Limited slip diff on XK8/R and XJ8/R

[NormanD]

I am in the process of converting the standard diff on the XK8/R as well as the XJ8/R diff's to limited slip.

Hoping to have more news in the next week or so.

Will update as more info come along.

[G_T]

Sounds good mate. It would be nice not to spin away the power all the time!

[Jaguar steve]

Intrested to know why you think there's a need for a LSD. I know you're putting a lot more power down than standard - does the standard traction control on the 8 and R not cope with more HP?

[NormanD]

Jaguar steve said:

Intrested to know why you think there's a need for a LSD. I know you're putting a lot more power down than standard - does the standard traction control on the 8 and R not cope with more HP?

Traction Control works by cutting power untill you have grip.
LSD lets you control the power to the road.

Likewise thats why the gearbox has bean converted so I have FULL control of the gear changes via the steering wheel

[G_T]

NormanD said:

Jaguar steve said:

Intrested to know why you think there's a need for a LSD. I know you're putting a lot more power down than standard - does the standard traction control on the 8 and R not cope with more HP?

Traction Control works by cutting power untill you have grip.
LSD lets you control the power to the road.

Likewise thats why the gearbox has bean converted so I have FULL control of the gear changes via the steering wheel

NormanD you must be pleased with the manual changes you've mentioned it a few times! Did it cost much to have done? Are you still running the standard box from your 4.0litre? Forgive my curiousity but I've plans to tinker with mine should more funds become available.

If I had the cash I'd have LSD, manual control and a twinscrew anyday of the week... Although (admittedly as somewhat of a layman) I don't think the x308 is the best base for modifications because of it's weight and the 4.2 seems a better call...

C'mon Steve, surely you're not so much of a purest you wouldn't want LSD?

[NormanD]

G_T said:

NormanD you must be pleased with the manual changes you've mentioned it a few times! Did it cost much to have done? Are you still running the standard box from your 4.0litre? Forgive my curiousity but I've plans to tinker with mine should more funds become available.

Yes the 4.0Lt box is strong

Had the gear change some 5/6 years now, can't remember the price but quite a few ££££

[a8hex]

Isn't the Merc box the one they use in the SLR?
It should be man enough for most things, I remember there being questions in the mags about why they were using the "old" 5 speed box in the SLR when they had a newer 6 speed unit, the responce was that it was the only box to take the torque.

[Jaguar steve]

NormanD said:

Jaguar steve said:

Intrested to know why you think there's a need for a LSD. I know you're putting a lot more power down than standard - does the standard traction control on the 8 and R not cope with more HP?

Traction Control works by cutting power untill you have grip.
LSD lets you control the power to the road.

Likewise thats why the gearbox has bean converted so I have FULL control of the gear changes via the steering wheel

Yes I knew that, surely though ultimate traction depends on the level of grip from the tyres?

I can appreciate what you're trying to achieve, but I had got the impression that traction and stability control on newer Jaguars was a big advance over a LSD - could be it's because I've never driven anything with the amount of power you have.

Interested to know what you think once the conversion is done.

G-T: no, not a Purist at all - If it works and I was going down the modification road as far as Norman I'd have it.

Edited by Jaguar steve on Tuesday 13th January 06:14

[G_T]

I thought the TCS was a bit of a kill joy but admittedly that's only been off road and not on the track. Surely it's always better to direct the power to where there's grip instead of just reigning it in? And it doesn't won't work in the snow!

[NormanD]

Also with TC you go to pull out of a junction, the grey computer under the scull says that you have time to pull out.

TC then says one wheel is spinning, cuts all power, you are left in the middle of the road with a large lorry bearing down on you, you foul your pants and then the engine gets back into life.

I want FULL control with all the power that I require driving both rear wheels.

[G_T]

Surely in that instance the TCS would reign in the power and release it so quickly that it would not affect your driving though? I personally haven't ever noticed a big lag between the power being cut and the power being released (Although the lights on the dash flash for ages).

Also, and in context, if you're spinning the wheels at a junction you're more likely to change the direction of the vehicle as well? Drifting when lorry bearing down = worse than (very) temporary loss of power. Thats the reason I leave my TCS on!

Edited: Although I do understand why you would LSD for "spirited" driving! I hate the TCS when I want full control.

Edited by G_T on Tuesday 13th January 12:59

[avos]

Only 1 wheel (with an open diff) needs to slip a bit, and the TCS will jump in and cuts power, even though another wheel could still have enough traction. There is a reason why Jaguar is now with its new 5.0 (just 510 bhp) engine introduces again a LSD.

Next to having more traction with a LSD (including much improved snow driving control), the situation NormanD describes is very noticeable on 4.0 cars I have driven, and also (bit less) a 4.2 car with DSC. Very frightening to loose power for a short time when turning on a road. With a LSD you can almost floor it thru such a corner ;-).

Andre.

[CHJ]

I think the trac control on my xjr8 is too sensitive due to the `lag` just when you really don't want it, but I leave it on for fear of possibly disappearing through a hedge on the slippery country roads I'm usually driving on.

I think Jaguar should have had another less sensitive setting rather than just on and off, perhaps linked into the sport mode. LSD would be an added bonus!

[G_T]

I used to have LSD on my MR2.I was great gave so much more confidence and predictability in low grip situations. Would seriously consider getting a set up for the XJR if it can be done for realistic money. Keep us posted Norman!

[NormanD]

G_T said:

Keep us posted Norman!

Will do.

I'm looking to put in the later ATB Type, not so much on and off
My Man is away at the moment, will update when I have further news.