Hi everybody,  

Does anybody happen to know if the internals of a 2. gen Jaguar IRS  (XJ40) are the same or will fit a 1. gen  IRS? I have a 2. gen laying around and a 1. gen comming in. The 2. gen has Power Lock and 3.54;1 gears wich will help alot in my overdrive 4R70W tranny. 
Do these parts interchange?

Thanks,
Mustsed

Hi all,

Looks like alot of work is stuck in there! Hope you post pics while going.

agree with phatomjock;
DAZE - thanks for keeping the site open!  It is the best single source on the interweb for IRS.

Mustsed
 

Hello and Hi to everybody on here!

I am a long time member of this very very helpfull forum but had health problems with my father so not much time to be here enough. I did a bunch of Jaguar IRS installs in all kinds of Ford vehicles and had never a complaint or problem with any of them. I changed all the installs to the cage type a la Daze and they are performing well. On the success stgories page, there is a burgundy '68 Mustang pictured which was one of my first or second install. 2 weeks ago I got the car back for some maintenance (after 4-5 years of hard abused driving) and started checking all and everything.
I noticed cracks in the cover sheet metal around the top IRS center mount bolt holes (ı used the stock Jaguar center mounting plate). After investigating the whole unit, it appears to be caused because the cage is mounted via bushings to the frame, the trailing arms are independantly mounted to the frame via harder bushings with less "give" then the cage bushings! The difference in "plays must have caused the cracking visible in the pics?!?! The center pieces is not stable in the bottom (because of the bushings) and tilts sightly front to back which in my situation causes the cracks. After further inspection I decided to remove the cage and mount all tie mounts to the cage itself, eliminating any and all play caused by the bushings "give". Hope I could explain the problem.
The drawback is that I had to run the new crossmember below the mustangs rear frame rails which makes them a little more visible. Now I just loosen the driveshaft, brake lines/e brake cable and the cage to lower the whole unit as one piece from the car if need arrises.

Just wanted to share!
Mustsed

Hi gravesgrg,

I guess the main problem would be the narrow mounting points of the IRS causing alot of stress in that area which might cause cracks. BMW's are known for that kind of cracks in the rear suspenssion area. I choosed the Jaguar because of the wide spreaded mounting possibility which gives some stiffness.  One more reason to choose the Jaguar IRS was the availability of ring&pinion gears in any imaginable size which shoould be a lack with BMW.

Just my 2 cents,

Mustsed

Hi everybody,

Never tought that a human kidney could set one out of live that long - what a pain but luckily a wil be on here more regular as before.

Welcome on board Yolo, you've just found the only IRS dedicated understandable forum on the www.

I have done 6 Jaguar IRS rear ends into 5 Mustang's and 1 F-100. The first and second (Mustang & F100) was installed using a crossmember on top between the frames and a second crossmember in front of the Jag IRS to have some points to install the differential and the trailing arms to. The rest used the cage a la Daze! 

I have the dimensions for a Mustang and can make a frame cage without having the car here to work on. All other brands that ask for such a cage  must have the car available to me so I can take meassurements.

NONE of the owners would ever go back to a straight axle when compared to the IRS. The cars handle much more stable and even maintain grip on high speed driving. Never had an issue with ground clearance but the stock Jaguar had the same hight also!?!? If you look from the back of a Jaguar IRS car, it SEEMS the car is lower but it is not. I have done the cage on my own '67 Mustang recessed so it will drop an additional 2".

If you read trough the post on here, you get very close to the right adjustments which are more accurate then the Mustang units had ever been. 

I agree that the Jaguar IRS might not be the "best" IRS out there but it is cheap, available, parts are easy to get or to make and most off all - affordable (even here in Turkey). 

Would I do it again? YES (anytime / anywhere)

I also look into other IRS units from BMW, Honda or Nissan but they are more work to install and more expensive (at least over here).

I have two more Jaguar IRS units in the garage and waiting for gears and a lock to fit them in one more Mustang and a '56 Victoria.

I am not affiliated with Jaguar :-)))

Mustsed
 

Thanks Ralphy,

I've read them all and was looking for specs according the hubs and the way they are attached to the center section. In the stock configuration they look like the HS are acting as the UCA like on a Jaguar based system but the second with the splined HS must have an UCA of some kind.

Another point is that the front has a cradle that is attached to the front leaf spring mounts but there are no rear mounts visible. The shocks appear to be mounted in their stock locations and as an added bonus there is a sway bar!

The center section must be mounted on the top via a flange that may be welded to the housing . There looks to be a slight tip in the suspension travel to the rear as long as I can see.

I would love to re-construct one of tese!

Mustsed

Hi everybody,

I thing that the idea of a cage mounted to the stock leaf mounts is a great idea and therefore needs to be credited to you Daze because I cought it from you!

