1992 Jaguar XJR-S

[anonymous-user]

Car is fit and well, a slight nip back up the the specified torque required after a 200 mile (£66 of fuel) run.

I have also confirmed that the car is in excellent health and will hit the rev limiter in 3rd.

toastyhamster said:

Good work. Back in the day I used to work for a garage specialising in these, I mostly did bodywork (never ending!), we did a few conversions to cabriolets, rebuilt a few of the v12s, fitted some TWR kits. Never really had many HE's in though.

Always fancied one, despite me knowing how painful it could be.

It is addictive. I think the later cars, particularly the late 6 litre ones, are very much less needy than the pre HE and early HE examples. If you want one do it quickly as prices seem to be getting to the point where you can't buy and run one on a whim. The six cylinder cars are still available quite cheaply as the auction linked here last month demonstrates, but I think if you've experienced the V12 they are always going to feel a bit lacking.

Edited by dme123 on Thursday 13th April 12:46

[anonymous-user]

melhookv12 said:

I'm glad to be of assistance.
Now all you need to do is buy my big valve heads and 7.0litre Lister bottom end. Then you'll have a real v12!!

I think I'd want to get rid of the three speed slushpump too in that case! You seem to be a man in the know with the V12, maybe you can answer something that I've been wondering: considering the changes made to the XJR-S (longer stroke, cold air inlet, different valves, cosworth pistons, bespoke and far more sophisticated ECU) why was the power increase over the 5.3 so modest?

[anonymous-user]

craigjm said:

I have the same engine in my XJC and my understanding was that all the difference is was a longer stoke and a wizzy ECU left over from racing? Are you sure it's got different valves and pistons? A link to the info would be great

I'll e-mail you the JaguarSport docs I can share on the XJR-S. Some are protected PDFs that I need their annoying software to open but what I do have will give you the gist.

ETA - Sent. It has a full list of parts that are different and their SPC part codes. Camshafts are standard, valves are unique, parts listing for those here

https://www.jaguarclassicparts.com/uk/jaguar-xjs-v...

One of the other documents states that they are forged alloy Cosworth pistons supplied in balanced matched sets, and the crank is forged steel. Gudgeon pins material is uprated, the crankshaft undershiled is different

The Zytek system has a 24 speed x 16 load map but they count position zero so it has 425 mapped positions. It has cut off on overrun above 2000rpm and reinstates at 1900rpm once coolant is over 75C.

19% increases in torque and power over a 1992 MY 5.3. If you have the pre facelift 6 litre engine then the ECU is open loop only and has no lambda sensors. You get less power and torque from that.

The transmission was modified too so that it shifts more quickly.

Edited by dme123 on Thursday 13th April 16:36

[anonymous-user]

melhookv12 said:

I didn't know the valves were different. Bottom end yes as you say cosworth bits.
In my view jaguar never exploited the v12. There are a few racing guys that have noticed a big difference by going to a modern ecu ( emerald ) and two separate coil packs like the late jaguar ( foRd 6.0 litre).

Breathing is a big thing, cold air, larger throttles, and exhaust manifolds. I have heard different figures ranging from 20-50 bhp with the above mods. I had a v12 on webbers, race cams and tubular manifolds that gave circa 400bhp. That was 10 years ago.

Changing to a manual gearbox transforms the car, it wakes it up, our first v12 would nearly hit 60mph in first gear ! It just depends what you want and how much you want to spend.

Someone is making/ selling group A inlet manifolds but they aren't cheap. But if you want power on injection they are a must.

I have tubular manifolds that are for sale. I've defected to supercharged v8. A long project to fit it to my xjs. It's a more modern, lighter compact engine.

I only found out my car was one of the factory manual cars when I stripped the engine bay to reveal the chassis number.

I can't see why the valves would be different, but they are listed with separate SPE part numbers with Jaguar.

I was surprised that in the XJS the factory 6.0 only made 300bhp to the 333bhp in the XJR-S, although I believe right up to the end it used batch injection and a separate ignition system in the XJS and never got the integrated engine management system and distributorless ignition that my X300 XJ12 had.

It would be nice to start to get real power out of the V12, but I suspect it would be an extremely expensive journey as you say!

[anonymous-user]

Covered about 500 miles in the last week or so, lots of motorway work and averaged 18.4mpg or so which I think is very good. It seems to get exactly the same fuel economy at every speed between 50 and 90mph. My old XJ6 was like that, it did 20mpg if you drove it like you wanted to and 22mpg if you drove like an absolute twinkle toes.

It really is a delightful way to travel, for all the climate control system is primitive it does seem to be effective at keeping the air in the cabin fresh and at an even temperature. It's as comfortable as a modern coupe with sporting pretensions, although there is more wind and road noise.

[anonymous-user]

SebringMan said:

I saw this car outside Warwick Sports the other day ; I am there most weeks during the evenings. My M3 was parked around a row away from it. It looked great at night time .

Initially I was wondering if it was an XJR-S until I checked the no. plate. It looks fantastic.

Thank you, it's nice to know the car was appreciated by someone else! It does look good at night, from a bit of a distance away.

Which brings me on to the latest news. I've sold it. A chap from the XJR-S nerd group had a friend who had been looking for one for ages. I took the car up to see them, which gave me the opportunity to get it connected to the only functioning Zytek diagnostic computer and have it looked over by two impressively beardy XJS/XJR-S people.

The consensus was that the trim was in fantastic condition, mechanically it was superb and drove well, but they found all sorts of rust in the sills and above the exhaust boxes that I didn't know about. As in "put your hand in here and you can poke a hole through it". Sobering stuff. Full credit to the chap who was looking to buy, he stood by the offer made before the rust was revealed and a deal was done.

It's going to benefit from a cost and time no issue restoration now, which is something that in truth I was not in a position to do. I've had six fantastic months with the car and covered all my costs so I consider that a good result. Now to find something completely different...

[anonymous-user]

Bill Whiteside said:

I own a 1987 TWR buit 6.4 XJS with Zutek ECU, I have built hardware which connects to the ECU and i am able to download the ECU code using a 1992 base file!! I am trying to reverse engineer the software but am needing another version of the base file for comparisons. Has anyone got any software information or another file anything would help but closer to 1987/8 would really help me.

I know a chap who has the Zytek interface but having just spoken to him he said he thinks he's chatted to you in the past and hasn't been able to help, which is a shame. All I can do is wish you good luck, sadly.