XJ XJ8 / XJR ( X308 ) 1997 - 2003

Gearbox question, driving style

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  #21  
Old 11-27-2012, 04:21 PM
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Originally Posted by danielsand
My VDP is in the "S" mode all the time. Average MPG is 19,4 (city+freeway). I burn 91 here in CA, and I am not concerned about fuel consumption. A mile or two (even 10!) per gallon more, will not make ANY difference in my life.

What's up with changing avatars all the time Sandy?
i dont have one which i would like so until i will have one with my kitty i will be changing them :-)

tested the gearbox today and it appears that it really shifts fast enough on down pressing as when one uses S mode. But i will now drive on S mode too if it is recommended. I thought it was something which you can use if need to, but too hard on gearbox for daily use.
On mercedes it even switches it self of with the keys, wont keep your last selection.
 
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Old 11-27-2012, 08:07 PM
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Sport mode has two advantages when it comes to wear. It always starts in first gear, and it shifts with less slippage.

In town, my combination on the Merc transmission is Sport+Fourth. It only gets slipped into Drive approaching a highway.
 
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Old 11-27-2012, 10:48 PM
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Originally Posted by plums
In town, my combination on the Merc transmission is Sport+Fourth. It only gets slipped into Drive approaching a highway.
Quite a good idea. There's no need in fifth in a city, so if you put in fourth there's no hunting and the tranny lives much longer.
 
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Old 11-28-2012, 12:46 AM
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Originally Posted by MoscowLeaper
Sorry, but i have to do it


P.S. No offence

This thread has significantly improved with new avatar.....

P.S. No offence....
 
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Old 11-28-2012, 01:08 AM
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Originally Posted by plums
Sport mode has two advantages when it comes to wear. It always starts in first gear, and it shifts with less slippage.

In town, my combination on the Merc transmission is Sport+Fourth. It only gets slipped into Drive approaching a highway.
is it because you dont want underreved 6th gear shift? Is it going to 5th gear so often? I cannot say, most of my driving is in the city but it shifts so smooth that i have hard times to count gears.
 
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Old 11-28-2012, 01:29 AM
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Originally Posted by sandy85
is it because you dont want underreved 6th gear shift? Is it going to 5th gear so often? I cannot say, most of my driving is in the city but it shifts so smooth that i have hard times to count gears.
If your speed is below, say, 90-100kph, it's better to use fourth. Less shifts=less wear. And, for me, fourth gear gives the better fuel economy in that speeds.
 
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Old 11-28-2012, 01:38 AM
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Originally Posted by sandy85
super, one learns every day, this forum is awesome.
My cat is almost perfect, need to fix only the mirrors, and new wheels and one day new color.
Whats wrong with the mirrors?

P.S. Mine is almost perfect too, just need to be polished (so the british racing green can shine in all his glory) and a hood should be repainted, but i'm waiting for the spring
 
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Old 11-28-2012, 02:20 AM
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Originally Posted by sandy85
is it because you dont want underreved 6th gear shift? Is it going to 5th gear so often? I cannot say, most of my driving is in the city but it shifts so smooth that i have hard times to count gears.
There is no sixth gear.

Fourth gear can easily take you in excess of 180 km/h, so except for more relaxed cruising it is not really detrimental. Sometimes I hit the highway and don't remember to shift up for quite some time. The usual routine is to keep it in fourth until accelerated to cruise and comfortably situated in the flow of traffic, then shift to drive.

Holding it in fourth means the torque converter never locks. In drive at part load, it will try to lock around 90 km/h.

In town, the shifts from second to third are smoother than when in drive. This is with Sport mode on so this may have something to do with the transmission adaptive routines for this particular car.

Also in town, the combination of Sport+Fourth actually yields better fuel consumption numbers. This is probably due to the fact that starting in first gear gets the engine up to peak torque faster.

In short, you get a more responsive car and better fuel consumption in city driving.
 
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  #29  
Old 11-28-2012, 02:20 AM
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Originally Posted by plums
In town, my combination on the Merc transmission is Sport+Fourth. It only gets slipped into Drive approaching a highway.
But it doesn't use fifth until about 80kmh/50mph in sport mode anyway..? Or maybe you just drive that fast in town. My combination in town is normal mode + third. That way it only uses second and third gear (Merc box). Less changes, smoother ride, less wear. The speed limit in most of our towns is 40km/h, some even 30km/h, so fourth gear is quite useless in town anyway. Of course, sometimes the occasion requires the use of sport mode, as you all probably know.
 
