i've searched the internet for aftermarket ARB/Sway bars for Jaguar XF. no such luck. i wonder can somebody point me in the right direction.. I am even willing to consider the XFR anti roll bar if it fits and is thicker than the XF bar. any ideas guys?

 

I don't think they make one for the XF.

Do you find the car to have too much body roll?

XF's cornering ability is excellent and is never going to be practiced to it's limits by most drivers.

 

the suspension is good.. firm, but the roll is quite obvious. i love corners, and the XF corners very well , but the roll....

 

What about the roll?

All cars roll when cornering, it's designed on purpose to do that. Even F1 cars roll in corners or they would be undrivable.

Your search will be in vain not because there aren't enough Jaguars to modify but because nobody will feel the need to reduce body roll on a car that already doesn't roll very much.

 

Gotcha.

The only source for the sway bar upgrade is probably going to be from a XFR and/or RS models. I don't know what the suspension looks like underneath, but you may have to drop the sub frame to exchange them. Can be a lot of work.

Also, replacing just the front or the rear will have negative affects on the suspension. You will end up with way too much over steer or under steer, depending on which one you decide to upgrade.

Best recommendation i can make, is possibly to replace your current XF with the SC model or even a XFR with CATs system, that tightens the car automatically when you start pushing it.

 

I thought the SC and the XFR suspensions and underpinnings were identical?

 

Likely they are.

No way anybody is going to build aftermarket roll bars for this car.

 

can you confirm the ARB is thicker? and if its a direct fit? that's my last chance. lol.

 

The CATS system alters the damping rate only, electronically and automatically. The roll bar rate may be different but that has nothing to do with CATS except softer dampers can compensate for stiffer spring rates to some degree.

Any dealer can tell you if the part number for the XFR roll bars is different. If it is they will be thicker, higher rate bars. You won't be happy with fitting them, I'll wager.

 

Ultra Racing has a few products listed on their website for early-model XF's (UR-LA2-1146 and UR-RL4-1147), but I don't have any direct experience with them and don't know what the true applicable range would be for the products. From what I understand, the company is reputable, but it looks like the product pictures are photoshopped, rather than being pictures of the products actually installed (at least for the Jag-specific products). Further, it looks like the picture of the Front Lower Bar / Front Member Brace (UR-LA2-1146) isn't even of an XF. And, I don't think there are any available bolts for use for use where they have the Rear Lower Bar / Rear Member Brace (UR-RL4-1147) positioned in the picture. But, as always, I reserve the right to be completely wrong.

Try this link for additional information... >>> Jaguar XF-SV8 4.2 (2008) Aftermarket Performance Parts / Accessories / Spare Part - Ultra Racing Product Catalog

 

Unfortunately Jaguar owners tend NOT to be very demanding when it comes to the ultimate, precise handing. That is why after market manufacturers do not bother with making a wide choice of suspension parts for our cars. If you really like to tune your suspension you have to go to a different brand.

On my '05XK they used a ridiculously small diameter roll bar that was mounted under much of the suspension and I was able to manufacture a custom larger diameter bar to get rid of that horrendous understeer and the resulting inaccurate steering. On my '08, the understeer was moderated but still bad and the steering was still not responsive for my taste (my taste is referenced to race car quality handling). They burried the rear bar under a bunch of components so it was not practical for me to build an other one.

My XF actually set up and handles better than either of my previous XKs but, still could use a larger rear bar for skilled drivers. I doubt you will be able to buy one and I have not even looked to see how hard/easy it would be to fabricate a custom bar. Really, it is my wife's car and good enough for her.

Factories undersize the rear sway bars because it introduces a lot of understeer which is safe when an unskilled driver drops into a corner too fast. A truly neutral handling car will spin out under that scenario. So, it is a matter of safety. In the earlier XKs they went so far with understeer that the car handled like a PIG. The XF is not bad but, still understeers more than I would personally prefer. Nice thing, however, that it is close enough that by keeping the RPMs within the range of 4 - 6000, you can use the engine torque to compensate for much of the understeer in the corners.

Albert

 

I have had one of their bars on my 2000 9-5, it transformed the heandling... but it was not designed well. They solidly connnected a floating part of the subframe to the underframe and it really stiffened it up a lot. My car lasted longer that a lot of others but it ended up breaking from teh stress of the moving section against the fixed.

In any event, it did work and I was thinking about getting the bar reinforced ( it broke at the poorly done welds) and looked as though it just needeed some more attention at the joints, but I decided not to put it back on. IIRC it was made in Indoneisa

 

I can attest to the high quality of their products. We installed the front & rear undercar braces as well as rear sway bar on my 2000 XKR. They are well made & bolt straight on. I would highly recommend them.

