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Discussion Starter #1 (Edited)
I will be doing a Ford 8.8 differential swap in my car to handle my power goals without worrying about parts breaking. I Know the outboard stub Axel's are weak and I will deal with later. But I was wondering if anyone that has done the swap can post pics of how it was done so I can get ideas or follow. I have researched and a few threads mention that a jig was going to be made so we could buy a swap kit. Did that ever happen? Anyone that has done it have any tips or pics they could post so I can get some ideas going? All the threads I saw kinda died so I was hoping to start one general post to accumulate all ideas and pics for anyone else thinking about the swap. Thanks for the input!
 

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If you're patient I'd suggest waiting... It requires modding the front crossmember, a new rear one, and a new sway bar.
 

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Discussion Starter #3
Oh sorry I will edit my post. Its for the Ford 8.8 differential. I want to swap out my Toyota 7.5 for the Ford 8.8 but keep my irs. Sorry for the confusion I will edit the first post.
 

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That would be quite the thing, as far as I understand they are really common...as a live axle. Explorers, Rangers, most Mustangs (I think). Pretty sure there were select Mustangs with the 8.8 and IRS, but this is all straight from memory when I was learning how to do it to a Yota pickup last year.

If you can make it happen from a junkyard Explorer, that would be amazing. LSD units are totally common.
 

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Umm there's probably about a thousand irs 8.8s for every mk2 ever made...
 

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Discussion Starter #6
Yea I know a few members here have done it. My buddy is doing an 8.8 in his ae86 and I went to help him pull it. He needed the solid axel. For every solid axel 8.8 there was about 5 irs that we found. So my plan is use the housing and then upgrade the internals to the 31 spline Axel's (cobra internals) that are very cheap and common and just about any gear you want. They even make in inboard stub Axel's in billet so you can have custom Axel's made really easily. Those are kinda costly but they are rated for insane power levels. I will probably have a Fab shop do most of the work but if I could drop off ideas or a plan it might cut down on the labor cost and with this post everyone could see the solution and know how to get it done. Thanks for the replies everyone.
 

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Uhm, there's like 1 guy here who's done it. And he's pretty much a master fabricator working at a speed shop with access to all sorts of crazy tools. He made custom A arms, a custom diff cradle, custom axels etc to pull it off. I wouldn't quantify this as "the ford 8.8 swap". This is the work of a mad scientist with lots of time, skill and tooling. Unless that describes you as well, I would do what everyone else does and stick a Trutrac in there, perform the camber mod and move on with your life. There are a couple axle upgrades available now if you've gotten to the power level where those start to fail (450 - 500rwhp +). And like you said, the outer stub axles are the next weak point and I'm sure will fail before the 7.5 axle and trutrac diff.

If you are super serious about upgrading beyond the factory 7.5, look into swapping the entire IRS from another car. It is far simpler and nets you a far better suspension and will be way cheaper.
 

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Discussion Starter #9
Yea I saw Mike's build. His skill is far beyond mine. After searching I found a few other guys that posted that they were working on the swap themselves but those threads went dead. I was hoping they finished it successfully but I guess they didn't. Yea the overall power goal is 550. I will do some research on the true trac and see if I want to go ahead with trying the Ford 8.8 or not
 

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I bought a 99 GS400 I was gonna chop shop and investigate stealing the rear subframe for the Supra but it had no title which really complicates disposal, so I ripped out the engine and tranny and sold the rest to a guy who really wanted it. It has some pretty killer tubular frames going on under there, front and back. Worth a look for sure. The Lexus SC shared all those parts with the MK IV Supra.
 

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There's a guy on the Toyota Mini (pickups) owner's forum who scabbed in an entire IS300 rear end.

I know the GS are open diffs but I figure that's a thing that can be corrected. I actually got in touch with the guy who bought it off me since I posted that, I may still be able to get that from him.
 

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If you want the IS300 one with an LSD just buy the BRZ/FRS/86 one which has the Torsen stock. They are the same thing and a lot newer in 4:10 and 4:30. If you're planning on using the stock suspension I think you'll find most of the newer Toyota diffs are going to foul with the front crossmember.

Maybe I was a little fuzzy earlier, but I have a design ready to mount an 8.8 IRS in these car. I'm a little torn on the best way to proceed with handling it though. Right now I'm thinking of building 2-3 sets with myself taking one of them. The shear cost of doing it, by the time you do everything, stacks the odds for the average Mk2 owner doing it.
 

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I would be interested, but want to retain the factory antiroll bar. Is it that much of a clearance issue with an 8.8?
 

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Discussion Starter #16
Yea I have a few ideas myself. Adding up all the costs it will be close to 1200-1300 maybe more all said and done. That's just ball parking it. I do want the 8.8. My plan is to get the 8.8 in then there is a company that has been posting on FB. They are making an scca car for their customer and it's a mk2 Supra. They have made a new control arm that uses the sentra bearing and hub assembly. Although they said you could use others. So with the 8.8 and this new control arm (they said they will sell them after testing) I will convert my rear diff and weak outter stub Axel's to stonger ones and a better bearing design. One piece press in. That way I can keep my car alive with more modern parts that are easily had and fix a lot of the weak problems that the back axels have.
 

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At least the Addco hits the the rear cover on the version I have. I don't have any of the other versions to try, but considering they are mostly unobtanium its probably not a wise choice to depend on them. The 8.8 is wider across and deeper to the back. The sway bar I'm planning on has like a dozen different rate options available for tuning. The downside is the initial cost to make the arms, endlink, brackets, as so forth.

You're dreaming if you think you can do this for $1200 bucks all in when the axles will cost more than that alone.
 

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I still remember the information you gave me on the custom sway bar. It's the best one for high performance custom modifications, and inexpensive.

Definitely the one to go with.
 

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If you want the IS300 one with an LSD just buy the BRZ/FRS/86 one which has the Torsen stock. They are the same thing and a lot newer in 4:10 and 4:30.
Disagree. First off, getting IS300 diffs with a factory LSD is easy... at least up here. Maybe Toyota made the LSDs standard or common for Canadian cars as they used to in the past on Cressidas and Supras, but I can get is300 rear pumpkins with the factory Torsen LSD here all day long no problem, 200 to 400 bucks for the whole thing pumpkin. 2nd, you're forgetting the age range of the 2 cars. FRSs are like 2012+. Whilst IS300s are early 2000s and are fully depreciated. They are super easy to find guys parting out right now and in wreckers and the parts are cheap. Also the IS has better rear brakes (aluminum 2 piston monoblock), and the diffs can be had in 3.72 or 3.91, which are generally better ratios for turbo swaps.

As for the diff that's in the GS Lexi, which is the same as the one in all RWD Lexi off that era except the Supra 6spd Turbo and LS4xx, yes solving the open diff problem is easy, it just takes about $1000 to $1600 dollars. For some reason, that specific diff is really hard to get factory LSDs in. Even all of the JDM Soarer 2.5GTs coming in here have open diffs for some reason. I don't think you can get anything like a Trutrac for that diff, its all the usual jdm suspects for aftermarket ones, Cusco, Greddy, TRD, KAAZ, etc. The only reliable application for getting a factory LSD that fits that case is the mk4 Turbo automatic. And those aren't exactly lining up in the wrecking yards. Its actually a lot cheaper and easier to find a used 6spd TT mk4 lsd as people actually upgrade those things.
 
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