This is an annual testing of hot performance cars at Virginia International Raceway, and was done with the 2010 XKR back in late 2009. I thought some of you might be interested. Instrumented testing on various parts of the track, timing of the full 4.1 mile laps, multiple driver feedback and 2 days of testing many hot cars gives their results and driving impressions great credibility. I've driven this course a number of times, and not only is it a very challenging and high speed road course, but its layout really does test every aspect of performance imaginable.

The XKR's lap time of 3:06.4 was within 0.6 second of the Porsche 911 Carrera S and the Cayman S. You'll see in the linked article the results of many cars tested under identical test conditions, and a listing of C&D's results from this same testing going back to 2006. All cars were supplied and tested with all available factory performance options. Tires will make a substantial difference, and while the XKR's are good, they're certainly not as good as some.

Here's what they said about the 2010 XKR...

"The XKR was a shock—that is, its lap time was. The newly revitalized R model, with a 510-hp, supercharged 5.0-liter V-8 underhood, is tremendous fun. It offers nicely balanced handling, excellent midrange power, a wickedly malevolent growl under hard throttle, and capable brakes, although they did finally give in to fade after repeated lappery.

The XKR’s steering feels overly light on initial acquaintance but is very communicative when the car is pressed. Although the R’s tail will easily get loose, oversteer is quite controllable and very predictable. We also like the quick-shifting automatic transmission controlled by paddles mounted on the steering wheel. Our only complaint, other than a lack of under-butt sculpting in the seat, is that the throttle pedal has a lot of friction near the end of its travel."

While I haven't experienced fade during 30 minute enthusiastic lapping sessions (but likely haven't pushed quite as hard because I actually had to pay for the car!), nor any throttle friction, it agree that it's tremendous fun and nicely balanced on the track. I'm glad they also noted that the steering is very communicative when pushed, and that oversteer is quite controllable and very predictable. I've had the tail out numerous times under hard throttle exiting a corner, and under throttle through a high speed sweeper with a nasty dip in the track that can unsettle the car, and a slight steering correction is all that's been required. I think oversteer is more of an issue on cold tires when too much throttle is applied for the conditions as opposed to any issue with the car's setup.

Lightning Lap 2009 - Car Comparison - Car and Driver

Now power and handling improvements have been made to the newest crop of hot cars that result in lower lap times, including the XKR-S, and you can read about it at

Lightning Lap 2013: Hot Cars, Hot Track, Hot Laps – Feature – Car and Driver

At the end of that article they list results from 2006-13. Test conditions would likely vary slightly from year to year. There's only 3 cars on that list that were quicker than the 2010 XKR that I would want to own, and that's the Ferrari 430 and 458, and the Lexus LF-A. And since none of them have a back seat or trunk worth mentioning, I still feel exceedingly happy with my XKR
Maybe we'll see the F-Type tested in the next one!

Bruce

 

The C&D lightning lap issue is the best issue of the year. I'm not surprised the xkr had a good lap time after driving it on the track at the R academy. Thanks for posting it.

 

The historical lap times pretty well tell the story. The XKR(s) variations are quicker than their direct GT competitors from BMW but, can not come near the top 2 seaters or even some Camaros and Mustangs. The 911 Carrera is over 2 seconds behind the Camaro ZL1 on this power course, which is a little more than the 1 second for the Camaro at Laguna Seca, which is more of a handling course. The time differences increase when looking at the historical list and comparing models by the manufactured dates. The superiority of cars, like the late model ZR1/ZO6 and GTR among the high priced exotic and purpose built race/street models is stunning. I think they should be seen as the target for the F-type on the tracks. Will it be close?

The ZR1's (or even the late ZO6's) 5 seconds advantage over the track-specific Porsche GT-3RS and 7 seconds over the 911 Turbo is huge, like being entirely in a different class altogether.

Again, the XKR is a GT car so, lap times should not be a primary factor in making a purchasing decision.

Albert

 

Great stuff. Very interesting comparison to be made between the 2010 XKR and the 2013 XKR-S. None of the "heart in mouth" comments on the XKR, but they spill like crazy from the driver of the XKR-S.

