Throwing it out there for the knowledgeable jag techies. What exactly is the difference, or rather what would it take to upgrade the 5L XF SC to the performance of an XFR? There are the obvious appearance modifications externally and the seats, but what exact internal engine, suspension, and drivetrain components are upgraded that actually affect performance? The general categories I am assuming are:

- engine internals and tuning
- suspension
- brakes
- exhaust?

Not that I'm not happy with 470 hp. I think the SC was such a bargain for the performance but I'm curious to know what it would cost to bridge the performance gap with the R.

 

I've wondered also. i think the brakes differ only in caliper. The e-diff is the same, suspension is same. Cosmetics like hood scoops. I think for 40 hp it's likely exhaust, breathing and tuning.

I have asked about exhaust differences before (my sc bas quad tips) but did not get an answer.

 

I have owned a 2010 Premium Lux with the 5.0L which was a faster than you ever need to be car with a great ride and drivability. I had test drove a 2011 XFR in spring and after driving it found that with 500+HP it was difficult to control from a drivabilty stand point plus the upgrade was $36k with my car. I passed because from an all around experience why pay all that money for the same car thats hard to. drive? In fact I had traded in an Infiniti G35X S because when you touched the gas it took off and when you braked it threw you forward and had a rough ride. The XF Premium Lux was so much better and got 8 more MPG on the highway. I could not stop smiling while driving. In fact I bought my wife a flawless 2004 XJ Vanden Plas for $15k, so now I have 2 for less than the upgrade.

That was until last week, the dealer had received a 2011 SC and still had the XFR with additional enticements. I test drove the 2011 SC against the XFR and preferred the SC. The suspension, exhaust and braking are identical however the mild detuning down to 470HP from 510HP made it just drive better. In fact this particular SC was a special build with 20"Selena wheels, the XFR seats and also Piano Black interior trim not available in 2011. The difference basically was the diameter of the supercharger pulley which lowers the boost. The dealer offered that as an option. Now I have 0%,an extra year and a half to pay about the same payment, 5 years of service free,plus warranty and a free set of winter tires plus a really sweet ride.

 

The importance of driveability for a car driven as a daily driver in real traffic cannot be overstated. We buy these cars for daily driving and ultimate track type performance is just not relevant.

Amusing that Jaguar knows the XFR is over tuned, the smaller drive pulley not only ups the peak boost it also brings in the boost much more rapidly. Similar problems result fom accelerator programming (if electronic drive by wire) or throttle plate actuation cam profile. North American designed cars suffer from over aggressive tip in and many import manufacturers build their North American versions in this fashion. This makes the car lurch off the line. Add grabby brakes and you find yank tanks very hard to drive smoothly.

 

Um... not to be too blunt, but what the heck are you guys talking about? I've owned my XFR for a while now and I haven't experienced anything like what you're talking about.

Too much power? Its not like you press the accelerator a bit and get 500hp leaping down your throat. The monstrous acceleration and driving dynamics of this amazing vehicle don't get enormously impressive until you get into WOT situations and threshold braking. Until that happens, this cat is as tame as a kitty.

Some of the above comments seem tinged a bit greenish to me.

 

Well, if you want to go through all the minutia on equipment etc., attached are a couple of documents to help you out.

Cheers,

 

To help bridge the gap, we are offering an ECU upgrade.

ECU Upgrade - XF SC

 

For a review of the SC model check the link in the current last post in the no burning rubber thread.

Seems some prefer the Q ship character and looks of the SC.