The official LSD gearbox thread

Suspension and other discussion

The official LSD gearbox thread

Postby CMS-GT4 » Wed Apr 06, 2005 3:08 pm

Sticky this one please.

I will post what I learned about 185 and 205 models. Someone else will have to elaborate on the 165.

This link has specs and ratio info on gearboxes.
http://www.celica.dds.nl/en/celihist.htm

All models used a 5speed manual.
4 Gear boxes in all.

All gtfour models had a center VC (viscous coupling) lsd, except for early Japanese 165 models that had a manaul locking center lsd. It had a switch in the cabin.

165 and 185 models came standard with open front and read diffs.
185 models had optional rear torsen lsd but can only be indentified by opening the lsd.

You can learn more about torsen and VC lsd's at this link.
http://www.rallycars.com/Cars/4wd_turbo_cars.html

185 RC/CS/GA and 205 models came standard with rear torsen lsd.

They all have open front lsd and center VC lsd. There is a rumor that the WRC 205 uses a front lsd, but there is not proof as of yet.

There are lsd suppliers for the alltrac.
185/ 205 lsd's are interchangable while the 165 needs modification to use thier lsd. I have heard it needs other rear axels, but I am unsure.

MR2 LSD Conversion for front LSD
We have found that the Mr2 lsd may fit by fabricating a center shaft that has a smaller make end to fit the mr2 lsd. Stock mr2 lsd is VC. This may be a good option for those who rally as VC front and center seems to be a popular choice for rally cars.
Torsen and clutch type lsd's are also available for the MR2 that should fit by the same means as the stock mr2 lsd.
I am going to investigate if parts from the alltrac front diff might be used to modify the mr2 lsd rather then make a new shaft.

GtFout lsd options
Front /Center:
Quaife makes a front torsen type lsd for the gtfour.
http://www.quaifeusa.com/
TRD made a center and front lsd combo for the gtfour that has been discontinued. I have been told by a few rally drivers, one who claims to own one that it is a VC unit. It is a listed as a clutch type, which is a possibillity. Being that they are so hard to find, and expensive at that, they are most likely not an option, and stock center VC will be retained.

Rear:
Cusco and TRD produce rear lsd for the 185 and 205.
Cusco can be obtained through Japan parts.com I have heard good things about them, but never used them myself. Use at own risk.
http://japanparts.com/shop/shop.cgi?mod ... 7s%2fDiffs

Rear torsen from 185 RC or 205 models will be a good upgrade for a standard 185 open rear.

I have read that adding a front lsd can cause understeer, depending on how it is set. From reading the Subaru forums, it seems front and rear clutch lsd cars w/ center VC have a tighter setting for the rear lsd then the front to maintain oversteer.

Supra rear lsd swap:
Another option I read about on http://www.specialstage.com/ is using a rear (lower ratio) supra diff and modify the output of the diff to accept the alltrac axels thus changing the front and rear ratios casing oversteer. If that is a possiblilty then all of the supra lsd options would work for the rear end and give more possibilities. One possible issue is the center diff may over work due to front and rear moving at different speeds and may ruin the center VC. This has yet to be determined.

Gear Sets:
http://www.quaifeusa.com/ Makes a close ratio gear set for the alltrac.
There area couple of other companies that have produced gear sets in the past, I am still looking for their info.

Anyone add what ever useful (factual info) they may have.
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92 st185 (205 swap) | 03 350Z Track (sold) | 13 Pilot | 17 Mazda3
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Postby furpo » Wed Apr 06, 2005 8:56 pm

very interesting thread.

since my jdm st 185 has a front lsd of some sort and i will rebuild it sometime soon i maybe able to answer one of the questions above as to makes.

with having driven other st185's with two open diffs compared to mine with two lsd's the understair overstair is not a huge issue. even a rear lsd can cause turn in understair. in the end of the day it is a complete package. the suspension geometery, diffs and driver.

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Postby Kyoto » Tue Apr 19, 2005 1:41 am

Does anyone know how difficult it would be to adapt another make of rear LSD to fit the (open) GT-Four's rear setup?
Tim // Melbourne, Australia

1986 ST165. 152,000km on chassis
ST205 WRC engine / IC system / rear LSD with 82,000km
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Postby furpo » Tue Apr 19, 2005 5:48 am

the best idea is to find some clutches out of some other lsd that are about the right size and build a new diff. it is quite straight forward and that way you can get clutches easily.

my mini lsd clutches are from a honda city turbo. the reason i choose them is because of the size and the price.

