New to forum, New to jags, any tips for my project?

(Bryce) #1

Hello jag lovers,

  I recently purchased a 1987 xjs and instantly fell in love. The lush interior, sexy curves and gut wrenching speeds are exactly what I wished for for christmas :). At 77,000 Km’s and no mechanical issues I couldn’t be happier with my purchase. Now to make it the car of envy. I’m not a mechanic by any means (more of a physics geek), but I can build/fix anything. So I began planning my project while the car sat over the winter months. I would really appreciate any tips on where to start and any problems I’m likely to encounter in relation to my project aspirations. 

Step 1: We need more power!
I have seen many posts about swapping engines or going for a manual transmission. But how about a turbo? I’m considering installing an electric assisted turbocharger to increase my compression and still give me that pop that a supercharger would without the drag on my cam shaft. Not sure if I would have to replace the pistons, rods or anything else but it is a race car so my hopes are high.

Step 2: Happy wife happy life
Being that this is going to be a touring car it’s gotta be wife friendly. I recently came across a video for a 2018 Volvo XC90 excellence and thought “I can do that!”. Turning my passenger seat into a first class experience for the wife on long trips is just the justification I need to convince her that what I’m doing is totally worth it.

Step 3: I’m # 1
In the end it’s my car. And I plan on taking her around the world if I can. So why not be comfortable. Installing an electronic 10 way seat positioning module w/lumbar support would be a good start. Or maybe a heads up display? LED lights for better clarity perhaps?

Any advice/tips would be appreciated. Again I’m not a mechanic so be gentle. So far I’ve replaced my fog lights, windshield and some chrome trim. I’m doing it at home by myself so it’s a slow process but I will update with pictures when I can. Thanks to all in advance and I’m happy to be a jag lover too.

(Mike Milton) #2

Hi, Bryce and welcome.

I’m and e-type-person vs XJS but here is my take on your plans.

The XJS is usually more about touring than racing and that might fit your interests much better than a ‘race car’ since much of what you wrote seems to center on touring rather than track of hill climbing.

On ‘power’: be careful what you ask for. I have more than a few friends who focussed on power and ended up with a less drivable car. So be sure your goals are compatible with each other (or, at least, not conflicting). Many of the enhancements that are the most popular focus on torque and spirited driving more than getting the most hp at max RPM. It might be worth doing a bit of homework about what YOU think performance means and how best to pursue that. It might be that the XJS is already close to your optimum compromise. In any case, driving the car for a while will surely allow you to identify specific things you might want.

As to touring upgrades and flashy do-dahs, a few good long excursions might be the best way to create a list of things to improve. Spending your money on things that make touring a grand experience for you and your wife will result in better outcomes that are specific to YOUR tastes. Again, spending some time behind the wheel will help inform you about priorities.

All the best speed in your enjoyment of the car.

1 Like
(Aristides Balanos) #3


Welcome to the forum.

First, where are you located?

Second, is it a V12 or a 6 cyl.?
If it’s a six others with more experience might give you more info.

But if it’s a V12 my take on your power issue is to leave it as it is…
You say you plan on taking her around the world if you can…
Remember, in real world mechanics everything is a compromise, rarely there is the “perfect” solution…
More power = more headaches, more fuel consumption in a already very thirsty engine and more possibilities of things going wrong in a already very complex machine.
Besides, 290HP are plenty enough for some very fast cruising.
I would focus instead on reliability, (especially if you plan to travel with this car) and there is plenty of room for improvement there.
The V12 engine as is ,is very well made and extremely robust. It’s the peripherals that need attention:

  1. Cooling
  2. Ignition
  3. Gaskets and seals - all of them
  4. Boushings - all of them
  5. Brakes
  6. A/C and climate control… the list is long…

If you want a manual gearbox it’s doable, many did it so there is plenty of info, but me personally I love the luxurious feel of Automatic.

As for the suspension, only modern cars can compare with it’s comfort and handle characteristics.
Upgrade yes, alter no…

As for the interior comfort, I once did a 6.000km trip with mine (albeit a XJ12) and I could easily do 1.000km in a day with no problem and zero complaints from my significant other on the passenger seat.