 

Stiffening up the rear roll on an XK can reduce traction in corners because there's no LSD.

 

You would have to be cornering super hard at track racing speeds to come close to lifting the inside wheel to cause traction loss in the XK. Not likely in such a heavy car. A rear sway bar, say size 3/4" to 7/8", would do wonders for the XK's handling and to its steering responsiveness, which is rather poor right now.

Albert

Edit: Sorry, I lost track of which Jag forum I was on. The last comment regarding the poor steering response was NOT intended for the XF (which is fine) but, for the XK.

 

You don't have to lift a wheel to reduce traction. The inside tire always smokes first with an open diff. More roll bar makes this worse.

Also there is a difference between spring rate effects and roll bar effects. The drop throttle "spin out" you refer to is caused by weight transfer more than by roll stiffness.

Whether to up the spring rates or the bar rates is a tricky question. Also, tuning suspension for road use is an entirely different matter from track use.

Jaguar is pretty much perfect for road use.

 

Here's the response I got from Ultra Racing regarding their early-XF-specific Front Lower Bar / Front Member Brace (UR-LA2-1146) and Rear Lower Bar / Rear Member Brace (UR-RL4-1147) when I asked about the installation pictures and potential fitment onto my '11 XFR...

"Hello,

Thank you for your email, we couldn't confirm if the parts will fit on the XFR. The product photo is the actual picture where the product's being fitted onto the actual vehicle; it is only the Ultra Racing logo that was pasted onto the picture because the prototype parts don't have a logo sticker on them.

Should you have further inquiries, please do not hesitate to contact me again.

Before you order:
Please be informed that most Ultra Racing products are being fabricated based on Malaysian/Asian(Right hand drive) model of vehicles so please consider about left/right hand drive issues and engine capacity before purchasing any products from us.

Packing and delivery
Please allow a certain period of 3 days - 1 month just for packing your orders before shipped out. Please always ASK for your estimated shipping date before you place an order as it will always depend on our current orders on hand.

Thank you and we hope to hear from you soon.

Best Regards,

Junloong
Ultra Racing Marketing Executive


No.25, Jalan Bukit Permai Utama 3, Taman Industri Bukit Permai , 56100 Kuala Lumpur Malaysia.
Tel:+603-42804213 Fax:+603-42804313 Hand Phone :016-2387825
junloong@ultraracing.com.my
http://www.ultraracing.com.my/"

 

Jagular

I do not know about your expertise on suspensions but, let me suggest that I had raced cars for decades, quite successfully, winning countless races and a good number of yearly championships with SCCA in various race cars and classes. All that time I constructed each of my race cars and tuned the engines and suspension for them. Since in road/track racing suspension setup rules when it comes to winning, I think it is safe to assume that I know a bit about how to properly set up not only racing cars buy my ultra performance street cars.

The Jaguar XK, the present edition is far from perfect for road use. It still understeers like a PIG, rolls too much and the steering is not responsive. If you drove my present sports car with the properly tuned custom suspension you would be absolutely blown away by the HUGE difference.

Having said all that, my general guiding philosophy in constructing both race and street suspensions was to set the spring rates relatively soft, just enough to keep the suspension from bottoming at the minimum ride heights. Then, use heavy roll bars to set up the roll resistance. Also, use dampers with at least an adjustable rebound which is far more important than the compression rates. Many street manufacturers tend to put too stiff springs and way too heavy compression rates on their suspensions, thinking that the stiffer they make it the more "sporty" it will become. Big mistake. A car with softer springs and less compression damping will maintain much better contact with the pavement over surface irregularities then a stiff setup. As you may know, not only streets have bumps and irregularities but, race track surfaces are also far from perfect.

The present generation of XK is set up for boulevard cruising and not for performance driving. It understeers far too much, rolls too much and the steering is not responsive enough for any serious canyon driving. It needs a lowered suspension (too bad Jaguar does not allow for camber adjustment on the rears), different-rate adjustable dampers AND a much stiffer rear anti roll bar with poly bushings. Those would absolutely transform the car for the better while still maintaining reasonable ride comfort. Loss of cornering traction would not be an issue at all for me as I never light-up the tires coming out of any corner. If you do, in any car, you will be going too slow and will finish last.

Generally speaking, the larger rear sway bar is the biggest handling improvement for the buck on just about any street car application.

Albert

 

Didn't you know?...He's thee EXPERT on EVERYTHING

 

my search goes on.. its pretty futile at the moment..

thanks for all your comments. especially axr6. i fully concur the arb is the biggest bang for buck improvement. i have no intention of touching my suspension,the balance is perfect for me now, some handling without too much harshness, but i sure could do with a little less body roll. if you have a contact for a custom arb, please do share.