Different web sites are giving me very different numbers, what are the performance specs (0-60, lateral-Gs, etc.) for the various X308s?

The specs that I have seen shows the VDP as the same 0-60 as the XJ8 & XJ8-sport which might be the case, but at 250lbs heavier and with bigger-softer tires on smaller rims, it seems illogical.

 

Edmunds has a comparison test with the XJ8L and I think they say it hits 60mph in 6.6. The xj8L specs are going to be the same as the VDP. I'm not sure if they have the same suspension though. I think they do though.

 

I saw some other site saying 6.9 for all 3 XJs in 2002 except XJR which was about a second faster (which seems too small of a difference for 30% more power)

 

From the 2000 brochure, there is only 133 lbs difference between the lightest x308 and the heaviest.

XJ8 -- 3946 lbs
XJ8L -- 3988 lbs
VDP -- 4010 lbs
VDP S/C -- 4079 lbs
XJR -- 4050 lbs

The only performance numbers advertised was 0-60 for the supercharged cars--I guess they assumed the non-S/C buyers didn't care?

5.2 XKR coupe
5.3 XKR convertible
5.4 XJR
5.5 VDP S/C

Mid-to-high 6's sounds about right for the non-S/C cars.

TTYL
David

 

A one second difference 0-60 is huge! It might notlook like much on paper but it's like driving a different car.

Cheers
DD

 

Its amazing that the long wheel base adds so little weight.

 

Also interesting (well, to me anyway) is that the X308s seem to be anywhere from 100 to 300 pounds lighter than the X300s.

I don't have my books open but I think the XJR/6 came in at 4215, the X300/V12 at almost 4400, and the standard XJ6 about 4100.

The ony XJ8 0-60 specs I found were 6.9 seconds <shrug>



Cheers
DD

 

The AJ-V8 and ZF 5hp24 are alot lighter than the AJ16 and 4 speed auto. Does anyone know if the 'new' front suspension on the X308 is any lighter than the X300? Is the suspension actually all that different at all?

 

My Car: 2002 XJR

0-60 Specs from Jaguar(Right out of the brochure)
XJR 0-60: 5.4 seconds
XJ8 0-60: 6.9 seconds

Jaguar seems to "sandbag" their performance figures, other manufacturers do that as well

I have a GTECH PRO RR unit which is a pretty accurate tool for 0-60. My best time on that unit was 5.087 seconds.

I recently got a GTECH PRO SS Fanatic unit (New tool from the same company, GPS based instead of accelerometer based) and with barely any fuel in the tank I was able to get 4.913 seconds out of it.

I have run the car to 60 many times and you sort of have to get "lucky" to get an awesome time. You have to get the kickdown just right, not too much wheelspin off the line, and I have discovered that leaving the J gate in 2 also helps (Redlines in second gear at like 65 or so MPH)

 

I will time mine and post the results too. Our 05 XJR seems to go a lot faster than advertised. XJR02 is right about wheel slip, if you gun it too quick it can ruin your time. When I disengage the traction control and put it in sport mode, it makes a huge difference! I will say that there are many cars out there that can defeat the 0 to 60 times of a Jag, but not many that can keep up on a steep hill! Thats when I laugh, point, taunt, and fly by the people who tailgated me the whole way down the mountain in the rain...

 

I hope what I'm about to say isn't taken wrong, but.....

I frequent umpteen automotive forums and those GPS and accelerometer devices always show 0-60 times that are faster than factory advertised and/or faster than published road tests.

I've *never* heard of one showing matching results or slower results! That sorta makes a guy wonder. I'm not saying that anyone is telling lies. I'm saying that something about this method of testing always seems to produce a faster than expected result.

Or perhaps those getting slower than expected results remain silent? :-)

I dunno.

I'll admit that I'm an electronics idiot and I don't fully understand how they work or how they are used so I may well be talking outta my hat.

Cheers
DD

 

The 6 cyl engines was heavy -- same for the GM trans in the old R.

