changing diff ratios with new crown wheel & pinion?

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changing diff ratios with new crown wheel & pinion?

Postby 92mr2paddy » Mon Apr 14, 2014 9:28 pm

just wanting to know if its possibly and if its been done, currently have a A02B diff in supra which is torsen LSD with 3.7 ratio (used to be auto) which is crap with the 6spd conversion, i havent been able to find the BO3B diffs anywhere so wondering if i buy a A01A open diff (has same 3.2 ratio as a BO3B) and swap the crown wheel and pinion if this will work and then give me a torsen lsd with new 3.2 ratio??

any place that might do something like this? (in auck.) thanks pat
current: 96' Supra RZS single Gt42 490kw at 20psi, daily - Hiace 2.7 van '05
previous: 92' mr2 g-limited, fuls gen 2 turbo conversion, steel ct20b, external etc etc :)
drift car: 94' silvia s14 sr20det 307kw @18psi
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Re: changing diff ratios with new crown wheel & pinion?

Postby fangsport » Mon Apr 14, 2014 9:51 pm

i can't recommend any on in particular, but any transmission/ gearbox workshop should be capable (some more than others), but curious as to what the 3.2:1 ratio came out of and what size crownwheel does it have ?
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Re: changing diff ratios with new crown wheel & pinion?

Postby 92mr2paddy » Mon Apr 14, 2014 9:52 pm

out of a celsior i believe? 200mm crown wheel like all the "small" diffs.
current: 96' Supra RZS single Gt42 490kw at 20psi, daily - Hiace 2.7 van '05
previous: 92' mr2 g-limited, fuls gen 2 turbo conversion, steel ct20b, external etc etc :)
drift car: 94' silvia s14 sr20det 307kw @18psi
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Re: changing diff ratios with new crown wheel & pinion?

Postby Mr Ree » Mon Apr 14, 2014 9:53 pm

The A01A is a 4.083 FD ratio

The 3.266 came out with the A03B and the B03B, the former being the 200mm crown wheel, and the latter, 220mm.
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Re: changing diff ratios with new crown wheel & pinion?

Postby 92mr2paddy » Mon Apr 14, 2014 10:04 pm

ree, thats what i always thought aswell after reading through the different diff ratios etc but maybe different from being in a different car to a supra?
http://www.trademe.co.nz/Browse/Listing ... =715830017

thats the one in question
current: 96' Supra RZS single Gt42 490kw at 20psi, daily - Hiace 2.7 van '05
previous: 92' mr2 g-limited, fuls gen 2 turbo conversion, steel ct20b, external etc etc :)
drift car: 94' silvia s14 sr20det 307kw @18psi
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Re: changing diff ratios with new crown wheel & pinion?

Postby Mr Ree » Mon Apr 14, 2014 10:26 pm

Sorry, I just presumed you were meaning a JZA80 diff lol. If it wasnt from a Supra, then yes, the codes do get a little blurry.

Can you toyodiy the CW&P to see if the part numbers are the same on each platform?
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Re: changing diff ratios with new crown wheel & pinion?

Postby evil_si » Tue Apr 15, 2014 8:45 pm

Go see tony at steelie gears, station rd in otahuhu
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Re: changing diff ratios with new crown wheel & pinion?

Postby fangsport » Tue Apr 15, 2014 9:56 pm

92mr2paddy wrote:out of a celsior i believe? 200mm crown wheel like all the "small" diffs.


is that as tall as they go ??

2.9/3.1 would be better
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Re: changing diff ratios with new crown wheel & pinion?

Postby wde_bdy » Tue Apr 15, 2014 9:58 pm

fangsport wrote:2.9/3.1 would be better


I've got 2.92 T series for my KP Starlet. :lol:

Callum
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Re: changing diff ratios with new crown wheel & pinion?

Postby fangsport » Tue Apr 15, 2014 10:05 pm

wde_bdy wrote:
fangsport wrote:2.9/3.1 would be better


I've got 2.92 T series for my KP Starlet. :lol:

Callum


T axles wouldn't last very long in this concoction !!
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Re: changing diff ratios with new crown wheel & pinion?

Postby steroidcontaskie » Tue Apr 15, 2014 10:42 pm

Tony at Steelie Gears swapped a torsen centre from a manual non-turbo supra into my open diff (JZZ31, same as JZA80). So I kept the same ratios with a torsen.

If the whole diff pumpkin is a direct swap into your car then you could just swap your torsen centre into the new open diff.

If it isn't a direct swap then the you probably have 3 options,

1. You could ask Jason from Jap spares if the diff is going to be compatible, but last time I tried to ask him about a fitment issue his response was so bad that I decided never to go there again. I will hazard a guess that he will tell you to look it up on the internet, even if he knows the answer.

2. Ask Jap spares if you can take the diff to Tony at Steelie Gears so he can have a look at it and tell you if he thinks swapping the crown and pinion will work.
(Jap spares is about 2 mins drive from Steelie Gears.)

3. Buy the diff and chance it.

Cheers
Edward

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