I agree that all these numbers are somewhat useless, however, I do think the most accurate is what Jag and/or Ford discloses. That being said, from what I have seen, Jag USA claims both a 5.3s for both models. THAT is only for the 2005, BUT by then all the updates have been made and the STR stayed the same until its premature death in 2008.

Obviously there is a flip side to the coin, if you take the stance that numbers are not accurate than someone else could take the stance that the driver of one vehicle or the other CANT DRIVE. A straight up stock drag race, quarter mile, 3-4 runs will give an accurate indicator. Very hard to drag someone and find out the 0-60.

DOES ANYONE IN THE GREATER BOSTON AREA HAVE AN XJR???? Hell make it Massachusetts. I want camera crews there, sponsers, bikini models....the works.

This challenge should be posted ont he XJ side of the forum...who's gonna do it?

 

Who cares?

The S and XJ are dramatically different cars. Zero to 60 hardly figures in the distinction.

 

In the distinction, really?

We are talking about quickness and speed with vehicles that have some similar/same components, rated approximately the same 0-60, and ARE "R" models. That sir, is not a useless topic.

It is a discussion, none of us are going to lose any sleep over it, but it is a discussion nontheless.

If you would not like to be part of this particular discussion and add something useful, then with all due respect, beat it.

 

What I don't understand is how someone can argue with simple physics...

If both cars have the same engine/tranny and rear drive ratio (all the way, flywheel out to the tires), then, using the same driver on the same course, 0-60 time will be won by the lighter of the two - the XJR by about 300 lbs. At speeds above that, who knows, because aerodynamics are becoming more dominant... but up to 60, they have little effect.

If one wants to drag race, then driver becomes a factor, as do other things like how much fuel is being carried, tire pressures, and many other variables...

But, when comparing apples to apples, again, the lighter car is going to have marginally higher acceleration, and will be faster 0-60, period. Acceleration = force / mass ... with force being the same, and mass lower, acceleration MUST be higher.

 

If that is the case than why is the BMW 335i twin turbo sedan is faster than the coupe?

Is this a FACT= "same engine/tranny and rear drive ratio (all the way, flywheel out to the tires)"?

 

Great thread! The 0-60 is all determined by power to weight and how well the car hooks up. The same power in two different vehicles can have different launches. I have a stock 04 XJR with Michelin sports in Chicago. Let me know who wants to run.

 

Hey whats up Drew, I believe we do have some STR owners from the Chicago area. Anyone??

 

Once again since I busted into this..

I can say my 07 XJR felt quicker in flat out acceleration than my STR.
Not by much but just a seat of the pants feeling so to speak.

The STR handles much better due its smaller size and the lack of air suspension
while the XJR was no slouch it didn't inspire confidence at times.

very different cars in my opinion both amazing though.
I still by the fact that I believe the ride in the XJR is one of the best out there.

 

Thank YOU Bull..... These discussions are a blast and very valid... These forums are more than just talking about failed throttle bodies, bad coolant tanks, and crappy lugnuts.....

Hey, I'm up at 6:30 am on a Sunday So, maybe I am loosing sleep...Nah just beating the kiddies up on Easter...Bull, you have all this to luck forward to!

 

What spec sheets are you referring to? When you look back in the 5.6 vs 5.3 discussion you will notice that Jag goofed on both cars .... In their literature they do claim that the STR is 5.3 BUT also claim that the XJR is a 5 flat...

 

Are the suspensions identical? And the wheelbases (the XJ can be LWB as I recall)? And drag? Are their centers of mass the same? And so on.

I'd prefer the STR round corners at high speed.

These are just questions... I'm interested in an actual shoot-out too

 

Yep, you guys can yap back and forth 'til the cows come home (probably no cows in Boston, though) about specs and physics, but the question won't truly be resolved until two drivers of near-equal ability and weight pair off in their STR and XJR and have at it....

Keep us posted. Many inquiring minds want to know. But keep it safe as well....

 

Oh I was just going off of multiple articles that said "Jaguar claims.....", nothing directly from Jag.

I would LOVE to see a few runs at the quarter mile between these vehicles, either in person or on video.

Happy Easter to all that celebrate it, and yes Jeff, baby is coming, belly getting bigger by the day as well as my anxiety levels!

 

Bring it lol
although it will do nothing for this thread...as we will both be far from stock

and fyi, my book/manual that came with my xjr puts the weight at 3950 for a 04 xjr

 

so who's racing

 

http://www.youtube.com/watch?v=A0A-w...eature=related

 

There are many factors that would determine which is faster.

1. Weight: Every 100lbs usually means 0.1 seconds.
2. Power (HP/Torque): Torque being more important in a launch situation. What are the characteristics of the power curve?
3. Weight transfer: How much traction to the rear wheels?
4. Aerodynamics: A brick is slower than an arrow off the line.
5. Power transfer: What RPM is the stall converter engage? When does the tranny shift? What are the gear ratios?
6. Wheels/Tires: What sized wheels and tires are on the car? If both have identical trannys, larger tires will make a difference.

Some of these are not relevant due to the fact that both use the same engine/tranny but are both set up to shift the same way?

Other than that you have aerodynamics and weight transfer which play a huge role....

 

It seems like pretty much all of the reviews I've seen have rated the XJR faster. Not just in 0-60 but 1/4, 30-50 passing, rolling starts, etc.
The weight difference between the two cars does not seem to be substantial enough to make a difference. One thing I haven't read in this post is that despite having the same powertrain, the axle ratios are not the same in these two cars. I thought this would explain the difference but what I found was not what I expected. The XJR only has a 2.87 while the STR has 3.31 gears. The STR is the slower car despite having a lower axle ratio and bigger tires? Doesn't seem to make sense. I do find it interesting that the S-Type R reviews always complain about early shifting but I haven't read the same complaints about the XJR?

 

You've looked at the non-STR ratio. The STR is 2.87.

 

That is 100%. The cars are so close. Take just an XJR vs XJR of the same production day and with two different drivers the battle will go back and forth to no end.

Perfect example. I used to have a 99XJR and worked in an industrial park with many companies. On my way to work every morning I would run into the same 2006 XJR and 2002 STR. We all worked in the same park (different companies) and would race on the highway every morning. Sometimes all three of us and other mornings just two, but each day it was different. It was up to whomever was awake and aware that morning. Those year ranges were very different, HP, transmissions, engines, body style, body weight, but the cars were so close in an overall standing that it just came down to the driver.