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[PaulW]

Been googling, can't find anything concrete...

Apparently there are 3 FD Ratios for the LSD...

3.45
3.7
3.9

Any idea if this is true, and if so, what the ident numbers of each diff is to identify which ratio is which diff??

Cheers

[feeutfo]

Pass, but Albatross has been looking into all that.
Have seen posts along those lines.
 Maybe pm him or have a search in the mean time. Or he may pop in here later.

[Kevin Wood]

Turning the input shaft and counting the rotations per output shaft rotation is a fool proof way of telling.

Kevin

[PaulW]

I'll see what transpires when I finally get hold of one then  

[ngrainqey]

Been googling, can't find anything concrete...

Apparently there are 3 FD Ratios for the LSD...

3.45
3.7
3.9

Any idea if this is true, and if so, what the ident numbers of each diff is to identify which ratio is which diff??

Cheers

imo the 3.45's are off corvettes or monaros from what i'v read and 3.7 is the v6 ratio and 3.9 the 2.0 ratio (2.5 have 1 of both between manual and auto) according to haynes lol!

also i think from what i read on a thread somewhere the 2.2 have 4.2 ratio? *shrugs*

[Kevin Wood]

V6 Autos are 3.9 too, IIRC.

3.45 will be horribly tall except for a V8, I'd say.

Kevin

[Albatross]

V6 Autos are 3.9 too, IIRC.

3.45 will be horribly tall except for a V8, I'd say.

Kevin

I was unaware of that. I though that all V6 (Auto and manual) had 3.7:1 LSD or 3.9:1 standard.

If what youre saying is true then I need to narrow and focus my search.

[ngrainqey]

if your after an lsd nathan then try and get a 3.7 one rather than a 3.45 (you'd need shorter gear ratios in the gearbox to make use of that diff in the v6) unless you have a camaro (they do 60 in first on the autos)

[Albatross]

if your after an lsd nathan then try and get a 3.7 one rather than a 3.45 (you'd need shorter gear ratios in the gearbox to make use of that diff in the v6) unless you have a camaro (they do 60 in first on the autos)

I had no interntion of getting a 3.45:1 LSD, I was more intrigued by the statement that there is a "like for like" 3.9:1 LSD out there which would be consistent with the current standard differential ratio as is on my Mig now.

I'd not heard of them before; I'd like to know if that is the case.

[Kevin Wood]

Haynes manual says 3.9 in 3.0 auto and 3.7 in manual. I assume the same is true of the 3.2.

Personally I wouldn't want the gearing any taller than it currently is on an auto. It would blunt the performance too much, IMO, so 3.9 would be preferable.

Kevin

[Kevin Wood]

I wonder if you could swap the crownwheel and pinion over if a 3.9 LSD is rocking horse poo? Would need to set the mesh properly, but might be worth considering?

Kevin

[Albatross]

I wonder if you could swap the crownwheel and pinion over if a 3.9 LSD is rocking horse poo? Would need to set the mesh properly, but might be worth considering?

Kevin

How would you do that? I've been thinking about sourcing one from Finland. Almost all the Finnish Omegas were LSD.

[Kevin Wood]

If you strip the diff down you'll probably find that the crownwheel is just a ring that bolts to the LSD unit. Since that and the pinion (the input to the diff) determine the ratio, you could make a LSD of the correct ratio using parts from a non-LSD.

This does involve completely rebuilding the diff so if one is available in decent condition with the correct ratio it's by far the best option.

Kevin

[ngrainqey]

Haynes manual says 3.9 in 3.0 auto and 3.7 in manual. I assume the same is true of the 3.2.

Personally I wouldn't want the gearing any taller than it currently is on an auto. It would blunt the performance too much, IMO, so 3.9 would be preferable.

Kevin

thats from the later 98 and onwards... previous models have 3.7 ratios on the 3.0 manual and auto
(and thats what it says in the haynes manual just above what you must hae been looking at) (chapter 8-1)

[lee4206]

If you strip the diff down you'll probably find that the crownwheel is just a ring that bolts to the LSD unit. Since that and the pinion (the input to the diff) determine the ratio, you could make a LSD of the correct ratio using parts from a non-LSD.

This does involve completely rebuilding the diff so if one is available in decent condition with the correct ratio it's by far the best option.

Kevin

Not quite as easy as that im afraid(i wish it was) the crown wheel does unbolt from the lsd but it is thinner than the non lsd one so if you try to put the non lsd crown wheel on to the lsd if wont fit back into the diff.
lee