[baron95]

Does anyone have a recommendation of what cold tire pressures to use on the XF-SC or XFR for track days?

Specifically this is a fast track with three long straights with terminal speeds of 130-150MPH followed by heavy braking and long sweeping sustained turns. Each session will be 25 minutes long.

Options are:
1 - Start with factory street pressures 34/34psi, and assume that pressures will rise appropriately to something a bit harder.
2 - Start lower to prevent too high pressures after heating up.
3 - Start higher to prevent excessive sidewall flexing/folding and control pressure rises.

There seems to be a fairly even split between those advocating for starting higher as for those advocating starting lower. Which leads me to favor starting at the street pressure. But all say you have to "experiment".

So, has anyone experimented and know what works well on the XF-SC/XFR? Anyone knows what Jaguar runs at their track days performance academy?

Thanks.

[abasu]

Baron, the P-zeros are quite track-happy. Inflating slightly makes sense to me, but it's not a biggie.

At a Jaguar Association of New England slalom last year, they recommended inflating the tires by a few psi.

At Monticello last fall, there was no discussion and oddly, no pump in sight.

[baron95]

abasu, on 19 April 2010 - 04:18 AM, said:

Baron, the P-zeros are quite track-happy. Inflating slightly makes sense to me, but it's not a biggie.

At a Jaguar Association of New England slalom last year, they recommended inflating the tires by a few psi.

At Monticello last fall, there was no discussion and oddly, no pump in sight.

Thanks Abasu. Yes, there is no air at Monticello - you have to bring your own bottle or pump.

What pressures did you run on your 5 laps? 34/34?

[abasu]

baron95, on 19 April 2010 - 02:58 PM, said:

abasu, on 19 April 2010 - 04:18 AM, said:

Baron, the P-zeros are quite track-happy. Inflating slightly makes sense to me, but it's not a biggie.

At a Jaguar Association of New England slalom last year, they recommended inflating the tires by a few psi.

At Monticello last fall, there was no discussion and oddly, no pump in sight.

Thanks Abasu. Yes, there is no air at Monticello - you have to bring your own bottle or pump.

What pressures did you run on your 5 laps? 34/34?

Yes, regular street tire pressure..

[Long Islander]

baron95, on 17 April 2010 - 02:37 PM, said:

Does anyone have a recommendation of what cold tire pressures to use on the XF-SC or XFR for track days?

Specifically this is a fast track with three long straights with terminal speeds of 130-150MPH followed by heavy braking and long sweeping sustained turns. Each session will be 25 minutes long.
Thanks.

I recall from my track days with BMWCCA, that I used to inflate my tires aorund 3-4 PSI higher than normal.

On which racetrack will you be driving -- the description doesn't sound like Lime Rock.

BTW, PCA has a track day coming up at Pocono International using the full course, which I've been thinking about. I've driven there before on the inside course and didn't like it. But the thought of perhaps hitting 174 MPH on the full course has me intrigued. Say, does your XF-SC not have a speed limiter like the 5.0's (which limits top speed to a mere 122 MPH)?

[baron95]

Long Islander, on 22 April 2010 - 05:33 PM, said:

On which racetrack will you be driving -- the description doesn't sound like Lime Rock.

I missed Lime Rock Track Day on the 12th due to a stupid business trip. I'll try Monticello, NY.

Lime Rock sucks anyway - boring track, all turns to one side except one, no run-off areas, etc. I don't get it why people think Lime Rock is so great. Maybe in 1930 or to drive a vintage car at 50MPH.

Monticello is a great track - I always wanted to drive it (not counting the 3 half laps courtesy of Jaguar )

Is the PCA at Pocono open to all car brands?

XF-SC has the speed limiter at 155MPH, but I'm told it cuts off a few MPH after that. My tires are Y-rated, 186MPH. So good margin. The Jaguar manual for the XF-SC recommends 34/34 PSI for sustained driving above 100MPH. So I'm thinking of going with that or something like 36/36, then let air out if that is too loose.

