I would start with the OEM springs and the Bilstein rears and see what it goes like. It is all too easy to wreck the ride!

Nitron do an E type kit, and also Motorcycle stuff some of which looks like it might fit an XJS rear, eg their NTR-1. Might be worth sending them a rear shock and asking what theycan match to it. AVO shocks work really well on the XJS rears too, I have them.
https://www.nitron.co.uk/files/nitro...rochure.pdfAre the suspension rubbers OK?

 

Parts have arrived and things are starting to get going

 

The rear subframe and suspension is being dropped out.

Not going to reinvent the wheel here, going to us Bilstein B6 Dampeners to match the ones already fitted to the front.

Then get the original springs powder coated and use them.

What I do plan to change is the diff, I’m going to swap it for a shorter final drive, a 3.54, I believe the existing one is a 2.88. The existing one is leaking quite a lot so needs attention anyway.

The only other minor quandary I have is whether to go the whole hog and convert to outboard brakes…..?

My existing rear end has new calipers, pipes and quite a few new other bits already so seems a shame to waste that.

 

Good decision! Check the existing diff ratio, as at some point facelift V12s were factory fitted with a lower ratio diff; I think when the 4 speed auto was fitted.
I say keep the inboard brakes, lower unsprung weight, and if put together properly will give years of service. As to the handbrake, this is how I fixed mine and it superb and has remained so.

Incidentally, do SP have any dyno before and after BHP numbers for their manifolds?

 

I believe the xjrs maintained the 3 speed and 2.88 throughout its production run.

 

No dyno numbers on the manifolds but I’m sure they will sound good.

sticking with the inboard setup

Going for a rebuilt 3.54 diff.

 

Diff is out and back soon.

New Alloy rad with twin cooling fans has arrived, please with it.

Original Dampeners etc out

 

Thats interesting, the shocks has multiple positions for the spring seats. I dont believe my aftermarket Bilsteins were like that.

 

Yes they are Jaguar sport specific ones.

I hope the B6 ones I have ordered are not a downgrade, but the car came with new front B6 shocks already and I wasn’t sure how the rears would be.

Now they are off they seem to be in reasonable
condition ie you can’t push them with your hand like a lot of knackered shocks I have taken off other cars.

Could get them rebuilt maybe but don’t have the matching fronts, will have to see how I get on.

From new the handling was actually praised quite a lot, even against at the time newer German opposition etc.

 

Thanks @Mobeck Tekniske Christmas came early! Very impressed! Look forward to getting it fitted.