4.1 torsen or 3.7 LSD on a 400bhp 1jz

Kb865supra

New Member
May 2, 2009
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Yakima, WA
bobiseverywhere;1346211 said:
I am not sure about power but i think the 3.91 would be a nice in between and a LSD instead of the torsen Dif would always be good in my mind

You mean a clutch-pack LSD (?) because the Torsen diff is also an LSD.
 

suprahero

naughty by nature
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Aug 26, 2005
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I have had the 3.73 and the 3.91. I currently have the 3.91 and I love it since I do a good bit of 1/8 mile drag racing and it still doesn't turn nine grand while trying to drive on the freeway.
 

bobiseverywhere

bobb'n for money
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Kb865supra;1346426 said:
You mean a clutch-pack LSD (?) because the Torsen diff is also an LSD.

i did mean clutch pack but from what i have seen from it working the torsen is not a LSD.

It will not force both wheels to drive but will favor the wheel with less traction

if it is supposed to make sure both wheels drive like a clutch pack LSD then i am not sure what was wrong with the one i saw...

either way the 3.91 i found was a nice compromise between the two so that you can keep the revs down for cruz'n but at the same time still have some nice acceleration. Also might be a good idea to replace the clutch pack in the 3.91 if it's getting on in the miles


NINJA Edit: I must have seen one that was messed up or something figured i should stop being stupid and look it up

http://en.wikipedia.org/wiki/Torsen


extra ninja edit this might be why i thought it was not as i was able to see one wheel getting most or almost all of the power as opposed to a clutch type diffy

How they work

The Torsen differential works by supporting a torque imbalance, the maximum ratio of torque imbalance being defined by the Torque Bias Ratio (TBR). When a Torsen has a 3:1 TBR, that means that one side of the differential can handle up to 75% while the other side would have to only handle 25% of applied torque. During acceleration under asymmetric traction conditions, so long as the higher traction side can handle the higher percentage of applied torque, no relative wheelspin will occur. When the traction difference exceeds the TBR, the slower output side of the differential receives the tractive torque of the faster wheel multiplied by the TBR; any extra torque remaining from applied torque contributes to the angular acceleration of the faster output side of the differential.

NOTE: The TBR should not be confused with the uneven torque-split feature in the planetary-type Torsen III. The planetary gearset allows a Torsen III center differential to distribute torque unevenly between front and rear axles during normal (full traction) operation without inducing wind-up in the drivetrain. This feature is independent of the Torque Bias Ratio.
 

xsjado

Engine bling!
Jul 15, 2007
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Jostar;1347203 said:
I think you have your numbers backwards:1zhelp:

I think you need to go research the diffs available for all A70 Supras.

bobiseverywhere;1347294 said:
what supra came with that?

GA70's had the option for a 4.56LSD from factory.

RockPaperSwoRD said:
its a custom drag ratio that sells on ebay

No, no it isn't.

Holding up to the power quite well. 2 years of abuse, 1 year of that behind a bpu 1jz and it is as good as the day I got it.

G255 for those who don't believe me :).
 

Kb865supra

New Member
May 2, 2009
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Yakima, WA
bobiseverywhere;1347284 said:
i did mean clutch pack but from what i have seen from it working the torsen is not a LSD.

It will not force both wheels to drive but will favor the wheel with less traction

if it is supposed to make sure both wheels drive like a clutch pack LSD then i am not sure what was wrong with the one i saw...

either way the 3.91 i found was a nice compromise between the two so that you can keep the revs down for cruz'n but at the same time still have some nice acceleration. Also might be a good idea to replace the clutch pack in the 3.91 if it's getting on in the miles


NINJA Edit: I must have seen one that was messed up or something figured i should stop being stupid and look it up

http://en.wikipedia.org/wiki/Torsen


extra ninja edit this might be why i thought it was not as i was able to see one wheel getting most or almost all of the power as opposed to a clutch type diffy

How they work

The Torsen differential works by supporting a torque imbalance, the maximum ratio of torque imbalance being defined by the Torque Bias Ratio (TBR). When a Torsen has a 3:1 TBR, that means that one side of the differential can handle up to 75% while the other side would have to only handle 25% of applied torque. During acceleration under asymmetric traction conditions, so long as the higher traction side can handle the higher percentage of applied torque, no relative wheelspin will occur. When the traction difference exceeds the TBR, the slower output side of the differential receives the tractive torque of the faster wheel multiplied by the TBR; any extra torque remaining from applied torque contributes to the angular acceleration of the faster output side of the differential.

NOTE: The TBR should not be confused with the uneven torque-split feature in the planetary-type Torsen III. The planetary gearset allows a Torsen III center differential to distribute torque unevenly between front and rear axles during normal (full traction) operation without inducing wind-up in the drivetrain. This feature is independent of the Torque Bias Ratio.

Yeah, if I remember correctly, when you have the rear wheels off the ground and turn the driveshaft both wheels will turn the same direction, but if you only turn one wheel they'll turn in opposite directions. Unlike a clutch-pack LSD in which both wheels will turn the same direction.
 

Evilempire1.3JZ-GTE

SF what a waste of supras
Jun 22, 2006
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Dont use a factory 4.1 just sell it make money off it it will break in no time at all.
A factory 1JZ is pure fun with a 4.3 but will suck on the freeway
A upgraded 1JZ would kind of suck with the 4.3 because you go through shifts fast
You spend more time shifting then you do having traction. I would not use a 4.3 on an upgraded supra unless you have good wide drag tires to keep traction.

The best all around ratio is the 3.9 you get everything the best of both.

The 3.7 is to tall I would not use this one unless you do a lot of freeway driving and have extra torque like a V8 or 2JZGTE.
If I had a 2JZGTE i would use the 6 speed and custom diff then anyway.
 

2JZ_MA70

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Aug 28, 2007
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You have to look at what you would be doing with the car... Highway, Drag, Road Racing, Drifting.... Figure that out first.. What power are you running what tire are you running. What is your redline. Do you take the car on long trips or you just drive around town.
The smaller the gear number the longer the gear ratio's.

Personaly I like the 4.30 but I dont drive a lot in the car, drag mostly, I have a high Redline and also run 26" tires.... Also look on the "OTHER" forums there is nice tread on how to tighten up your differential.
 

Jostar

AEM powered 1JZGTE!!!
May 21, 2007
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Chicago
xsjado;1347454 said:
I think you need to go research the diffs available for all A70 Supras.



GA70's had the option for a 4.56LSD from factory.



No, no it isn't.

Holding up to the power quite well. 2 years of abuse, 1 year of that behind a bpu 1jz and it is as good as the day I got it.

G255 for those who don't believe me :).



I never said!! that ratio did not exist, I meant this=Sits at around 3100 at 60 though. With that ration i doubt it's gonna sit at 3100 RPMs at 60 mph, The ratio has to be lower to have the lower RPM... Thank you for playing, The higher the ratio the shorter the gears, The lower the ratio the longer ther gears...
 

xsjado

Engine bling!
Jul 15, 2007
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Melbourne
Jostar;1349058 said:
I never said!! that ratio did not exist, I meant this=Sits at around 3100 at 60 though. With that ration i doubt it's gonna sit at 3100 RPMs at 60 mph, The ratio has to be lower to have the lower RPM... Thank you for playing, The higher the ratio the shorter the gears, The lower the ratio the longer ther gears...

It was an approximation dude, next time though I'll go out and get the exact number just for you ok :).