with after market shocks?

I just got back from my first road trip of any significant mileage and found the Xj to feel a bit sloppy and "drifty". Had anyone tried stiffening the ride up a bit with aftermarket shocks yet?

Came from a long run of BMW's before pulling the trigger on the XJ and I guess I'm missing the crisp BMW suspension feel of the 750, let alone 5 series.

 

How many miles are on the tires? If they are older (even with plenty of tread), I've found that certain tires get really squishy and drift as they age. I out new tires on my XKR and the difference was like night and day. I almost thought my car had suspension problems before I changed them!

 

Does your XJ SC drive "sloppy" in Dynamic Mode? What is the air pressure in each tire? Are all four of your tires wearing evenly? Have you checked for loose tie rod ends or other excessive suspension wear, such as rubber bushings? Is your car still under warranty?

Go to your dealer and test drive another XJ like yours and see how it differs. Then take a Technician with you for a ride in your car.

Keep us posted. Thanks.

 

Here is one source: Jaguar XJ-Type Suspension, Shock Absorbers & Springs - CARiD.com

 

My feeling is they tuned the XJ to be comfortable enough to pick up all the Cadillac drivers coming over. Thats just it...the car handles like a Caddy.

My preference would be to stiffen the ride to be a bit crisper and more responsive.

Again, BMW always seems to get this right in their bigger cars with their oem suspension tunings. Another car that gets it is the Maserati Quatroportte that I test drove a month ago. To my perception, when I drive my XJ, especially on the freeway, the car seems to "float" over the asphalt like a luxury cruiser as opposed to making you feel as if your in touch with the road. It would have been awesome for Jag to have changed the suspension "feel" along with shift points when the driver decides to engage dynamic mode.

For me, just a simple tune to a stiffer shock would seem to work better but I see no aftermarket performance shock offerings for our XJ's. Not a one!

Ive heard mention of an owner or two upgrading their sway bar to the beefier XJR part but that would seen as if it would only address body roll. My issue is more crisp responsiveness where you feel a part of the road. Certain sedans are built with this tactile quality in mind, most manufactures aren't interested in this quality in their full size cars.

 

Hi Polarisnavyxj, can you tell us what year, wheelbase (swb or lwb), engine model and trim level you have. using Dynamic should firm up the cat, but there is a difference between v6 and non-supercharged v8s versus Supercharged v8s in suspensions (shock tuning, springs, and sway bars and all those were retweaked in 2013. For example I have a 2013 swb SuperSport and have upgraded my front sway bar to the XJRs (1mm thicker). Also alignment is critical as are tires and pressures.

 

Wouldn't it be great is we knew what XJ model you were driving so we all could responded with some knowledge and succinct answers. Maybe a short description in your signature would be great.

 

What you are sensing is a LACK OF proper rear sway bar sizing. As a long time racer, familiar with suspension tuning, I find the rear springs on the present line of Jaguars way too stiff. Jaguar appears to want to control body roll with stiffer springs instead of with larger diameter roll bars. I guarantee to you that if you replaced that puny rear sway bar with a 3/4" or 7/8" bar the whole handling behaviour of the car would change. I don't know what rear bar the XJR uses but, quite likely still too small. The steering would feel much more direct, more precise. You would have less body roll and the complete feel would be more neutral, more like what you are used to in well built BMW's. Main problem is; 1) no aftermarket rear bar is available for Jaguars. 2) Even if you get the aftermarket bar, installation is quite complex. In general, you have to remove the whole rear subframe to replace the sway bar.

Of course, when it comes to BMWs they are hardly exceptional these days. I remember one of the testers saying about the new M6 ride: "The ride was unbearable". Much of the blame these days go towards the ultra low profile tires that simply do not absorb road imperfections.

In short, replacing the springs with stiffer ones would just ruin the ride of the car but, would not give you the neutral, precise handling that you are looking for. You need a MUCH larger diameter rear sway bar to do that.

 

You are correct, stiffer sway bar(s) won't do diddly squat to address your "float" issue; only "stiffer" shocks will, and apparently none are available.

 

John, yes, the sway bars would make a huge difference in the feeling of tightness. The shocks and springs are more than stiff enough already (unless the OP has a failed shock). Try to press down on either end of the car, front or back, and see how much you can compress the springs and the shocks. Nearly zero, meaning that they are set very stiffly. The OP compared the handling of the XJL to a Cadillac. In comparison, if you pressed down on the back of that floaty Cadillac it would probably compress 6" and wallow. The XJL does not compress or wallow at all exactly because of has very stiff springs and dampers.

With nearly every car I owned, the first and biggest handling improvement was done by adding a larger rear sway bar. My wife normally would not notice if a wheel fell off her car but, after changing the bars on her cars she would be wide-eyed in praising the handling, how much more precise the steering got and how much less effort it was to drive the car over winding roads.

