Hi there,

Can anyone describe how the XJ8 (X350) behaves when one is cornering hard and the rear end gets loose? How about recovery? Easy? Not?

Of course I am talking about dry pavement and street tires.

A few days ago I was driving briskly on a mountain road when a new Nissan GTR came up behind me. I let him pass when I came to a pull-out, and then had a go at keeping up with him. We were not racing, (I'm not crazy, only dumb ), but I had to push the Jag very hard to even keep up with him. So I gave some thought to what would happen if I tried to go all out. Spinning my beautiful Jag into an embankment or going over the side and down the hill didn't seem very attractive though...so I thought I would ask what a stock X350 acts like when you try to play sportscar in one.

Anyone had any experiences?

Tom

 

A stock standard XJ8, on "comfort" shocks, stock ride height, stock tyres, no LSD...wouldn't be fun to try it on...

The only time a standard X350 get's into oversteer is if you lift off mid corner, and even then it's nothing too serious. The X350 is quite neutral, with a tendency to understeer IMHO.

The DSC is very active & will try to pull it together anyhow (1st hand experience of this), but if you go too far, well it's too far & you're a passenger until it comes to a halt.

Honestly I didn't try any "drifting" in my XJR until I had the LSD put in, primarily because i'd never driven a rear-wheel drive car with decent power that had an open diff. All my previous RWD V8's had LSD and were predictable. I felt the X350 was a little unpredictable with the open diff & DSC turned off.

 

I like a bit of oversteer,
Try 0.5 deg toe on the rear end rather than the standard 1deg
That will give you some very controllable oversteer

Cheers
34by151

 

I found a Jaguar promotional video from 2003 on Youtube. A Jaguar driver is seen drifting an XJ350 on a track. There are no obstacles to hit, only grass to slide on if you lose it. The track surface appears wet. He says that he is going about 70 mph.

Here is the link:
Tom

 

Yep seen that video before. There's a few things that need to be pointed out.

1. That's an XJR, on 20" wheels, a bit different to an XJ8 on 18"s
2. Mike Cross is a professional driver, and engineer who helped develop the X350
3. If he crashed that car, it wouldn't be coming out of his pocket, unlike us
4. The track was wet. You can drift just about any RWD car in the wet without much effort

You could see the inside wheel smoking, while the outside wasn't, no LSD.

Try driving an X350 like that, but in dry conditions; it would be bucking & weaving as the rear wheels fight each other, one with no traction, one with no power going to it. Not to mention the relatively soft suspension and high centre of gravity which wont' help much.

One of the suggested video's at the end of that clip was Tiff Needel's 5th Gear segment comparing the X350 XJR to the AMG CLS55. Honestly the XJ looks very untidy as he throws it around. And Tiff is a proffessional race driver.

 

Having taken my past X350 XJR to the track , I can say that the car is ridiculously easy to slide and control. Because of the open differential, power-on oversteer is extremely controllable with even aggressive inputs into the throttle and steering. The car did not have a tendency to become snappy even when pulling off the throttle mid slide. My current XFR is definitely a bit more 'edgy' when driving on the limits.

A basic understanding and some prior experience with car control is obviously important to feel out the dynamics of the vehicle. In my experience, the X350 XJR is very easy to drive fast, drive sideways, and drive down the freeway!

Here is a video of my X350 on the track. The last corner entering the skidpad (time in video = 2:05 and 4:00) is the corner where I was able to pitch the car sideways. Enjoy!

 

Thanks, I was trying to find that exact post but I couldn't remember who it was Patrick.

The OP is asking about an XJ8, but most of the examples we can find are of XJR's, which will be a bit different with the Sport suspension, tyres, and +100HP over the XJ8.

We did a few laps in a Diesel X350 at the Nürburgring last year, it was certainly not as stable or easy to drive on the limit as the XJR's that were there. The suspension, tyres, brakes of the XJ6D are the same as an XJ8, so I was trying to draw the comparison between those two cars.

 

The biggest issue I noticed with the X350 XJ8's (loaner vehicles I received while the XJR was in service) was with the tires. If I recall correctly, the USDM XJ8's were equipped with all-season tires; tires that absolutely lowered the handling limit the car could potentially achieve. I will admit that I put the loaners through their paces; using my XJR as a benchmark.

In all honesty, the XJ8's are also quite easy to drive. The cars are softer than the XJR and the brakes do not carry the same bite, however, whilst in oversteer the XJ8 is still very easy to control. The X350's all share a pretty long wheelbase which definitely attributes to the overall stability while in a yaw situation.

While I could force the XJR into a slide despite it not having a limited-slip differential, the XJ8 was definitely harder to get completely sideways due to the softer suspension unloading weight and causing the inside tire to light up. Power and aggressive steering input was the key element in getting the XJR sideways. Applying the same inputs to the XJ8, I found that it reacted similarly although to a lesser degree.

After all, I'm sure Jaguar did not want its target market to be snap oversteering into solid objects.

