The FD Explorer 8.8 is now released for purchase!
FD Ford 8.8 IRS mounting kit



Why? The Ford 8.8 is a substantially stronger diff than the factory Mazda rear end. It's available in a huge range of gear ratios (3.08:1 up to 5.71:1) just looking at Summit Racing. Gears are also cheap since Ford has used the 8.8 in so many varieties. You can also find just about any style of differential from factory clutch packs, to spools, to helical gears.

We use a donor rear end from a 2007-2010 Ford Explorer (some 06's work but it appears that there may be a half model year split, you want dual front mounts). It's Ford's classic 8.8" ring an pinion in a stout aluminum case. This particual case is noteworthy because it uses massive dual front mounts. The support points on the Explorer makes the Cobra 8.8 front mounts look tiny by comparison. Furthermore, the Explorer parts are both easier and cheaper to come by than the comparable Cobra pieces. The Explorer diff even has fins which the Cobra doesn't for slightly better cooling.

Here's the 8.8 Cobra from a terminator Mustang (note the tiny front mounts)






Explorer (in our test fitup!):




You're not breaking these ears off!




Our front mount is a weld in cradle which is well triangulated to the subframe. Everything mounts from the topside which dramatically improves the load path AND you'll retain close to factory like exhaust clearances.

Lots of space for exhaust!




The rear mount uses a sandwiched ring with the ears cut off the factory cover.




Note, depending on which year of explorer you end up with you may find that Ford changed the rear cover design. Some 2006 covers are the same as the 02-05 setup and use a high rib count. Here's the comparison with what the never cover looks like (cover on the left has already had its ears cut off).




Kit includes:

• Front Mount Support Bridge (weld in)
• Rear Mount Diff Ring Cradle (bolt on)
• 2X Custom 4340 heat treated axle bars (Ford to Mazda conversion)
• 2X EMPI CV boot kit 86-2127 (outer CV joints)
• 2X EMPI CV boot kit 86-2103 (inner CV joints)
• All Mounting Hardware
• RTV silicon (for rear cover installation sealing
• Instructions, specs, and recommendations on mating parts (IE driveshaft) sent electronically



Users must provide:

• FD Outer CV Joints (typically donor from the car being swapped)
• Ford 8.8" Rear End (2007-2010 Ford Explorer) including inner stub axles/CV joints
• A Driveshaft (install instructions include a variety of recommendations)
• FD rear diff isolators (user's choice of style but we like polyurethane).

Pricing will always be current on www.roninspeedworks.com but we're launching this at $1195. All in, including donor parts $1800 to $2000 is a reasonable budget depending on what you want for a driveshaft.

How much power will it hold? A LOT, but to be fair we don't really know since we haven't broken one yet. One of the early adopters is making 1000 whp in a road race application. No issues thus far.

-Joel

 

Any rotary folks making enough horsepower to find the limits of the OEM diff?

FWIW we have an FC version of the Explorer 8.8 based on the 2002-2005 Fords too.

 

Nice, will be contacting you guys very soon.

 

If anyone is curious there's a development thread all about this kit and early tester impressions over on the swap forum.

http://www.norotors.com/index.php?topic=15911.0



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We are going to be running this kit very soon with a 3.27 FD. I'm glad your kit is released because I wasn't pleased with some of the mounting designs of the cobra 8.8 kits out there.

 

Out of curiosity - do you have anything to mount the stock FD trans to?

I'm probably not nearly as high as some of the other people in here but I suspect I'll be finding 600+rwhp in the next month or so and would like an upgrade.

 

Got my kit the other day. Top Notch welds are amazing. Axle splines are perfect CV's go in with minimal effort. Hope to test it in about 2 weeks.

I will be going with a brand new Ford Racing 31 spline LSD($250). Cost about the same if you buy a used one ($130) then buy a new carbon clutch pack ($130).

 

Is the pinion flange on the explorer 8.8 the same as the one on the cobra 8.8? I already have a cobra setup and wondering if I went to this if I would need to get a new driveshaft made.

 

i seriously need to look into this. i have a 2jz fd making 740whp and 620tq. custom driveshaft and stock diff. my r154 has a trans brace already but the torque brace/ppf that i have recently broke. i think it will break again and my diff also soon to break.

 

Excuse us, must have missed this when you posted... We're working on our own version, but for now we'd recommend the standalone trans mount from Samberg Fabrication.

Thanks! Glad you like it. There was a great deal of effort that went into getting this just right. We had multiple testers verifying fitment and all our fabrication jigs have been optomized based on the feedback. At one point we had three subframes with three cradles all side by side to compare tolerances on the Mazda parts.

Yes it is. I'd say odds are very good for being able to use the driveshaft you have. All you really need is a new diff housing (vs the cobra) as you can swap the internals over as well (assuming you're into a nice setup internally already).

We'd be glad to help you. Let us know. Still no issues with our 1000 whp road race tester. At some hp level staying out of wheel hop becomes a critical factor for keeping parts living.

 

That's one beast of a rear end