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Old 11-28-2012, 03:28 AM
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Sport+Fourth is easier as the shift lever only has to go down and over. Third is down, over and up. Me==Lazy Of course that doesn't explain missing a good five speed manual

Try Sport+Third on your next tankful if you can do it all in town. Clear your trip computer now, take a average fuel consumption reading at 100 km. Do the same when you change to Sport+Third. Do both without hitting the highway. This is truly an experiment where the acronym "YMMV" applies.

BTW, less changes is not necessarily less wear.
 

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  #31  
Old 11-28-2012, 03:37 AM
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my mirrors are somehow not firm, they rotate (housing, not the glass inside) by them self. I will have to try to fix them because don't want to send it to shop again only for that, but for it needs to stop raining at least.

ok thanks for the answer, makes lot of sense. Never knew it would not use first gear when in normal mode.

when i was looking for my cat (long year) i wanted it to be automatic. i drive a lot in city and traffic and it is too much effort to drive a stick. I also do not need to wear special driving shoes with auto gearbox. I never had own car with auto gearbox before except about 3 months driving a B-Class as company car. I always had a stick before.
 
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Old 11-28-2012, 03:43 AM
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Originally Posted by sandy85
my mirrors are somehow not firm, they rotate (housing, not the glass inside) by them self. I will have to try to fix them because don't want to send it to shop again only for that, but for it needs to stop raining at least.
Do you have the power folding mirrors?

Apparently, if they have been pushed in by hand, they will flop around until reset by power.
 
  #33  
Old 11-28-2012, 04:33 AM
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Originally Posted by sandy85
Never knew it would not use first gear when in normal mode.
This only applies to the Mercedes built box in the supercharged XJR. Sorry about the confusion.
 
  #34  
Old 11-28-2012, 04:39 AM
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I have just replaced my mirrors - they are not power folding, but had become a bit loose about the hinge and moved quite easily with the wind at speed. I got some second hand ones and swapped them, it's really quite simple.

However if you want to fix them I think there is a friction device inside the mirror that allows the mirror to move inwards under hand pressure, not sure if you can replace this...I will have a look a bit later. It was just easier to change mine (the motors had broken).

That said (as previous post) if they are power folding you have to re-cycle them to get them to set out correctly.
 
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Old 11-28-2012, 05:23 AM
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no, they are not power folding but i guess it is the friction issue. They are just very loose. Any idea about how to fix it is welcome, thank you!
 
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Old 11-28-2012, 05:49 AM
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Aren't you supposed to be working?
 
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Old 11-28-2012, 06:37 AM
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Originally Posted by plums
Aren't you supposed to be working?
Life is just one long tea break.....
 
  #38  
Old 11-28-2012, 07:45 AM
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My car's 722.650 tranny has two modes: Sport (ex-normal ) and Race ( ex-sport ) Blue tops and some other mods done to the gearbox and TC.
 
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Old 11-28-2012, 09:22 AM
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Originally Posted by sandy85
no, they are not power folding but i guess it is the friction issue. They are just very loose. Any idea about how to fix it is welcome, thank you!

My cat came with a loose driver's mirror. I put off the fix until I was ready to replace the inner door panel. It had a thorn pocket (few of them), so I bought all four door panels (complete with all hardware and speakers) on the junkyard (plus all the seats, climate control with heated seats, and center console).

To fix the mirror: remove the door panel (explained elsewhere on the forum), there is a black "triangle" that covers the mirror from inside, it's glued in place with some black silicon based glue (pliable), you need to slowly pull on the triangle starting on the bottom, and it will come off, with all the glue still attached (and can be reused). Once the triangle is off, you will see one torx bolt, tighten that, press the triangle back in it's place, and reinstall the door panel. VERY simple.

The only thing you have to be careful about, is pulling the triangle off,....if you start on the upper corner, you WILL crack it, because of the way it's shaped. If you do end up cracking it, ......you can have another one off of the junkyard for pennies.
 
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Old 11-28-2012, 10:20 AM
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Just to add to above - I managed to remove the triangle without removing the door panel which made things very quick and easy....fitted it back ok too...
 


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