www.jec.org.uk

Good day all!

After reading the maker's man manual for the XJR/X300 I see that the XJR has a slightly different front section of exhaust which I assume is to make the most of the blower and associated timing differences.
Not having both exhaust sections to hand for comparison, can anyone tell me the difference in pipe length?
The reason I am asking is because I have an XJR6 engine awaiting fitting to my '92 4.0 XJS and am contemplating the ramifications of marrying the XJS system to the 'new' engine.
I have the fortune to own a car registered a month before the cat laws came into effect and consequently have the option of fitting a cat free exhaust from another AJ6 unit or fabricating something suitable.
Ideally I'd like to keep to the Jaguar parts bin (Engine management aside sadly) and any help on the matter would be greatly received!

there a number of XJR6 front pipes, depends on year and market of car, my guess is thet the bore will be greater on the R than on the n/a car, although like you I have nothing off cars to compare with at the moment

Andy Stodart is the man to contact, andystodart@metronet.co.uk

hope this helps

Rob

Well I think that i've got the answer to my question, and I may even have a slightly better grasp on exhaust principles to boot!

It turns out that the slight differences between the xj6 and xjr6 exhaust system are to do with space restrictions caused by installation of a different gearbox over standard models. The XJR6 exhaust is actually slightly more restrictive in this area due to the need to use a slightly smaller olive joining the sections here. The minor changes in length mentioned in the service manual are, I take to be, largely insignificant and again due to packaging restraints. If you take a look at the construction of AJ6 Engineering's offerings for the AJ6/AJ16 engines (which obviously have a lot on common with the XJR6 unit) then I think it at least adds some weight to my conclusions.

In short, I won't be worrying about the issue any more and will be happy with a little less kudos than a V12 but with a little less weight and a fewer of the other concerns associated with running a large complicated engine.

Thanks for your help.