RE: Shed of the Week: Jaguar XJR

[Fresh Air Ian]

Wow, what a car for £1,000. Top shedding.

[MX6]

Well I'm a fan of old Jag's and really like these 300 R's.

I had one before, bought a very clean looking one for £1,700 a few years back but unfortunately it was something of a nightmare. It never really did work properly, things broke on it quicker than I could fix them... Still, there were a couple of great sunny days where it was hanging together and I had it out on the road, that supercharger whine was quite addictive...

I'd say these are classic cars these days, not really sheds to daily drive about in unless you are brave and aren't bothered about sub 20mpg fuel economy. I'd say that anyone buying one like this should be prepared for the impending bills...

[amoeba]

Jaguar steve said:

Engine wise at least the X300 as well as the six cylinder XJS will almost certainly get noted in history as the most unborkable Jaguar ever made.

So should we (pistonhead-arati) be buying these to put the engines in Caterhams/Locosts/etc?

[MX6]

amoeba said:

Jaguar steve said:

Engine wise at least the X300 as well as the six cylinder XJS will almost certainly get noted in history as the most unborkable Jaguar ever made.

So should we (pistonhead-arati) be buying these to put the engines in Caterhams/Locosts/etc?

The AJ16 and the previous AJ6 are strong, mechanically reliable motors, I like them. Perhaps a bit long and heavy for such a light weight car though?

The other thing is they invariably came with a 4 speed ZF auto 'box, there were Getrag 5 speed manuals but they are very rare. I previously had a modified 3.6L AJ6 manual XJ40 which was great, the bore/stoke was more square that the 4.0L and it had no cats so rev'ed out better....

Here it was with my 300R...

[psi310398]

MX6 said:

The AJ16 and the previous AJ6 are strong, mechanically reliable motors, I like them. Perhaps a bit long and heavy for such a light weight car though?

The other thing is they invariably came with a 4 speed ZF auto 'box, there were Getrag 5 speed manuals but they are very rare. I previously had a modified 3.6L AJ6 manual XJ40 which was great, the bore/stoke was more square that the 4.0L and it had no cats so rev'ed out better....

Here it was with my 300R...

Not quite. The X300 normally aspirated six-cylinder cars used either a ZF four-speed automatic gearbox (4HP-22 on the 3.2 L and 4HP-24 on the 4.0 L), or a Getrag 290 five-speed manual. The X306 came with either the Getrag 290 or the GM 4L80-E automatic gearbox, as did the V12s.

[MX6]

psi310398 said:

Not quite. The X300 normally aspirated six-cylinder cars used either a ZF four-speed automatic gearbox (4HP-22 on the 3.2 L and 4HP-24 on the 4.0 L), or a Getrag 290 five-speed manual. The X306 came with either the Getrag 290 or the GM 4L80-E automatic gearbox, as did the V12s.

I take your point but I think the poster above was refering to the NA AJ6 and AJ16 motors, as was I, not the AJ16S supercharged X306 engine specifically. The XJ40 manual had the Getrag 265 'box.

[psi310398]

MX6 said:

I take your point but I think the poster above was refering to the NA AJ6 and AJ16 motors, as was I, not the AJ16S supercharged X306 engine specifically. The XJ40 manual had the
Getrag 265 'box.

Fair enough.

I plead in mitigation that the thread as a whole is about the X306. But I accept I'm being a nerd.

[Jagaddict]

psi - I assume you're referring to Mr Stoddart when mentioning the re-programming of ECU's.

The bottom ends are hugely over engineered, from back in the days when they couldn't design an engine for its purpose because they didn't really know what the limits were of most of the components. The reliable source above reckons the bottom ends are good for 600bhp

[psi310398]

Jagaddict said:

psi - I assume you're referring to Mr Stoddart when mentioning the re-programming of ECU's.

The bottom ends are hugely over engineered, from back in the days when they couldn't design an engine for its purpose because they didn't really know what the limits were of most of the components. The reliable source above reckons the bottom ends are good for 600bhp

I was indeed referring to the estimable Mr Stodart.

He has been extremely helpful in reworking my ECU, providing me with specs for a bespoke manifold and exhaust, dxf files for the flanges on the manifolds, wiring diagrams and the oxygen sensor bosses I need for the new exhaust.

[Lewis Kingston]

psi310398 said:

I plead in mitigation that the thread as a whole is about the X306

Was this designation ever formally used? I only ask as I'd always had it in my mind (and stated as such elsewhere) that straight-six XJRs were part of the X300 line – while the V8s, obviously, were part of the X308 range; consequently, there was no need to differentiate between the two in that respect.

I've also spoken to people at Jaguar – including some involved in the project – who don't recognise the 'X306' moniker and state that the straight-six XJR was never referred to as such (as it was was part of the X300 range). Similarly, specialists have towed the same line. I'd happily listen to any evidence otherwise, though!

I've seen a few buyer's guides and the like quote X306 but I think that's based off spurious fragments of information dotted around the internet which they've subsequently taken as writ.

