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The mkiv Supra Owners Club

Can the small diff take decent torque?


Scott

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As above. I've just been thinking through the jobs I have to do on my car and I'm now thinking about the diff.

 

I have a facelift RZ which I assume has the small diff? Can these take a reasonable amount of power or should I be budgeting for a big casing diff?

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Be ok unless you start drag racing it, big diffs are near impossible to find these days anyhow, i have them all :D

 

I'll be on the strip at some point, definitely. I'll be aiming to go for it too.

 

I'll just keep my eyes peeled and buy one when it comes up. What's the going rate on them Jamie? I take it I'll need the big diff prop too? Driveshafts?

 

Cheers

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What's difference between them.my original did only used to do 1 wheel burnouts.

Was a netto spec supra.bought another diff but took some getting it to fit

You got any pics of big diff against a small diff

 

 

Here you go,

The Torsen diff is a standard fitment to all 6 speed mkiv's, alot of the Auto TT's and you'll even occasionally find it on a NA. You can tell if your Supra has a Torsen diff by reading the Trans/Axle code on the Engine Tag which is situated under your bonnet. The last letter of the 4 character code (eg. B03B) denotes the diff type which is "A" for a std diff and "B" for a Torsen diff. The crown wheel on the B series is 220mm whilst on the A series it's 200mm.

The Torsen (TORque SENsing) LSD (Limited Slip Diff) works quite differently to the TRD LSD. The Torsen is a Torque Multipling type of diff with a multiplication ratio of around 5:1. What this means is that whatever torque can be sent to the wheel with the least traction, it can send up to 5 times that torque to the wheel with the most traction. Its biggest advantage is that it can do this extremely quickly and doesn't ever lockup the ratio, but is continuously "sensing" and adjusting the torque between the two wheels. Its only real disadvantage is that when one wheel has no torque available (say it spinning in mud), then 5 times nothing is still no torque to the other wheel, so you can get stuck just like a std diff. Once the car is moving however this cannot happen. The TRD LSD is a standard type LSD in that it uses clutch packs to transfer torque from one wheel to the other. Transferring torque via clutch packs will be a slower process then the Torsen transfer method and it will absorb more energy from the engine when doing so. However we are probably only talking a few hundreds of a second difference here and maybe a few hp. The main disadvantage of the TRD diff is that it can "lockup" the ratio between the two wheels at 1:1. This means both wheels will then turn at the same speed and if this happens on a corner, it would be exciting at the very least. This "lockup" is also its only advantage over the Torsen diff as even when one wheel is in the mud, the other wheel can provide traction to pull you out.

 

My personal preference is for the Torsen diff as it usually comes free with the car, reacts quicker and aborbs less power and will never accidentally lockup. However, if you want to go rally driving in your mkiv Supra (don't laugh, there's guys in the USA that do just that) then the TRD would be the better bet.

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Might buy 2 just on the off chance :D

 

With regards to the UK diff, do I need to add anything else? Would I be right in saying they have an oil sensor? Do I just get away with leaving that unplugged? Straight swap kind of thing?

 

If so, how much for the kit (Prop, driveshaft, etc)?

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Do YOU really need a big case diff? Wouldn't you be better off just pulling the torsen out and putting in a TRD or are you more concerned about cracking the case?

 

More concerned about BOOOOOMMMM.

 

As far as I know the TRD cores only fit the larger case?

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I don't think I could go down that route, if I bought it and it popped I would be raging... .not to mention a lot of money down the drain.

 

For now I'd rather get the big diff in place then maybe think about the TRD diff for better traction at a later date :)

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Might buy 2 just on the off chance :D

 

With regards to the UK diff, do I need to add anything else? Would I be right in saying they have an oil sensor? Do I just get away with leaving that unplugged? Straight swap kind of thing?

 

If so, how much for the kit (Prop, driveshaft, etc)?

 

You just join the oil cooler pipes together, you should also change the NS shaft and the rear of the prop, i prob have a back half of the prop.

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This has got thinking! Where is the torque felt or most likely to twist - input shaft , diff , two output shafts ? The diff is altering speeds so alters torque - hmm first thoughts are the prop shaft would twist/ shear before diff got any effect - ie long shaft vs compact diff gears ?

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This has got thinking! Where is the torque felt or most likely to twist - input shaft , diff , two output shafts ? The diff is altering speeds so alters torque - hmm first thoughts are the prop shaft would twist/ shear before diff got any effect - ie long shaft vs compact diff gears ?

 

Easy, Mark Newman, 2 launches 2 diffs, all teeth sheered off the crown wheel, changed for big diff and broke propshaft so theres your chain of weakness.

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For what it's worth, I ran 650+ whp (but I can't remember the torque figures) on a facelift 6 speed for a while. It also coped with a couple of 750+ hp dyno runs. However, no sticky tyre launches as I was concerned, as you are, about popping it.

 

I have since upgraded to the B03B casing with TRD centre - if you can't get one locally, you can buy either new or used from the US via MVP & Elmhurst Toyota. I bought a second hand diff from SF.com (can get for $1k USD), TRD centre with diff rebuild kit from Dusty @ MVP ($1k USD all up), and LHS axle from Curt @ Elmhurst ($250 USD), and Dusty shipped them all as one package to Australia.

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