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Postby Kyoto » Tue Apr 19, 2005 10:52 am

I don't really get what youre saying there. I seem to remember reading somewhere you could use the existing housing and get SW20 or 7MGTE Supra internals and get accordingly suitable output shafts???
Tim // Melbourne, Australia

1986 ST165. 152,000km on chassis
ST205 WRC engine / IC system / rear LSD with 82,000km
Blitz K1-380V
Apexi Power FC
Aussie 3" dump pipe to 3" catback system
TWM short shifter.
Whiteline front strut brace
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Postby furpo » Tue Apr 19, 2005 8:49 pm

if it is only the output shafts that need changing the above option would be the best.

if you have to change the gear ratio and bearing sizes to suit the st185 case then you are better off starting from scratch and building your own lsd like i had to with the front diff of my mini. instead of making your own clutchs as well you are better of finding some OEM clutchs that are about the right size and building a diff around them. the hardest part is getting the ramp angles right.

roger
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Postby beej » Wed Apr 20, 2005 11:42 am

furpo wrote:very interesting thread.

since my jdm st 185 has a front lsd of some sort

roger


hang on ur saying that the JDM boxes have a front LSD?????

coz i just got a JDM box, and i noticed theres an increase in torque steer under wheelspin, and this would explain it

that means i now have 3 LSD's :| shite
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Postby CMS-GT4 » Wed Apr 20, 2005 1:58 pm

I have a JDM RC box, and it does not have a front lsd. However the center diff seems more responsive. If I drive in a straight line, slam on he brakes and floor the gas pedal, I get rear wheel spin for a moment.
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92 st185 (205 swap) | 03 350Z Track (sold) | 13 Pilot | 17 Mazda3
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Postby furpo » Wed Apr 20, 2005 7:32 pm

beej wrote:
furpo wrote:very interesting thread.

since my jdm st 185 has a front lsd of some sort

roger


hang on ur saying that the JDM boxes have a front LSD?????

coz i just got a JDM box, and i noticed theres an increase in torque steer under wheelspin, and this would explain it

that means i now have 3 LSD's :| shite


my car does, the engine and box have been rebuild twice that i know of over its life and i keep on finding all sorts of differences with my car. who knows it may have an st205 box (with aftermarket lsd) or an aftermarket st185 one. i really dont know.

so you may ask how do i know i have a front lsd. first i with the car on a hoist if you spin one wheel all wheels spin in the same driction. even if you hold one of the other wheels it will try spin in the same direction. this was not proof of the pudding so i pulled the front half shafts out and looked through the diff and it is hollow.

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Postby gtfourdreams » Mon Apr 25, 2005 9:43 pm

have you guys tried looking at the AE86 rear LSDs? i believe they have a solid rear-end but i remember looking at my old (1993) TRD Japan catalogs and the numbers for AE86 vs ST165/ST185 rear diffs were very similiar. off by the last number, if i remember correct.
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Postby BraveUlysses » Tue Apr 26, 2005 2:18 am

AE86 is definately a solid rear-axle so there is no way a rear end for it would work on our car.

Cold--I doubt that your tranny has a limited slip up front simply because you could floor it and squeak the rear tires. My guess is that your RC box has different gearing (this has been established) and perhaps that gives you shorter gearing at the front wheels and taller gearing at the rear, allowing you to break traction.
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Postby CMS-GT4 » Tue Apr 26, 2005 12:16 pm

I know I don't have front lsd. The gearing should be the same on the front and rear diffs on all models. Its the final drive that outputs before the center diff that is the high ratio. 1st and 2nd of this box are lower ratios. I think it was casued by a more reactive center lsd. But its really hard tosay w/o getting the car on a testing course. I'll be gathering much more info once I get my RC clip.
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92 st185 (205 swap) | 03 350Z Track (sold) | 13 Pilot | 17 Mazda3
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Postby gtfourdreams » Wed Apr 27, 2005 2:20 pm

just wanted to add that TRD has the same part numbers for all 3 gens. the ST165 needs diff side gear shafts apparently. with that in consideration, other LSD's shouldnt be too different.

ST165 86.10-89.8 3S-GTE 41301-ST000
For rear. Side gear shaft required *2
ST185 89.10-94.1 3S-GTE 41301-ST000
For rear
ST205 94.2- 3S-GTE
For rear

*2 41309-20030 QTY 2
Use OE snap ring
(90521-28004*2)


curtesy of http://toyota-trd.jp/en/strt/d_lsd.html
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Postby mtbgael » Fri Apr 29, 2005 4:46 pm

CMS-GT4 wrote:I know I don't have front lsd. The gearing should be the same on the front and rear diffs on all models. Its the final drive that outputs before the center diff that is the high ratio. 1st and 2nd of this box are lower ratios. I think it was casued by a more reactive center lsd. But its really hard tosay w/o getting the car on a testing course. I'll be gathering much more info once I get my RC clip.


So there is no "final drive" in our rear differential? It's just simply a differential? This has been a concern of mine as I look into building my alltrac for auto-x in DSP. The class allows aftermarket LSDs, but I always thought if I got a 185 rear it would throw things off by being a different ratio.
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Postby Kyoto » Sun May 01, 2005 4:18 am

AE86 is definately a solid rear-axle so there is no way a rear end for it would work on our car


Hideki reckons he's running an 86 LSD??? :shrug:
Tim // Melbourne, Australia

1986 ST165. 152,000km on chassis
ST205 WRC engine / IC system / rear LSD with 82,000km
Blitz K1-380V
Apexi Power FC
Aussie 3" dump pipe to 3" catback system
TWM short shifter.
Whiteline front strut brace
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