So, Jag picked up 4 seconds, which is an eternity of course, but at a pretty high driver confidence cost, it seems...

 

You're right about them having a difficult and unnerving time hustling the XKR-S around the track quickly, and Randy Pobst indicated that difference between it and the XKR as well in testing at Laguna Seca. I had wondered if it was the 10mm lowering that affected suspension geometry negatively in pursuit of a sportier stance, or the related recalibration of the dampers that may have been necessary, or recalibration of DSC to allow for a little more tail out action. I find the throttle in the XKR has a bit of a hair trigger action when trying to squeeze on/off small amounts of power, made worse in Sport Mode, and if the XKR-S is also like that then it could be even more difficult with its extra 40 lb/ft of mid-range power.

But I have a feeling it's caused by the one thing that affects handling more than any other...tires. I believe it uses the Pirelli P Zeros, and here's another C&D Tire Test that ranks it dead last among 10 of its peers. That's 11 out of 11! And the test driver's comments are along the lines of those who drove the XKR-S for the Lightning Lap.


"The P Zero’s cellar position surprised us. We’ve been amazed at how this tire utterly transformed the Ford Mustang’s steering precision, and P Zeros are original equipment on exotics such as the Lamborghini Aventador and the Ferrari 458 Italia. But a blind test does not lie.

This tire’s best finishing position in any test was middle of the pack in the wet autocross, just a bit quicker than most of the extreme-performance tires. Geswein called the Pirellis “firm and skatey, and understeer oriented.” Wet-skidpad grip, at 0.79 g, and wet braking, at 111 feet, were worst in the test.

Lapping a dry track didn’t dramatically change our impressions. The P Zero struggled with understeer, and post-limit grip recovery was noticeably worse than with most of the other tires. Steering precision took a hit on Geswein’s ballot as he found himself overcooking corners. Ultimately, he thought the driving precision required for a clean autocross lap simply couldn’t be found for this set.

At $161 each, the P Zero is upper-middle class on the cost scale. A supple ride and quiet operation aren’t enough to pull the P Zero up the finishing order."

That's a complete condemnation of a tire if I ever I heard one. Here's what they said about the Michelin Pilot Super Sport...I'll be ordering a set of those very shortly as I've got 3 track days coming up soon.

"Two years ago, Ferrari launched the 458 Italia a few months before Michelin released its Pilot Super Sport (PSS). Because Ferrari wanted the PSS for the 458 but Michelin didn’t want to preempt its own release, some of the early 458s were delivered on “Michelin Pilot Sport PS2” tires. But those PS2s were actually PSSs. It isn’t hard to understand why Ferrari wanted the “custom” PSSs for the 458.

We praised the PSS for its steering precision in the wet, second only to the Conti. Having the most lateral grip in the wet, at 0.86 g, helped close the lap-time gap with the Conti, too, but the Michelin got there with less finesse and feedback.
It felt firm and planted on the dry autocross and brought the steering wheel to life in our hands, as did the Yoko, the Hankook, and the Dunlop.

The Michelin PSS finished with the second-quickest lap in both the wet and dry autocrosses, just 0.1 and 0.2 second behind the leaders, respectively.

The PSS has the best balance of wet and dry performance we’ve ever experienced in testing. The minute compromises in each discipline make “super” a worthy part of its name. It’s our winner."

Not sure how they can claim both the Pirelli and Michelin came on the F458 Italia.

The complete C&D Tire test is here...
Monsters of Grip: Nine Summer-Performance Tires Tested - Comparison Test - Car and Driver

Bruce

 

My ex-sponsor who owns a Goodyear tire and racing-tire dealership, as well as a racing fabrication shop, simply stated that "these days the Pirelli tires are JUNK."

In one of my rants about the 911 I said that many pro testers are treating it as a religion about which one says no bad things. They always think the 911 is without fault, at least until the next 911 variation, at which time they are allowed to mention some of the previous 911's eternal vices. From this test:

" The 911 is a car taken off its toes and put on its feet. Porsche smoothed out the 911's dartiness and jumpiness, and directional changes are less frantic than before, making it a more settled, more capable track car."