 

That would be understeer,
Oversteering is when you hit it backwards
Understeer is when you hit it forwards

You wont find many cars that dont understeer the one ones claimed as "a drivers car" usually still understeer just much less

Our suspension is very adjustable so if you want more start to play with reducing the front caster and rear toe

If you really want to know more I'd suggest reading
Competition Car Suspension, Allan Staniforth and Race Car Vehicle Dynamics, Milliken & Milliken

Cheers
34by151

 

I am quite aware of the differences between understeer and oversteer. Rather than writing a rebuttal using a few mechanical terms that are beside the point of this entire thread, my explanation is saying that the X350 does not exhibit a snappiness that is characteristic of most dedicated sports cars. And please understand that as an avid 'weekend warrior' of local track days, I have spent quite some time adjusting the geometry of my track vehicles.

Although pieces of literature may provide information of what happens to a vehicle when certain areas of the suspension geometry are adjusted, I'd rather comment on the behaviors of the X350's when adjusted to the specifications directly from the factory. Experience at the helm is invaluable compared to reading a book.

Here is an example of snap oversteer:

 

Pardon my hobbyhorse !

In my youth understeer and oversteer were simply terms that described how the steering handled in a corner when cornering 'with a bit of spirit' but with all four wheels in good non-sliding contact with the road.

Oversteer meant that as you cornered at constant speed you had back off the steering input, whereas with understeer you had to keep winding in. Or, to put it another way oversteer meant that the car had a tendancy to tighten the rate of turn after the initial set-up, where as with understeer it tended to run wide.

What are now called oversteer and understeer were respectively called a rear wheel skid (a controlled skid if you keep the back end from swinging right round), and a front wheel skid (very difficult to control).

[One S.Moss was of course the master of the controlled four-wheel skid, better know as a four wheel drift].

I suspect that the terminology has over the years been changed by second rate auto journalists who want to give the impression that they know what they are talking about, or worse, that they know more than the reader/viewer [UK for example: Clarkson et al ]

The problem is if you now allow the new meanings ... what terms do you use for the old meanings ?

 

Very interesting video! I gotta ask, though...do you get a lot of looks taking a four door sedan out on the track?

 

First of all, let me say many thanks to all who have replied to my question, especially Patrickw813. Willow Springs and AAA Fontana are both in my general area and I will probably be attending a track day at one or the other this year.

Now, concerning your question cjd, here is a reply from my point of view. I have taken my xj8 to the local drag strip twice, and will be taking it to a track day before long. As to the "looks" I might get I would just say, "who cares?"

When I went to the drags I saw a lot of guys in my age range running their cars. I'm 72. Car guys are car guys. The last time I went there was one guy who had just bought a new Taurus SVO (360hp with turbocharger) and was racing it. He was 88!!

By and large, most folks just enjoyed watching the racing. If anyone had problems with me or my old guy's car, I am not worried about it. I came to have fun running my car...and I did. So did my wife, though she preferred to watch from the grandstand.

In my youth I was a sports car fan and followed that and European GP racing instead of baseball and football. I got to see some real greats drive, such as Phil Hill, Masten Gregory, Chuck Daigh, Richie Ginther, Max Balchowski, Dan Gurney, and many more. At one race I got to see Chuck Daigh , driving a chevy engined special, whip the wheels off of S. Moss, Jean Behra, Roy Salvadori, Joachim Bonnier and some others in some of Europe's best marques. (A little cheering for the home team. ;-) )

Later on as I went through military service, college, career, kids and so on, I got away from actually having great cars and drove family haulers and pickup trucks. Now I am retired so I have the time to "follow the joy". If someone has a problem seeing this old timer on a track in old guy's car...I hope they get over it quickly and have some fun.

That is my $.02

Tom

 

Ok - that was fun!

John, I've been to a bunch of track days at different tracks - there's a contingent of 4dr Caddy boys, E55s, (even an E63) 4dr Porsches and of course BMWs - I totally agree with Tom - you know why you are there and other than that who cares?

 

folks, here is a youtube video of a Jaguar xj8 at the Nurburgring. The driver and passenger chat a bit, and to me they sound like guys from the UK. Enjoy!

 

Didn't mean to poke at you guys. It's just the last time I thought about taking a big sedan to the track I was in high school and snuck out with Dad's car to see what it would do in the 1/4 mile. Laplace, la. I see times have changed.

 

From the reactions of almost all of the individuals who are at the track days I attend, I definitely do get a lot of attention for having a large four door sedan on a track.

It is quite funny when I am able to pass many sports cars that are more at home on a track! The usual reaction is asking what is under the hood followed by what car I am driving. Although people usually know it's a Jaguar, they usually say that they "never knew a Jaguar could do that on a track".

It's always good fun!

 

Since the discussion has veered off into the kinds of cars one expects to see at track days, take a look at what shows up on the Nurburgring at 0:45 seconds.

 

X350 XJR steers perfectly... Even with open differential and disabled traction control.
When i've had a chance to try it - wow, i was impressed.