Explorer 8.8" IRS
 

Hello,
I met with Mr. Bruce in the Pittsburgh area today - thanks a lot for your hospitality and guidance!! We started talking about using the IRS from a newer Explorer. Someone posted pictures of the Diff but not the hub carriers, half-shafts and brakes. Has anyone adapted this set-up to a Cobra replica? Anyone have pictures of this IRS?

Thank you,

Al Keller
al_keller@earthlink.net

The Explorer IRS differential has a much stouter mounting system than the T-bird IRS that lots of guys use for the Cobras. I'm not sure, but I believe the output splines are the same as the T-bird IRS, so you could use the T-bird CV's, Knuckles, spindles, and hubs to make it fit up to existing mounting systems and parts.
If the output splines are slightly different, you just need the inner CV and you can have a halfshaft shortened with the proper spline to match the inner CV spline and you're all set. www.dutchmanaxles.com does them for $84 a pair or you can have all new axles made up that are much stronger than stock for around $300.
As long as you can figure out how to mount it, it should work just fine.

Al
I think, though not 100% sure, that the IRS unit from the Explorer is a 31 spline output as in the 03/04 Cobra Mustang. The T-Bird uses a 28 spline output.
The CV joints are probably stronger with the more splines but harder to find. If you find them, let me know where as I'm still collecting parts for mine.
Larry

I have installed the diff, hub carriers, shortened half-shafts and brakes from a 2001 Mustang Cobra in CSX style frame. I made custom upper and lower control arms to mate it all together.
I also made a mount system to hange the diff. in the CSX frame with out any mods. to the frame.
I've put about 700 miles on it so far, being pushed by a 408W and it seems to hold up just fine. I'm sure the Explorer stuff will work good too. It looks just like the Cobra Mustang parts I used.

Respectfully, Gary

My 2001 Cobra Mustang axles are 31 spline too.

Sorry Al for jumping in here!

Gary,
Did you have the production axles shortened or custom axles made?
Larry

Larry,
I shortened the Cobra axles to fit. I'd have to check my notes, but I think, I took about 2.5" off each one.
That is some hard steel to turn down. But it does weld very nice.

Respectfully, Gary

Awesome! Thanks Gary.
There was some disscussion on another site that the Mustang Cobra axles couldn't be shortened. No one explained why though, so that's why I wondered.
Thanks!
Larry

Gary,
I'm putting the Tbird IRS into a CSX chassis. I'd sure like to see some pictures of how you fabbed your control arms for your set up if it wouldn't be too much trouble?
I just finished my control arms and it was a real head-scratcher to figure out how to make it all work! But I think I finally got it together. Should get the trailing links in tomorrow.
Lots of scratch builders on this forum who would love to share some of this info.
Thanks,
Bob

I installed the 03 Cobra IRS into my Replica, in Fact I installed everything out of a 2003 Cobra:
http://cobra4me.com/phpBB/viewforum.php?f=9 <- the whole build here

http://members.cox.net/rjsliwa/socalcobras/J12th1.jpg

http://members.cox.net/rjsliwa/socalcobras/70000013.jpg

Explorer 8.8" IRS
 

Thanks for all the info on the Cobra and TBird IRS units. I'm trying to find out if anyone has any info/pics on the IRS units used in the later model Explorer vehicles. One of the members (OLDGUY I think) posted pictures of the center section. The housing looks much stronger than the Cobra housing. The hub carriers may be similar to the 427 Cobra hub carrier. The units may be less expensive than the Cobra. I think the axles (at least the inners) are 31 spline. Does anyone know about the brakes and wheel bolt pattern?

Thanks again.

Ak Keller
al_keller@earthlink.net

The bolt pattern is a standard Ford 5 on 4.5" for the cobra.
The gear case is the same as the Explorer, but the rear cover and rear mounting is much different that the cobra.
I'll try to round up a few pictures to post soon.

Respectfully, Gary

I looked at the newer Explorer hubs and decided it wouldn't be worth the hassle to try to mount them. Very different mounting set up and I think it would be very difficult to find a way to mate up a suspension system to them. As long as the other parts can be made to work together, try finding some T-bird knuckles and buy Cobra hubs/spindles to fit. They press right into the same T-bird hub bearings and will give you the correct bolt pattern. However, for less money, you can have the T-bird hubs/spindles drilled from the 5x4.25 to the 5x4.5 bolt spacing you need. I think I paid $60 to have mine drilled out on a CNC machine.
If you're interested in going this route I can forward a couple names of people who perform this service and do a great job.

