In my last car it adjusted the electronic shift-point logic and (I think) increased pneumatic pressure for quicker shifts.

What does the X308 sport-mode actually do?

 

Yes, it changes the shift points and firmness of shift (based upon current driving parameters)... If you're still driving like your grandma, you won't notice much of a change. If you're pretending you're Mario Andretti, you will notice a much more aggressive shift sequence. I believe it also changes the suspension stiffness for those with the dynamic suspension system (I do not have this so can't give absolute info).

 

Thanks, but how is it doing that? Purely from the computer or mechanical change too?

Lol, I gave a few driving lessons to my grandma but she has otherwise never been behind the wheel...

This smoothness of this car has me driving miss daisy mostly (my last car roared and taunted me to go fast, this one is so much more refined that it is fun at any speed), but I have Al Uncer Jr. moments...

 

Since the tranny is computer controlled, the computer selects shift points and the severity with which gear changes occur - a combination of pressure used to drive the pistons and the timing between letting go of one clutch and engaging another, I believe. The days of single clutch packs (which dictated how 'stiff' the shift was) have gone the way of the dinosaur with 4, 5 and 6 speed auto trannys with OD and locking converters.

Now days, (if you're an engineer at the tranny factory) you can play all day with adjusting timing between, say, 1st gear clutch dis-engagement and 2nd gear clutch engagement to get a plethora of driving experiences from between Rolls to Formula One, all from the same tranny and just controlled by a couple of software coded variables in the computer. In our case, pushing the Sport button just changes the variables the computer uses.

 

Is it true that many automatic transmissions can create additional gear ratios (in our case 6 or more ratios) via clutch adjustments and etc, but the ratios are totally useless bc they are either wayy too long or too short? Someone was telling me that this was possible.

 

So sport only controls the shift pattern, no other components? (for vehicles with passive suspension)

Quad, is clutch dis-engagement mean when the clutch plates separate to freewheel or touch to transmit the drive rotation?

 

Yes it only controls the transmission. Steering weight, fuel mapping, traction control and etc. are not affected by the sport button.

 

Sorry old friend but I have the CATS Adaptive suspension on my XJ8 and can confirm it stiffens it up and it makes a huge difference.

I have also noticed the steering has more feel to it when "S" is engaged. These cars have a system that as you go faster, the power steering system works less to give you more control and feel at higher speeds.

I have also noticed a change in engine sound but this may be because it is accelerating quicker than normal.

 

I think you have some placebo effect going on there. Trans Sport Mode involved nothing but the transmission in all models until the XF. Jaguar describes it this way for the 4.0L NA and the 4.2L.

4.0L NA
Sport Mode
When sport mode is selected by the driver using
the mode switch, the sport pattern is only
activated when a set cornering force is achieved,
or the kickdown switch is pressed. The vehicle
speed and the difference in speeds between the
two front wheels is used to calculate the amount
of cornering force.

4.2L
Information: Transmission Shift Strategy
Please be advised that on the 6HP transmission, the 4.2 NA in Sport mode will select 6th gear at 49 mph with a closed throttle. At less than 10% throttle opening, 6th gear will be selected between 49-54. Above 20% throttle opening 6th gear is not available. The vehicle has an adaptation feature in sports mode and will adapt to how aggressively the vehicle is driven. There are five levels of "Shift Maps" and in super sport (most aggressive map) 6th gear is unavailable.
The 4.2 SC has the same feature as the NA. In sport mode 6th gear is available at 55 mph with a closed throttle. At less than 10% throttle opening, 55-60 mph, and above 35% throttle opening 6th gear is unavailable, and again in super sport mode 6th gear is unavailable.

Now the 4.0L SC with the Mercedes box is different yet. In Normal Mode first gear is locked out and you start in 2nd all the time. Sport Mode just gives you 1st gear. There is no shift strategy difference between the modes here.

Hope that helps.

Cheers,

 

The suspension does change, and I'm not the only one to notice this. My mechanic noticed this, as did my Dad (Ex Racing Driver) and my Pal who is a race mechanic. Not to mention a friend of the Family who is a very High ranking Jaguar Test Driver who explained to me how the CATs system worked. It is adaptive so therefore adapts to sport mode.

 

I'm sorry, the Adaptive Suspension module has no inputs from the transmission system, it is not even on the CAN Network, and is an entirely stand alone system. It operates only on accelerometers, a brake switch input and vehicle speed from the instrument pack. All the technical documentation I can find says the same thing.

It does have a serial data line for diagnostics, however; to retrieve fault codes.

Cheers,

 

Oh OK. So I guess the man who was in charge of testing for the X308 range and every model since is wrong? Jaguar themselves who made the car is wrong? Two Racing professionals are wrong? The man who has just rebuilt the entire suspension with new bushes and mounts is wrong? Oh well never mind.

I'm not looking to argue with anyone but I can't believe that Jaguar would install an adaptive suspension set up that doesn't adapt to anything. I think I'll sit the rest of this one on the fence.

 

Sorry Stu but you, your dad, your pal ,your Friend of the Family and your mechanic are wrong.

