jag irs , how strong?

In a now famous bit of British TV, the Top Gear team took an old XJS V12 and fitted a nitrous kit. They claimed that this increased the engine to 780 bhp (And it certainly went like lightening) -

For my experience the weak bit of the whole set up is that rear diff and the clutches inside, everything else is just nice thick steel - So I guess if anything is going to break its these clutches. Try the earlier type of diff (No speed sensor fitted to diff casing) as this is the traditional sort.

Stu

cheers for your reply . kit car will have a bored and stroked 351 ford cleveland in it , roughly estimated torque figures are about 500ft lb. So hopefully earlyish jag irs system will be strong enough. just one other thing I have heard the later jags xj 40's have a altered setup. Outboard breaks and a different lower wish bone. Any thoughts on this?

Marc

I have to say that I have never worked on the later version so dont really know how its put together. The IRS system has been very popular to use in other cars because its a nice unit that is self contained within a cage.

Best of luck

Stu

Hi Marc,

You know the Jag rear can really look nice all chromed or polished, but FORD used a nice setup in the Thunderbird SC and holds up nicely to tire-nuken demonstrations. Kit cars are light so the forces on the diff are less than you think.

Blake

Marc, If only you could combine the best of the two IRS systems!! The XJ6 and the XJ40 systems are fairly similar in design, having re-built both. The advantage to the XJ40 is that the hub and the brakes are outboard making it FAR easier to change rotors and pads whilst everything is on the car. The same operation on any XJ6 or XJS can be a nightmare with the inboard system. The problem with the XJ40 design is that the bearings on the stub axle coming out of the differential are large diameter ball bearings. Recommended average life is about 40,000 miles. They are a terrible weak point. The XJ6 has roller or taper bearings which are much better performers than the ball bearing type bearings of the XJ40. The question you need to find out is if the spline for the 1/2 axle of the XJ6 will fit into the hub of the XJ40. If they will match up, then you can replace the XJ6 wheel hub with the one from the XJ40 and have outboard brakes. Unfortunately, the stub axles have different bolt on patterns and you can't swap one for the other at the differential end. The other negative (or possibly a positive) about the XJ40 is that it does not come in "cage" like the XJ6 and XJS. The differential and rear suspension are anchored into a LARGE crossmember stretching nearly the width of the car that bolts into the frame. I think it is actually a bit of a better design, but that is personal opinion. Here is a link to a website with photos of a cage removal from an XJS. It will give you a good idea of what you are working.

Webserve

"marc" wrote in message news: snipped-for-privacy@4ax.com...

WHOOPS! Forgot the link!

Webserve

I have bought a jag back end in apperently good condition for a 100 , I think its an xj 40 . will have good look at it and try and figure out a good compromise. Thanks for your input it will come in handy. Marc