What's the cornering supposed to be like in these x350 s/c cars with working air suspension? I've never drove one besides the one I just recently bought, so trying to set expectations. What can it be compared to? BMW M cars defy physics versus Lincoln Town Car that wallows and tails out at the slightest lateral force.

I've got several maintainance items that I'm addressing in the next few weeks that could impact handling (which is not particularly impressive at the moment), trying to figure out what type of handling should be expected from the vehicle though once I replace the worn items (ie tires.)

 

A SuperV8 has the same shocks (air struts) as a XJ. Definitely does not compare to a M Series. Better than a Police Interceptor Crown Vic the same vintage.
The active shocks help prevent body roll.
Bad is; the rubber bushings and other bits fail rapidly. When I purchased my XJR is 2015 every bushing and rubber boot was either disintegrated or collapsed. Think Texas heat may have speed up this process. But that was seven years ago.
Since upper control arms were loose and upper ball joints had no boots that was easy. The rear lower arms were shot too. Sway bar links, front and rear tie rods ends, curved arms, rebush straight arms, lower ball joints and it handled very nicely. Not was well as the wife’s 335i w M3 Sport package, or even my A8 with Sport package.
I expected a XJR with all new rubbers to be tighter than a same vintage A8 with only UCA bushing replacements. But not so. Think the body is very flexible on the XJ. Even with perfect suspension and great tires in with never feel tight as a M series. Or even an A8.

 

If you want to see how an XJ does on the track, this video puts an XJR up against the Mercedes-Benz CLS 55AMG.

 

Ugh, comparing to a Crown Vic is not inspiring, lol. That video is not looking good either, the car was basically going sideways the whole time, OMG...

Did swapping the control arms make a noticeable difference? That was in my planned maintenance soon. Everything else in the suspension is either recently replaced or appears to have the rubber bits intact.

 

Replaced all those in one swap. All were bad, only the subframe bushings were still solid.
Replacing everything at once made a huge difference. Not sure how many ball joints were bad, but none still had boots. The driver side LCA had bolt on arm. One toe adjuster was almost separated. Boots had been gone a long time on a nine year old car.
One thing the XJR does really well is Lane changes. I had experienced someone pulling out of a driveway when I was going 60. The transition from one lane to the other was hard, tight, and no sway. No understeer either.
Like on rails. Transition back to original lane was confidence inspiring, was getting close to rear ending a slower moving vehicle.
I assumed the system jacks up the air pressure to counteract sway in fast lane changes. But reading here about eCAT system it switches the shock setting to hard to combat lean and understeer. And then switches back to normal. To settle quickly.
Watching the video it really looked bad. But lap times were 1 second off the AMG. AMG should looked easier to drive.
For some reason European carmakers are not fans of LSD. I thought the wife’s 335i convertible had a limited slip. Had the M3 Sport package. Found out almost no BMW’s came with LSD. No Jags either.
The Jaguar traction control is a hillbilly rig. Applies the brakes to the spinning tire.

 

These x350 vehicles do NOT have active responsive air suspension, it says so in the mechanics documentation from Jaguar (which I've read to learn about how this car works), so your lane change would not trigger anything in the air suspension that wouldn't be already active while traveling straight. The main point of the air suspension according to the docs is leveling load and smoother ride quality over mechanical suspension systems.

 

My take on it is it is neither Town Car, nor M5. What it is though is a very good A to B car. It is surefooted, and responsive, that translates into; you just find yourself arriving a bit earlier, through no fault of your own. I'd prefer not to have Nuremberg Ring tuning in a street driven car.

 

Having had several M5's (and now, an E46 M3 cabrio), I can say that the XJR simply ain't in the same league. And, thank goodness for that - its a far better traveling car, and a much more liveable daily driver. With most M cars (and some AMG's), you'll find that people dislike riding in them, particularly on rough roads. Same people love the XJR...
A few notes:
- All the suspension bushes need replacing on most X350's I've come across. Don't forget the sway bar bushings - this makes big difference in "tightness"
- Ditto the air struts, which may have worn dampers even if still airtight (I went around and around on this, and finally installed Arnott spring struts - which I recommend for XJR, but may be harsh for XJ8)
- Michelin Pilot Sport AS work well on these cars (I'm on my second set)
- The XJR is initially a little "loose" vs German cars, but has high limits after taking a "set" in a curve
- Numbers aside, the travelling comfort and kickdown punch of a good XJR are hard to beat...(I planned to buy an E550 Mercedes last Spring, only to back out after test driving. Not a patch on the 'ol Jag, nor as easy on the eyes)

 

I've not driven an M5 but have been in one (2002 bwm m5 e39) considerably in Houston track. This was around in 2008 and 2009. Also in the BMW m6 in 2006 with the limiter removed (computer speed limiter).
The E39 m5 would completely wipe the floor any x350 or x308 that I've driven in cornering. There's no comparison. Imo you are comparing a performance drive car. In my opinion the e39 chassis has got to be one of the best designed chassis ever in a car.

