Skyline diffs - what fits in what?

[Rollin]

Hi people, first post here, i am actually a big ford fan but even more of a turbo Inline 6 fan, so im not all bad

anyway, i would like to know a little about skyline diffs - i know the crownwheel and pinion from a R31, VL commonwhore (possibly later models too?) and EB/EL falcons are the same, but i was wondering what is the extent of the skyline interchangability?

like, is an R31 crownwheel and pinion set (LSD and/or open center) interchangable with an R32 or an R33 diff?

reasons behind my query:

my car came with a 3.45:1 LSD standard (its an EB XR6 Falcon) and last year i got a 3.9:1 lsd built for it, and slapped that in - car hammers, fuel consumption, not so good.

i went on holidays to cairns last month, and swapped diffs with a mate (3.08 open) for better fuel consumption, and he is now in love with the diff, wants to keep it, so im on the prowl for another 3.89:1 gearset - i already have another LSD center, housing, axles etc, i just need the gearset now - so, in short, what model skylines can i get a set out of?

much thanks in advance for your help

[SteveL]

is an R31 crownwheel and pinion set (LSD and/or open center) interchangable with an R32 or an R33 diff?

No.....R32/R33 use 'stubby' R200 and IRS, but locally built R31 uses BW live axle diff so is totally different.

Import R31 uses R200 with IRS, but diff is the 'long nose' type and CWP is also not interchangeable with R32/33 type.

[predator]

As he said.. and i think the import diffs are viscous as well ??

Best bet is just an aussie R31 w/ LSD (bit rare) or VL turbo.. All Skyline Silhouette

models come with them so if you can track down one of them (difficult) you'll get a nice LSD. TI's also are more likely to come with LSD, but not all come with them.

Don't XR6 (or is it XR8) also come with LSD available as an option?? In fact when I asked recently, most R31 guys recommend looking at an XR6 or XR8 to find an LSD centre due to easier availability.

Unfortunately.. they usually tend to put poxy low ratio diffs in the aussie cars while 3.89 is nice, 4.11 is better

I've got a bit of an interest in this, as my diff in my r31 is getting a new centre put in thursday. I was going to go LSD, but unfortunately the cost, and even just finding an appropriate LSD centre was pretty hard.

Actually, seeing as your in QLD, you could always call the guys mine is getting done at to find out your options: NERANG DIFFERENTIAL SERVICES PTY LTD : (07) 5596 4963..

[Rollin]

Don't XR6 (or is it XR8) also come with LSD available as an option?? In fact when I asked recently, most R31 guys recommend looking at an XR6 or XR8 to find an LSD centre due to easier availability.

thats pretty funny - all the guys from fordforums are racing round import wreckers and stuff looking for skyline LSD centers and CWP sets to put in their falcons!!

im pretty sure that all EB and ED XR6/8 falcons came standard with LSD, and after that (EF onwards) it became an option? i really dont know...

as i said above, my car came with 3.45:1LSD stock, but i didnt get that built with the 3.9 gearset - i actually sold that diff entire (axle to axle) to a mate with a ED fairmont, for cash and his diff exchange (yet another damn 3.08 open center) i got that diff built up to 3.9 using a LSD center from a 2.77 NA fairlane diff (which required getting a machine shop to build a spacer for the crownwheel - 2.77 centers have different offset, but 2.92 and shorter the offset is the same) so i have been threashing that diff for about a year, still going good.

funny thing though - i have the 3.08 diff in my car from my mates ED futura, my mate has my diff which was built from an ED fairmont diff, and his girlfriend just bought the ED fairmont that donated its housing to build my diff - the original plan was to put the 3.45s (my original diff) into the futura, the 3.9s back in my car, and the 3.08s in the fairmont again :S diff swapping shenanigans!!! bugger that - i will just get this one done and leave the poor cars be.

mal wood automotive in/near gatton has a few LSD centers, and at a reasonable price if you want them, i just happened to get lucky and find a cheap center from a stacked Falc - now i need to get lucky again and find a cheap gearset too!

i think i will put an add in the wanted section on here...

[predator]

oy, stop stealing our LSD's!!

I was reading up a little on the fords.. appears XR6/XR8 and Falcon Ghia, Fairlane and LTD have the LSD's, but they are fairly long ratios.

Aussie R31 generally come with 3.7 for the manual (edit: thanks steveL), and 3.89 for the autos (mine).. but most are opens. Bit nicer, doesn't seem to chew through that much petrol either. I do a stack of highway driving and get around 9L/100km with the RB30E.

Guess you can mix and match like you were saying.

Thanks for the pointer to Mal Wood. This open spinner will probably be fairly temporary if I do what I want to do, and chuck an RB20DET in my R31. If that is the case, i'd probably want to go an LSD after I have ground the other one into little pieces

[SteveL]

Aussie R31 generally come with 3.41 for the manual

All Oz R31 manuals use 3.7 diff except GTS3 which had 3.9. If you want to go even shorter (ie numerically larger) Oz spec R31 Pintara's had 4.1 gears in all models.

[Rollin]

yeah..i need to find someone wrecking a R31 or getting a shorter ratio or something - 3.9 is the shortest i will go, as the car nearly hits the rev-limiter in 4th at the end of the quarter with 3.9s - with 4.1s it will definately require a shift to 5th

if any of you hear of a 3.9 gearset sitting around anywhere let me know please!!