310 replies to this topic

[DanWA]

that should have read 3 3/8th backspace

a set has come up... 8" with 4.5" backspace... would these absolutely fit?

the fronts have 3.5"

Also... for Perth people... after waiting way too long for my brother's boss to do my diff rang Final Drive in Oconnor

$400 to mod the housing (i bought bracketry kit from mc donald bros) and fit new top arms

$200 to mod axles and re-drill the rotors

Rang everywhere for blank rotors and everywhere said the same thing (need to order 50)

The Mc Donald bros kit was $160 delivered

Just thought i'd add that for Perth people!

[76lxhatch]

Probably, check out page 4 of this thread:
http://www.gmh-toran...hx/page__st__75

[MR77LX]

Hey Guys,

Great thread with heaps of info!

Just a quick question and sorry if it has already been spoken about.

I want to order a set of Show wheels. 17x7 fronts and 18x8 rears.

What size backspace do i need for an LX torana with flares. 4.5" all round?

I have 290mil hopper stoppers brakes at the front and R31 Diff at rear (28 spline)

Thank You

[TUF 308]

hi guys has any one got pick of how to mod the propotional valve please and anything else i need to do for the disk rear?

http://www.gmh-toran...lhx-rear-discs/

Just do this conversion, Much better pedal feel than standard torana booster anyday.

[76lxhatch]

I think someone here suggested it was because with the VN diff having to be narrowed they could place the cast centre in such a position as to use the maximum amount of axle tube both sides for welding the upper mounts to. This isn't a big difference:



(The above is R31, note by keeping the original position it keeps the driveshaft fairly central). Personally I think if they're that concerned about welding to the cast steel then they're not the right person to be doing so. Once the mounts have been removed there is no other difference between a VN housing and an R31 housing other than it has already been shortened for you!

The other possible issue is converting the R31 axles from four to five stud; again this can be done by a suitable competent person with the right equipment. If you really don't like the idea then you can just get aftermarket axles.

The attraction of the R31 unit is less modification - if you plan on narrowing it then it doesn't matter which one you start with, they will require equal amounts of work.

[TerrA LX]

Yes, yes and yes.

[dattoman]

McDonald Bros do a bracket kit you can buy to save you having to cut the ones off the Banjo ... might be nice to start with new metal

http://www.mcdonaldb...tbracketry.html

 

R31 housing is the right width... should be plenty of those about

People used to rob the 4.11 centres out of them and leave the housings at the wreckers.. .so if you can find one bare.. .and cut the brackets off... might save you some coin too

R31 diffs come in Pintara and Skyline configuration... basically Pintara are 25 spline and weaker.. Skyline are 28 same as Ford and Commodore (Stronger)

Of course then you need to decide on brakes and axles.... depending on what stud pattern your using

28 Spline axles are readily available... if your going with Commodore or Ford pattern they will be easy to get. If your going with HQ or Torana you'll need to get them modified to suit

Commodore LSD's are fairly easy to find in 4 pinion design at a sensible price on ebay (sadly no new avail genuine atm) but you can spring for a Harrop Trutrac if your cashed up

 

Just my 1c ... I'll probably add the other 1c later

[76lxhatch]

All the Borg Warner axle lengths are different so that the driveshaft is more centred (equal length axles means the driveshaft has to be offset) and the R31 is no exception. Its only a small difference to original and doesn't cause any issues with the driveshaft.

The R31 brakes will go straight on as long as you don't narrow the diff (they will foul on the shocks if you narrow it). You just need to adapt the hand brake cable and brake lines etc - all the information is in this very thread, go back over it for more info and photos. The only thing is apparently replacement discs are a little harder to get now.

[TerrA LX]

R31 diffs come in Pintara and Skyline configuration... basically Pintara are 25 spline and weaker.. Skyline are 28 same as Ford and Commodore (Stronger)

Just my 1c ... I'll probably add the other 1c later

 

 

Would that make the Pintara diff a BW75 and the Skyline diff a BW78?

[dattoman]

Nope

They are both BW75's

So are Commodores

[TerrA LX]

Nope

They are both BW75's

So are Commodores

So not all 4pinion 28 spline VL-VS diffs are BW78 (BTR 78 Series) same as R31 Skyline.

[dattoman]

No Commodore diffs are BW78's

They are all BW75's... unless its a VZ ute.. .then you got a 78

Skylines are 75's also

 

Fords have 78's in them

 

Its written on the crownwheel

0575 for a 75 series

0578 for a 78 series

[TerrA LX]

So Holden's publications (Example I have in  front of me is VP/VQ Volume 2) would be incorrect in stating in the specifications;

"Rear Axle Assembly ........ BTR Engineering 78 Series"???

[dattoman]

I believe so yes

 

Would you like me to email you my spreadsheet ?