IRS diff

Cadge · 24-04-2011, 11:12 AM

I know this has probably been asked before, but..

I know there are two different types of diffs, IRS and.... ??? cant remember the other one.

1) what is the difference
2) can they be swapped between cars
3) can a centre be swapped over
4) how do i tell which is which?

Thanks

FGII-XR6 · 24-04-2011, 11:28 AM

IRS and live axle they can't be swaped without welding mounting points in and IRS isa diff in a cradle with drive shafts to eack wheel where a live axle is a solid unit disk to disk

Cadge · 24-04-2011, 05:12 PM

Ok, cheers for that info... How do I tell what my au has? Is it just after a certain time they changed over, ie different models?

Beer Baron · 24-04-2011, 05:25 PM

If the exhaust goes under the diff its IRS if it goes over its live axle.

Fairmont ghia's, XR8's, Fairlanes, T series all had IRS. It was an option on all models though except utes.

Reaper8 · 24-04-2011, 08:02 PM

if it looks the same as say xf, xd, xc then its live axle. If its got control arms and also drive shafts off the centre to the wheels then its irs. a quick glance will answer it they look totaly diff

bodes-sh · 24-04-2011, 08:10 PM

poke your head under the back and rock the car up and down. if the car moves and the diff stays still it's live axle, if the diff moves with the car it's irs.

Day-mow · 24-04-2011, 08:45 PM

Quote:

Originally Posted by Beer Baron

If the exhaust goes under the diff its IRS if it goes over its live axle.

Fairmont ghia's, XR8's, Fairlanes, T series all had IRS. It was an option on all models though except utes.

Anything with a VCT in it has a live axel i do believe

FGII-XR6 · 24-04-2011, 08:52 PM

Quote:

Originally Posted by Day-mow

Anything with a VCT in it has a live axel i do believe

other way around VCT or V8 = IRS
this is what an IRS setup loks like in the AU http://cgi.ebay.com.au/ford-au-xr6-x...item2563102fe9

Day-mow · 24-04-2011, 08:54 PM

Quote:

Originally Posted by au3xr6

other way around VCT or V8 = IRS

hahaha epic fail. thats what i mean. cos i have a VCT

Dave_Obsession · 24-04-2011, 10:04 PM

So can a centre from a 3:45 IRS diff be transferred into a live axle housing?
If not, how do I get my 3:08 AU3 live axle rear diff to become a 3:45?

SLO AU XR8 · 24-04-2011, 11:01 PM

Quote:

Originally Posted by au3xr6

other way around VCT or V8 = IRS
this is what an IRS setup loks like in the AU http://cgi.ebay.com.au/ford-au-xr6-x...item2563102fe9

Not all V8's got IRS. Any VCT 6, XR8, Fairmont Ghia or Fairlane sedan range got IRS.

FGII-XR6 · 24-04-2011, 11:17 PM

Quote:

Originally Posted by dave93761

So can a centre from a 3:45 IRS diff be transferred into a live axle housing?
If not, how do I get my 3:08 AU3 live axle rear diff to become a 3:45?

as far as I know you can't change centres but all you need to do is get a diff out of a non VCT XR6 (HP engine) these are 3.45 LSD and bolt straight in. you will need a black speedo gear from memory

SLO AU XR8 · 24-04-2011, 11:34 PM

Quote:

Originally Posted by au3xr6

as far as I know you can't change centres but all you need to do is get a diff out of a non VCT XR6 (HP engine) these are 3.45 LSD and bolt straight in. you will need a black speedo gear from memory

3.45 yes, LSD was optional

Beer Baron · 24-04-2011, 11:43 PM

I think AU2 HP's all had a LSD's and AU3 they had to be optioned to get one.

SLO AU XR8 · 25-04-2011, 12:09 AM

Was optional from AU. Even early build AU's it was an option.

bodes-sh · 25-04-2011, 10:06 AM

Quote:

Originally Posted by dave93761

So can a centre from a 3:45 IRS diff be transferred into a live axle housing?
If not, how do I get my 3:08 AU3 live axle rear diff to become a 3:45?

centre will go straight in.

you can't really swap a live axle centre into an irs cradle because it doesn't have the retaining clips to hold the cv's into the diff.

Dave_Obsession · 25-04-2011, 10:18 AM

yeah I think I get that now....

So for example there are these diff gears on ebay:
http://cgi.ebay.com.au/HOLDEN-COMMOD...#ht_1306wt_905

Now it says it can be used with either a single spinner or LSD centre - what does that mean? How are they different?

EDIT - I should clarify - I know the difference between LSD and single spinners in how they work....but the actual structure of the part itself is what I'm referring to...

I'm assuming if I were to put the abovelinked parts into my current diff, I'd go from a 3:08 single spinner to a 3:45 single spinner, correct?

If so, what part do I need to get my hands on to make it LSD??

Beer Baron · 25-04-2011, 10:31 AM

The crown shell and pinion is the same between a 3.45 LSD and a open 3.45. It's in the centre of the crown wheel that is different. It will have clutch packs if it's a clutch LSD or cones if it's a cone type LSD where the planetary gears sit. The planetary gears still work the same as an open centre but the clutches will grab when enough force is applied by your right foot also how tight it has a been shimmed has a big play as to whether it will be closer to a locked diff or an open centre There is also torsion but you won't find one of those in any
falcon.

My old te72 had a Trd 2 way LSD so it would lock both wheels under acceleration and under deceleration. Good for drifting but not good normal wet weather driving.

FGII-XR6 · 26-04-2011, 12:10 AM

Quote:

Originally Posted by SLO AU XR8

3.45 yes, LSD was optional

LSD was standard in XR6 http://www.fordforums.com.au/photos/...php?photo=1362

Rfordsfun · 07-03-2016, 09:48 PM

Hi fellas, got my 3.45 lsd out my irs carrier, and want to fit it into my live axle 3.08. Now is it easiest to just make the 3.08 lsd, by fitting the crown to the lsd center, so the live keeps the 3.08 crown and pinion, but it will be lsd ? Cheers, thanks in advance