Diff Guru's.......?

[takearidewifme]

Im thinking about building a hybrid 6x6 and was deciding what diff to use... I have heard that the VN commadore diff would rival a 9 inch in strength... Is this true? I have seen these things hold up to massive abuse with over 5lt eng and big / wide tyres.... Surely with all this u beaut technology we now have things have improved in the diff scene.....

Mark

[pongo]

a jag rear end are made by dyna. The use unis instead of CV's and have inboard brakes.

You can even get them in a quick change rear end from the states.

Cheers

[chevJ40]

the vn ss diff would definatly rival a ford 9 inch in strength ive done a few conversions of this into old toranas with big ponts and never broken a diff or axle has to be out of a v8 model though

[kempster1]

the vn ss diff would definatly rival a ford 9 inch in strength ive done a few conversions of this into old toranas with big ponts and never broken a diff or axle has to be out of a v8 model though

That would be why Holden V8 supercars use Ford 9 inch diffs

[mickyd555]

the vn ss diff would definatly rival a ford 9 inch in strength ive done a few conversions of this into old toranas with big ponts and never broken a diff or axle has to be out of a v8 model though

That would be why Holden V8 supercars use Ford 9 inch diffs

I thought V8 supercars had fully locked diffs, preety hard to compare them.....but i could be wrong

[pongo]

the vn ss diff would definatly rival a ford 9 inch in strength ive done a few conversions of this into old toranas with big ponts and never broken a diff or axle has to be out of a v8 model though

That would be why Holden V8 supercars use Ford 9 inch diffs

Thered be plenty of reasons to use a " 9 inch" over a holden rear end. All the parts for the 9 inch would be off the shelf items, Proven time and time again in all modes of racing. Id say almost a bolt on affair for the teams v's full custom mods venturing in to the abyss.

Could even by regualtory they run a 9 inch type diff ,

food for thought

[pongo]

But, wouldnt the easiest/ most reliable method be getting the diffs out of a 6x6 ex army landrover, or something similar.

[mickyd555]

i have seen a 75 series cruiser with 6x6, he used a 9" for the first rear diff then the standard 75 diff for the last. He said the 9" allows for two pinions to be run of it, on on the rear. It then had a short shaft connecting the two diffs. I dont have too many particulars on it cause he was a weirdo and i didnt want to hang around him for too long.

edit: im not a diff guru, this is just what the guy told me

[ISUZUROVER]

But, wouldnt the easiest/ most reliable method be getting the diffs out of a 6x6 ex army landrover, or something similar.

A military 6x6 landie runs 2 basically stock Salisbury (like a D60) diffs with a seperate drive shaft to each. The drive to the rearmost axle is provided by a PTO type arrangement from the T-case - so the diffs are nothing special, the T-case is.

Some 6x6s have "drive through" setups, where a 2nd pinion is fitted to the back of the crownwheel, and a drive shaft connects to this which goes to the rearmost diff.

If you don't use either of the above options, then you need to build some sort of 1:1 drive to the nose of the forward diff (e.g. a chain drive from the housing upward), which can have a propshaft connected to it.

I would have though the first thing to do would be to select diffs that could easily be modified by either of the above 2 methods???

[takearidewifme]

OK lets take the v8 touring cars out of the picture cause Im not thinking of building one of them.. Im looking for a strong readily available unit. the way they will be driven is one facing the other ( front rear facing backwards and centre rotated) the rear does get most of the stress.. and using a transfere case or similar have a 1:1 box stepping the drive shaft from over the top of the diff to pinion...I have no intention of running great hosepower but I do have evey intention of using dual transmissions for low speed torque.... What do you think... te 2 diffs in the rear should spread the load and stress... Do you think a holden would hold up?

Mark

[cloughy]

They use 9" centres because the pinion shaft follows right through the housing and runs on 3 bearings not 2 like most, 9" in comparison to a 4 spider gear equiped borg warner, e.g. SS snot o door XR8 etc are comparable for most road going hoon cars, but the 9" is physically bigger and 3 bearings on the pinion make them stronger, most 9" centres in hi po cars will generally run a billet carrier as oppossed to cast (cast carrier being the week point of a 9")

[timbocruise]

the vn ss diff would definatly rival a ford 9 inch in strength ive done a few conversions of this into old toranas with big ponts and never broken a diff or axle has to be out of a v8 model though

That would be why Holden V8 supercars use Ford 9 inch diffs

no they use harrop 9 inch diffs, not one ford bit in them

[pongo]

well isuzurover and take a ride, Im now officially a diff apprentice, Im watching this space.

Thanx

[jeep97tj]

How is this thing going to flex? will they pivot in the middle and just have side to side flex? like the front supension on a loader?

[ISUZUROVER]

Borg-Warner (V8/SS diff). Only available in 3.07-3.91 ratios.


Ford 9" - available in 2.75:1-6.5:1


Apart from not having a decent choice of ratios, The Borg Warner V8 diff doesn't look like it would be anywhere near as strong as a:
60s/80s cruiser diff
Big nissan (H260) diff
Ford 9"
Salisbury/D60
etc...

And a hilux diff would probably be just as strong or stronger too.

Work out the torque a stock SS commodore can put through its wheels, and then the torque that a 4cyl 4x4 with dual T-cases and 35's can put through it's wheels in first gear double-low.

[RED60]

Wifme, the transfer between the diffs is a "novel" idea but i think you'd go broke settin up suspension that worked. 555 the shaft in and out of the front diff then feeding the back diff would also work if u can change the side the crown wheel is on by running the rear diff or at least the centre, upside down.
I have actually seen the chain idea also mentioned here. T/shaft from transfer runs to an enclosed input/output shaft and sprocket, mounted to upper left of diff centre, with another sprocket mounted on pinion of forward diff. There is a short tailshaft running further rearward to drive back diff.
The chain drive was a purchased settup, so someone must have them available to the public, but i got no idea who. I saw it on a six wheel tour vehicle on Fraser Island. I have also heard that 6 wd vehicles that can't be taken back to 2wd tend to get a lot of windup in the rear.

[takearidewifme]

thanks for the replies.... as for the suspension set up Ive been trying to post pics of my idea but basically it is similar to Bill Larmans design in the 80's if anyone remembers that..

Mark

[DaveS3]

Here's a pic of Bills thing