The old "volvo diff into celica conversion"

[Toy77]

G'day all,

there was a bit of info on the old forums on this, but i thought i'd refresh the idea here.

Volvo's from around 1970 through to 91 used the same diff, albeit with different ratios. There are 2 different hemispheres though, one from 3.7 ratio down, the other 3,7 ratio upwards. so you can get 3.7 in either... but you cant put a 4.1 into a 3.01 housing...

Benefits of this diff for early celicas...

Very strong
width of 1400mm ( compared to 1370 stock for 28) so narrower than the comon hilux.
large range of suitable ratios for turbo/passenger vehicles (opposed to hilux)
has discs on rear, with twin piston calipers - internal drum handbrake
tail shaft does not need to be shortened
they are VERY VERY cheap and easy to find.
they are a dana 30 diff (same as front end of jeep) so there are various aftermarket centres available.

Dissadvantage

There are no (well extremely rare) factory lsds for them.

the conversion is quite easy, with a diff shop in newy charging me $500 to reweld mounts on to diff and change stud pattern. i had already cut the old mounts off the volvo, and had a set of celica ones cut off ready to be welded on.

i managed to make the volvo handbrake mechanism conect to the celica lever with little trouble

so far this diff has taken alot of abuse behind my celica with the 1g, including big launches on slicks at wsid. no problems yet. there are a couple other celicas now with thi conversion, with no problems i have heard of, and joel has actually got off his bum and got a lsd centre from the states for his (mine is locked) so he may be able to add how that worked.

if there are any questions, post here and ill try to remember the answers....

Cheers
Stew

[SeptemberSquall]

Hi,

What's the factory stud pattern? Any idea what specific range of ratios is common in which cars? How much was your diff to buy?

Cheers,
Michael

[Fattony]

Interesting, being a Dana series diff, there should be a real wide range of ratios available, and you should be able to have a ARB air locker installed into them as i eventually intend to do to the front of my jeep, so you could have it locker actiavated via a switch.

[thechuckster]

i thought there was a weight issue with ovlov diffs? or was that if choosing the early model 4-spot calipers for front branke conversions?

[o_man_ra23]

im working under an Ovlov atm, and the diff looks like its got way too much metal in it. Ill report back if i think there may be other issues while im under there.

CHeers, Owen

[Cool1]

When I was playing with diff conversions I found the Volvo diffs to be a hellofalot heavier than the Commonwhore/Coon Borg Warner. I eventually picked the Borg Warner which turned out alright and was cost effective.
I then pulled that out and sold it off and upgraded to the RN25/27 diff.

[Toy77]

hi there,

i think the weight from memory was around 75kg..... i did weigh it. it was less than 15kg heavier than the stock one.

as for ratios... i did have a complete list of what came in each car, but was lost in a computer reboot (done by a professional!) but they run from around 3.01 all the way up to high 4's... (4.8 i think)

any way, one beauty of the volvo is they have a plate on the snout of the diff telling you the ratio, which makes life easier.

there is alot of metal down there, but i think alot of what you are seeing is the strange brackets volvo use, which are cut off in this instance.

i was actually given my diff by a mate of my fathers, who used to wreck volvos - he has only ever sold them to speedway guys, apparently it is quite popular there.

but they are commonly available for around $200 complete.

as i said in my first post there is definately aftermarket centres available, like the airlocker etc. but there are more interestin centres than that available, including the lock right, no slip centres etc... lsd most the time, but lockable when required.

http://www.rocky-road.com/noslip.html

have a look for your self...

i belive the factory pattern is 5x100 or 5x120..... it is definately 5 stud, and is NOT 5x114.3 which i changed mine too (i have also changed one to 114.3x4)

Cheers
Stew

[mrshin]

I have memories of them being 5x110, or something else similiarly weird/annoying/European...

[Toy77]

that rings a bell.

either way, just bank on a pattern swap and all is good.

[Jayem]

Stud pattern is 5x108.
Just a interesting side note but my friend had aluminium case volvo diff.

[GTtwin]

Stud pattern is the same as Torana, I measured 5 x 105.

