Another interesting article from Hemming’s from a few years back, comparing the face-lift V-12s and straight sixes. One thing I found rather disturbing is that, despite the higher h.p. with the V-12, it has a slightly SLOWER 0-60 acceleration than the 4.0s and a top speed only 2-3 MPH or so above that of the 4.0. wth? So what’s the purpose/advantage of even owning the (problematic) V-12s?
At least this article seems to finally put to rest the debate over the '92-'93 V-12 rear reflectors/“lamps”. At least one vendor of NOS replacements mentions in their listing that supposedly the reflectors were red when installed at the factory but somehow “became transparent” over time (presumably due to ultraviolet sun exposure ). However, I had wondered about that claim, as I can’t imagine a top notch manufacturer/supplier of reflectors to Jaguar making that basic and costly of a flub. This article makes it quite clear (no pun intended ) that the '92 MY reflectors were indeed transparent, but that this lack of colorization was not acceptable to U.S. regs, so they were changed to red color with the '93 MY. (phew - and here I was getting set to have to shell out $170.00 or so for one of the last pair of red NOS ones to “correct” my '92 5.3 ).
Timeisrelative
(Jason Miller 1993 XJS 4.0 convertible, 1997 XK8 coupe )
3
That’s one of the reasons I was fine with, and in fact preferred and wanted the 6 over the 12. Mpgs are a little better too! Of course I did find out with my 93, that not all 93s had outboard brakes smh. From what I’ve seen mine was made only 7 or 8 units before the change, so probably a week too old lol . Oh well it’s fine with me since the previous previous owner had it redone for about $3k a couple of years ago then didn’t really drive it due to dying
I had thought the '92s, being the first year of the face-lift, also had the new outboard brakes, but that article seems to indicate that is not the case. Oh well, like you, supposedly the PO had paid some $$ for “brake work”. I’ll know for sure when I finally start driving her. Nevertheless, the factory service manual doesn’t seem to make it look like - at least on the '92 - a rear brake job is that disastrous, e.g. “having to remove the (entire) rear end”. IIRC, there is a rear support strut or cross member of some kind that has to be removed first, but then the rest of it looks pretty conventional.
1 Like
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
6
The Jaguar V12 is poorly matched to the GM400 transmission, which seriously impedes its performance potential. Those of us who have replaced the A/T with a 5-speed know what a difference it makes.
Also, the stock GM400 and vacuum modulator, as well as exhaust system, are set up for quiet and smooth Limo-style driving. A B&M Shift kit, an aggressively-set vacuum modulator, and removing much of the exhaust system have made my V12 wake up.
1 Like
Timeisrelative
(Jason Miller 1993 XJS 4.0 convertible, 1997 XK8 coupe )
8
I wonder what difference those mods would make with the 6. It might still be a close race.
I have no business commenting in yet another “6 vs 12” thread. BUT, to compare the acceleration between the V12 with 2.88:1 and the I6 with 3.54:1 rear end…?
Even if the gearbox is manual, 2.88:1 is not going to make too much of a difference from the line.
If one wants more “fair” comparison, take a look at the number for MY 1994, which have the same rear end, and are both equipped with 4-speed automatic boxes.
4.0L I6
0-50 mph (sec):
6.2
0-60 mph (sec):
8.1
0-100 mph (sec):
22.3
6.0L V12
0-50 mph (sec):
5.1
0-60 mph (sec):
7.3
0-100 mph (sec):
18.8
As everybody else that has driven a V12 will confirm, that engine shines at speeds above 60 mph and it is clearly seen in the 0-100 mph times.
With all due respect to the author, this article is full of dis-information.
MY 1993 V12 did not exist. Jaguar had a “gap” year in 1993 as far as V12 XJS production is concerned. There is MY 1992, the first year of the facelift styling and the LAST year of the 5.3L V12.
Then there is the MY 1993.5, when the Jaguar introduced their own 6.0L V12.
In between, the US market saw 50 coupes and 50 convertibles, all of which are MY 1993 and are sold as XJRS (aka Jaguar sport, or the TWR version).
The article also claims that the 5.3L V12 has a 4L80E 4-speed transmission, which is INCORRECT. Those boxes are only mated to the 6.0L V12s and the supercharged AJ16s.
As far as the rear lights – they never changed after 1992. I am still looking for the color-version of the official Jaguar brochure, and in the meantime, this is what the B&W scan has to say on the subject:
Timeisrelative
(Jason Miller 1993 XJS 4.0 convertible, 1997 XK8 coupe )
13
I’m sure with some Clorox or oil while power braking, it’ll spin em, shucks even while just power braking it might. I’ve never really tried. I’ve got my Malibu for that lol (of course it’s stuck in the barn for now )
Dang, never seen any (stock production) Jag do that! What mods did you make? I remember though one time in my X-300 I was stopped at a stop light in downtown Dallas in rain. Somehow I hit the “sport shift” button inadvertently and didn’t realize it was activated (I almost never use it). I hit the gas to start out after the light changed and the car spun out 180 degrees while sliding down the street in the direction I was headed. whoooahhh! Lucky there was no other traffic around my car at the time … Hopefully other motorists thought “what a showoff”
So what’s the purpose/advantage of even owning the (problematic) V-12s? 
). However, I had wondered about that claim, as I can’t imagine a top notch manufacturer/supplier of reflectors to Jaguar making that basic and costly of a flub. 
This article makes it quite clear (no pun intended 
) that the '92 MY reflectors were indeed transparent, but that this lack of colorization was not acceptable to U.S. regs, so they were changed to red color with the '93 MY. (phew - and here I was getting set to have to shell out $170.00 or so for one of the last pair of red NOS ones to “correct” my '92 5.3 
).
. Oh well it’s fine with me since the previous previous owner had it redone for about $3k a couple of years ago then didn’t really drive it due to dying 
Oh well, like you, supposedly the PO had paid some $$ for “brake work”. I’ll know for sure when I finally start driving her. Nevertheless, the factory service manual doesn’t seem to make it look like - at least on the '92 - a rear brake job is that disastrous, e.g. “having to remove the (entire) rear end”. IIRC, there is a rear support strut or cross member of some kind that has to be removed first, but then the rest of it looks pretty conventional. 
.
whoooahhh! Lucky there was no other traffic around my car at the time … Hopefully other motorists thought “what a showoff” 