The small weight difference in the LWB is interesting -- did they put an aluminum hood and trunk lid on them?

Mercedes would do that -- I can't remember if JAguar did this.?


I have never loved the way Jaguar set up the transmission for the R - always felt that 1st in sport is a little high. I always get the feeling that the transmission is not staying in the power band.

I normally leave it in sport around town - but I actually like the way it will hold the gear on the highway. Engine has a lot of power (torque). I always loved my SAAB turbos for the same reason.

 

sometimes I do get a slow time if I get a huge wheelspin or the traction control takes over too much. The best way to get a reasonably accurate time is to run the car 20 or so times, record the time for each run, and then make an average. If I averaged all of my times, I would probably end up with around 5.2 or 5.3 seconds, which is still a bit under manufacturer's posted time

 

The faster than advertised times are simple, for apples-to-apples manufacturers are supposed to publish an average of 0-60 in opposite directions on the same track, that way wind and track-inclines cannot be a biasing factor.

The uphill acceleration on my VDP is mind-blowing, quite a thrill to stop at the base of a steep grade and then floor the 2-ton cat and feel the G-forces; I can only imagine the XJR must be a real thrill... I would be shocked if even the highest-compression turbocharged four-banger could keep up on a grade, nothing like RWD torque for smile-making

The LWB is only 5-inches extra at the point where the extension only requires longer doors/windows (and obviously body, driveshaft and lightweight things like fuel lines/wires). I have seen different GVW specs for the XJ8 around 3850 and similar specs for VDP at 4050 which is 200lbs difference - no idea who has the correct numbers but either way 5" is not that much steel.

 

I can tell you that vdpnyc is correct in stating the times, power ratings are averages. Having worked for an automotive manufacturer for over 15 years as an engineeer, i know the power numbers are almost always avertised lower than they actually are. Manufacturers have been doing this for years for several reasons.

The first being that it's much easier to explain why a vehicle shows more power when dyno'ed than having to explain if it had less than advertised (Mustang Cobra debacle)

The 2nd being CAFE. Manufacturers report lower numbers to "manipulate" their CAFE ratings across vehicles lines.

All good news for us gearheads. Love my 00' XJR btw!

 

You must also take into account wear in. Take a look at long term car test results like car and driver. Nearly every vehicle is a couple tenths faster at 40k then new. Over time bearings loosen and spin with less resistance etc. and you usually get a little quicker. Honestly if you can put on some drag slicks I think you might be able to see the mid to upper mid 4s on a 308.

With about a 1/2 tank of gas my XJR weighed in at 4030 at the local dump scales which are pretty accurate since they use seperate ones for in and out weighs.

 

Benebob FYI, half a tank on the meter is 12.1 gallons (21 gallons on the meter, 1.6 gallons reserve below the "E") which is about 120 lbs of gasoline weight...

Is GVW measured normally on a full or empty tank?

 

I would say your a little high. Gas weighs about 7-8lbs a gallon but yeah, that changes things a bit. GVW for bikes is dry weight, no oil, gas, brake fluid etc. Cars I don't think most people pay too much attention unless you're buying a lotus or a excursion when weight is a bigger issue.

 

Well, I can see that my questioning of the GPS results was misplaced !

As far as power ratings go there was a new, stricter SAE rating standard introduced a few years ago but compliance was voluntary, not mandatory. I think Chevy came on board with the Corvette...but who else? I've wondered if the Cobra debacle played into this? I suspect it did.

For those not aware, Ford got their you-know-whats in a wringer a number of years ago (geeez...probably ten years ago. Time flies) over power ratings. Evidentally a slew of Mustngs were built with the wrong combination of parts and the true power output fell way short of advertised output. Or something like that. They had to repair quite a few cars, though.

Cheers
DD

 

GVW...Gross vehicle weight... is the maximum allowable weight including all passengers and cargo. I just have to think it includes a full tank of gas.

Curb weight assumes full tank and fluids but otherwise empty, as far as I know.

Cheers
DD