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Ford 8.8 IRS Conversion


SUNNY Z

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Well I picked up an 8.8 for an explorer. It looks like this one has a different housing, I wounder if the one front mount it has is in the same location as your double .Time to start looking for a mustang diff housing.

 

20130105_205355.jpg20130105_205335.jpg

Edited by wrighttool
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The one thing you'll want to add if you haven't already taken it into account is a pinion snubber.  The ears will not hold the front of the diff from lifting and will eventually break on a V8 car.  Just a piece of square across the top with a basic rubber block should be good enough. 

 

Cary

Unless you go Delrin busings to prevent flex. I have heard the poly bushings on the front are the problem to the cover breaking and the ears. Everyone that switched to aluminum bushings or delrin had no problems. If your diff is moving up far enough to compress your bushing then you are going to have issues. Dont be scared. Get rid of those poly garbage bushings before you are back to square one.

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Well I picked up an 8.8 for an explorer. It looks like this one has a different housing, I wounder if the one front mount it has is in the same location as your double .Time to start looking for a mustang diff housing.

 

 

 

I would bet big money that it is.

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SUNNY Z:

 

I have purchased a 8.8 inch Ford IRS differential to do what you are.  What is the inside and outside diameter and length of the tube in the middle of each up-right?  What is the dimension of the tube to one end of the up-right?  I will purchase the same rear differential cover that you are using for this project.

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I've skimmed through all 105 posts on this topic and didn't see discussion about using the Ford outer CV joints, shortened shafts,

and OE hubs with custom fabricated knuckles / hub carriers.   Has anyone thought about doing this?  I have taken some rough

measurements and it looks like it could work if I raise the strut tube holder/ socket a few inches, above the CV axle centerline, possibly using the Tokico Illumina BZ3099 cartridge or one even shorter if it exists.   

 

I am just getting started on my 280 Z project, planning to use the LS376/480.  I bought the MM 5 lug hubs and CV adapters already, but reading on some of Sunny Z's experiences have me thinking about adapting the Ford 8.8 diff, axles, and hubs with custom fabricated knuckles, and selling my MM hardware, even though I think his inner stub breakage problem is directly due to the stresses from the welded diff.  

 

Steve

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rsicard - I'll try to get some measurements the next time im working on it.

 

SteveO - You might be right in saying that the welded diff was a factor in the breakage of stub axles. However, I will have much less in this whole swap than I would if I'd bought a LSD and had it installed.

 

Strength+ easy changes = win in my book.

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SteveO - You might be right in saying that the welded diff was a factor in the breakage of stub axles. However, I will have much less in this whole swap than I would if I'd bought a LSD and had it installed.

 

You don't have to convince me.  I think the 8.8 diff is the right direction, and I'm seriously considering it for my project, but I am thinking / planning on fabricating custom hub carriers to use the Ford outer CV joints and hubs, and a shorter strut secured above the axle centerline.  Thinking about making a jig using the original Nissan strut / hub carrier assembly, and my new 5 lug stubs that I may never use!   I already bought the MM stub axles and adapters but will try to sell them off if I do end up going this route.    The torque biasing diffs for the Ford 8.8 are about half the price of the Quaife for the R200, gears / parts are plentiful and cheap, I agree.  

 

Having said all that, I think that either your uprights are going to crack right where you welded in the diff. cover mounting bosses, or will loosen / break the upright mounting bolts.   Will be anxious to hear which.   Did you get them stress relieved after welding?  I know the Nissan engineers could have done a few things better in hindsight, but I am confident their decision to isolate the diff mounting from the suspension arm mounting was a good one.   Could you not have made some modified uprights to give room for a custom made mustache bar that would mount to the Explorer cover (or Cobra cover) and to the original mounting points in the rear subframe?    I don't have any of these parts in front of me (yet), so am going off of imagination only...

