FC Explorer 8.8 Diff Kit

[frijolee]

This project's been done and we have a bunch of folks that have been rocking these for a while now with no issues to date.  It seems to be a great way to up your rear end strength, minimize or eliminate wheel hop, and run your choice of gear ratio and LSD.  You can order at roninspeedworks.com whenever you're ready.   Specifically:

http://www.roninspeedworks.net/index.php?route=product/product&product_id=70

There's a great many pictures and reviews scattered throughout this thread.  We've tweaked fitment a few time but the basic design of the first post is still accurate.  I'm adding a few shots of our custom halfshafts that let you make the conversion from Ford inner CVs to Mazda outers.







The rest of this thread remains the original and is kept for posterities sake.

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It's time to start sharing more details about what we've been working on for the FC's Ford 8.8 IRS kit.  For the moment these should only be considered development pictures as we're still working out a few details.  That said, I wanted to start getting folks excited and I'm rather proud of our progress to date. 

Assumptions:

-Weld in front mount requiring a minimum of mods to the stock mazda subframe
-Front mount will support diff from below so a secondary capture plate will be provided to provide a redundant load path to the top (see nuts in the side of the weld in portion)
-02-05 Ford Explorer 8.8 being used due to better packaging with the single sided front mount (also used in Lincoln Aviator and Mercury Marineer).  These are plentiful, cheap, and have aluminum cases w/ lots of support fins.
-OEM style rear mounts let you run whatever kind of bushings you want.
-2 to 3 degree target front pinion angle
-Two piece slip yokes will be required for DS removal
-Target pricepoint of ~$1800 (user's total cost for everything)

Front mount:

Support nuts for redundant load path:


We have a crush tube welded in for the main front bolt (edges will be ground flat):


Fit check in car w/ Explorer diff (redudant load path not shown but will wrap the top surface like an upsidedown "L")


It indexes off the tie rod mount hole and follows the contours well.


Fit check from above (ignore the t2 diff, just showing how well this fits on a spare subframe prior to weld in)



Cover modifications:

We're not using the stock mount ears on the explorer diff cover because that puts us into the gas tank straps (clearing the subframe w/o significant cutting puts this slightly further aft than AndrewB70's Cobra version).

Stock:


Cut using a 4.5" angle grinder:


End result:



Rear mount:

First article welded up:









Note, we're still optomizing fitment.  For example in the last pic above we found we need about 1/8" more clearance to the fuel line bracket.  As such we've only welded up one of the rear mounts.  We also have some slightly differences between the first article and our mockup mounting so we need to get that squared away prior to welding up the others so we can ship these to our testers. 

That's progress to date.  After we get the final fitment nailed we'll transition into halfshaft design.

Regards,
Joel

[ImportEvolution]

Glad you guys are doing this!

[346fc3s]

That looks awesome, just out of curiosity how are you getting the driveshaft flange to clear the subframe?  I had to notch my subframe a bit to clear it, although part of that was hinson's driveshaft flange being larger than the flange on the diff, but still, it was damn close.  The stuff you cut off the diff looks just like what I did to mine except I cut down the speed sensor too just to make it look a little cleaner. 

I don't know if you tried it without the L bracket to cover the top of the front mount but let me tell you it is vitally important that you have something up there.  I just had a bolt with a washer on it at the beginning and the first hard launch I did ripped the center out of the bushing.  A new bushing from ford and a washer large enough to cover the entire bushing and it's been fine ever since.  I have a good amount of experience with axles and brakes that will match your mandeville setup very nicely if you're interested. 

[3 fingered willy]

Hey Joel, Nice work guys!

Hey I think that back cover mount may work with my setup with the T bird rear and my crossmember. I'm going to have mine apart in a while here, if you'd like to have me test fit it for you I could.

I have to take mine out to install a baffle into the inside cover to deflect fuild from the breather. So if you think you would like to try it, PM me. maybe we can work out something.

