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Discussion Starter · #1 ·
OK. i have pics to back this up, but no way to get them on the computer as my compact flash reader died, so here is a brief over view which will be followed by a complete how to with pics when i get them up loaded.


The MKIII supra has an 8 inch differential that is identical internally to the is300. to be honest, you can use the cover plate off of the mkiii on a stock IS diff. the holes line up. inside, the metal fins are the same, the gears are the same size, albeit different ratio's, and the lsd will swap right in.

In an MKIII supra, the 86-89's have a clutch type LSD, where as the 90-92's have a torsen type. the clutch type is a true 1.5 way lsd, and is stronger and more consistent than the torsen type. this is desirable obviously, and since the IS came with a weak ass torsen, which from what i've heard first hand blows for drifting or any kind of sliding whatsoever, this is a good upgrade.

another perk, as if getting a sweet ass clutch type lsd isn't enough, is that if your like me and you drive an N/A IS, your tired of being slow as balls. Guess what....the Supra diff you just bought for the lsd, has a very nice set of 4.10:1 or 4.30:1 ring and pinion gears. add to this new found gear ratio knowledge your now pre-existing knowledge that the internal cases are identical, and now you've figured out that instead of your low 3.7-3.9:1 gearing, you can give your stock ass IS some balls and hang with a slightly faster crowd if you just swap in the sweet ass 4.3 gears from a supra.

Now, i have done this swap in my own car. then the next day i went on a crazy all day mountain adventure where i drove my car harder than i ever have before. the lsd performed, silently, and flawlessly. the gear ratio allowed me to keep up with the g35 and the other IS that were leading, and when down shiftng, i could feel both wheels keeping traction and allowing me to stop faster. the higher gearing is amazing. my top speed is down a bit, my mpg's are down a tad, but all in all the get up and go made it all worth it. unofficially, I am almost certain that my car, which has only a 3 inch straight pipe catback, and this gear mod, is faster than several other cars boasting much higher performance figures and manual transmissions. all in all, it cost me 46$, Take that 5-700$ IHE.
 

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Discussion Starter · #3 ·
with the 4.30:1 rear end?
 

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unofficially, I am almost certain that my car, which has only a 3 inch straight pipe catback, and this gear mod, is faster than several other cars boasting much higher performance figures and manual transmissions. all in all, it cost me 46$, Take that 5-700$ IHE.
I know you are not talking crap about my car, I had the only manual there, except Brandon's G35. I can't wait to see the pics, especially the messy garage pic. All I can say to anyone wanting to do this swap is prepare to bust out the BFH.
 

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Discussion Starter · #5 ·
talking shit? no. real talk? yes. thus the unofficially. i have no idea just how fast either of your cars are, but i know that i was up brandons ass, without trying, and that on the straights, i didn't feel like you pulled away from me. however, i don't know exactly how hard you were driving either.
 

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I didn't do the install - the dude that built my car this fall did. However I know he changed around the gearing when he installed the mk3 rear end. Since then, my car pulls like a 1000cc rice rocket in first gear (its almost useless - I can literally drop the clutch and let the wheels spin until 2nd), has lowered top end speed, worse gas mileage, and the speedo is off quite a bit.

You can't beat the lower gear's torque, though - freakin nasty.
 

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Honestly I floored it less than 10 times all day... Next time we meet up we will have to race head to head. It was the first time I felt like my car was not horribly underpowered. Damn you for making me think about replacing another part of my car I thought I was done with. First it was my trans, then my coilovers, and now my LSD. You are a bad influence.
 

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Discussion Starter · #8 ·
Honestly I floored it less than 10 times all day... Next time we meet up we will have to race head to head. It was the first time I felt like my car was not horribly underpowered. Damn you for making me think about replacing another part of my car I thought I was done with. First it was my trans, then my coilovers, and now my LSD. You are a bad influence.
and tiresssssss....hehehe. what are friends for?
 

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where can i find one of these sweet little MK3 diffs??
From what I've heard, plenty of the Supra forums around have members who are getting rid of them for under $100.
 

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Discussion Starter · #11 ·
very true. junkyards and supraforums, or supramania.
 

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OK. i have pics to back this up, but no way to get them on the computer as my compact flash reader died, so here is a brief over view which will be followed by a complete how to with pics when i get them up loaded.


The MKIII supra has an 8 inch differential that is identical internally to the is300. to be honest, you can use the cover plate off of the mkiii on a stock IS diff. the holes line up. inside, the metal fins are the same, the gears are the same size, albeit different ratio's, and the lsd will swap right in.

In an MKIII supra, the 86-89's have a clutch type LSD, where as the 90-92's have a torsen type. the clutch type is a true 1.5 way lsd, and is stronger and more consistent than the torsen type. this is desirable obviously, and since the IS came with a weak ass torsen, which from what i've heard first hand blows for drifting or any kind of sliding whatsoever, this is a good upgrade.

another perk, as if getting a sweet ass clutch type lsd isn't enough, is that if your like me and you drive an N/A IS, your tired of being slow as balls. Guess what....the Supra diff you just bought for the lsd, has a very nice set of 4.10:1 or 4.30:1 ring and pinion gears. add to this new found gear ratio knowledge your now pre-existing knowledge that the internal cases are identical, and now you've figured out that instead of your low 3.7-3.9:1 gearing, you can give your stock ass IS some balls and hang with a slightly faster crowd if you just swap in the sweet ass 4.3 gears from a supra.

Now, i have done this swap in my own car. then the next day i went on a crazy all day mountain adventure where i drove my car harder than i ever have before. the lsd performed, silently, and flawlessly. the gear ratio allowed me to keep up with the g35 and the other IS that were leading, and when down shiftng, i could feel both wheels keeping traction and allowing me to stop faster. the higher gearing is amazing. my top speed is down a bit, my mpg's are down a tad, but all in all the get up and go made it all worth it. unofficially, I am almost certain that my car, which has only a 3 inch straight pipe catback, and this gear mod, is faster than several other cars boasting much higher performance figures and manual transmissions. all in all, it cost me 46$, Take that 5-700$ IHE.
Did u install it??
 

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Does the LSD come in auto or manual like the IS? If it comes in auto you think the gear ratio will be better? Do you have to take the internals out and transfer them into the IS housing?..lol. Sorry for all the questions, it early, I just woke up and my eyes are burning me and I just skimmed through what you wrote.
 

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Discussion Starter · #17 ·
i did install it with the help of a friend.
look for a full how to with pics tonight after work.
there is no correlation as far as anybody can tell between auto vs. ,manual and gear ratio.
lsd's came in both auto and manual.
as far as i know, clutch types where in the 86-89 models only.


to change gear ratio's you either need balls and a sledgehammer or a press. i didn't have a press.
 

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Cool. In for pics. Thanks.
 

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This should be a fantastic how to. Crazy thing about Lexus in general is that they run their engies about 15% richer to keep engine noise down. So if you got a tuning device such as an AEN F/IC you can regain your lost mileage. Ever wonder why Lexus vehicles get lesser MPG than toyota models yet they use the same engine?

Good job on the install!
 
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