, the acceleration figures are factual and useful. Our test car, which, as we said, was a roadster, had a modest speedometer error, being 3 percent fast at an indicated 100 mph. Thus, we got 0 to 100mph in 16.0 sec, but the time to 103 mph was 16.7 sec, achieved, by the way, without using 4th gear. One of the most frequent questions we hear regarding the Jaguar’s performance is “Does it outperform the Corvette?” The answer is a qualified no. A showroom stock fuel-injection Corvette will just “nip” the acceleration times of the Jaguar, but it won’t go as fast at the top end. This, of course, indicates that a Jaguar with the optional 3.54 ratio might just equal the Corvette and, as the Corvette has a 3.70 axle ratio, a similar ratio (though not available) would give the Jaguar a definite margin. However, here we must remember that the hot Corvettes running in competition have a 4.10 axle and turn 7000 rpm. Thus, the Corvette has a definite advantage “on-paper” over the XK-E, but a well-tuned “E” may produce a few surprises when it gets into competition in this country, despite its much smaller displacement.
As is well known, the engine is the same unit as used last year in the XK-150-S model. In 13 years of development, the XK engine has remained fundamentally unchanged, except for a larger cylinder bore introduced two years ago. Yet, minor revisions have provided a power increase of 65%, from 160 bhp in 1948 to 265bhp at present. The three-carburetor version, as applied to the XK-E, seems even smoother and quieter than before, possibly because there is no engine-driven fan. During the test runs for acceleration data the engine temperature never went above 730 C, with the outside temperature at the same reading in Fahrenheit. Because the electric fan comes on only at 800 C, it is obvious that it will seldom run, and when it does it draws only 7 amps, about the same as one headlight.
Despite the three large carburetors (2-in. size), the powerplant is extremely flexible and will accept full throttle at 1500 rpm without bumbling. Thus, while 3rd gear would normally be used for cruising through 35-mph zones, it is possible to drive at 15 mph in 4th gear without jerking or back-lashing. The unit doesn’t like full throttle at this low speed, but it will accelerate smoothly and briskly if a little initial care is exercised. The tachometer has a caution zone from 5500 to 6000 rpm. While the engine is designed for 6000 rpm, this speed is really a bit harsh for a unit having a stroke of over 4 in. Our test results are all based on a revolution limit of 5500 rpm, though the maximum speeds in the gears are given for 6000 rpm. (See data panel; true speeds will be slightly higher because of tire expansion, particularly in 3rd gear.)
When the XK-E was announced, it was stated that the designer’s goal was to achieve family sedan-type comfort with sports car handling qualities. In driving the car for the first time, the superb riding qualities do indeed make an immediate impression. In fact, the ride is so good we will say without equivocation that only one other sports car has a comparable ride, and it also has independent suspension on all four wheels. The Jaguar ride may not equal the soft boulevard characteristics of our prestige-type sedans, but we do not think it should. The XK-E has soft, yet extremely well controlled springing.
But what is even more remarkable is the car’s uncanny adhesive characteristics. A car of this power-to-weight ratio can be a real handful, even dangerous, if a heavy foot is used on the accelerator. But this car is very difficult to “break loose.” Of course, in 1st gear, which is very low (or high, numerically), it is possible to spin the rear wheels on dry pavement, but even here the limited-slip differential (standard equipment) makes all the difference—there is no tendency to go sideways at take-off unless the driver deliberately sets up wild wheelspin of the type that gets nowhere.
In normal driving 1st gear is seldom used except for a short initial start, because this gear is so low, slightly noisy, and not synchronized. Another reason for this is that 2nd gear is so handy and useful, despite the fact that its synchromesh unit is not very effective. This gear, at 6.16:1 overall, is just a fraction too high for normal starts from a standstill—it can be done, but it’s not recommended. But once underway, 2nd gear is a very useful ratio and, with a speed range of from 5 to 76 mph, it can provide magnificent cornering over and around twisting mountain roads. If you get over-exuberant the rear wheels break loose, but control is excellent and you can hold a “tail-out” attitude with very little practice. In general, the steering characteristic is just a trace of understeer at all times, with the possibility of induced oversteer if an indirect gear is engaged and throttle applied.
In this connection, the steering also rates as very close to, if not actually, the best we have experienced. There is just the right amount of road feel, no kick-back, moderate parking effort, and a ratio that is quick without being too sensitive or tricky at high speed. (The number of turns lock to lock, at 2.6, sounds very quick, but the turning circle is not too good.) We might also mention that the Jaguar’s weight distribution is somewhat unusual; 50/50 at the curb or 49% front, 51% rear, with driver and full tank. This gives a basically neutral-steering car, in which only very slight compromises in suspension geometry are necessary to give modest understeer and high-speed stability. The net result has to be experienced to be believed.
As with the steering, the disc brakes just can’t be criticized. It is virtually impossible to feel the booster come in, and the pedal pressure is moderate without being overly sensitive. These are disc-type brakes, so the problem of fade is non-existent and, incidentally, there was no sign of the squeals or squeaking sometimes encountered with metal-to-metal brake pads.
While there has been some criticism of the interior seating space, we liked the layout very much, particularly the way the steering wheel (which is adjustable over a range of 3 in. in and out) is placed well forward. At the same time, the interior dimensions are not satisfactory for over-6-footers, and the present brake and clutch pedal angles are a little awkward. We understand this is being changed and that the seats are to be redesigned so that they will move farther aft (present adjustment range is only 3 in.).
Instrumentation is very complete and the white-on-black numerals are strictly functional, as they should be. A heater and defroster are standard equipment, but we had no opportunity to try them. The heater includes a fresh-air vent, but this appears to let in warm air only and ventilation might be a bit of a problem in a summer rainstorm. When the side windows are lowered, a wind-beat noise is very noticeable, and the cockpit is too drafty for long-distance touring with top down, at least if speeds of over 80 mph are contemplated for any length of time. The fastback coupe is better in this respect, for its hinged quarter windows can be used to give an extractor effect.
An unusual feature is the provision of three windshield wiper blades. These are driven by a 2-speed electric motor and are said to be adequate for driving in the rain at slightly over 100 mph.
The overall appearance is, of course, what attracts most people and we have yet to hear a detractor, though the roadster’s soft top isn’t as attractive as the optional hardtop. Sheet metal protection front and rear is minimal for American parking conditions; the front parking lights, in particular, look vulnerable and the rear bumper is located very high, exactly 6 in. higher than the front bars, in fact. This exposes the twin mufflers and tailpipes. The plastic headlight covers are also vulnerable.
Obviously, the Jaguar XK-E is one of the most exciting sports cars ever produced. While it is unfortunate that a strike at the body plant has delayed production, this lull may prove to be beneficial, in that Jaguar can make the few obvious corrections that are needed before real production commences.