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On my z-car, the rear of the diff is mounted via the thin aluminum rear cover with just 2 studs screwed into it.  The rear diff cover is held to the diff case with about 10 bolts that are torqued to like 12 foot pounds.  My RT mount bolts to super thin sheetmetal in the tranny tunnel.  Honestly, the stock diff mounting system is not real impressive, yet mine hasn't broken (neither has jnjdragracing with his wheelstands).  I think SUNNYZ's system is gonna be fine.  How about you guys get your welding machines out and build something or leave a brother alone while he toils away!  I just hope he makes it cheap so we can do a group buy.

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Looks like its coming along good, I just now read back from where I last posted, glad to see your going with the TTT backing plates. It might be earlier in this thread and I forgot, but what did the DSS quote you on axles with the 8.8 inners and the Z31/Z32 outers or whatever you plan on using? I've got the line on a Z32 TT R230 setup for a steal and will be taking a machine shop class this semester and might be fabricating some backing plates/strut tubes similar to the TTT design. Just trying to figure out if using the R230 and just getting shorter axles would be cheaper than finding and IRS 8.8 and getting custom axles. The diff/gear choices of the 8.8 sure is a good selling point.

 

If I can build the backing plates/strut tubes it will end up being cheaper than a solid axle swap and should be close to bullet proof

 

-Will

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The axles from the DSS would be about 1100, going the route i'm going. This is a billet 31 spline input stub made to mate to a porsche 930 cv. Custom length bars, and upgraded internals for the Q45 outer CV's.

 

Inner CV's - $500

Bars / Rebuild / Boots - $600

Outer CV's - $50?

 

I'm not sure if you could utilize a stock ford inner cv, with a q45 outer, and just have a custom made bar. Might be something to look into, but I know the ford inner 31 spline CV's are hard to come by ($$).

 

I got the front mount finished up, and trimmed the fat off it. I'll post a pic of that later.

 

here are the T3 strut tubes and GC coilovers that showed up. Backing plates aren't far behind. Definitely quality pieces. Powdercoat looks nice!

 

2013-01-16_19-51-16_232.jpg

 

Going to hopefully buy the bearings and hubs tonight or tomorrow, and be able to assemble all of it, and measure for axles / driveshaft.

Edited by SUNNY Z
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Not a big update.

 

I took a bunch of parts over to a buddy's house and sand blasted / re- coated them.

 

Found several cracks in my tranny x member. Welded them up, and went on with business as usual.

 

The backing plates from T3 should be here this week, then i'll measure up all the axles and driveshaft. 

 

Bought some axle bearings / 4 lug hubs off a local and cleaned them up. going to order ARP studs, and possibly a bearing or two (kinda gritty see: 23 yrs old), and then i'll have more to report!

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SUNNY Z:

 

I have been closely following your build threads.  Would be great to have some kind of dimensions on where to make the round holes in the uprights.  It looks that the Ford IRS diff is biased to the right hand side of the vehicle.

 

On another subject of this conversion, which outter CV joints to you plan to use that will withstand the torque supplied by the Ford IRS diff?  Any info on these two items will be GREATLY appreciated.  Thanks.  Please advise.

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I'm using Z32 NA outers, as they are 27 spline, and i can use a 4 lug hub with them, or upgrade to a 5 lug.

 

the Z32 TT hubs and axles are 28 spline, and no 4 lug option.

 

 

 

I'll try to get some measurements for you. Its kinda hard to get motivated when its 8 degrees out there.... :(

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SUNNY Z:

 

I understand well the lack of motivation when it is that COLD.  I came from Minnesota and know all about it.  I really appreciate your pictures of the uprights getting beefed up.  I am going to do the same!  I will follow your Ford 8.8 IRS project as I will want to do the very same to my 1971 240Z.

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I have a badass update.

I found a guy who parts Z32 cars on the side (has like 10 of them)

 

And I bought:

- pair rear NA axles

- Pair wheel bearings

- Pair 5 lug hubs

- Pair calipers / rotors / e brake assemblies

 

all for $350 shipped!!! this guy is the man in my book. Located in springfield, MO, fwiw.

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