FD Explorer 8.8 Diff Kit

[largeorangefont]

Yes the Truetrac is most certainly worth the cost. Glad you are liking yours wickedrx7.

Markfluko- at least you know the rear end is solid. You will just have to swap the carrier when you get the Truetrac.

[wickedrx7]

Yes the Truetrac is most certainly worth the cost. Glad you are liking yours wickedrx7.

For sure!  Thanks for all your help in deciding to go that route, it is definitely worth the extra money. 

[osburn383]

Looking at trying to source a diff for the swap but not sure what gear ratio to go with.
I'm running a 2004 t56 from a gto. Not going to take it to the strip but would like to occasionally road race. This is my daily driver.
Any input would be great.

[wickedrx7]

Under 400RWHP I would go 3.73. 

[largeorangefont]

Looking at trying to source a diff for the swap but not sure what gear ratio to go with.
I'm running a 2004 t56 from a gto. Not going to take it to the strip but would like to occasionally road race. This is my daily driver.
Any input would be great.

3.55 or 3.73 for sure. If you want a little more zip at the track, go 3.73.

[markfluko]

I've got 378 RWHP and I have the 3.73.

Would also recommend. I like it.

[osburn383]

Ok that's what i was leaning towards.
Thanks for the replys.
Now I just need to find one.

[stbrn19]

Finally got my car sorted and on the road with my 8.8 kit.  I have a 3.55's with Ford TracLoc.  Everything is seamless with the rear end.  I have even pulled out the housing to service and verify condition of the diff/gears after my driveshaft failure. 
My car drives like a dream, no strange noise. Most important I can get on it with 7-800 ftlbs of torque and drag radials and not leave chucks of the rear end behind me.  I like the design and the fitment in the car. If your looking to put an 8.8 IRS in your rx7 this kit is the best option currently available.

[Gyan]

Well I finally got this Ronin kit installed with an Eaton TrueTrack LSD installed in the diff. My FD had the stock 2002 Camaro LS1 & 4L60E tranny with the stock diff & PPF attached to the 4L60E. I have polyurethane bushings through out the car, including the rear diff subframe support and otherwise bone stock FD suspension. The car with this setup had severe wheel hop. It didn't when I first built it, but gradually it came on. I thought either something had loosened up or the poly bushings had issues. Neither was the case. Today I burned up my cement driveway (lots of traction) with completely smooth axles ! This kit is awesome! A couple of things to note:

1)  The Ronin diff location is 3/8" further back than my stock FD diff flange.
2)  The instructions say you MIGHT have to move some fuel lines... you do definitely.
3)  There is 2 forward subframe stiffeners that bolt in, that I had to make 4, 1/2" spacers for. (otherwise the universal had no clearance for the stock aluminum speader bar)
4)  I had the rear FD driveshaft flange machined to fit the Ford 8.8 flange, and drilled & tapped the Ford flange to bolt this on. According to my power train shop there was no conversion universal joint between metric (Mazda) and standard (Ford) If you have to build a driveshaft for a new build this is no issue but I already had mine done.

Kudos to the Ronin team for an excellent product. I've been driving my LS1 FD for three years on the stock diff, always worried about it grenading. I'm glad I waited for this kit...it's worth it!

[CKxx]

I'm late to the party.  Is there any way to use a Cobra diff with this kit, possibly by machining an aluminum spacer/bushing?  I've already got a fresh built cobra diff sitting un-used on my Samberg subframe.  I'm getting back into finishing my car after over a year away from it and I really want the added strength of this (top) mount, along with the added exhaust clearance.  I was about to have an exhaust made for my car and after seeing this I'm definitely not having it made to clear my current subframe.

EDIT:  Forgot to mention I've also already got DSS bars installed between the Cobra inners/FD outters, so being able to keep all that would be fantastic.

[jeffp5]

Ok that's what i was leaning towards.
Thanks for the replys.
Now I just need to find one.

Did you settle on a ratio? I also have a 04 GTO t56, and i would think 3.73 gears would be no good. I have the Auto FD 3.90 and it sucks. I was actually thinking of going 3.27 with my ford 8.8.

[largeorangefont]

Ok that's what i was leaning towards.
Thanks for the replys.
Now I just need to find one.

Did you settle on a ratio? I also have a 04 GTO t56, and i would think 3.73 gears would be no good. I have the Auto FD 3.90 and it sucks. I was actually thinking of going 3.27 with my ford 8.8.

Yes, you will want 3.27 or 3.31, especially if you are over 450 WHP. Possibly 3.55 of you are going to track the car a lot.

[UH-60Pilot]

Did you settle on a ratio? I also have a 04 GTO t56, and i would think 3.73 gears would be no good. I have the Auto FD 3.90 and it sucks. I was actually thinking of going 3.27 with my ford 8.8.
[/quote]

I'm running a t56 Magnum with 3.31 gears. 75mph and im turning 2,000 rpms, and my first gear is usable now. 

[gnx7]

The GTO 1st gear is 2.97 and is there to move a heavy 3800lb car.  Putting that trans into an RX-7 that is under 3000lbs means the gearing is a bit off.  I don't like the gear spread in 1-4 either.

I sell the T56 Magnums and run one also in my FD.... Diff has 3.73's with 520rwhp.  Out back I am running R-compound 335/30/18's to put the power down.  Running 3.55's in the future has crossed my mind as my next motor will have 150rwhp more..... but 3.31's IMO are too tall and take away performance. 

This is the gearing for Fbody/Magnum(M6) vs. GTO (M12)

Gear MM6 Ratio (:1) M12 Ratio (:1)
FIRST 2.66 ---------- 2.97
SECOND 1.78 ---------- 2.07
THIRD 1.30 ---------- 1.43
FOURTH 1.00 ---------- 1.00
FIFTH 0.74 ---------- 0.84
SIXTH 0.50 ---------- 0.57
REVERSE 2.90 ---------- 3.28

The Magnum has a .80 5th gear and .63 6th.  That closer 5th gear is nice!

Another huge benefit of the Ronin kit is the exhaust clearance.  I run the Cobra style and a 3.5" single exhaust underneath is tight.

[hardbodeez]

Can someone tell me what torque spec you are bolting the sub-frame back in with?  I'm talking about the sub-frame up into the body of the car.