The diff types for 240 series, 1975 to 1993 are as follows;

Type 1030 - 3.54:1, 3.73:1, 3.93:1, 4.10:1 or 4.30:1
Type 1031 - 3.15:1, 3.31:1, 3.54:1, 3.73:1 or 3.91:1

All these were avaliable as optional LSD, as Toy77 said extremely rare.
Most LSD's came in 6 cyl 260's, which all had auto trans in Australia, so if you do find one expect it to be a pretty tall ratio.

[BigWorm]

Yep, quite a good diff, I'm quite happy with mine.
The whole diff assy cost me I think $150 from pickies, but then I went a bit crazy & bought all new discs, pads, shoes, caliper rebuild kits, & had all new bearings & seals fitted to the diff. The bearings & seals were done with the welding of the celica brackets & straightening the housing, having the axles and new discs redrilled & new studs fitted, and having the LSD fitted & pinion/backlash adjusted, which all up cost a grand.
It also required at least a modified tailshaft, but I went for a new 3" jobbie with much bigger unis.
On top of all that I had some issues with the pinion & new tailshaft hitting the floor thanks to all my new found LSD grip, so some adjustable upper trailing arms & new lower trailing arm bushes were installed.
As you can imagine, it wasn't cheap in the end, but hey I shouldn't have to touch it for a few years now.

The LSD is a Detroit Truetrac I purchased from here: http://www.drivetrainspecialists.com...duct-5408.html
and works out to be $440 Aussie pesos (they were only 400 when I got mine), which sounds bloody good, but the postage ended up being way more than what was quoted (over $150) & I got stung another 100 rubles by customs.
Other sites to check out are: http://www.reiderracing.com/detroitlocker.htm
http://www.differentials.com/index.html

But then the first time I pulled out of my street it all became worth it!
It has since put up with a few 2nd & 3rd gear burnouts & 6000+rpm clutch dumps on slicks at WSID. It didn't seem too impressed with the 3rd gear burnouts, but hey it didn't break.


The only thing I'd like to change is the 3.73 ratio, I even bought myself a 3.91 setup but the bastard didn't fit! The pinion was too long for the 3.73 housing, so the 3.91 housing was tried & the LSD didn't fit that!

So GTtwin, if you're telling me there's a 3.93 available for my particular housing I'll be stocked!
I was under the same belief as Stewy, 3.7 & up and 3.7 & down. Only thing, any way to pick the difference between the two without the id sticker on the back? I did have pics of the 2 diffs stickers on my phone, before it got formatted of course.
I'm guessing it would be the 1030, as I'm positive the 3.9 I tried was 3.91 & not 3.93, but I'm gonna need more evidence than just my pretty ordinary memory......

[BigWorm]

I think this diff conversion would be a worthy option for most RWD live axle toyotas.
It would be a a bit wider for most early corollas I imagine (but I'm sure still managable), but is 10mm narrower than AE86 diffs (1400mm vs. 1410mm), so would give that little bit more room for wider & dished rims, & would be narrower than 2nd & 3rd gen celicas too (I have no idea of the actual measurements, anyone care to give us something accurate?) so would make use of all that inner guard area making.
I know with my celica (RA23) I have a good 3 inches between my inner guard & wheel/tyre, with 205 tyres on 7" wide rims with a +25 offset. Because the volvo diff is slightly wider than the original I'm stuck looking for 8" wide rims with at least a +50 offset- and a 4x114.3 stud pattern.
Don't worry, I'm not holding my breath in anticipation.....

For a budget conversion, you could get away with it for under a grand I reckon- $150 for the complete diff, $5-600 for the bracket welding and disc & axle drilling, $100 to have the tailshaft modified to suit and $1-200 to cover any suprises (new pads, or caliper rebuild kit, or discs machined; you'd obviously choose a diff that had all these parts in reasonable condition).

[MWP]

So how strong is this diff compared to a G series?
Estimated HP before it would start having problems?

I was going to put a G series diff in my RA28 behind the 1UZ-FE, but this diff if strong enough sounds like a better option due to the width.

[Cool1]

I reckon the Volvo diff could handle 1200hp easily!