LSD needed?
#1
1JZ Single SC400
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LSD needed?
Since my 1JZ swap I have noticed the rear end is getting a little squirly. What I mean, is that while in boost, low or high, the rear end is swaying back and forth at ALL speeds. This is now more noticeable since the wheel and tire change from ADR Decadence style rims running run flats (Bridgestone Potenza), to G35 Ray's forged aluminum, which are much, much lighter. I originally started with 245/40/19 in the rear on Michelin Pilot Sports tires. I figured since I was originally running a 275 on the ADR's, this is what the problem is. I then switched the tire size, and put a 265/35/19 in the rear on the G35's, with another set of Michelin Pilot Sport tires. No change. I am also running spacers, size 10mm with extended studs. I also have a bad right rear wheel bearing, which is on the way from Aliga.
I made several phone calls today to confirm nor deny what the possibilities are. Many of other SC owners say its not the rims or tires, its because I need a Soarer LSD or one out of a Supra TT. This is because when the boost and torque comes on, the rear wheels are not spinning together, they are spinning uneven, and trying to play catch up. This does indeed make sense.
Another member said to switch out the rims and tires with another set of rims and then take it for a ride. Then report back. This would eliminate the wheel/tire theory all together. They all stated to try and find the LSD out of a Soarer, but like trying to find a needle in a haystack. I tossed around the option of welding the differential together, it would be the cheapest, but it would chew up the tires more rapidly. Other person said not to do it, since my car is so nice and clean, don't half do nothing, just try to find a LSD rear end.
The point of this thread is to determine which route to go, and what do you think is causing the swaying in the rear end. Again this is done at ALL speeds while in boost.
Another main points is that I have somewhat new struts, strut mounts, sway bar bushings, and all of the rear bushings have been replaced.
I appreciate any comments with help in this matter.
I made several phone calls today to confirm nor deny what the possibilities are. Many of other SC owners say its not the rims or tires, its because I need a Soarer LSD or one out of a Supra TT. This is because when the boost and torque comes on, the rear wheels are not spinning together, they are spinning uneven, and trying to play catch up. This does indeed make sense.
Another member said to switch out the rims and tires with another set of rims and then take it for a ride. Then report back. This would eliminate the wheel/tire theory all together. They all stated to try and find the LSD out of a Soarer, but like trying to find a needle in a haystack. I tossed around the option of welding the differential together, it would be the cheapest, but it would chew up the tires more rapidly. Other person said not to do it, since my car is so nice and clean, don't half do nothing, just try to find a LSD rear end.
The point of this thread is to determine which route to go, and what do you think is causing the swaying in the rear end. Again this is done at ALL speeds while in boost.
Another main points is that I have somewhat new struts, strut mounts, sway bar bushings, and all of the rear bushings have been replaced.
I appreciate any comments with help in this matter.
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1JZ Single SC400
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You are correct. I have been web searching for one for the past two hours. I also have notified my two Japan contacts for one also. I am awaiting their findings.
#6
Lexus Test Driver
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what tranny do you have? Get the auto TT diff or if you are happy with the gearing in your rear end just get a TRD LSD and be done. Look to spend about 1k for a rear end. Auto TT diff are 700-900 depending on the deal you get and a TRD LSD for 1000. You don't need a soarer rear end or wait to source one from japan.
Last edited by jwin; 03-15-13 at 12:39 PM.
#7
1JZ Single SC400
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what tranny do you have? Get the auto TT diff or if you are happy with the gearing in your rear end just get a TRD LSD and be done. Look to spend about 1k for a rear end. Auto TT diff are 7-900 depending on the deal you get and a TRD LSD is 900-1k. You don't need a soarer rear end or wait to source one from japan.
What are the differene in gearing between the TRD and the Auto TT? I think I am a bit confused.
Everyone is recommending this upgrade, but is this my problem? Has anyone else seen this type of sway in the rear end with 400-600 rwhp?
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#8
Pole Position
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I have the OEM Soarer R154 tripod tranny. It has also been built.
What are the differene in gearing between the TRD and the Auto TT? I think I am a bit confused.
Everyone is recommending this upgrade, but is this my problem? Has anyone else seen this type of sway in the rear end with 400-600 rwhp?
What are the differene in gearing between the TRD and the Auto TT? I think I am a bit confused.
Everyone is recommending this upgrade, but is this my problem? Has anyone else seen this type of sway in the rear end with 400-600 rwhp?
The TT Auto Diff is also a LSD but it's a Torsen Diff, which means that when one wheel senses that the other is slipping it catches up to spin at the same time. It was explained to me at one point that it's probably spinning together 90% - 95% of the time versus the TRD LSD at 100% of the time. The TT Auto Diff has 3.76 gearing as well.
A TRD LSD can be installed in a TT Auto Diff or a Six Speed Diff...