Bob

Three Peaks I would be interested in names for redrilling Tbird hubs, was that 60 per hub or for both? If you haven’t already gotten the axles and shortened them already you might look at the Explorer shafts as I believe they are already shorter. I went by the Ford store yesterday to get what dimensions I could. The only thing I could find out is that the inner tire to inner tire on the explorer is 48". by extrapolating that seems like the axles might just be the right width. I plan on using an explorer housing with Torsen dif and 3.55s and MK VIII spindles with MK VII brakes and generally Rorty plans http://locost7.info/files/suspension...RSAssembly.pdf I'm building a 393 powered Lotus 7 which is generally the same as the Cobra but with a space frame. A lot of info can be gathered at http://locost7.info/mirror/mirror.php there are more similarities than differences.

For hub redrilling and other IRS services, get hold of Stu Spencer at IRS Machining Services a http://www.geocities.com/stus_cobra/irs_machining.html

You'll have to check out his site for his prices as different services are different prices. You'll need to replace your bearings also, which Stu can accomplish.

I already had my axles shortened quite awhile ago at dutchmanaxles.com. It is right here in town and they do a great job and great turn around times. I think it cost me $84 for the shortening for both axles.

I don't know for sure if the explorer axles will work or not. I know the hubs/spindles are different and I'm not sure if the CV axle splines match up to the T-bird IRS hubs.

Thanks his work looks great. I got the spindles for $26 so a full on rebuild would still be reasonable. I am going to find out about the splines and if different could a hybred shaft be assembled reasonably. I could go with the full width Tbird/MK VIII shafts since I don't have to fit within a body and simply make the front A arms longer to match track. From what I've heard of the MII the arms could stand a bit of lengthening anyhow.

What I have:
03 explorer housing and back cover

2 MK VIII knuckles

31 spline Torsen T2 (OEM) I've been told it won't work with IRS)

What is coming:
2 03 Cobra hubs

Tbird half shaft

03 Cobra half shaft and extra 03 diff side (31 spline) stub/CVJoint

Currie Johnny joint is a spherical bearing which is rebuild able, they have one version that the outer shell is 2" diameter 1.5" width and the trunion is 2". this appears to be a pres in fit for the knuckle bushings and would considerably cut friction/bind they are $37 ea but if a GB might be able to knock price down a bit.

What I'm trying to find out:
Will My T2 fit an IRS housing

What are the differences between the Cobra 28 & 31 spline Tbird/MK VIII and Explorer half shafts?

The best/cheapest way to put big brakes on the Tbird/MK VIII knuckles

How good/bad an idea is using ABS on this light a car

Flange to flange width of 03 Explorer, 03 Cobra, and Tbird/Mk VIII, The Explorer is 48" inside of tire to inside of tire.

What I'm working on:
I'm talking with a shop that builds half shafts that has stopped breaking shafts & stubs for drag 03 Cobras. He will get a set of Explorer half shafts in the next week and should have some answers on differences. He has different length of shafts in stock they cost 99 and moved the breakage to the outer CV stub shaft. he has a heavier level that replaces the outer stub and hub assy with 35 spline that appears to have moved the breakage to the tie rod on 03 Cobras. I'm working up a cost for a 28 spline that fits Cobra/Tbird/Mk VIII hubs and Explorer 31 spline diff.

I have found a source for reasonably priced Explorer diffs and rear covers.

What seems to be the best mix:
Tbird/MK VIII knuckles
Currie Johnny rebuildable joints instead of bushings
03 Cobra hubs
Cobra rear brakes
Cobra/Super Coupe/MK VIII diff housing (allows 2 front mounts and has mounts for 4 channel ABS)
03 Explorer rear cover (better mounting)
Rock Krawler .75 shank rebuildable suspension joints
Stock Car Products threaded steel tie rods to build A arms

I will pass on info as I get it and would appreciate any comments.

This may help with the differences between the 03 Cobra axles and T-Bird stuff. http://i21.photobucket.com/albums/b262/LMH1/Axles.jpg

If you search around on his site ( www.Cobra4Me.com ), there may be more info to help.
Larry

Oh yeah, for brakes, check out http://discbrakesrus.com/make/ford/mustang19871993.htm.
They may have kits like your looking for.
Larry

Larry
Thanks. I was all over Cobra4Me & diskbrakesareus sites. What is needed is the similarities between the stubs, i.e. will the Cobra 31 spline fit the Explorer diff, will the Explorer or Cobra fit the Tbird/Mk VIII hub. I'm frugal/cheap and am trying to find production parts that will accomplish the need. I did find stock t-bird irs flange to flange 63.50" +/- on a thread here.