A very good start would be to read the “Book” (all 700 pages) by our fellow Kirbert Palmer:
After that you will have a better idea of what I am talking about.

As for gadgets, there are plenty !!


1 Like
(Bryce) #4
   Wow I appreciate the rapid response and engagement already! I am located in northern Alberta and it is a v12.

I think you hit the nail on the head mike. I want a touring car more so than a race car. That being said it is a race car and I fully intend to treat it as such :). Although I would love to only upgrade certain parts of the car but it is not original as is. I will post a full detail of mods when I return from work (eta 2 days?). My first priority is to get an accurate measurement of the O2 not being used by the combustion process and the amount of residual carbon build up in my exhaust system (ie heads, manifold etc). From there I want to tweak the air/fuel ration via a turbo/upgraded carb maybe? The draw backs of the RPM requirements of any turbo can be circumvented through electric assist and have variable control so it seems like a good choice and relatively easy to do.

Again; NotAMechanic

Thanks to all who reply :wink:

(camcor) #5

Welcome NotAMechanic, with that being said why di you buy a Jaguar XJS? Being mechanically incline is not mandatory but it helps, as Aristides states they are a very complex piece of machinery. I have an 85 XJS that has topped 110 MPH and felt like 55 MPH and I live near Denver, Colorado.Because of the suspension and the quiet cabin and leg room it makes driving a treat. Enjoy, download the book and I’m sure you will find more information than you ever thought was available.

(Dzia) #6

Before I would do any modifications, I’d get the car to stage zero. Stage zero is an effort to restore all systems to close to original as possible. This will give you a data point to gage any improvements.

Aristides mentioned the systems that likely need attention. Once all the consumable bits have been replaced and the car is running as designed, (which will improve reliability while touring) should one consider making major changes to the car.


(scrimbo) #7

Don’t want to rain on your parade, just a little fog…I like my 88 but they are mechanics nightmares and they become a hobby of fixing stuff all the time…If you have DEEP pockets you can hire anything done…If you are not financially well off but mechanically inclined and can do at least some of the stuff that is another thing…These cars have been modified many different ways…just read through this forum…remember they are getting older all the time and to be honest I would worry about long distance touring because of age of car…500 miles from home maybe, if something breaks it can be trailered back reasonably…long distance ? well it could be expensive…I know some would disagree with me, but this is only my opinion.

(scrimbo) #8

I am beginning (after thinking overnight) to wonder how sincere this article is or is somebody just pulling our legs

(JLo) #9

If you want to change the XJ-S character to such an extent then perhaps a different kind of car is more suitable for you.

If you want it to be a race car AND more comfortable then that will be a true oxymoron!

I have a series 1 E type and it is the very opposite of the XJ-S. It’s hot inside, noisy, and not very comfortable.
However, it’s agile like you would expect a short wheel base race car of that era to be.

I much prefer the comfort of a grand tourer like the XJ-S.
It silently propels itself along in a suave and sophisticated manner.

Of course we would all love more HP but you must realize what the automakers in Detroit failed to ever realize. There is a delicate balance between HP and proper handling.

(Greg) #10

You don’t simply add a turbo to an engine. That requires someone with a wealth of engine building experience. More than many mechanics. Yet you are not even a mechanic?

Are we being trolled?

1 Like
(BobPhx) #11

JLo, you should write ad copy.


(scrimbo) #12

one last thought on horsepower, torque etc…On the highway no one needs excessive hp…legally you can only drive so fast…plus environmentally it can be a problem…just about anything with piston engines has already been accomplished…so why invent the wheel over and over…I know that the gearhead bunch doesn’t like to hear that…I would rather see new ground broke on improving reliability and safety…wwII advanced airplane engines to the nth degree…then jets…where is the jet car…but better yet electric sounds even better…of course we could debate this with a lively conversation but it is mostly a moot point anyway.

(chris gruchawka 1988 XJ-SC) #13

just add the flux capacitor driving the 100hp pancake electric motor housed before tourque convertor in bell housing, maybe eliminate starter. :innocent:

(chris gruchawka 1988 XJ-SC) #14

Sorry too many paint vapors today, spilled a pint on the workshop floor, cleanup not totally successful. Still the idea of capacitor vs battery for storage is a future we might like to see.

