rebuilding irs diff

[ricky bobby]

I am going to be putting aproximatly 800 hp and equal amount of tourqe through my irs.
i am going to prepare to buidl a new pumpkin and am looking for advice on parts to use for it.
The car is mainly a street driven car with asperations of being road raced ocationaly.

[SHAKN' 04]

dss level 5 halfshafts, replace all bushings, irs brace, those are the main ones that come off my head. I had an irs on my mach a few yrs back, only replaced the differential bushings to help "stop the hop", worked then went back to SRA.

[ricky bobby]

the irs has level 5 shafts now. i hope to find a fore cover.
what carrier is suggested using and brand of gears.

i got an outstanding deal on a new diff cooler already.

[NastyNate]

Ditch the IRS and swap in 9in SRA !

[ricky bobby]

stay on topic this is not a debate.
apples and oranges

[Charles236]

I use a Detroit True Track in my IRS pumpkin. Because of the absence of clutches, there is less heat buildup in turns, plus there is no clutch slippage. I used a Thunderbird 8.8 iron housing, since temperature change won't affect it as much as aluminum and it is stronger.

[Fastkurve]

Originally Posted by Charles236

I use a Detroit True Track in my IRS pumpkin. Because of the absence of clutches, there is less heat buildup in turns, plus there is no clutch slippage. I used a Thunderbird 8.8 iron housing, since temperature change won't affect it as much as aluminum and it is stronger.

Carrier brg side load is twice the one from iron case...temperature won't affect it !


I change my carrier (from oem open one for an Auburn) in my 2004 Explorer, which has the aluminum hsg, as the cobra has, need a spreader to expand the hsg to avoid damaging it while seating the carrier/brg's assy into it...

[vertigyn]

I've rebuilt mine plenty do to breaking and I only have 475 at the wheels but beat hte piss out of the car...here's what I have now that seems to be holding up so far:

1. Thunderbird iron housing (I cracked 2 aluminum housings on the front mounting ear/tabs - the one that came with the IRS and a brand new one from Ford Racing)
2. DSS Level 5 shafts with stock hubs (the DSS hubs are skinnier and weaker than stock hubs...I cracked one and it damaged the spindle which is really pricey to replace...call DSS and ask them if they can swap some stock hubs onto your level 5's. The level 5's aren't meant for corners - as they informed me after the fact...)
3. Diff cover/Diff brace - I have a Billet Flow brace and have never had a cover issues...LPW makes a solid cover as well...Fores are sweet...but a lot of money and not really worth it
4. The full solid bushing kit from Full Tilt Boogie Racing with grease fittings (I used the Maximum Motorsports solid rear diff mount as the FTBR and prior MM bushings failed and caused clunking back there - I think FTBR has since redesigned theirs)
5. True Trac differential - good for both road corses and drag strips - no worry about clutches or wearing out as long as you keep fluid in her
6. A good set of coil overs or shocks/springs (I'm running the MM sports series coil overs and am happy)
7. Gear - I'm running a viper spec 6spd and chose 4.10's - they are good for me but do your research for your application

Things you might want to consider adding to the IRS/rear (they are on my list for future mods):
1. Reinforced/stronger tie rods
2. Bump steer
3. Subframe support plates (Billet Flow sells these)
4. Rear tower brace

That's all I can think of at the moment. Good luck with your build! The IRS isn't cheap to play with, so get it right the first time with the strongest parts possible =)