I just wonder if it's terminology that's sprung up later in order to differentiate between XJRs (in the same way that XJR-6 is often used), rather than being an OEM thing. Just curious, as I'd rather know which was actually correct!

[Jagaddict]

psi310398 said:

I was indeed referring to the estimable Mr Stodart.

He has been extremely helpful in reworking my ECU, providing me with specs for a bespoke manifold and exhaust, dxf files for the flanges on the manifolds, wiring diagrams and the oxygen sensor bosses I need for the new exhaust.

Yes he knows his stuff

Are you looking for more power...if so how much?

[psi310398]

Lewis Kingston said:

Was this designation ever formally used? I only ask as I'd always had it in my mind (and stated as such elsewhere) that straight-six XJRs were part of the X300 line – while the V8s, obviously, were part of the X308 range; consequently, there was no need to differentiate between the two in that respect.

I've also spoken to people at Jaguar – including some involved in the project – who don't recognise the 'X306' moniker and state that the straight-six XJR was never referred to as such (as it was was part of the X300 range). Similarly, specialists have towed the same line. I'd happily listen to any evidence otherwise, though!

I've seen a few buyer's guides and the like quote X306 but I think that's based off spurious fragments of information dotted around the internet which they've subsequently taken as writ.

I just wonder if it's terminology that's sprung up later in order to differentiate between XJRs (in the same way that XJR-6 is often used), rather than being an OEM thing. Any input, as ever, appreciated!

TBH, I'm no longer sure but X300 or X306 is the first question I'm asked when scouring for parts.

Specialists I've dealt with use X306 precisely because many parts are not interchangeable between the N/A and the S/C models, nor between the SWB and LWB, nor 6 banger and V12. Which would make sense.

The designations I have seen in common use are X300 for the XJ6, X330 for the LWB, X305 for the XJ12 and X306 for the XJR6. Where applicable, read the cognate Daimler model.

I also dimly remember seeing the designations in a book (? by Paul Skilleter or Peter Crespin), sadly not to hand. I seem to recall that they were introduced after the Ford team had scrapped the XJ90 project and they might only have been "working titles", so it is possible that Jaguar used the designation less than Ford might have hoped.

[psi310398]

Jagaddict said:

Yes he knows his stuff

Are you looking for more power...if so how much?

In a sense.

I'm dropping the engine into a Series 1 E-Type. (Don't worry - no desecration here: it is a 2+2 and had been wrecked and lumped with an SBC and the engine and gearbox installation will be reversible).

I asked Andy for help in allowing the engine to operate independently of the donor car and in designing the parameters for the exhaust system etc for the new installation.

But, with a free flowing exhaust, no cats, porting and polishing on the inlets etc, I might easily hit 400 bhp without trying very hard.

The stock output of the six-cylinder AJ16 s/c engine is 326 bhp (243 kW; 331 PS) and 378 lb⋅ft (512 N⋅m) with the use of an Eaton M90 supercharger and an air-water intercooler. However, everybody accepts that the engine is horribly constricted.

The XJR6 base kerb weight was 1875 kg, and the gross weight of 2295 kg. The Series 1 E-Type 2+2 had 1400 kg kerb weight, and gross weight of 1700 kg. The XK 4.2 engine weighs about 275 kg with flywheel and manifold while the AJ16S aluminium blocked engine is around 220kg with s/c, flywheel and manifold.

Offset against that, my E-Type has additional reinforcement built in and I cannot believe that the GM 4L80E box is lighter than the original Borg Warner Model 8 transmission. Overall, however, I think the car will be appreciably lighter than stock, so it should accelerate better and be capable of attaining a higher top speed than the XJR6.

On the rather heavy original donor car, the 0 to 60 mph (0 to 97 km/h) time was generally around the 6 second mark. The 1/4 mile drag time on the 1995 saloon was recorded at 14.1 seconds which puts it in contention with the 1971 Maserati Bora (or the much more recent Porsche Macan S V6 Twin Turbo).

While the donor car had a 3.27:1 diff, my E-Type has 3.31:1 (so no material difference) not least as the wheel/tyre combination will probably even out with the 15" wheels and taller tyres compared to 17" inch wheels and low profile tyres.

I'm told by the Andy that the XJR was not artificially speed limited, so tyre speed rating (and absence of electronic gizmos) apart, the notional top speed of my E-Type may be well above 155 mph, although I'd not want to find out on wire wheels.

The planned work on the engine, as we are just going into dry fit on the body now, is next on the order of work:

Ignition advance tweaked (per Andy bracket)
ECU tweaked
No catalytic converter
NOS Abarth exhaust pipes
Uprated supercharger pulley
Bespoke manifolds optimised to clear exhaust gases
Intake manifold de-restricted, ported and polished
Improved air filter and improved intake positioning.
Supercharger ported and polished
Better radiator and fans
Better water pump
Better/more inter cooling capacity (and possibly separate s/c cooling from engine cooling)
Using waterless coolant?

All that should enable the car to move at some lick, and that's before any engine rebuilding or other expensive engineering.

