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13.622 @102.57 mph. My fastest time. I have had faster 60 ft times and should have done better. I've hit a 2.16 before and I've seen times closer to 2.0 before elsewhere. This would perhaps bring the ET closer to 13.5 may be. Even with the LSD it was easy to lose traction and go sideways
I've had a trap speed that's faster at 103.86 mph also (with a 13.683 ET).
Car is close to stock
List of mods
X100 XKR 4.2 air box with 'barn door' modified to fit- gains close to about 10 bhp
Mina Gallery induction tube- I don't like the small diameter and curved duct into throttle but its definitely lower restriction than stock. What would this give me?-2-5 bhp may be?
K and N Airfilter
AMG 'blue top' shift solenoids in the W5A580 Trans
"15HU" (XJ40/X300 style) 3.07 rear end with 'HD dana 44 style (1.875" pinion shaft diam vs 1.552") ring gear and Torsen T2R
Street Michelin Pilot Super Sport XL tyres
Temperature was about 50 deg F
Last edited by Count Iblis; 10-15-2018 at 01:40 PM.
I want to take mine over to the local strip and see what it pushes. But you did that with a 3.07 and a sweet 50F cool pack of air to run in, ...nice. I'd have to do it in humid 90%+ air at around 85-90F, so I'm not looking at much better than a mid 14, even 15. I'm running Michelin SS's also, no mods yet. You know what I want to do Count....
I want to take mine over to the local strip and see what it pushes. But you did that with a 3.07 and a sweet 50F cool pack of air to run in, ...nice. I'd have to do it in humid 90%+ air at around 85-90F, so I'm not looking at much better than a mid 14, even 15. I'm running Michelin SS's also, no mods yet. You know what I want to do Count....
Actually I don't have a cool pack, that was the ambient temp. Earlier in the summer I go times in the 14 to 15 as it was super humid and 90 plus degree ambient.
Is the compression down or are the cats blocked?
My engine is quite new- like 30-40k miles- so that helps, diff is new etc.
She's just old No catalytics and comp is good, but with 170k on the original Eaton M112 its a bit asthmatic, still would run a 13.4-13.5 on a cool day. She's retired from all racing at the moment until I do a major overhaul
I’m puzzled why X-308 owners would try to modify a car that was meant to do X, into a car that does Y.
To end up with a car that accelerates to the max — giving low 0-60 and 1/4 mile times — makes sense if you’re starting with a Mustang GT or a Honda Civic Type R. Their manufacturers designed them for this kind of duty and outfitted them with the beefed-up hardware that could take the punishment of bottom-end drag-racer acceleration.
Jaguar, on the other hand, are in the business of building luxury cars. Their motivation to supercharge their small-displacement 4.0L V8 was torque, not horsepower. Jaguar's AJ-V8 is a fine engine, but due to its fuel-sipping design, lacking somewhat in the low-end grunt department. As in, when merging onto freeways with a short entrance ramp. Or, on the interstates, dealing with the miles-long grades in the Rockies,
With its blower, the JXR version of the X-308 enables its driver, without having to engage Sport mode, to simply dip the throttle into that vast wellspring of torque and power through driving challenges. It’s a maxim that a luxury car have sufficient power on tap to deal with most situations. And Jaguar followed through with the XJR and Vanden Plas Supercharged.
But those blown Jag sedans were NOT designed for drag racing. For one thing, their rear differential will break if subjected to drag-race starts. It’s the same diff as used by the naturally aspirated engines, and cannot withstand the abuse.
Add to this the 4.0L version of Jag's wonderful all-British V8 just plain lacks the cubic inches required to bring a big sedan up to speed at rates reserved for today's ultra-expensive German performance sedans. I read three car mags monthly, and have noticed our blown X-308s barely make it to the bottom rung of today's performance cars in terms of acceleration, even when they are pretty cheap compact performance cars.
And while our Jags' Bilstein shocks and fancy suspensions keep our big sedans well under pilot's command in the big sweepers, it would be wise to avoid pink-slip showdowns with M5s or AMG 6.3s. Or Audi S7s for that matter. Those models were designed to produce near-supercar performance numbers, whether on the straights or in the twisters, at the cost of a six-figure price tag, a buckboard ride, and a noisy exhaust. Our cars had a completely different, and I suggest more practical mission statement, and continue to pull it off wonderfully in the real world,
When we get back to the real world of today's non-motoheads, you know what? Most passengers in luxury sedans expect to be cosseted, not scared cross-eyed by violent acceleration and at-the-limit cornering.
A couple of weeks ago I took a friend who is not a motorhead, and in fact owns a new Mercedes C-Class sports coupe, out for a dinner engagement in my 2001 XJR. It was his first time in a British saloon car. Upon entering the car I noticed he was coming to terms with the very un-German notion of luxury for its own sake.
As I am prone to do now that I’m in my 60s, I drove chauffeur style, easy on the gas and brakes, no side forces in the corners. This relaxed my companion, and he made mention of my car's sybaritic interior, resplendent in hardwood and Connolly leather the like of which no Merc sedan has ever known, not even the legendary S600.
At one point, pulling away from a stoplight and onto a freeway on-ramp, I put my foot in it enough to get us moving but not enough to trigger a downshift. That flat torque curve just hauled us smoothly up to freeway speeds, with zero drama, Involuntarily, my companion said, “Wow.”