[Long Islander]

baron95, on 22 April 2010 - 02:34 PM, said:

Long Islander, on 22 April 2010 - 05:33 PM, said:

On which racetrack will you be driving -- the description doesn't sound like Lime Rock.

I missed Lime Rock Track Day on the 12th due to a stupid business trip. I'll try Monticello, NY.

Lime Rock sucks anyway - boring track, all turns to one side except one, no run-off areas, etc. I don't get it why people think Lime Rock is so great. Maybe in 1930 or to drive a vintage car at 50MPH.

Monticello is a great track - I always wanted to drive it (not counting the 3 half laps courtesy of Jaguar )

Is the PCA at Pocono open to all car brands?

XF-SC has the speed limiter at 155MPH, but I'm told it cuts off a few MPH after that. My tires are Y-rated, 186MPH. So good margin. The Jaguar manual for the XF-SC recommends 34/34 PSI for sustained driving above 100MPH. So I'm thinking of going with that or something like 36/36, then let air out if that is too loose.

Lime Rock is desirable mainly due to its proximity to NY, Hartford and Boston. The track is very short, and you can see through all the turns -- unlike Bridgehampton, which was an incredibly challenging track with its 2.86 miles, 13 turns (most of them blind), non-existent run-off, and 1/2 mile long straightaway. And, for me, Bridgehampton was a very easy drive away. I didn't get to look at, much less drive on, the full track at Monticello. The short track that Jaguar used was more fit for go carts than cars.

The PCA Pocono full course day on June 18 is open to all makes, which is rare. Here's the link to the calendar. http://metronypca.org/de_schedule.html

I would check on the fire extinguisher requirement, which is usually mandatory. The fire extinguisher has to be mounted within reach of the driver and using a metal bracket. There are nice mounts that are easily removable for Porsches, but it may be trickier to install one on an XF.

[baron95]

Long Islander, on 23 April 2010 - 01:29 AM, said:

The PCA Pocono full course day on June 18 is open to all makes, which is rare. Here's the link to the calendar. http://metronypca.org/de_schedule.html

I would check on the fire extinguisher requirement, which is usually mandatory. The fire extinguisher has to be mounted within reach of the driver and using a metal bracket. There are nice mounts that are easily removable for Porsches, but it may be trickier to install one on an XF.

Actually I have never ever been to a PCA event. Are they good? Do they qualify for insurance as HPDE?

There are quite a few events at NJMP, which I hear is a very nice new track - anyone want to make an XF date of it? We can show up with a squad of XFs

Monticello full course has a 3/4 mile "straight" with a flat out "kink" 2/3 of the way and heavy braking for 3 connected short "S" turns at the end. Must be fun

[Long Islander]

I've been to several local PCA autocrosses, but never to one of the track days -- mainly because there are no tracks that are close enough that I wouldn't have to stay overnight and leave my Porsche outside at a cheap trackside motel.

The autocrosses are very well run, so I would expect the track events to be similar. The Pocono full course day this year is open to all makes, which is the first time I've heard of a PCA track event that was open to non-Porsches.

I've never heard of insurance HPDE requirements.

Enjoy your day at Monticello.

[baron95]

Thx.

I know what you mean. I'm hoping to make this track day at Monticello. I'll let you know how it is - will be my first time with this organization (all ex Skip Barber guys).

If they are good, we can have a Jaguar XF day on one of their future events

[OzSV8]

Try this link for good information - http://www.carbibles..._bible_pg3.html

[abasu]

baron95, on 23 April 2010 - 09:27 PM, said:

Thx.

I know what you mean. I'm hoping to make this track day at Monticello. I'll let you know how it is - will be my first time with this organization (all ex Skip Barber guys).

If they are good, we can have a Jaguar XF day on one of their future events

Good thinking Baron, will look forward to that! Have a blast at your outing and have someone take pix so you can post!!