I don't see where an argument can be had, on 1 hand we have peoples perception ( or placebo effect as Steve call it) and on the other hand we have technical facts

Instead of being very sarcastical in your reply to Steve, maybe you should have taken the time to read/learn the technical data regarding the system

Here is how JTIS (Jaguar Technical Information System) describe the operation of the system:

OperationThe system selects the soft or firm damper setting according to the current road and driving conditions, to optimise vehicle ride and handling.With the vehicle stationary, the dampers are in the firm setting, but will normally switch to the soft setting when the vehicle exceeds 8 km/h (5 mile/h); all dampers are switched simultaneously.Sudden movement of the vehicle body, in response to road inputs, is detected by the vertical accelerometers, and the ADCM switches the dampers to the firm setting to give improved damping of the resultant oscillations.When cornering forces are detected by the lateral accelerometer, the ADCM switches the dampers to the firm setting to reduce the roll rate and improve wheel control.After the event has passed, the dampers revert to the soft setting.When the footbrake is applied, the ADCM receives a signal and calculates the rate of vehicle deceleration. If the deceleration rate is greater than a certain threshold, the dampers are switched to the firm setting to reduce the pitch rate and improve wheel control.If a system failure occurs, the ADCM grounds the output line to the instrument cluster message center, which displays a text warning SUSPENSION FAULT and illuminates the amber warning lamp. Under fault conditions the system always fails to the firm setting, so that the vehicle will be safe to drive under all road and driving conditions.


If you need any more real technical information such as the PDU User Guide for details of diagnosing and testing the Adaptive Damping System, just let me know.

 

There are two things to consider here, neither of which is mutually exclusive.

1. Technical documention is written by technical writers. They do not always get it right, nor is the document necessarily complete. This is not unusual. In fact, it is sometimes deliberate.

2. The sport switch is a digital input to a computer. Tracing such a signal is not like tracing old relay circuits. Once it enters the computer, unless you know the complete algorithm, its effect is unknown.

There is only one way to know for sure: attach a recording vdvm or ocilloscope and go for a drive under a variety of inputs.

 

I appreciate the backup, luc.

Precisely why I do my best to cross-check the technical information before I chime in. I don't want to mislead. Guys I train often ask, "You know how this or that works, why are you always looking it up??" Simple, stuff changes, sometimes from one year to the next, sometimes in the middle of a model year. If I don't know exactly how a system is supposed to work, how can I effectively troubleshoot it??

Actually the Sport switch is just that, another switch. Nothing digital about it; other than it is either off or on. Simply indicates the guy in the seat requests another shift strategy.

 

Beside the JTIS description of the system operation, for the sport swich to have an impact on the adaptive damping that would require an input to the ADCM (Adaptive Damping Control Module).
The ADCM has 5 inputs:
1/ Front vertical accelerometer
2/ Rear vertical accelerometer
3/ lateral accelerometer
4/ Brake switch
5/ Vehicle speed

As Steve correctly pointed out, the ADCM is not connected to the CAN network and without any input from either CAN or directly from the TCM (Transmission Control Module), the ADCM can't send output ( to the shocks) based on the sport swich.

Now, if someone can explain to me how the ADCM can have an sport switch based output without any direct ( switch/TCM) or indirect (CAN) input from it, I'm all ears???????

Re-reading my 1st post, I'm afraid that it came out not sounding too friendly toward Stu. I apologize for that, was not the intent.
as for the placebo effect, one of the best example are lound pipes on Harleys or other vehicles, drivers will swear that their vehicle is faster when in fact most of the time they lost HP ( An engine need some back pressure to help scavenging the cylinders)

 

Your analysis is 100% correct, Luc, and unless someone can also prove that the wiring diagrams are wrong (in addition to assuming the technical writers are wrong) then these facts prove that the ADCM is stand alone with no input from the sport switch.

Eventually, conjecture fails in the face of absolute fact. In reality, Stu, you are not incorrect... the ADCM DOES adapt to operations in sport mode (assuming one drives more aggressively when in sport mode), but only through it's own measurements of vehicle performance and driving conditions, not via sensing the position of the sport button.

 

Good info - thanks! Does it also apply to the 6HP26 in the S-Type (e.g. STR)?
Also.... which publication (or other source) is that from please?

 

The 4.0L business was in the AJV8/5HP24 Technical Intro, the 6HP26 came from the Trans Training course 201. All that stuff applies to your STR as it does all 4.2L Jaguars.

There is a LOT of stuff going on in the 6HP that most people don't even realize.

1. When cold it upshifts later to warm up the engine and catalyst quicker
2. Picks wheel speed off the CAN network, so it can prevent up or downshifting if you are in a turn. [mismatched tires can keep you from upshifting!]
3. Recognizes a sustained period of level speed and will downshift for power with very little throttle depression [not necessary to floorboard the throttle]
4. Hill recognition, makes it hold a gear longer for torque when pulling a grade.
5. Cruise Control Strategy, prevents/reduces shift business [hunting] and torque converter clutch off/on cycles if cruise is engaged.
6. Uses a "Stand by Control" to release a clutch at a stop light to unload the engine for reducing fuel consumption.

Those Germans, they think of everything, huh??

Cheers,

 

Aha! Thanks for those, especially the 6HP26 one.

That must be a newer T201 than the one I got from TOPIx (when it was GTR at the old jaguartechinfo site), as it did include the 5HP but not 6HP - or I missed it

I sure wish jag had a (granted, large) list of what's on TOPIx so people could figure out what they'd get for how much money (and could plan which to download). Or that you could browse for free. Otherwise the cost soon mounts - as you no doubt know!