JAG IRS Shock Options

[Mike_I]

I am converting my midstates with a Ford 9" over to a JAG IRS setup and would like to know what spring and shock's most are using on the Jag setups. Mine will be identical to the contemporary setup. Also, please include PN# and or length shocks and springs are most using.

Thanks for the info.

[Mike_I]

Anyone Using a Jag IRS?

[patrickt]

Mike, I have the custom outboard brake ERA rear, not a stock Jag rear, but with a stock Jag rear I do believe that ERA specifications call for the same shocks as a stock Series II Jaguar XKE. ERA likes Spax stuff so for a shock without height adjustment they like the Spax S200 (externally adjustable damping) and with a height adjustment they recommend Spax G640. (I just pulled that from my manual for you -- like I said, they are not on my car.)

[Mike_I]

Very Good info patrick. Thanks

[tboneheller]

I am using some stuff that I got from Cobra Restorers LTD. It rides nice.

[Excaliber]

Height adjustment is a must have to assure clearance with various tire sizes. I've had many different size tires on my car and have had to adjust accordingly. Ride height considerations AND left to right adjustments to level the car side to side are also required! In addition to that adjustment, the damping may also be required. To keep those BIG meats from rubbing on a bumpy surface or when "getting air" off a jump ramp.

While you might start with something like the Goodyear Bill Boards, you may want to try Avon's or even road race slicks at some point. Avons are bigger than Bill Boards as are the Goodyear road race slicks, even WHEN the tires sizes say they are the same. Not all tires are created equal in that regard, it's just a ball park number.

[legenmetals]

I'm using Qa1 adjustables with springs that were on the Konis.I checked the spring rates and they are 300 .lbs each. my car is a contemporary with Jag. rear end. I found that the larger the angle of the shock installation the higher the spring rate that is needed.I will try and dig out the Qa1 part number for you.

[Mike_I]

Originally Posted by legenmetals

I'm using Qa1 adjustables with springs that were on the Konis.I checked the spring rates and they are 300 .lbs each. my car is a contemporary with Jag. rear end. I found that the larger the angle of the shock installation the higher the spring rate that is needed.I will try and dig out the Qa1 part number for you.

Thanks for the info. Please do let me know if you find a part #. I have had really good luck with the QA1's on my ford 9". I think the part # that I have on the ford 9" is DR4855P. Maybe I could buy 2 more and use them on the Jag rear as well?

-Mike

[Mike_I]

Originally Posted by legenmetals

I'm using Qa1 adjustables with springs that were on the Konis.I checked the spring rates and they are 300 .lbs each. my car is a contemporary with Jag. rear end. I will try and dig out the Qa1 part number for you.

Did you ever get a chance to check on the part numbers of your QA1's?

Thanks, Mike

[427cobra65]

Originally Posted by legenmetals

I'm using Qa1 adjustables with springs that were on the Konis.I checked the spring rates and they are 300 .lbs each. my car is a contemporary with Jag. rear end. I found that the larger the angle of the shock installation the higher the spring rate that is needed.I will try and dig out the Qa1 part number for you.

I am very interested in the part numbers for the rear qa1 did you use a 10 inch high spring?
is your front end coil over also?
thanks john

[bill37341]

John- on my scratch, I used a series 2 rear. Speedway # 255-3235 small body shocks, (11"); and AFCO 8" chrome springs # 106-282501CR (250#). You may need 5/8 shock eyelets, #255-1818b. Total cost in 2013 was $602.00. Hope this helps, Bill.

[427cobra65]

Thanks bill for your resonce!
this is were i am at!
the car car as it sits has a ride height of 4" off the frame rails in the rear with the the springs max out on there adjustment
the shocks are spax =when fully extended they are 13" which does not seem correct for the fact the perfect ride height would be 12.5 from shock eye to eye with frame rail at 5.5" which only leaves 1/2" of upward travel on the shock, that does not seem correct to me.
am i missing something?

[Tom Wells]

Mike,

Shock specs depend on which Jag rear you use, as the lengths of the lower arms (wishbones) are different.

As far as I know there are three stock Jag lower arm lengths, from shortest to longest: XKE, 3.8S (and related), XJ6/XJS. Track width varies accordingly.

The shocks you need will depend on which arms you use, or if you are changing the lengths of yours (i.e. shortening the XJ6 arms).

I use the middle length, for the 3.8S sedan length wishbones, and the four shocks are from Aldan: PAS657.

I agree there is a "correct" length for each, as mine were too short to begin with and made for some interesting pucker moments on the track; as the car rolled a bit during a turn, the inside wheel would lift - picked up by the shock which was fully extended - and cause the car to skip sideways. Lengthening the rear shocks helped immensely!

Studying the ERA site (their 427 Jag rear specs specifically) leads you to this shock they use: Rear Jaguar damper, adjustable

Recognize your shock mounts may be different either from theirs or my Aldans...

Happy hunting,

Tom

[DOORGUY]

Mike,

Here's a few photos of the Aldans on my Power Performance with XKE rear.