www.jec.org.uk

I need some feedback please on your opinions of Gearboxes, whether it is better to have a sport box or just the auto box. Does it make that much difference to the ride? Does it reflect on the value of the car?
I am currently looking at a 2001 coupe with auto box, 31,500 miles, Silver for sale buy a dealer on Autotrader.

Hi John,
I take it you are talking about an XK8/R?
They are all automatic transmission (J-gate) and a Sport button.
I am not sure what you mean with your question

______________________
Karl, XK8 Coupe, MY2000

What Karl said

Thanks for your comments, I seem to have my wires crossed. XK8s are being advertised as being Automatic or Sports auto in relation to their transmissions, it seems from your replies these are the same just worded differently. In the pictures of the interiors there are either one or two buttons by the J gate, one i know is the sport button.
I wish there was some clarity in the advertising as you could be looking at two same spec cars but with different teminology in the wording, I will get there eventually.

The second button on the J-gate is the cruise control button.

The second button on the J-gate is the cruise control button.

On older models it was. On the '02 or '04 facelift, the second button is the Automatic Speed Limiter button.

John,
I hope the replies clarified your query.
Just to recap, all XK8/R's have automatic transmission - and very smooth it is too. The Sports Mode button, fitted to all models as standard, just increases the rev-range for the automatic gear change, which gives you some more 'ooomph' when increasing your speed.
If you want even more of that, you can go over to the manual mode and rev up to the full limit.

If you want even more of that, you can go over to the manual mode and rev up to the full limit.
I though that if you accelerate with full throttle in "Sport" mode the box will hold each gear to the red line. The subsequent auto change will surely be quicker than selecting the next gear manually and thus performance will be optimised. Also there will be no danger of exceeding the red line!

I originally had a 1996 XK8 and as I understand it the 'J gate box has always had a 'sport mode' button on the J gate console surround. This was to increase the rev limiter as previously said by 'Grand Tourer'. My 2001 model has the 2 buttons on the console and the second button is indeed for the cruise control. Personally I always leave the box in sport mode, I like to have the power there as and when I want it, if petrol consumption was of a concern to me then I would have gone for a 'Fiesta'! I like to get out onto those windy country roads and open her up. The XK8 is limited to 155mph electronically via a rev limiter, when you use the J gate box on the manual side, 1st to 2nd gear is changed automatically but then 2nd gear is held until you manually change to 3rd, if you leave it in second and keep accellerating you will feel the rev limiter kick in, you really have to be driving her hard for this to happen and in my opinion is not the way to drive her, the way to do it is to manually change to 3rd, just before the rev limiter kicks in and then keep accellerating, by this time you will be travelling at an awesome speed and you will have realised that the car is a little bit more than a Grand Tourer, no offence to 'Grand Tourer'. After 3rd gear on the manual side of the J Gate box is D. This 'D' is actually a fourth gear and is more responsive than the 'D' on the auto side of the box. You will find this useful on motorways as the 'D' on the auto side of the box is more of an overdrive.
To summise, the gearbox has many guises, Touring, Manual and Sport can all be achieved, it is a fantastic box to go with a fantastic car.

I hope this has been of some help and am sure you will have lots of fun discovering the capabilities of this unique piece of engineering know as the Jaguar 'J Gate Gearbox'

Well said, b5gmg , saved me a lengthy reply

No offence taken on your interpretation of 'Grand Touring' - in fact, I can vouch that the car 'grand-tours' quite well at 130-155mph on German Autobahns (conditions permitting of course)

B5gmg, I didn't think the 155mph limit was on the rev limiter, as I have had the speed limiter removed from my 8 and it will now comfortably exceed 155mph well before the rev limiter kicks in

Apart from limiting changes to 4th (or 5th with six speed box) when you move the gear lever to the left hand side of the gate you also remove the torque converter's lock-up clutch facility (for good fuel economy). Hence, acceleration is brisker, courtesy of the torque converter's torque multiplication effect as noted earlier in this correspondence. Mike.

B5gmg, I didn't think the 155mph limit was on the rev limiter, as I have had the speed limiter removed from my 8 and it will now comfortably exceed 155mph well before the rev limiter kicks in


Sharfrs2 - If you have had the limiter removed and you exceed 155mph well before the rev limiter kicks in then this does indeed suggest that the 155mph limiter is not on the rev limiter, is it the rev limiter kicking in well after you exceed 155mph or is it just the engine begging for mercy?

Out of curiousity, at what speed does the rev limiter kick in now that you have had the limiter removed

The speed limiter and rev limiter are different. I believe the rev limiter is set at around 6800, or 3000 if in park or neutral. I haven't taken it to the rev limit yet, but hope to have a go soon. I do know of an R owner who has had his car up to 186 GPS indicated, and he hadn't reached the rev limiter, just ran out of room on the Autobahn.