altezza rs200 diff ratio compatability questions

[Titties]

I have a '98 RS200 altezza, with a 4.1 LSD diff in the rear.
I have this piece of info off another site :

"it is known that the altezza 7.5" crown n pinion gears + lsd will fit in the f series heads. i have done this myself. should see no reason it shouldnt go the other way too.
trd list the same lsd part number for altezza as ma61, ta63, gx61, mx73 etc

the more common F series off the top of my head... rounded to one decimal place
Ratio / Code / sources
3.7 F30# (ma61 celica-supra has it)
3.9 F30# (common)
4.1 F29# (common gx61, gx71, ta63)
4.3 F28# (estima van)
4.6 F25# (cr30 4wd Liteace van rear diff)
4.8 F36# (ms112 Crown)"

Does this mean i could goto any old wrecker, get my hands on one of these diffs and then change over the pinion/crown wheels for a higher ratio diff?

I'm after something much shorter, i just think the fact you can hit cutout in the top of 4th gear to be a waste.
I'm happy with the fact that i'll prob sit on 3500 RPM @ 100km in 6th, i just want the performance of the closer ratios.

Has anyone done this before or does anyone have any info on this??
I know the Altezza of differing years come in 4.1 and 4.3 ratios, the TRD set is 4.556.

Cheers, Mike

[piw]

I'm happy with the fact that i'll prob sit on 3500 RPM @ 100km in 6th, i just want the performance of the closer ratios.

Cheers, Mike

No matter what diff you fit it will not make the ratio's any closer,

It will just make them all lower. The rev drop between gears will stay the same.

[KinLoud]

I have done some homework on this also - looking to put the altezza torsen diff I have into an older F series IRS housing. I think that the crown and pinion swap will work fine for you. A diff expert will need to setup the backlash and contact patch for you (unless you are suitably experienced)
Also look for a 4wd liteace - some of these have a 4.78 ratio F diff in the rear (front is T series)

Ken
Ham
021 408 863

[Titties]

No matter what diff you fit it will not make the ratio's any closer,

It will just make them all lower. The rev drop between gears will stay the same.

Hmm thanks for that, i hadn't really thought of it like that,
i'll do some more research into it and see what i come up with.

If all else fails i'll just get a 4.3 from the later model Altezza, there is one at a local wrecker.

Thanks for your comments, keep em coming!
Mike

[gepsk8]

off subject but do i need a 4wd or 2wd townace diff assembly to fit a Altezza lsd into?
gona run f series not g series(hulix) in dx corolla as im after little less weight.
im guessing 4wd.
thank

[strx7]

IDoes this mean i could goto any old wrecker, get my hands on one of these diffs and then change over the pinion/crown wheels for a higher ratio diff?

Yes and no, you'd need to pick on a dismantler who'd have that type of thing just kicking about and in this day and AGE you might have to try a few. Ringing arounf first would probably be your best bet.

[AE25]

i just think the fact you can hit cutout in the top of 4th gear to be a waste.

the answer... change into 5th... then 6th.

info quoted in first post sounds like something i'd write
one thing i've yet to check on in altezza head (which i've seen before in irs) is an IRS head has oil grooves on the inside diameter of the side gears where the axle fits into.. this i assume to pull oil away from the side seal? (correct me if im wrong). live axle don't usually have the oil grooves. whether it affects operation or causes leakage?? dunno, prob not.

another observation is the altezza side bearings sat a little wider than a live axle F series head (could be wider bearing or could be wider carrier, i havent measured). so swapping the whole carrier from tezza to live axle, the difference can be taken up with the adjustable side nuts, whereas irs use shims.. so new shims would have to be ordered/made to fit a live axle carrier into an irs housing.
if only swapping crown and pinion gears, the side bearing will not be an issue.

more F series altezza lsd conversions here.. read the bottom of the page http://toymods.net/forums/showthread.php?t=14640

i could have a 4.55 ratio altezza head for sale. housing and gears only (was aftermarket lsd fitted prior).

[Titties]

AE25 i'd be keen for that diff head, i might try to track down a MX5 gearbox and swap the gearsets over (for the better ratios).

Is it true that the s15 silvias boxes gearsets are compatable?

Send me a PM and let me know what you want for the Gears, i shouldn't need the casing also.

Cheers, Mike

[RomanV]

AE25 i'd be keen for that diff head, i might try to track down a MX5 gearbox and swap the gearsets over (for the better ratios).

I've talked to a few people who seem to think that the Altezza has the best ratios of all of the AZ6 aisin gearboxes anyway...

Their site only lists the gearbox as being used in the MX5 and Altezza, so I dont know if there's any truth to the claims that it's the same gbox as the S15 and S2000 etc.

[toyrota mota]

Sorry just going to hijack this thread abit. 1st ive got a 79 tt132 corona wagon does this have a t-series or f-series diff?
2nd would a f-series diff with an altezza lsd centre in it be strong enough to handle the torque of a mildly modded 1uz? Or would it just snap axles as soon as it got abit of sh*t