Looks pretty close to what I perceive as  TOE Control bar.
The central location is probably a problem looking at the subframe.


Cheers - Jim

Last edited by phantomjock (12/01/2011 3:58 pm)

That's an SN95/99 Mustang Cobra IRS modified to fit an early Mustang.

No, it does NOT lose the upper arms; if it did the whole thing would fall apart.   Just can't see them up above the axle in this pic.

It runs coilovers on the OE shock mounts because...well, that's what there was room to do.   That isn't to say there might not have been other approaches, this looks to be the easy way out.

The early Mustang floorpan design is quite different from the Fox-derived SN99 and there probably wasn't room for a spring on top of the arm in the stock location.    The key design consideration for the Cobra IRS was that it had to bolt up to an unmodified SN99 Mustang floorpan using the mounting points and spring/shock locations of the stock four-link stick axle.

Last edited by JEM (12/02/2011 10:40 am)

Ralphy wrote:

Gotcha. so the 8.8 uses a toe rod with one upper and one lower mounting point  at the hub? Then the 7.5 uses one upper mount and two lower mounting points at the hub?

Uh...no, not quite.

7.5 and 8.8 just refer to two different final drive designs. 

The 7.5 in stick-axle form was used in a bunch of different Fords - Mustangs, Rangers, etc.  IRS versions were used in the non-SC MN12 Thunderbirds and I believe the DEW98 Lincoln LS/Boringbird/Jag S-type also uses a 7.5 (might be wrong.)  The MN12 application is an iron case with two narrowly-spaced mounts on either side of the pinion snout and one V-block mount bolted to and cantilevered out behind the rear cover; I believe the DEW98 case is aluminum, and the mountings are certainly different and more typical of, say, BMW practice with one offset front mount and a pair of widely-spaced mounts in back.   I believe Ford's also had a 7.5-in ring gear axle in some of their (other-than-Jag) European products but I can't say whether it has anything in common with this one.

The 8.8's also been used all over the Ford product spectrum as a stick axle from Crown Vics and F-150s to Explorers and Mustangs.  The first IRS application was the '89 MN12 Thunderbird SC/Cougar XR7 and the FN10 Lincoln Mark VIII; it was subsequently used in the '99-04 Mustang Cobra and '02-09 Explorer.   The 'Bird SC case was iron, the Mark VIII and the Cobra shared an aluminum case design; both mounted as noted with the 'Bird 7.5 above.   The aluminum cases are not known for breakage, but the mounting arrangement and especially the thin aluminum rear cover ( used even on the iron 'Bird cases) are notorious weak spots.   The '02 Explorer unit is far beefier, a much stouter and heavier case with a very strong ribbed rear cover.   The Explorer assembly also uses a mounting arrangement similar to the LS, with a single offset mount forward and a pair of widely-spaced bushings in back.   

Just about everything about the Explorer unit is different and will not bolt into the earlier assemblies, but you can bolt the Explorer rear cover onto the earlier housings, which is what I'm doing with an iron SC housing in my Galaxie installation.  It'll require some fabrication to make the rear mount arrangement work, but it should be far stronger and far more stable.  I think this arrangement will prove far too bulky to fit in the Mustang Cobra IRS though.   It'll actually have four mounting points - the two original pinion-snout mounts and a pair of E39 BMW bushings at the rear.  If someone convinces me three-point mounting is better I'll just leave out the left front mount bushings and bolt.

This all has nothing to do with the locating arm arrangement of the suspension in which the unit is used.   None of these designs bolts the arms to the diff housing or uses the axle as a locating link.   The MN12/FN10, DEW98, Mustang Cobra, and Explorer suspension layouts are all quite different from one another.

Last edited by JEM (12/04/2011 10:50 pm)