What I really don't understand is why someone would come on a Jaguar enthusiast forum and just slam the Jaguar V-12 and feel justified in their actions. The Jaguar V-12 was called a marvel of engineering and is an amazing, super smooth, turbine like power plant that with correct and proper maintenance and upkeep will provide mile after mile of terrific service not to mention good fuel economy at highway speeds. It is also able to more then hold its own in the performance category with some very simple modifications or even more performance with different gear ratios or trans adaptions. The constant slamming by a few individuals on here is getting extremely old and I'm amazed that it's tolerated by the moderators of this singularly JAGUAR forum. If you've got nothing nice to say about a Jaguar or its power plant it would probably be best to share that on a non- Jaguar forum not one where people revere the Marque and its powerplants.

 

Thanks!

 

One of my colleagues has a V8 Commodore with an LS engine and he gets similar MPG to me around town. So the LS is not so fuel efficient as we are lead to believe.

I have had my XJS V12 for nearly 7 years and have done many road trips including driving coast to coast across Australia (Australia is about the same distance east to west as the USA). No reliability issues. Try doing that with a 1980's V12 Ferrari.

Lets put this in perspective, the XJS is a 1980's V12 sports car,

What 1980's Corvette could hit 170mph.
What 1980's V12 is as reliable and cheap to service as a Jag V12.

 

Based on your logic perhaps you should pull the V8 and install a modern turbo charged inline 4 pot. After all if you have removed the V12 already its not like you have a soul to lose anymore.

 

Compared to a V12, a V8 is a super common engine. Kind of like the 4 cylinder is. How many coupes were available with a V12? Not many... So I think - to be honest - a V8 is super boring. Especially if you sacfrice a piece or art in a super rare car to fit a common V8. May well be that many brands have them, and? Many brands have hybrids. Does it mean they are worth installing instead?

To each their own, but a well maintained and cared for V12 will live for ever. I could whack the V12 out and stuff a Volvo B230FT in which will turn out 300 hp with a few tweaks... And more torque... But why? I bought the XJ-S V12 because I wanted an XJ-S V12. I don't buy a car which has an engine I don't like and replace it with another emgine...

 

170 MPH = Delusional
https://www.jaguarforums.com/forum/x...p-speed-86362/

Comparing an XJS to a Ferrari = Even more delusional

Comparing a friends Comodore LS mileage engineered to some unknown level to an XJS or LS convert you dont even have = silly

Performance from Simple Modifications = Fantasy, there are no simple modifications for the V12. Other than No2, there are no dyno proven performance upgrades of any significance available for purchase.

Many of you have bullied away converts. The tone here has surely cowed others to the point where this board is basically dead and merely exist to perpetuate the V12 greatness myth. Most posts are self congratulatory to the point of delusion like the reliability, Ferrari comparisons and 170 MPH claims. I often see new members post and never post again. Someone even scared away a new poster who was doing a v12 quad turbo to the point that they had to apologize and beg for them to post details and return. Recently someone referred to the XJS engines as "bullet proof" The two posts above were, "engine died", "car wont turn over". Yeah thats bullet proof, no car/engine is bullet proof. Get real. Affordable V12, yes...bullet proof and reliable, no.

If you like the v12, good for you, enjoy it. As for soul, I don't derive any sense of spirit from an engine alone I'm just not that simple and dont place that much value in what a pair of british engineers thought up at some point in their lives. Additionally, the Jag V12, like all production engines is a set of compromises. Specifically the Jag V12 engineers compromised on the easy to produce head design, open deck block design, ignition, and crutched fuel system which are all serious aspects.

If anyone wants to pit their V12 coupe, modified or otherwise against my v8 Jag coupe in a friendly competition, 1/4 mile, standing mile, hill climb, top speed, mileage then I'm game. I'll bring the time and speed measuring devices and you bring a "soul-tron 1000" soul measuring device to get the edge in the competition. I'm serious...but I suspect I'll get no takers because internet talk and reality are very different and the two tend lines almost never meet.

 

And there's the problem. And I'm not saying that as an insult or criticism towards you but, rather, as an explanation.

The subject of Jaguars having a soul comes up very often. Nothing new there. I've been driving Jags since 1997 and been involved with Jag owners since then. A great many owners really do have a sort of emotional attachment and they 'feel' something from the car. I know I do. It is 100% natural that this feel extends to the engine.

If you don't have that feeling then it's very hard, perhaps impossible, to connect with those who do.

I hate to go overboard personifying cars and engines but insulting Jag engines, or even being a bit too gleeful in pointing out faults we all agree on, really is a bit like critcizing someone else's children. Hey, I can criticize my kids all I want. If *you* criticize them , though, you'll have hell to pay!






Yeah, that's a bit insulting. But it further illustrates the divide.


It might be that you are just too darn smart for the rest of us. I dunno. That's just speculation. But I'm 99% positive you're nowhere near sentimental enough !

Cheers
DD

 

Ditto...