Hmmm... until the next new Porsche this will have to do. Then, we'll be told how terrible this one is with the very same rear-end vices. Actually, Porsche did move the engine a little bit forward so it is not that radically rear-engine biased. I am sure it helps but, it is still rear-engined.

Albert

 

I could not agree with you more. I just wish Jaguar would have decided on the PSS or something better instead of the PZero for this car.

It probably would not only have provided better traction, but also lift the confidence in the driver and by doing so also significantly lower lap times.

I was impressed with the XKR-S top speed on the straight, 147.1 MPH, the 4th highest of all in the test. With a better tire and higher exit speeds I think 150's would have been obtainable.

Oh well, its fun to guess what "might" have been...

 

Matt, slap on some MPSS and I could pretty much guarantee 150...in even an XKR, never mind an R-S. I believe this because I hit 140 mph on that straight in my Supra on race tires at VIR, and the same 140 at the end of the straight at my home track, Mosport (now renamed Canadian Tire Motorsport Park). Last year I was hitting ~145 mph in the XKR after my 3rd lap in the car...on worn Dunlop Sport Maxx tires that were only rated as average back in 2005. Tires have improved dramatically since then. I think I could find 2 seconds with fresh Dunlops and careful monitoring of tire temps and pressures, and another 2 by upgrading to a better tire like the MPSS or Bridgestone S-04's. I'd find the last second in that extreme brake zone where my Supra brakes faded considerably every lap, and the XKR brakes have proved to be more resistant to fade. If they held up there 150's a done deal.

I see the brutal F-Type V8S also still uses the P Zero for some stupid reason...but since even its exhaust is reportedly able to beat the XKR into submission I'm going to have to predict a solid 151 mph for it

...and then the Stingray and Viper will give it a try!

Bruce

 

It's a plausible thought, the tires. Tires are consistently underrated as factors in track performance. But what's puzzling is that the XKR-S driver give the tires short shrift in his discussion of the car's performance. He talks about the performance of the tire changing over the course of the lap to the negative, as I recall, but doesn't really seem to take that into account in his overall criticisms of the car's performance. Was the XKR scary because its suspension was not properly damped, etc., or was it scary because it was being driven on tires that were not up to the task? You'd think a driver of some skill and experience would make this distinction more clearly....

As it stands, comments the driver made along the lines of "dreading" to set a best time just make you wince.

 

Another excellent source of useful comparative performance information is Motor Trend's "Best Driver's Car" testing. This year's testing started today and includes the F-Type and a bevy of other desirables...or are they?

Here's a trailer for it showing the cars being tested...
Motor Trend's 2013 Best Driver's Car Week! - Starting August 19th - YouTube

And here's the 2012 testing and results video...

I saw a Viper, Cayman, Aston, Audi R8, Mercedes SLS, F-Type, BMW and Bentley and a couple of others. Not sure about some of the specific models. Let's identify all the contestants if possible and make our predictions to later compare with their results!

Bruce

 

Is it Randy Pobst driving again? I think Mercedes SLS, F-Type, BMW, and Bentley will be on the bottom. Randy Pobst seems to like more communicative, responsive and lightweight cars (especially since he is testing them on a racetrack!).

 

Not seeing the Vette is unexpected. I can not imagine that they would not include it in this year's test. Not sure what the Bentley is doing there? It is not, by any measure of imagination, a track car to be tossed around at Lagua Seca.

Will be interesting, because Laguna is a wonderful handling track. The Cayman should do very well in handling there but, its meager HP will hurt it in the long uphill sections.

I would not be surprised to get a good lap out of the F-type for the final tally. How many good consecutive laps can you get out of a 4000 lbs car at the steep downhill braking areas of Laguna will be a good question.

