differential swap or not
 

i have n/a supra, i'm going to swap the TT motor soon. should i keep supra na differential or swap out the differential. the ratio on the TT automatic 3.769 and manual 3.133 or swap Lexus SC 98 differential with 3.266 . anyone doing it before please help ? what it involve or direct bolt up ?

from what i remember the tt differential is a lot better than the na differential, and its more durable, you can use the lexus differential if you want to, i believe they are drop ins so its not gonna require a lot of modification if any

Hi supraman,

The comment that you made regarding the differential being the same as the Lexus...I'm curisous to know how it is that you found that out? Are the Lexus parts better quality than the ones that are specificaly made for the supra?

I'm an Auto Mechanics studant, I'm curious to know how much of what is out there that is in fact the same stuff packaged up and sold as if it's differant.

In europe the parts for the Scoda are VW parts but half the price (they are also both owned by the same co , VW ;) )

Well considering Lexus is toyota they are the same motors and parts as toyotas because they are the same motor company. The IS300 has the same motor as the supra which is a 2jz. The trannys are similar with better technology and so are most of the bolt on parts. Now with a diff I couldnt say for sure but I wouldnt be suprised if they were transferable.

On the other hand, get a TRD diff. My friend has a 98TT that he blew the stock diff when he down shifted. The TRD ones are bulletproof.

skilmatic is right, the motors are hte same, teh trannys are pretty much teh same wit some minor differences, as for the diff, the diff in the lexus...is300 and sc300 are the same as in teh na supra since all three cars are na in stock form, the turbo diff is a little more rugged, and lexus parts are the same as toyota parts since lexus is the high end version of toyota

Yeah its the same basic concept as Nissan and Infinity. The 350z and the g35 use the same motor which is the VQ35.

Now I am trying to get ahold of my buddy who is a tech for toyota and see if he knows anythign on the possible diff swap between the alteeza and the supra.

IMO I think the teething is different because of the fact they use different sized drive shafts which i think have different size teeth by 3/16. However, I am prolly wrong. Thats just what I am assuming.

i think the best set up is used the supra auto TT differential. the ratio on the Auto tt LSD, it will launch faster than the manual LSD. my friend tried the GS300 differential, It fix perfectly but lack top end. the 93-98 SC300/400 suspension parts are mostly the same but i'm not sure about the Differential bolts. The IS300 is different set up and the ratio is suck.

Well your diff has nothing to do with top end capabilites. That would be the type of gears you have in your tranny. All the diff does is make wheels turn thats all. It takes whatever torque/power the tranny makes via the engine and is transfers that power to the ground. So your whole concpet there is a little misguiding IMO.

And I dont know how the IS300 is a different setup cause its the same motor and tranny as the supra it just has a little better technology than a 93-97 vehicle. If anything the IS300 should be better cause its like almost 10yrs newer therefore newer and better technology is involved in that car. Is this making sense?

due, you know what you talking about?

well sometimes i do sometimes i dont. However, I am going to be fair about this. I am going to tell you the same thing I tell everyone who doesnt agree with me.

Please if you can refute anything I say by posting a link with facts to back your side up then I will gladly admit I was wrong. I did this to another guy on the supra or bmw thread and I have yet to hear from him. So now the balls in your court.

the differential does more than just turn the wheels. people spent thousand dollar swap differential to get the car faster. read this and you might understand better http://www.z1motorsports.com/PDFs/TT...earendswap.pdf . i'm not a smart guy . i just wants to share about stuff that i know.

well he was pretty much right...though the top end part i did not know, but wut he said about putting power to the ground is correct, since thats what a diff does and allows the wheels to turn, the diff just makes it easier to transfer the power to the wheels without losing it all through lost traction

Well your talking about converting a single wheel turning diff to a LSD(aka limited slip diff) or a ATB(aka automatic torque biased diff). These diffs are also bullet proof none the less. Your stock gears are much more brittle than a forged diff. So when you get a cusco, or a quaife you are able to downshift at higher rpm's much more smoothly and effortlessly. And they make both wheels turn at the same rate. Stock diffs do not do this. This is why they cost so much. You are paying for precision machining and anytime you deal with that your talking some coin. I payed all together with instalation and new spider gear about 1500 for my quaife diff. And it was money well spent.