What I will say however is the M5 has a far harsher suspension than the X350/X308. This was notable during the ride to Houston and back. Dont get me wrong it's not bad but it's also not amazingly comfortable like it was on the m6 which in my opinion has superior comfort, aerodynamics but I feel that the chassis sacrificed some maneuverability for comfort, then again the m6 was one of the first cars I was in that did 160-170 mph and it felt like we were cruising at 60mph in terms of comfort and noise. Iirc he had explained acoustic glass in the front. It was a stupidly nice and expensive car, also went to the shop often (the m6). I think he went in like 3 times for the transmission.
The M5 was another story, at 140mph+ it was very stable but boy you could feel and hear the road.

I've driven original bilstein sport XJR, and "comfort" Xj8. My XJR has Arnott's sport suspension and it reminds me of the Bilstein to be honest. I really didnt notice a difference in either bilstein or arnott other than my arnott being louder (clunks).
I've also driven in converted to spring XJ8's, and one XJR but the XJR had a engine issue and felt like it lost 50% of the power, so i wont compare it. The Coilovers I do not know which were used but felt hella bad, would not be surprised if they used suncore or cheap conversion kits. One of the XJ8 had lowered sports suspension, I believe eibach but didn't confirm. Definitely a sport suspension but still had some body roll present. I just think the way the chassis and suspension was built it just wasn't made to corner as well as the M5 or event AMG Benz. I passed on that Xj8 because I really disliked the suspension, it felt like it didn't belong on the car.

I've only gone the speed limit on my XJR but once I went to what "FELT" like I was going over 140 mph on a straight empty road. The car felt fairly stable to be honest, but definitely not something I would want to shift lanes in very quickly at that speed. It can barely handle doing turns at around 30-40mphs without feeling like it's going to loose control due to the lack of LSD and body roll. I am sure a more experience driver could control it, but it was a little too much for me.

 

Yeah, sure, that's the ticket...

Tell that to the judge - lol

 

This all happened in mexico. Like everything on youtube regarding cars seems to happen.

 

I drove an XJR for years. I would agree with you. The softer suspension can initially deter your confidence but with time you discover that you can push the car a lot harder than you think and nothing bad happens. I was never able to find the actual absolute limits of my XJR. And I tried. I ran out of courage before the car ran out of grip.

This BMW v Jag conversation is nothing new. You can go back decades and discover that magazine road testers and actual owners have been reaching the same conclusion all along: when dealing with the comfort vs cornering compromise Jaguar always goes for a bit more comfort, sacrificing a bit of cornering prowess.

So much depends on just how aggressively you drive. I like fast driving and competent suspensions....but I don't attack every corner as though I was a rally driver

I'm an expert at absolutely nothing. However, I've driven a lot of cars that are renowned for superior handling/cornering. Impressive, yes, but sometimes actually less-than-pleasant to drive when you're not in fast driving mode. The hard ride and hyper-sensitive/responsive steering can be..... irritating.

I've never felt irritated driving a Jaguar.

Anyhow, just my two cents. Ignore at will

Cheers
DD

 

I like wafting in luxury. Or my wife does.


From all review reports I've read, the car also has excellent handling, at least compared to previous XJ's.
And the eCATS does do something. Sorry you coilover guys, and not that I would know.

 

OT: has anyone with regular XJ8 or XJR upgraded the sway bars to something more aggressive for better handling? Will the XJR parts fit a regular XJ8?

 

someone had a source foe stiffer roll bars. Kind of one offs. As long as the Bilsteins are used the active dampening really helps with body roll. At least on mine.
As far as compared to M3, my wife’s 335i Convertible had M3 Dport. After being a second car for 13 years the rough ride, cramped interior, and no usable back seat caused her to trade in on a Q5. Thirteen years old and 58,000 miles. I had replaced the entire suspension on it too. One of the struts gave up at 50,000. Started to squeak.
I am wide, did not fit in the car.

 

Does anyone know if the XJR sway bars will bolt on a regular XJ8? Does anyone know any aftermarket upgraded sway bars?

 

THE XJR sway bars are a direct replacement. The have to be, same antiroll bars. You found the stiffer bars mentioned in the past.
The only way to keep the existing cornering is keep the eCAT struts.

 

The original sports air suspension in the XJR isn't too bad for body roll but I don't believe it will be anywhere close to a BMW M class. If you change to the Arnott's coilover, the vertical comfort is still there but the body roll is very much worse than the original XJR sports air shocks and it really needs an upgraded set of anti-roll bars. The uprated ARB's do not solve the problem of the car bottoming out if loaded up with 5 persons. If you use the uprated ARB's with the original XJR sports air-shocks, my guess is that the handling would be excellent.

 

my experience with ARB upgrades and air struts is with Audi A8. In the D3 (2003 - 2009) series Audi used three sets of bars. A8V8, A8W12, and S8V10. Some dealers did not want the owners swapping.
But several swapped to the stiffer bars. All said handling improved. All said ride was stiffer. The A8 cars understeer badly. Weight distribution is way off. 60/40 or worse. Stiffer rear bars helped the handling more. Stiffer front effected the ride more.
The x350 bars look very flimsy compared to even the A8 V8 bars. Wish Jaguar had seen fit to using stiffer ARB in the XJR model. All three Audi ARB bars are around 1” in diameter.