If they bring their track-specced Viper GTS, it should sweep the indicated field. Despite the transmission ratios, I would still think the 2014 Vette should be second in this line-up. I am most interested in the F-type and the Vette performance figures. Of course, we know that this is the base Vette and much higher performance versions are in the works. Too bad they are not ready, yet.

Albert

 

Randy drives for the lap timing but there are multiple test drivers that vote. They stated that last year's top pick was unanimous. "Communicative" and "responsive" are descriptive of handling, and certainly essential parts of what makes a great driver's car, so I'm glad he seems to like those things

Weight is something that generally adversely affects handling, but is really only an issue if it does. He likes the GT-R because it handles well, despite it being heavy. It has the same power as the XKR-S, but the AWD system that contributed to that weight also allows it to get that power to the ground, whereas the XKR-S struggles to.

They judge the cars based on both road and track impressions. I guess canyon roads might not be the best place to sort out their high speed handling limits!

Bruce

 

Just thought to attach this link for the fastest lappers at Laguna. Should be a reference for the upcoming track tests.

2013 Chevrolet Corvette ZR1 vs. 2013 SRT Viper GTS - Motor Trend

Notice that the ZR1 with its larger bodyworks and supercharger+related accessories is still a full 100 lbs lighter than the 2014 base Vette.

Albert

 

Laguna Seca testing is being broadcast already...are you guys catching this?

2013 SRT Viper Hot Lap! - 2013 Best Driver's Car Contender

So far Vanquish, SRT Viper, AMG Wagon and Cayman have run. I think the F-Type is going to have it's hands full...but who the heck knows!

Bruce

 

1:36:43

Not bad for one of the early laps. He'll likely squeeze more out of it before it ends. This is the base Viper, so it is interesting what the GTS will do.

They are running times that we were running in the GT-3 race group; around 1:35 there. Impressive, never though to see street cars doing these kind of times.

Back to my project; I'm in the process of switching wheels between the XF and the XJL to exclude tires and wheels from the ride issues. Report on the results a few hundreds of miles later.

Albert

 

You can click on the link boxes at the end of that video to see the previous and next contenders...4 in total so far. The Bentley is the final next contender shown but the link doesn't work yet so maybe that will be available to see tomorrow.

There was almost no difference in times between the base SRT Viper and GTS in previous testing by MT at Laguna Seca when the TA model took back the track record from the ZR1 earlier this year.

I hope the wheels swap helps figure things out.

Bruce

 

So, thus far:

Viper = 1:36:43

Aston V12 = 1:40:71

Porsche Cayman = 1:41:26

Mercedes E63 Wagon = 1:42:39

No surprises, thus far. The light and very powerful Viper is far out in the lead. the nearly 600 lbs heavier Aston V12 follows and the light weight champ Cayman @3152lbs is third, just as I suspected, limited by its power on the uphill stretches. A ridiculously heavy E63 @4700+ lbs is in the back. I think that F-type should easily be in second place in this field.

But, where is the new Vette?

Albert

 

Possibly excluded because they aren't technically available on the road just yet.

The F-Type may come in ahead of the Cayman in lap time but I'm afraid it will trail as a driver's car...unfortunately. Porsche nailed its goal with the Cayman, as did Jaguar with the F-Type. But the goals were just different enough that in this particular contest I think the Cayman will come out ahead

Bruce

 

They explain why the Corvette was not available for this test (too bad). The list of cars, in my wild Laguna Seca lap time ranking (guessing):

1) Mercedes SLS Black Edition
2) Viper SRT
3) GTR Track Edition
4) Audi R8 V10
5) Jaguar F-type
6) Porsche 911 Carrera 4S
7) Aston Martin V12
8) Porsche Cayman S
9) Mercedes E63 Wagon
10) BMW M6
11) Bentley Continental GT
12) Ford Focus ST

Nice field for the F-type to meet. The real struggle I had was between the placing of the F-type and the Carrera 4s. While the Carrera is 600 lbs lighter, it is a 911 and 911s are generally not among the fastest ones at the track. I bet on those racing ratios in the F-type transmission and its 95 more horses to pull of a quicker lap than the Carrera.

Albert