From the looks of the back plate/cover part, its got to be really close to 1 inch forward of CV axle center. Am I correct?

[DeaconBlue]

This looks very cool Joel!
 
I really like the rear brace design - somewhat similar to others designs but with a much stiffer over the top strap reinforcement for better side to side torsional strength/rigidity.  You can also use a support griddle cover with your design as well - which is important with higher HP/torque levels. 
 
A couple of questions.  Will the SF cross member be owner modified or will they be done on a jig and supplied by you on an exchange basic?  How much have you changed the axle center-line position at the differential?  Is that change going to pose an issue during hard acceleration as the tire tries to move forward or with the suspension geometry and triangulation during articulation, both squat or extension?

Keep up the great work and many thanks from the FC community.

[Marshessn]

Dude this is awesome. keep up the excellent work. I will definitely be interested in this.

[largeorangefont]

Looking great guys. I can't wait to get my hands on this.

How much clearance is there around the vent tube area? It looks like we will need to run a 90 degree fitting.

[ALLslowNOshow]

Will the subframe have to be dropped once the Ford diff is installed, like the way the stock set-up is designed?

[346fc3s]

Just out of curiosity how much does that mount weigh? It looks like you've got delrin bushings in there, will you have options for poly or rubber for those that don't want the NVH of solid mounts?

[V8-rx7]

Well since Joel isn't answering the questions, I'll answer a couple.

The subframe will need to be dropped to drop the diff, just like how it was before with the Mazda rear.

You should be able to run some poly bushings in the back, and something with some compliance in the front, but I think it is better to run solid mounts.

The mount weighs somewhere in the 12lb - 15lb range, but I don't have an actual weight. I will throw it on a scale when I get a chance.

The subframes will need minor mods that anyone capable of doing a swap should be able to do. You will need to trim the lip of the subframe slightly and weld in the front mount that will come with the kit. The front mount as you can see in the pictures indexes off the subframe contours and the sleeve for the toe link. There is really no way to screw it up, you then will need to weld it in place.

Anthony

[largeorangefont]

With this setup you will want to run all 3 mounts with similar levels of compliance. If you want to run rubber, you will need to run rubber in both the front and rear mounts. If you want to run solid, you will want to run delrin in the rear and a solid alumnium mount in the front. You will also want to run solid subframe bushings if you choose to go solid with the diff mounts.

The rear diffmounts are the OEM size so you can run OEM, Mazdacomp stiffer rubber, or delrin mounts.

I will be running all solid mounts. I have talked to Joel and I believe (don't quote me on this) that there will be an alumnium front mount for the Explorer diff available as an option for this kit. That is what I intend to use for a front mount.

[DavidPHumes]

I will definitely be putting funds aside for this when it's full production. Just one less thing to worry about once this is installed.

[ALLslowNOshow]

I was hoping my subframe dropping days was gonna come to an end.

Anyways, can we get a break down of what the $1800 consist of?

[Tweek]

i feel like a little kid waiting for christmas!!!! 

[largeorangefont]

I was hoping my subframe dropping days was gonna come to an end.

Anyways, can we get a break down of what the $1800 consist of?

Dropping the subframe is not that hard. If you have the tools, more than one jack and a couple jackstands you have have it out of the car in 30 minutes.

As a rough list you will need:

02-05 Explorer diff and at minimum the complete Explorer inner CVs
TII outer CVs
Custom halfshafts to mate Explorer inner CVs to TII outer CVs
Driveshaft with proper yokes (this will need to be longer than the C4 driveshaft)
Ronin Explorer Diff mounting kit

You will need to source your own diff and Explorer inners for sure. Ronin will provide the mounting kit and at minimum recommendations of where to source the correct driveshafts, yokes, and custom halfshafts needed to complete the conversion. Some of these auxilary parts may become productized by Ronin but I can't speak to those exact details. Rest assured that nothing will be left up in the air.

I will be one of the initial testers for this kit, and as such will be working with the Ronin team to finalize the exact parts list.