So again, the transmission transfers power(hence the terminology trans-mission) its mission is to transfer power. And the differential just takes that power and turns the wheels. I guess you could say its transfering power from the tranny to the ground but the tranny doesnt create power it just transfers it. Now the correct analyzation would be that the diff distributes(not transfers) the power to the wheels. I hope that helps a little.

distributes...transfers....same idea...but yea....putting in a quality diff is not gonna be cheap

Actually they mean completely 2 different things. So they arent the same. But I understand why someone would be confused because they are somewhat similar.

Hell, I'm a brand newbie on this board and I plan on buying a supra TT in a couple of years.


However I am not a newbie in mechanics so I couldn't resist to add some information here.
What kkiepvvessau wants to say, is that the differential does more than just turning the wheels. It also amplifies power just like a gear.

So lets say your engine devellop 200lb of torque at the flywheel. 200lb of torque isn't really alot to move a 3000lb and + car. Thats when the tranny and differential comes into play.

Lets say your first gear got a ratio of 3.0 and your differential a ratio of 3.1
The power your wheels will put on the ground will be: 3.0*3.1*200=1860lb/tq

Now that more likely to move your car. If you swap a lower gear ratio diff, you'll get: 3.0*3.7*200=2220lb/tq. Thats 360lb of torque to the wheels more right there just with that new differential. Not bad huh.

Anyway, I dunno if you all were aware of that, don't want to sound like a smart ass.

No that was a great post. However, it still distributes the power that was transfered from the tranny. A diff does nothing but distribute power to the wheels. It has nothing to do with power transfer. In order to transfer something you must change it to another form. Which the tranny does. The diff just takes that power from the tranny and distributes it to the wheels. I hope I am making sense too.

I think there is a bit of missunderstanding here. Yes you are right, the differential does only one thing: The distribution of the power to the wheels, just like you say. I was talking about the FINAL DRIVE, which is often in the differential housing of a FWD car so I don't know about RWD cars like a supra. But that could be why there is alot of articles that talk about a 3.7 differential instead of saying a 3.7 final drive.

O ok sorry if i misconstrued your demeanor.

No no its my fault :)

glad to see everyone is playing well ;)

There is no reason to be mad. Everyone here is very cool. This is why I love this forum. Everyone is so polite to each other. Every other forum I have been to its like a flame fest or something.

I've limited experience as far as auto mechanics, but I've worked as an engineer in a few different departments in automotive suppliers, including a supplier that ran lexus, mitsubishi, toyota, and GM all on the same line. The difference? Each and every Lexus part was checked for any imperfections by about three different people, looking for anything that so much as LOOKED imperfect, even if they were sure it wouldn't affect function. The GM parts? the machine spit them out into the box, and they were shipped, with occasional checks being performed throughout the shift. The people making decisions as to whether a part was good or not are aware of which customers are going to scrutinize the parts and which ones are going to blindly accept anything, and decisions are made with this in mind both those people.
Now, this isn't to say you should expect junk in the generic box, or that the parts that aren't this brand or that will come apart, but if they are sold under a different name, there probably is a reason for that. My guess is, a process is not capable of making parts to the specs the designers desired 100% of the time, but the second-rate parts are 'mostly' functional, just might not last as long. So, they sort them for the specs that the designers wanted, and sell the second-rate parts at cost, to reduce the material scrap costs.
Also, in other industries, there are often parts that are aftermarket that come in, are checked, are out of spec, and someone says "oh, that's aftermarket, that's good enough", and send them on.
SOO... Just because the parts are made by the same company, or even the same factory, or even the same assembly line... doesn't guarantee they are the same.
Depending on the designer's perspective on things, many times the second rate parts work perfectly well, but if the designer really knows what they are doing, then the spec will reasonably match the functional limits that you will want, and the second rate parts you're not going to want. Just something to keep in mind!