#9
Lexus Test Driver
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TRD LSD is a clutch type and the auto TT is a torsen type. When you buy the TRD lsd its just the LSD no gears and anything and you use the gear that is in your car. Usually when you buy a auto TT LSD its a complete pumpkin so its more of a plug and play type. It is really up to you. The TRD LSD is stronger than the torsen LSD. Torsen is gear based and the TRD is clutched base. Clutch base LSD are a little more aggressive than the Torsen but I have not heard anything bad about the TRD LSD. What rear end do you have in your car right now? if its the stock sc auto rear end you might wanna get the auto TT 3.76 gearing or a GS400 rear end with a TRD LSD. I have a r154 with a auto TT diff. I like it but again I am not turbo charged yet.
I want to say that I am 80% sure that is your problem you just have too much power and with a open diff you have one wheel spinning and the other one isn't spinning as fast causing you to get the sway action in the rear. It probably doesn't help the situation if you have a the stock sc rear end as its geared highed
I want to say that I am 80% sure that is your problem you just have too much power and with a open diff you have one wheel spinning and the other one isn't spinning as fast causing you to get the sway action in the rear. It probably doesn't help the situation if you have a the stock sc rear end as its geared highed
#10
Lexus Test Driver
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The TRD LSD is used mainly for strenghthening and if I'm correct, it's 100% LSD at all times, meaning the two wheels turn simultaneously. There are no gearings involved with it, it's basically beefed up internals.
The TT Auto Diff is also a LSD but it's a Torsen Diff, which means that when one wheel senses that the other is slipping it catches up to spin at the same time. It was explained to me at one point that it's probably spinning together 90% - 95% of the time versus the TRD LSD at 100% of the time. The TT Auto Diff has 3.76 gearing as well.
A TRD LSD can be installed in a TT Auto Diff or a Six Speed Diff...
The TT Auto Diff is also a LSD but it's a Torsen Diff, which means that when one wheel senses that the other is slipping it catches up to spin at the same time. It was explained to me at one point that it's probably spinning together 90% - 95% of the time versus the TRD LSD at 100% of the time. The TT Auto Diff has 3.76 gearing as well.
A TRD LSD can be installed in a TT Auto Diff or a Six Speed Diff...
#12
1JZ Single SC400
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The TRD LSD is used mainly for strenghthening and if I'm correct, it's 100% LSD at all times, meaning the two wheels turn simultaneously. There are no gearings involved with it, it's basically beefed up internals.
The TT Auto Diff is also a LSD but it's a Torsen Diff, which means that when one wheel senses that the other is slipping it catches up to spin at the same time. It was explained to me at one point that it's probably spinning together 90% - 95% of the time versus the TRD LSD at 100% of the time. The TT Auto Diff has 3.76 gearing as well.
A TRD LSD can be installed in a TT Auto Diff or a Six Speed Diff...
The TT Auto Diff is also a LSD but it's a Torsen Diff, which means that when one wheel senses that the other is slipping it catches up to spin at the same time. It was explained to me at one point that it's probably spinning together 90% - 95% of the time versus the TRD LSD at 100% of the time. The TT Auto Diff has 3.76 gearing as well.
A TRD LSD can be installed in a TT Auto Diff or a Six Speed Diff...
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what tranny do you have? Get the auto TT diff or if you are happy with the gearing in your rear end just get a TRD LSD and be done. Look to spend about 1k for a rear end. Auto TT diff are 7-900 depending on the deal you get and a TRD LSD is 900-1k. You don't need a soarer rear end or wait to source one from japan.
Also a Supra auto 3.76 diff is in the $1200-1400 range and the 6spd 3.26JDM diff is in the $1500-$1700 range both are torsional.
All TRD parts have gone ^^^^ about 30% in the last approx 6-8 months.
#15
1JZ Single SC400
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TRD LSD is a clutch type and the auto TT is a torsen type. When you buy the TRD lsd its just the LSD no gears and anything and you use the gear that is in your car. Usually when you buy a auto TT LSD its a complete pumpkin so its more of a plug and play type. It is really up to you. The TRD LSD is stronger than the torsen LSD. Torsen is gear based and the TRD is clutched base. Clutch base LSD are a little more aggressive than the Torsen but I have not heard anything bad about the TRD LSD. What rear end do you have in your car right now? if its the stock sc auto rear end you might wanna get the auto TT 3.76 gearing or a GS400 rear end with a TRD LSD. I have a r154 with a auto TT diff. I like it but again I am not turbo charged yet.
I want to say that I am 80% sure that is your problem you just have too much power and with a open diff you have one wheel spinning and the other one isn't spinning as fast causing you to get the sway action in the rear. It probably doesn't help the situation if you have a the stock sc rear end as its geared highed
I want to say that I am 80% sure that is your problem you just have too much power and with a open diff you have one wheel spinning and the other one isn't spinning as fast causing you to get the sway action in the rear. It probably doesn't help the situation if you have a the stock sc rear end as its geared highed
Thanks everyone for their contribution on this thread. I believe also that it is due to the rear end as well. I will get under it tomorrow and double check all the bushings and in the drive train including the rear end bushings. Maybe this is a contributing factor as well.