diff questions.

[mr sinbin]

hi guys,

i am currently looking into new diff options for my wb van as it has commodore v6 in it and is a bit too sluggish off the mark for my liking. its great on the highway, cruising at 110km\hr but i would like a big more get up and go around town like the commodore use to have before i ripped the motor out.

anyways i know very little about diffs, and ratios confuse me :knockout:, but after reading ozbox's post on diffs in here i am lead to believe that my wb has the small 10 bolt diff, is this correct? it was originally a blue 6. what ratio are these tho?

the commodore i pulled the motor out of, as far as i can gather, has a 3.08 diff ratio.

basically im asking if i want a bit more get up and go, is it possible for me to change diff ratios to get closer to the commodore ratio? or just get a new diff? i wouldnt mind an LSD, but im guessing this would mean buying a new diff then setting this up with the right ratios i want. what kind of diff would allow me to do this? :Chin:

as use can probably see all this ratio business is outta my depth, so any info or suggestions on a good course of action would be much apprciated.

thanks guys

[HK1837]

If your WB was originally a 6cyl it probably has a 3.55 diff in it, possibly 3.36 if it was an auto. Putting a 3.08 will make it more sluggish. You won't find a small salisbury diff lower than 3.55. If you want to run 3.9:1 you can easily do that by finding a 6cyl HQ-HZ ute or van diff housing and coarse spline and fit that to your WB. Grab a LH-LX Sunbird or 4cyl Torana 3.9:1 diff centre for it and you are away. Tailshaft, brakes, U-bolts etc are all identical. Your best bet would be a HZ housing though as it'll have the RTS sway bar mounts on it. You can also fit a V8 diff into it (big 10-bolt) from a HQ-WB ute, can or tonner but these come in the same ratios, only one lower than the 3.55 is a 4.44. This too will fit straight in but will need tailshaft mods.

If it has the factory V6 memcal in it with a 3.55 or 3.08 diff the lock up torque converter and speed sensor (and cruise control) won't be working correctly. You need to get a memcal re-written with the right ppk (pulse per kM) constant for the tyre diameter and diff ratio. Things like idle when coating to lights etc can be affected.

[mr sinbin]

If your WB was originally a 6cyl it probably has a 3.55 diff in it, possibly 3.36 if it was an auto. Putting a 3.08 will make it more sluggish. You won't find a small salisbury diff lower than 3.55. If you want to run 3.9:1 you can easily do that by finding a 6cyl HQ-HZ ute or van diff housing and coarse spline and fit that to your WB. Grab a LH-LX Sunbird or 4cyl Torana 3.9:1 diff centre for it and you are away. Tailshaft, brakes, U-bolts etc are all identical. Your best bet would be a HZ housing though as it'll have the RTS sway bar mounts on it. You can also fit a V8 diff into it (big 10-bolt) from a HQ-WB ute, can or tonner but these come in the same ratios, only one lower than the 3.55 is a 4.44. This too will fit straight in but will need tailshaft mods.

If it has the factory V6 memcal in it with a 3.55 or 3.08 diff the lock up torque converter and speed sensor (and cruise control) won't be working correctly. You need to get a memcal re-written with the right ppk (pulse per kM) constant for the tyre diameter and diff ratio. Things like idle when coating to lights etc can be affected.

thanks for all the info, and sorry it took me so long to reply, didnt even realise i had had an answer on this thread lol.

so you think that maybe the reason my van doesnt seem to be taking off as fast as the commodore use to is because of the memcal? do u know who i could ring or talk to, to find out weather this may be the case?

also ive had a few people tell me that the small ten bolt, originally in the van isnt really strong enough to take the power of the v6 and that i am better of replacing it with something stronger, what is your opinion on this?

i am also looking at buying a rear disk brake setup for the van just to help it stop a little better, but am unsure if i should just get axles, calipers, disks etc off another diff and fit them to mine, or upgrade the diff altogether with one that already has disk brakes.

sorry about asking even more questions, but i would rather get clarification from someone who knows there shit, then go in all gung ho and stuff something up.

cheers again

matt

[Gaddy]

Question? How do you tell a small 10 bolt from a Big one? [MENTION=119]ozbox[/MENTION] or anyone else who knows!

[V6HQUTE]

visually the normal sals inspection plate whatever its called is more of a oval shape, wb 6 looks rounder, there was a thread or shed post about it ill try find it

--- Updated ---

found it
http://www.mysandman.com.au/forums/s...IALS..or-diffs

[Gaddy]

Thanks Myles!!

[V6HQUTE]

no worries

[ozbox]

visually the normal sals inspection plate whatever its called is more of a oval shape, wb 6 looks rounder, there was a thread or shed post about it ill try find it

--- Updated ---

found it
http://www.mysandman.com.au/forums/s...IALS..or-diffs

no..read the text that goes with the pictures..the large salisbury is rounder and the small is oval shaped..

[V6HQUTE]

you sure, large is more oval shaped according to your measurements and my eye, not that i really matters the general idea was given

LARGE 10 BOLT SALISBURYS..
the hat on a large 10 bolt measures up and down 250 ml and side to side 290 ml..

SMALL 10 BOLT SALISBURY..
the hat on these measure 250ml top to bottom and 240 ml side to side..
note the different shape of the hat to the large 10 bolt..

[ozbox]

to do a visual..exclude measurements..the large is rounder by eye..the small has straight sides making it an oval shape....not everyone carries a tape measure when buying a car and looking underneath it...