Jag I.R.S.brake upgrade / Watts ?

[KobraKarl]

I know a lot of you are running the jag irs, some say its perfect, others say it has weeknesses in a hot rod application.

I think i am going to at least upgrade to Watts link ,and maybe brakes depending on the feed back i get.

Iwould really like to hear from any one who has done either of these upgrades regarding expense/difficulty/improvment/whatever.

also have type 1 front single pot jag brakes that are just so-so stoppers. any one redone them ???




thanks Karl

[Jon Miller]

Hi Carl,

The Watts linkage is a great setup, but the cost for the linkage and the hubs that you need to run it is way more than I could justify.

I used a radius rod setup that attaches to the rear hub pivot and then runs to the rear frame cross member at a point in line with the inner pivotpoint of the lower control arm. My E-M has a much larger rear frame member than your Contemporary, so I was able to weld directly to the frame. For the Contemporary I've seen a bolt on piece that they use for the rear mount. I can email you pictures of my car, and the Contmporary setup if you would like. (I'm not smart enough to get them to post here). The total cost for the Radius rod setup was about $60, not including the hub brackets which I built on my lathe.

If I were you, I would use all that money that I saved on the Watts linkage and upgrade all 4 brakes to Wilwood.

Good luck!
Jon Miller

[KobraKarl]

John,

I like the simplicity of the radius rods, but someone told me they create a different problem because they are mounted to a fixed point . When the rear suspension flexes up or down this puts a lot of strain on the lower arm as the radius rod gets effectivly shorter relative to the degree of flex in the suspension.

[Jon Miller]

Karl, It's kind of hard without pictures, but what I think that you are talking about is the conflicting radii of the arms as they go through their travel. The lower control arms will cause the wheels to move in and out with suspension travel. The stock Jag trailing arms will try to pull the wheels fore and aft with travel. On paper this would create a suspension that would not move, the solution is found in the form of big rubber washers on the trailing arms that allows them to have some fore/aft give. The problem is that this fore/afm movement is just what the arms are there to prevent.

With the radius rod having both inner and outer pivot points alligned axially(I think that's a word...), you are effectively creating a big stable triangle. I've seen some Jag based rears where they have replaced the lower control arm with two rods with heim joints at each end, and the entire fore/aft load is carried by radius rods.

-Jon

[RACER X #99]

Karl,
I have the radius rods from CWI on my early Contemporary and they are very long so I don't beleive that the up and down motion has much effect on toe. They attach about mid point of the frame rails and you have to bend them and also notch the rear sponson so they don't hit. Tom T also has them on his Contemporary.
I also agree with Jon go for the Wilwood brakes all around.

Cranky

[Tom T.]

Karl,

I think you've gotten responses to one of your earlier inquiries on the radius rod topic, but anyway, they're about three feet long, as I recall, and CWI will certainly know for sure. I can say that in my experience the addition of those rods completley eliminated the feeling I had that the rear suspension was "nibbling" and somewhat unstable through high load turns. I've got Wilwoods up front, and have been very satisfied.

TT

[Jon Miller]

Here goes another attempt at a picture.......

[KobraKarl]

Jon.. thanks for the pic , are my eyes deceiving me or is that rod mounted aft?

Cranky/ Tom T

what did you use for rotors/caliper mount/ uprights? Ihave early series 1 that are apparemtly not too adaptable

[Tom T.]

Karl,

Bought a complete Wilwood set-up from GT Jaguar--put the name into your search engine and you'll probably find their website. A fair number of people with XKEs upgrade their brakes this way.

TT

[RACER X #99]

Karl,
I studied the Wilwood catalog real carefully and picked a rotor and hat assembly that i figured would fit. I made my own caliper mounting brackets.

Cranky

[B. SMITH]

"UNIQUE" USES A NEAT REAR FRAME MOUNTED RADIUS ROD SYSTEM. THEY COMPLETELY TAME THE SERIOUS AXLE SHIFTING IN THE JAG IRS.

B. SMITH

[LeonardU]

I have a Contemporary Cobra and would like to know exactly how the radius rods work and how they are set up. If the rods attach to the rear, don't they hit the gas tank? If you have to make a bracket to clear the gas tank, doesn't the bracket look ugly when the car is viewed from the rear? I would install one using heim joints at each end. Could you sent inform and pictures if possible to my new email at Leonardu2@sbcglobal.net.

I installed Wilwood brakes on my Contemporary with Jag front end and spent a lot of time researching the topic. I looked at all the Jag kits available and was unhappy with the quality and price. I was able to use a Wilwood stock disc and caliper. I fabricated a hat and caliper bracket. The design was time consuming, but the assembly was beautiful and it works well. When it was installed it was spot on. The only problem was that the Wilwood discs were not true. You need to have the Wilwood discs checked to determine if they are true before you install them. I would be happy to share my drawings and dimensions with anyone that needs help.

Thanks,

Leonard

[Tom T.]

Leonard,

I've got the CWI set-up, which leads to the irs from the outriggers area near the middle of the car; thus, there is no need for brackets that hang below the body line at the rear of the car. The type that lead from the irs to the rear of the car--I've seen a couple of photos only, and those did have brackets that dropped a bit below the rear body line, but I don't know if that always has to be the case. Anyway, I live in Novato--you're welcome to drop by sometime and take a look for yourself.

TT

[KobraKarl]

Leonard

the radius rods for contemporary are mounted forward. Iam pretty happy with almost any tool in my hand but i get pretty weak when it comes to something like caliper bracket/hat fabrication,who makes a setup out of the box?

Tom t

so you are saying because the mounting points of the lower arm and the radius rodare consistant axially for and aft there is no toein on compression?

Karl

[Tom T.]

No, Karl, I'm not necessarily saying that--and I don't want you to make your choice based upon my views about how well the system works. It works for me. This was a $150 modification, vs. much more $$$ for Watts. I talked with Michael at CWI before I made my choice, and I'd suggest you do the same to get your questions answered from a truly knowledgeable source. As I understand it, the radius circumscribed by the CWI rods is on a wide arc (due to the length of the rods), minimizing suspension geometry changes under lateral loading. In my book, the radius rods work great. Cranky feels the same, as I recall. Can't really tell you whether you'd be satisfied with them or not. Again, why not just call CWI directly? Michael is a great guy, and really knows his stuff.

As to the front brakes, to repeat, GT Jaguar sold me the complete set-up. Simply a matter of bolting it on.

TT

[RACER X #99]

Karl,
I will take a picture of my radius rod set up. Keep in mind the bottom of my car has not been cleaned since I blew all the oil out of the side of my oil pan. (another thread).
Cranky

[RACER X #99]

Karl,
Picture #1
Shows the radius rods that are bolted and welded to main frame rails.

[RACER X #99]

Karl,
#2

[RACER X #99]

Karl #3
Shows the radius rod attached to rear swing arm at same location where sway bar was attached. Sway bar attachment moved to inside of same mount. Also notice notch in rear sponson that I welded a half round piece of pipe in the maintain strenth.
Sorry for the poor picture quality. Video cameras take lousy stills.

Cranky

[LeonardU]

Tom T.,

You purchased your Wilwood conversion from GT Jaguar. Is that Gran Turismo Jaguar? If it is Gran Turismo Jaguar, anyone considering doing business with Gran Turismo Jaguar should talk with me first about my experience with their products and their customer service.

Thanks,

Leonard