power outputs.

[wightlander]

Hi All, I am given to understand that power outputs for the later cars were less than the early versions, usually with a car the longer it is in production the bigger the power output. Mine is a 1990 5.3 convertible, what is its power and torque compared to the early cars and why is this so? Many thanks,mike.

[dhdove]

Hi Mike and welcome to the JEC XJS Forum

Briefly (all figures 5.3 V12)

pre HE 285 BHP- 294 lb/ft at3500rpm
P-Digital 300- 318/3900
HE 299- 318/3000
Cab 291- 320/3250
Conv. 291- 317/3000 (your car)
F/lift 280- 306/2800
TWR Sport 300- 350/3000
XJR-S 299- 318/3000

As you can see the variations were minimal and involved head design (HE), ignition systems (P-Digital) etc. apart from the TWR Sport models which had been breathed on by the Tom Walkinshaw Racing organisation and the XJRS, a development of the same.
I think Jaguar thought that the power was about right for the car in a smooth understressed way and consequently never developed the engine over its life for increased power output (at the expense of refinement)

You'd need to read one of the several excellent books on the XJS for the details, these figures were taken from our own Nigel Thorley's excellent tome "You and Your Jaguar XJS" (Heynes). Brian Long's "Jaguar XJS" (Veloce) is also excellent alternative.

Regards

DH Dove