Re: Fw: [xj-s] Re: XJS 62.5 shift

["Emile A. DesRoches" <DAHOTSHOE@sprintmail.com>]

Kirby

I guess the flippant response would be "my genuine JagSport tachometer".
I've not had the motor apart, but something (based on feel) is definitely
different in the valve gear dept.  There appears to be less torque off
the line than other ('94) 12 cyl 6L cars I've driven, but far more over
4000 rpms.  Another possible explanation would be the Zytek management
system which as I understand it is totally different than that in the non
"RS" variants.  Once I sorted out plugs and wiring (splitfire plugs
w/Taylor radio supression race wires), the additional oomph was
pronounced.

A good friend of mine regularly turns his 5.3L '89 motor to 7000 and
slightly beyond racing.  To my knowledge, his motor has not been apart
either.

Sorry I could not provide a more definitive response.  I might however
begin a controversey regarding the manner of driving one's XJS.  A couple
of local XJR-S' here (St. Louis) appear to have perpetual computer
difficulties (Zytek won't reset except by application of laptop by
dealer), whereas my own never appears to have a problem.  I discussed
this with the Jaguar zone rep who was down to work on one of the
problematic cars.  His theory (he claimed little or no literature was
available, hence it's only his personal theory) is that combustion
chamber carbon causes misfire and after a couple of these, the computer
goes into "limp home" mode causing "check engine" setup to go on.  Since
my car is raced regularly (a couple of times monthly in warm weather) and
therefore run hard, no carbon builds, hence no computer problem.

I can testify to the fact that the car does run considerably better
(smoother, more power and cooler) when pushed regularly than when driven
in typical city mode.  I guess the moral of the story is that the 62.5
shift occasionally is as good for the v-12 as for the driver's psyche.

Emile

'93 XJR-S
'94 XJ40
'95 XJS 4.0

Kirbert wrote:

> > From:          "Emile A. DesRoches" <DAHOTSHOE@sprintmail.com>
> >
> > For the record, my XJR-S is redlined @ 6,700.
>
> Interesting!  What do you supposed qualifies that engine for 200 more
> rpm than the rest of us?
>
>  -- Kirbert      |     If anything is to be accomplished,
>                  |     some rules must be broken.
>                  |          - Palm's Postulate

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