If that guy does not like Jags, then he should stay away. I don't criticize the V6 Jags just because I dislike V6's. I have owned 50+ cars in my life and really have not had too many issues with any of them. I have always stayed on top of maintenance and drove my cars. The MPG of the V12 is fine with me because I have had Muscle cars that were lucky to get 6MPG. LOL. The key with any car is that you need to drive them and make sure they are sorted correctly. The Jag V12 is a great engine... I would love to see it in a new Jag with modern day coolant systems and electronics but I could say that about a lot of other engine makes/models.

 

Interesting reply Doug but I think you missed the qualifier with the word "alone". To me, my fast, nimble, reliable, efficient Jag Coupe in total has the automotive spirit or soul that I want. My issues have always been with those who characterize a convert as dirty or diminished in some way and the V12 as the engineering Holy Grail. That rhetoric has to some degree poisoned the well by scaring off others interested modifications such as a converts or turbos. New people with new ideas have gotten that point quickly and moved along and I don't see that as beneficial.


My Jag Coupe, with its John Lingenfelter intake, Ed Cole designed V8 Block, AFR heads and Jaguar body and suspension has the right mix of soul and spirit to me and I regard it as enhanced, not diminished. My wife does refer to my Jag coupe as my 5th child so when someone insults converts it does get my attention.


My criticisms are always in response to someone elses v8 criticism, thinly veiled insult or question about a V8 convert. In this thread I was answering the reply..."I don't get it... Why ditch the great V12 for a boring V8? The Best thing about the car is the V12"


As for the simple, the sentimental and smarts, they're subjective and all of us posses all those facets in our own ways.

 

You have your wish, there isn't much I can contribute at this point. All I can offer is on the record and I find myself repeating the same things over and over. Thank you for showing me the door. I guess everything is right in the world for you now. I'll check back now and again to see if anyone takes me up on my challenge.

 

As you quoted me, I think I ought to reply.

Regarding powergains: there are enough Bolt on parts which will add power. I assume your V8 has a carb. Chuck 6 Weber tins on the V12, add a standalone ignition and you can tweaks it to put out loads of power. There are different cars as highrisers and co. There are also different headers. Different maps. You just have to use Google and a few search terms and you get pages like AJ6engineering and co come up. Different trannies, ratios, exhaust systems. Most parts are really 'bolt on'. A good 500 HP can be done without going to the Turbo/Supercharger as a booster. A 24 head conversion is another route.

Personally, as we seem to be getting personal here, I love the Sounds a V8 makes. The rumble and not totally perfect setup. But that V12 limp up front makes the car an XJ-S. And if it overheats, then because it isn't set up right (something damals etc.). My V12 leads every fluid it can even carry. I've just replaced the entire cooling and fuel system. The oil seals and co are next. It runs like a gem. Even with the old misfire here ans bad start there. But as has been said, it is 't a sterile German machine. A machine which will do it's job perfectly. It'll cough when starting. Make a rattle here, a drone there, maybe Run a little rough. Or sometimes won't start at all. But that is how I know English cars. They have some personalities...

 

Any waaaaaaay my car gets hot.......

 

How hot is "hot"? And under what conditions? And what has been done so far?

Cheers
DD

 

Can you elaborate on these a little more? I'm aware of the torque plus kits and, of course, modifying the exhaust as well as tweaks to the cooling system. What about this standalone ignition? Details on specifics on acquiring (cost, p/n's, possibly directions?) What kind of gains with this one alone? Please and thanks!

 

Sorry the 7 is right above the 4 on the keypad I meant 140mph

XJS compared to a same vintage Ferrari V12 not delusional, the 400 was a direct competitor to the XJS.

The Commodore LS is a stock GM offering compared to a stock XJS V12 in around town mileage. So a valid comparison.

You know everyone has their opinion and this is an XJS forum, you do not see Jaguar fans polluting GM forums bagging the LS engine (a very good engine I know).



I don't think anyone here is bagging V8 converts, we are car enthusiasts and I think we all can appreciate a car for what is is, and if you like your LS XJS then that is all that matters.

I originally bought my XJS to convert it to LS, but after driving it for a while decided to keep the V12. The best part of the V8 converts is it will eventually increase the value of my original numbers matching V12 XJS

 

The torque plus kit as far as I can see is a waste of money. The most power will come from.

1 Exhaust - from the cast manifold back.
2 Intake mods - open up the intake pipes and cold air from OTR or behind the headlight.
3 Intake manifold and TB mild porting and matching.
4 Electronic Ignition upgrade (Model dependant) the Marelli ignition can make good power but is not configurable.

From there it starts to get more expensive.
5 Mild head porting
6 Multi angle valve cut
7 ECU - aftermarket including electronic ignition

 

Is your's a Marelli car?

My Marelli car starts first time every time, even after being left idle for 6 weeks while I was OS, she started first fire.

I found on mine misfires are usually fouled plugs or bad ignition leads.

 

Yeah, Marelli. She does basically start every time but due to some issues with gaskets and a few sensors, she didn't want to start up when warm and stood for a couple of minutes. And every so often she'd run rough. But I'm currently sorting all that out at once. New gaskets, seals, hoses, plugs, HT-leads, possibly new coils, etc.