The Record
Did the E-Type really do 150 mph?
Jaguar claimed 150 mph at Geneva in March 1961, and two road tests published within days of each other appeared to confirm it. Both of those cars ran racing tyres. One of them, on later examination, had a gas-flowed cylinder head. Autocar itself now says its test car was most likely specially prepared. None of that means the figure was invented. It does mean the number everyone quotes belongs to two particular cars on two particular days, and that a standard 3.8 did not generally reach it.
The claim, and the two tests
Jaguar claimed 150mph at the Geneva launch in March 1961, and two road tests published within days of each other appeared to confirm it. What is documented about those two cars complicates the picture considerably.
| Publication | Date | Car | Axle | Maximum | 0 to 60 | Notes |
|---|---|---|---|---|---|---|
| Autocar | 24 March 1961 | 9600 HP, 3.8 fixed head coupe | Not established | 150.4mph mean, 151.7mph best | 6.9 sec | See below on this car's preparation |
| The Motor | 22 March 1961 | 77 RW, 3.8 roadster | Not established | 149.1mph | 7.1 sec | Standing quarter 15.1 sec, 21.3mpg imperial |
The full road test table, covering every published test the archive has located from 1961 to 1972, is on the specifications page.
The tyres
Both press cars ran Dunlop R5 racing tyres, which have a larger rolling diameter and lower drag than road tyres and therefore raise top speed for a given gearing.
The cylinder head
9600 HP, the coupe Autocar tested at a mean 150.4mph, was found on later examination to have a gas flowed cylinder head carefully matched to its manifolds, described by one account as possibly worth an extra 20 to 25 brake horsepower. That is an estimate, not a measurement.
Autocar itself now concedes the point. Its own modern retrospective says the car was most likely specially prepared for those tests. That is the strongest single statement available: the magazine that published the figure says its car was probably not standard.
What this does not establish
The archive should be careful about what this does not establish. The Heritage Trust's own page on 77 RW, the roadster The Motor tested at 149.1mph, makes no mention of special preparation, and the gas flowed head is attributed only to 9600 HP. The allegation should not be extended to the second car.
Two figures that belong to other cars
A third car is frequently confused with these two. 6162 RW carried an aluminium sump and a 3.07 axle, and with it Paul Frere achieved 159mph at Monza, with Motoring News reporting over 160. Those figures belong to that car and not to the 1961 road tests.
And Motor Sport's Bill Boddy calculated a pretty genuine 155mph on the M1 at 6,100rpm. That is an rpm and gearing calculation, not a timed two way mean, and it should never be tabulated alongside measured figures.
Where that leaves it
What can be said fairly is that a standard 3.8 did not generally reach 150mph, that most cars failed to reach it, and that around 135mph is the figure quoted for a standard car.
Common questions
Did the E-Type really do 150mph?
The two 1961 road tests recorded 150.4mph and 149.1mph, but both cars ran racing tyres, and the coupe was later found to have a gas flowed cylinder head. Autocar's own modern retrospective says its test car was most likely specially prepared. A standard 3.8 is generally quoted at around 135mph.
Which cars were the 150 mph road tests carried out on?
Two factory press cars: the fixed-head coupe registered 9600 HP, tested by Autocar and published on 24 March 1961, and the roadster 77 RW, tested by The Motor and published on 22 March 1961. The figures are a fair record of what those two cars did on those days. They are not a specification to expect from a production car.
How fast is a standard Jaguar E-Type 3.8?
Around 135mph is the figure usually quoted for a standard car. The archive has not located a period two way timed test of a car established as unmodified, so that figure is a general one rather than a measurement it can attribute to a named test.
Sources
- Autocar, 24 March 1961 road test of 9600 HP, and Autocar's own modern retrospective on that car's preparation.
- The Motor, 22 March 1961 road test of 77 RW.
- Motor Sport archive, including Bill Boddy's M1 account and the reader correspondence of May 1961 quoting Autocar's published data.
- Jaguar Daimler Heritage Trust page on 77 RW.
- Classic and Sports Car, on the test car's preparation.
- Motoring News, on Paul Frere's Monza runs in 6162 RW.
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