The things I'm most concerned about are (i) getting enough cool air to the supercharger in as un-turbulent manner as possible and (ii) minimising heat soak, and keeping the engine as cool as possible. Fortunately there is a long bonnet and quite a lot of space to play with under there. Apart from the above, there may well be the opportunity for charge cooling or water/methanol injection if justified.

But my aim is to have something comfortable on motorways (a long range GT/cruiser) rather than a Santa Pod screamer so I won't be chasing additional horsepower simply for the sake of it.

[TooMany2cvs]

psi310398 said:

Jagaddict said:

psi - I assume you're referring to Mr Stoddart when mentioning the re-programming of ECU's.

I was indeed referring to the estimable Mr Stodart.

I can't be the only one to have read that as Stobart...?

[and31]

Brilliant shed!!
What a bargain-my father owns a 1996 model,great fun to drive-effortless 100 mph cruising.unfortunately his has sat outside his house for the last year or so as he is no longer able to drive it,and is still digging his heels in about selling it....
I have to say that I preferred my old series 3 xj6 sovereign -lovely place to be wafting along in that when I was in my mid twenties!! Slightly leisurely performance compared to the xjr though!!

Edited by and31 on Friday 21st September 22:20

[XJR500bhp]

I can tell you now that you won’t get 400hp from those modifications. The charger can’t spin fast enough and the injectors will max out before you get there. My car has bigger injectors and the charger from a 4.2 and even then it only just makes over 400 but huge 650nm of torque.

Andy knows his stuff but if you want proven big power then contact Tom @ Swallows Jaguar Bristol who runs the sister XJR we race. Great advice for proven big power

Cheers

[psi310398]

XJR500bhp said:

I can tell you now that you won’t get 400hp from those modifications. The charger can’t spin fast enough and the injectors will max out before you get there. My car has bigger injectors and the charger from a 4.2 and even then it only just makes over 400 but huge 650nm of torque.

Andy knows his stuff but if you want proven big power then contact Tom @ Swallows Jaguar Bristol who runs the sister XJR we race. Great advice for proven big power

Cheers

Thanks,

I'm not especially chasing 400 bhp or any other particular number. The engine, without further modification, is plenty powerful for the job it is being asked to do.

It was a not especially careful, not even bag of fag packet, guess at the effect of a lot of little jobs (that either cost next to nothing or are required anyway) a couple of which could each add 25-odd bhp (uprated supercharger pulley and porting the rather asthmatic supercharger); and some smaller gains, each of which could add the odd 5-10 bhp here and there (better air filter, porting inlet and outlet plenum, cat-free exhaust etc).

It's just, while it it is pieces, it would be rude not to do a bit of polishing and porting and the other things like bespoke manifolds and cat free exhaust are necessary jobs anyway.

We'll see where it gets to but I'd imagine the safety rating on my tyres will be reached before VMAX.

[strangehighways]

BFleming said:

Brits do love a British car... the rest of us see something that was hardly desirable at any stage of it's life, and even less so now. Look at what this would have been pitted against when it was new, and the opposition was offering at the time. A Merc W140? The W126 was a hard act to follow, it was heavy (double glazing didn't help), and a certain Paris crash destroyed the reputation overnight - unfairly. The BMW E38? The cheesiest Bond ever drove one. Cheesy, but a great car. The Audi D2? Superb, but positively near-worthless now. All infinitely better than the Jag.
I would love to know how many they made, and where they sold well. I speculate the cars I've mentioned above sold more uniformly outside their native countries than the Jag.

Although I currently have a Jag XJR, I've also owned an E38 740i in the past and am certainly not a Jag fanboy. If anything, I'm an Alfa nut! However, this post seems a little bitter? All infinitely better than the Jag? Why is that?

I will compare the two cars mentioned I've owned.

Ride/Handling - Jag wins.

Interior - I love the Jag interior but objectively the BMW wins as its way bigger and ergonomically more sound.

Build quality/ component quality - One would think the BMW would walk away here, but the E38 had a fundamental problem which was a fuel tank which corroded!! I had it pissing out fuel in the Tesco car park and had to replace the tank. Sourcing a spare was hard as so many E38s had this problem. Both cars had/have rust issues, though the Jag is worse and corrosion is probably the biggest issue with the Jag. The mechanicals are generally good. I sold the E38 to a friend who had it for 2 years but he had a lot of problems with sensors needing replacing and the day he sold the car, the auto gearbox failed. This is only a sample size of 1 for each car but I would not say that the BMW is better made than the Jag. I guess the switchgear feels better.- Draw.

Special feeling - Jag wins.

Of all the cars listed, if I was being chauffeured about, the Jag would come last, but as a driving experience, I can't see the others being better to drive. I haven't driven a 140 but would be amazed if it was as good to drive. Not sure on the Audi.

[cybertrophic]

Top shedding 👍
Whiff of dashing appeal? Check.
Good steer? Check.
More fondly remembered than they were reviewed at the time? Check.
Potentially ruinous to run? Check.

I even like the colour.