Most factories undersize the rear bars, because:

1) "legal" issues. If you put the proper size rear bar on a car for precise, neutral handling, the car will spin if an unskilled driver tries to take a corner too fast. With the puny little bars, like what our Jags have, the cars understeer a great deal, making you dial-on more steering in the corners, rubbing off speed instead of spinning out. Years ago Porsche was sued for making its 911s handle neutral and causing lots of spinouts and deaths.

2) Using a large, stiff swaybar cuts down on the independence of an independent suspension. Not a real big issue, since most cars, including the Jags use something, like a 1.25" sway bar up front that definitely effects the independence of the left vs. right suspension. So, going to 3/4" or 7/8" at the rear would be hardly noticeable in ride quality.

The last Jaguar I was able to increase rear roll stiffness was my '05 XK where the rear bar was still located in the conventional, accessible location. Since there were no aftermarket bars available, I added a second stock rear sway bar in parallel. It made the handling much better but, was not enough. 2 x 0.5" does not come anywhere close to the stiffness of a single 3/4" or 7/8" bar which a car this heavy needs for sharp handling.

 

I tend to disagree if "sloppy", "drifty" and "floaty" on a road trip means that the car doesn't follow road undulations well, and doesn't settle down immediately after encountering a dip or hump in the road.

In these situations the wheels on the left and right side of the car act in unison and the anti-sway bars have no effect at all. In fact you could remove both the front and rear anti-sway bars (like some mid-fifty Buicks) and not notice any difference in ride characteristics under such conditions.

Cancelling the tendency to rebound or continue to undulate after the car goes over a bump or dip is the job of the shock absorbers, or dampeners, and thus decrease "floating".

Since anti-sway bars do have the effect of increasing the spring rate of individual wheels encountering a bump or dip, they also serve to make the suspension less compliant, decreasing its ability to follow undulations in the road encountered only by the left or right side of the vehicle.

So, yes, increased sway bars are helpful in negotiating winding roads by minimizing sway and weight transfer, and keeping all four wheels in contact with the road. But they will do nothing to minimize "float" on straight sections of road.

Incidentally, newer Cadillacs are some of the best handling cars on the road, and definitely don't "float".

 

Guess Id have to live with it then, theres nothing available aftermarket

 

I own a 2112 XJ SC

 

Hi Polarisnavyxj what tires and pressures are you running and have you had the alignment checked? According to your year and model it may have lighter springs and sway bars than were introduced on the 2013 models. If you have a good dealer and a helpful parts guy there ask them to check some of the part# available for later cars. The parts counter can plug in your VIN and find out what your car has now. Again I have found tire pressure (I run 38 to 39psi as is recommended for my model) and alignment are critical to the feel and handling of the XJ. I'll attach an alignment readout that my XJ is set to.

 

I agree to what you are saying above, however, my understanding of the OP was that the sloppyness was seen in "handling" conditions, such as winding roads. If the OP's car is sloppy in straight driving conditions, there is something definitely wrong with the car. My XJL is not at all sloppy in general. Yes, understeers more than I would prefer but, altogether a tight driver.

I think the 2013 models came out with lighter springs and dampers, per the factory brochures. I know because I had an ongoing ride issue with my 2012 and was trying the 2013s to see if they were different. No real difference in feel, however.

Your alignment values show some of the built-in understeer, that some people may feel as sloppyness. Generally, I would put more front camber into my cars than rear camber. That allows the car to turn in more precisely, quicker. Again, those values reflect Jaguar's conservative take on driving dynamics. Not only they place very small rear sway bars on the cars but, align the car with more rear camber than front. All of my last 5 Jaguars came with that bias. My preference in alignment would be around 1.2 - 1.4 neg camber in the fronts, and somewhat less, around 0.8 - 1.0 negative at the rears. Not sure why Jaguar places less camber in the front driver side. Perhaps that seem to compensate for the driver's weight and resulting suspension compression on that side. I always set all my cars the same left to right.

The best handling Jaguar in my last 5 is the 2010 XKR. Much less understeer than the regular XK or the sedans. The XF is second best, the XJL is third and the two XKs were bringing up the rear. Still, the XKR uses rear springs that are far too stiff, limiting exit traction from corners. Looks like they must have followed the same concept on the F-type as everyone mentions how tail-happy the cars are under hard cornering. Dropping the rear spring rates while increasing the sway bar sizes would do wonders for these cars.

On my XF the max. camber I could get on the driver front was -0.1 degrees. Not really enough for me but, that is all the adjustment gave me. The passenger side would go to -1.3. That is too much variation side to side. The rear cambers are non-adjustable for all late model Jags. (Not sure for the F-type)