(Bryce) #15

Forum dwellers,

Back from work and what a response! Thanks again for taking the time to respond. And to all those who doubt my sincerity i understand. You are probably used to talking with these other “mechanically inclined” gentleman (and ladies?). I assure you I am indeed going to continue my project. I will take your advice Aristides and start at the top of the list, the cooling system. I’ve never noticed it burning coolant or any leaks. All the hoses are tight and my engine temp is stable both at idle any highway. Is their any sneaky secrets I should look for? I took it in to the mechanic to get a new fuel filter I ordered installed as the old one was… well old :p. If this car is only gonna take me 500 miles (doubt) then maybe it is not the car for me. But I believe this “complex piece of machinery” can be built to last with the right amount of ingenuity (and helpful insight ;p). And Chris, there are capacitors for cars on the market already, I encourage you to look it up. I would post a link or w/e if I knew how. Thanks again to all who reply.


(David Jauch) #16

If you want reliability, control all the rubber hoses and vacuum tubes. Ideally rod out the radiator and then you should have a reliable and comfortable car, as the cooling system seems to be the only real danger on the V12.
Do a few ‚shakedown runs‘ and inspect the suspension, change fluids if needed and grease the grease points; then you should be good to go.
I think a better transmission is the best upgrade for more power, but there have been blown XJS that ran. No way this effort is justified.
The interior is up to your liking!


(Matt Furness) #17

Not a Mechanic…If you took your XJS in to a mechanic to install a fuel filter you purchased then this is not the car for you. You would be better off hiring a digger and digging a verrrrry deep hole in your back yard. Then invite some friends around on a regular…say weekly or monthly…basis and have them watch you throw $10 notes into the hole …all the while drinking the free beer you are going to provide…until the hole is full of notes…compressed by yourself jumping into the hole from a slightly elevated platform…so the notes are moderately compressed…then push some topsoil over the hole and dig another hole and repeat the process until you run out of back yard.
An old Jaguar requires an owner who is prepared to,learn how to be either an amateur mechanic …or a digger driver!!!

(Doug Dwyer) #18

A couple thoughts…although nothing that hasn’t already been said, I reckon.

Very few of these cars get the care they need. Unless previously owned by an ardent Jag enthusiast I can virtually promise that your '87 XJS is gonna need a LOT of remedial work just to get it back to ‘square one’. This is a bit of a challenge and learning curve for even fairly well seasoned DIYers.

In the rehabilitation process there are lots of small upgrades you can jump on along the way…and the car will respond well to them. Depending on what you’re accustomed to driving, and what your goals are, you might find that you get a really satisfying improvement without re-engineering half the car. But when you start talking about turbocharging, 10-way power seats, and the like, well…I can see tens-of-thousands of dollars being spent.

I can’t help but notice that you haven’t mentioned what your budget will be for this project :slight_smile:

I was tangentially involved in a Mustang ‘resto-mod’ project recently. A full modernization of an old car. Suspension, interior, engine, electrics, etc. it was a $300,000 project. Admittedly, a lot of that expense was body/paint/chrome/cosmetics and, since no DIY labor was used, the bill soared even faster. But, as someone already mentioned, there comes a point, in my opinion as well, where you have to consider just
going out and buying a car that already better suits your desires and requirements. Perhaps a more modern Jaguar.

In any case, with these old Jags you’ll find tons of great internet help and resources…more so than some other hobby cars. Virtually all problems areas and fixes are known and documented…and the info freely shared. That’s a big plus. Others before you, such as Kirby Palm, have blazed the trail.


1 Like
(Andrew Waugh) #19

I’m inclined to agree with Matt. Until you’re comfortable with all of the regular service on these cars, the last thing you should be contemplating is performance modifications.

Unless, of course, you have incredibly deep pockets.

1 Like
(Greg) #20

To give you an idea, to get my 88 XJS V12 driveable and the engine back to square 1, I spent $3000 in various parts and improvements over 6 months. I did all the labor myself. If I had to pay a mechanic, easily add another $3000.

And I still have probably another $3000 in parts to go, but luckily I can now do those slowly over the course of several years.

So go for it, as long as you’re ok spending lots of $$$.