Yes there are sme differences mainly because of time limitations and I only got 5 days to work on that car. Ford tolerances are more then I tought when using my own '67 as a jig for the cage. I had planned to mount a section of  U channel to the front leaf spring bolts and then use some bushings on the CM ends to hold it there. Have done them but no time to make it to the car again. So it will wait a bit more till they will bolt on the car. I can't remember from where I got the 3 upper shock mount bosses idea but they allow a bit of adjustability up there. 
I did the trailing arms at home and send them to a mechanic who installed them but they will be replaced by threaded rods with adjustable joints that are sold by Kugel ($55 a piece - that hurts). If I can talk the owner to lift the car up and take some pics of them, I will post them here. All in all he is very very happy with how the car handles and stays on the road as it never did before!!!!
The plates form a rectangle at the end of the lower control arm which stiffens up the mount boss / tube / fork triangle.

The preparation took a few months but the installation was not a big of a deal (except the variable meassurments on these Mustangs and the extra work that show up because of this) and I think that it is worth every cent invested.

Mustsed

This should help a lot!

http://home.bresnan.net/~dazed/JaguarIRS4.html

At least it did when I was rebuilding one differential like Daze.

Mustsed

Hi everybody,

I had that idea years ag but instead of using upper and lower control arms I just tought of using a complete front end off of a big FWD Van!

Fabbing a system to keep them straight, making a LCA pivot point and a strut rod for it. On top you just verify the location of the strut shock and make an adjustable plate to place it. There will still be the need for a differential but that won't be to difficult.

Would love to see this done.

Mustsed

Please do not forget that forums that are categorized might be good for the group that is in each individual group but will stop trading ideas from each group into another. What I'm trying to say is that sometimes I take an idea from a Cobra IRS or a BMW IRS and apply it to a Jaguar IRS because I can fallow it in this ONE forum instead of browsing all forums for which I don't have the time. IMHO I believe that each group will beat their system to dead and after a while just repeat their info to newcomers.
Not so with new systems introduced to everybody on this one forum where anybody can chime in and put some salt into the soup.

That's just my point and my view to this.

Mustsed

So, there I am in the same boat as KLR250!!

All attempt to locate a first gen. Jaguar  IRS for a friends '68 Mustang failed! The only Jaguar IRS that could be located is a second gen. assembly (according a telephone call with the owner and his description). Never paid attention to these units but looks like they will work too.

How are these differentials called and what kind of locking carrier works for them? What kind of spring/shock are you going to use? How wide are these and can they be shortened or did you shorten them? These are the questions in my mind and am not able to find these on the www.

I have no way to see that part before purchase and still looking for someone who could take some pics and send them to me but would be great if KLR250 would chime in and give some info on the 2.gen. Jaguar IRS.

Thanks in advance!

Mustsed

I have my Mustang since 1989 and most of the time it has been sitting in the garage and having updates done to it. Lot of these upgrades are removed because they didn' work out as well as tought!!!!  Anyhow, the car is really a million decades away from the stock factory configuration and drives great. It should be enough but the government forces me to do my last two mods. The first is for the high gas prices over here = EFI and the second is for the mountain roads over here = IRS. I will stop doing anything besides regular maintenance to my '67 Mustang.

The reason why we do it is = because we can do it!!  Spending hours in the garage or shop to improve something nobody except yourself will notice. That's why it has to have a end!! I love my car and have to son's waiting for me to pass it over to them. The last few years I am looking for a 4 door big Ford which will only get good brakes, good steering and some comfort items like A/C - that's it!

And now to your points;
1.  Top of the hub watts link
**To much distance to the LCA hub pivot point, braking and accel might cause to much stress on LCA bushings.

2.  Watts link in place of trailing arms
** That's what I'm doing or plan to do!

3.  Linear anti-squat adjustments.  In other words being able to set the suspension to have a consistent rearward travel through the full range of  suspension motion.
** My car will have a hard short travel and I don't think that this will be a problem therefore ditch any mod according this.

4.  Reactive anti-squat.  In other words anti-squat that is initiated by hard acceleration or extreme suspension travel.
** Same as #3 answer.

5.  Rear steer created by slight toe adjustment due to extreme suspension movement
** Don't thing that this will something  I will considering to adjust.

6.  Tubular LCAs
** Stock jaguar's are tubular .

7.  Inboard disc brakes or outboard disc brakes?
** This is a missing visual expectation on open wheels therefore I did it on my setup. This car is

Alot of parts have to be custom made or at least the parking brake cables have to. To much hassle for such a small advantage.

I like the idea of welding the holes and redrilling with the new bolt patern. This will give the best result and I can use the added space for deeeeeeeeeper dish wheels!

Mustsed

Ralphy, If they turn in the same direction, you wouldn't be able to make a U turn but go sideways. There has to be a changeover from slow speed (opposite turning front&rear wheels) to higher speed (both wheels turn into same direction)!

If they only turn the wheels on higher speed driving and keep them streight locked in slow speeds, then it is useless IMHO.

Mustsed

BTW, to get back to the orginal post!

How areyou going to steer the rear wheels?

In very slow motion they have to turn opposite the front wheels tu make turning radius smaller but at higher speeds they have to turn same with the front wheels to chage a lane for example - how will this be controlled at what speed and how much rear wheel turn for how much front wheel turn?

I know a few guys overhere that have off-road cars with fron taxles in the front and in the rear with reverse cut ring&pinion gears. During offroad use it is beautifull but if you gain speed it turns faster then you can imagine and the results are not that funny anymore.

Mustsed