And that, my friends, is how a luxury sedan delivers power. Its mission is to reassure both driver and passengers that whatever on-the-road challenges come up, it is on top of — all the while delivering a traveling environment remeniscient of an Edwardian gentleman's club.
To reduce this car's mission statement to lowest-possible quarter-mile times dishonours both the marque and the committed gearheads who live by the quarter mile. Both have a purity of vision but it is not the same vision!
You don’t go shooting geese with a Hawken rifle. It would be equally unwise to challenge a recent 8-cylinder Mustang while driving an infinitely more sophisticated European luxury saloon. Just give them their due and rise above it, And take comfort that you are in possession of the high point of luxury point-to-point transportation.
The new XJ series, with its huge wheels and ultra low profile tires, just rides like a buckboard. And the new S-class might be brilliant but it is too far outside an American owner's learning curve to take advantage of the amazing tech.
Out of all the choices we've we’ve had over the years, and having driven most of them, I can only conclude that we X-308 owners have enjoyed the optimal luxury car of the modern age. If this is my last car I will not feel denied,
My question to you John is... "..why not"? I like to put my passengers into the seat with a red light release, they tend to not like my description of how well she corners as we're doing that.
To be informative, Count Iblis was on the Jaguar design team of these saloons. Like any of us who have a hot rodders heart, we attempt to get more out of what we're told we shouldn't or can't and the Count is a Mopar man also, so I believe his blood is a 10w 30...lol. The Count (on his own) has designed a beefier differential using 14HU components and his own gathered material... https://www.jaguarforums.com/forum/x...ar-diff-59936/
But why not make a car that can surprise those "made to perform" ones? I surprised a Mustang GT one day when I stayed with him on a rolling start. Mind you, a standing start would of been in vain, but he was surprised nonetheless. His statement was "...he needed to go buy some more HP." Heck, my indy had an S-Type R that could lay down 11's, he's a saucy Irishman, good guy. He never would tell me if he added anything to it. The car wasn't built for this either, but this member ran her at Sonoma... https://www.jaguarforums.com/forum/x...y-club-206135/
I myself love the smooth ride of the 308, but to have that SC available with the CATS, I just have to see what more can be brought out of her. If your desire is to just cruise her, hey...that's the forte of this wonderful automobile. I've owned 4 Mustangs and still love them. As a matter of fact, as soon as I finish building the Corvette and sell it off, a Mustang may take its place....but the new 2020 Bronco has my eye. Its all in your heart of desire for what you want to do....its hot rodding baby!
Well some of us want our pizza on a bagel and to eat it too!
You can make a car go fast in a straight line and ride well. My favorite example is the bonkers SL65 my aunt owned. The Jekyll and Hyde aspects are a giant hoot.
You're obviously a distinguished gentleman of taste and understand subtlety and class. These kinds of folks are very rare now in the UK and here. Me and the former Chief Engineer (now in semi retirement) of the Jaguar AJV8 were just discussing how the appeal of Jaguars has changed now. The X308 was indeed targeted to a gentleman who wouldn't flirt with quarter mile statistics and would scoff at Track day runs but even with the S type R this was changing. The S type R was the first car we took out to the Nürburgring to get track times. It involved a lot of minor redesign- including the differential for better cooling etc. The X308 wasn't subjected to this kind of programme but even the X350 was.
Regarding the differential- you're correct, but as Highhorse pointed out, I've fitted a strengthened differential of the former '15HU'/X300 design and put in an LSD also. My whole aim is to keep the refinement but let the performance flourish! This isn't easy- I've fitted the XKR 4.2 AJ34 air box and a Mina gallery intake tube and the car is noisier. This isn't suprising as the Helmholtz and quarter wave resonators are now gone with the aftermarket Mina gallery intake. My intention is to recalculate the sizes of new quarter wave resonators and refit them. I'll probably also add some intake 'wadding' to further dampen the sound.
For the ride and handling, I've been really impressed with the similar era BMW M5- its NOT a harsh riding car but has excellent body control. The front to rear weight distribution and the torsional rigidity of the X308 vs the E39 M5 are in the same ball park so the wheel rates of that car will be my starting point.
I did beat both an AMG Mercedes on the track and an Audi S7.
I think you can be an English gentleman and have class with an X308 and also be able to take the trophy home with minimal drama.
13.622 @102.57 mph. My fastest time. I have had faster 60 ft times and should have done better. I've hit a 2.16 before and I've seen times closer to 2.0 before elsewhere. This would perhaps bring the ET closer to 13.5 may be. Even with the LSD it was easy to lose traction and go sideways
I've had a trap speed that's faster at 103.86 mph also (with a 13.683 ET).
Car is close to stock
List of mods
X100 XKR 4.2 air box with 'barn door' modified to fit- gains close to about 10 bhp
Mina Gallery induction tube- I don't like the small diameter and curved duct into throttle but its definitely lower restriction than stock. What would this give me?-2-5 bhp may be?
K and N Airfilter
AMG 'blue top' shift solenoids in the W5A580 Trans
"15HU" (XJ40/X300 style) 3.07 rear end with 'HD dana 44 style (1.875" pinion shaft diam vs 1.552") ring gear and Torsen T2R
Hahahaha, ...what's that old saying..."its bark is worse than its bite". He made a heck of a lot of noise, only seemed to know how to push the peddle all the way down and burned off a good chunk of tire as you rolled down the stretch.