Proper differential choice
12-30-21, 09:21 AM
#1
Driver School Candidate
Thread Starter
Proper differential choice
I hate to make a new thread on this topic but I知 looking for a few specific answers that I知 finding mixed results on. First, planning on swapping my soarer to a CD009 and was wondering if the factory 3.9 auto final drive would create drivability issues with the short ratio 6spd? I believe factory manual 350zs come with a 3.53. I daily the car and don稚 want to be cruising at 3500RPMs on the highway if that can be avoided. Seems like a good bet would be to get a differential with a lower drive like the 3.76 TT Supra or take the internals from a 3.6 LS400 differential. Curious to see what people who have done the swap are running. Was also wondering where our speed sensors are located. I致e found threads online saying they get it from the hub and others from the trans. If I dropped in a lower ratio diff before I swapped the trans would it screw up the speedo? Thanks
12-30-21, 07:30 PM
#2
The VSS 3-wire speed sensor is located on the transmission on these cars. With a CD009 you will have to use either a wheel somewhere on the driveshaft or at the differential with a hall effect sensor or you'll have to use a GPS-based speed sensor.
As to which drive ratio you should use that will come down to which engine you have and what state of tune you have it in.
The Supra TT Auto 3.76 ratio (also found in some model years of the SC430 with an open diff only) is very good when paired with an R154's ratios. I run that combination myself and it's very good all around as a balance between streetability and highway cruising. The 1989-1995(?)ish LS400 3.615:1 ring and pinion should be usable as well if you harvest those parts and do a full differential rebuild with an SC diff housing and axles.
Your other available ratios are of course 4.272:1, 4.083:1, 3.916:1, 3.266 and even supposedly 2.937:1 from a 2007-2017 Lexus LS460 as the very lowest available ring and pinion that is compatible.
To be clear, the early LS400's 3.615:1 and the LS460's 2.937:1 are *only* possible by removing the ring and pinion from either. You can't use the full differential housings from those cars in your SC, only the R&P.
It has been said that the CD009's ratios are somewhat close to that of a V160's ratios. For Export Supra MKIV's 6-speed final drive ratio was 3.133:1 (with the 220mm "big diff") so the 3.266:1 ratio that is compatible with our 200mm SC diffs may be a similar match if you have a turbocharged JZ engine in your build.
Some Supra MKIV TT 6-speed owners have commented that the factory ratio feels a bit long geared... and it is just a bit since it's set up as a high speed car. This might mean that instead of 3.266 you may want to consider the 3.615 ratio. But I would look up as many threads and builds with your intended engine, state of tune and CD009 combination to see what the prevailing consensus is on which final drive ratio is the most recommended.
A limited slip differential is recommended anyway if you have a turbo. A Supra MKIV TT Auto / Aristo / Soarer Torsen T-1 LSD is great (I run one myself at a mild 350hp) however if you'll be making 600whp+ out of the gate you should look at aftermarket diff options in a used TRD, Kaaz, Cusco, or OS Giken.
As to which drive ratio you should use that will come down to which engine you have and what state of tune you have it in.
The Supra TT Auto 3.76 ratio (also found in some model years of the SC430 with an open diff only) is very good when paired with an R154's ratios. I run that combination myself and it's very good all around as a balance between streetability and highway cruising. The 1989-1995(?)ish LS400 3.615:1 ring and pinion should be usable as well if you harvest those parts and do a full differential rebuild with an SC diff housing and axles.
Your other available ratios are of course 4.272:1, 4.083:1, 3.916:1, 3.266 and even supposedly 2.937:1 from a 2007-2017 Lexus LS460 as the very lowest available ring and pinion that is compatible.
To be clear, the early LS400's 3.615:1 and the LS460's 2.937:1 are *only* possible by removing the ring and pinion from either. You can't use the full differential housings from those cars in your SC, only the R&P.
It has been said that the CD009's ratios are somewhat close to that of a V160's ratios. For Export Supra MKIV's 6-speed final drive ratio was 3.133:1 (with the 220mm "big diff") so the 3.266:1 ratio that is compatible with our 200mm SC diffs may be a similar match if you have a turbocharged JZ engine in your build.
Some Supra MKIV TT 6-speed owners have commented that the factory ratio feels a bit long geared... and it is just a bit since it's set up as a high speed car. This might mean that instead of 3.266 you may want to consider the 3.615 ratio. But I would look up as many threads and builds with your intended engine, state of tune and CD009 combination to see what the prevailing consensus is on which final drive ratio is the most recommended.
A limited slip differential is recommended anyway if you have a turbo. A Supra MKIV TT Auto / Aristo / Soarer Torsen T-1 LSD is great (I run one myself at a mild 350hp) however if you'll be making 600whp+ out of the gate you should look at aftermarket diff options in a used TRD, Kaaz, Cusco, or OS Giken.
Last edited by KahnBB6; 12-30-21 at 07:33 PM.
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chase711 (12-30-21)
12-30-21, 07:38 PM
#3
Driver School Candidate
Thread Starter
The VSS 3-wire speed sensor is located on the transmission on these cars. With a CD009 you will have to use either a wheel somewhere on the driveshaft or at the differential with a hall effect sensor or you'll have to use a GPS-based speed sensor.
As to which drive ratio you should use that will come down to which engine you have and what state of tune you have it in.
The Supra TT Auto 3.76 ratio (also found in some model years of the SC430 with an open diff only) is very good when paired with an R154's ratios. I run that combination myself and it's very good all around as a balance between streetability and highway cruising. The 1989-1995(?)ish LS400 3.615:1 ring and pinion should be usable as well if you harvest those parts and do a full differential rebuild with an SC diff housing and axles.
Your other available ratios are of course 4.272:1, 4.083:1, 3.916:1, 3.266 and even supposedly 2.937:1 from a 2007-2017 Lexus LS460 as the very lowest available ring and pinion that is compatible.
To be clear, the early LS400's 3.615:1 and the LS460's 2.937:1 are *only* possible by removing the ring and pinion from either. You can't use the full differential housings from those cars in your SC, only the R&P.
It has been said that the CD009's ratios are somewhat close to that of a V160's ratios. For Export Supra MKIV's 6-speed final drive ratio was 3.133:1 (with the 220mm "big diff") so the 3.266:1 ratio that is compatible with our 200mm SC diffs may be a similar match if you have a turbocharged JZ engine in your build.
A limited slip differential is recommended anyway if you have a turbo. A Supra MKIV TT Auto / Aristo / Soarer Torsen T-1 LSD is great (I run one myself at a mild 350hp) however if you'll be making 600whp+ out of the gate you should look at aftermarket diff options in a used TRD, Kaaz, Cusco, or OS Giken.
As to which drive ratio you should use that will come down to which engine you have and what state of tune you have it in.
The Supra TT Auto 3.76 ratio (also found in some model years of the SC430 with an open diff only) is very good when paired with an R154's ratios. I run that combination myself and it's very good all around as a balance between streetability and highway cruising. The 1989-1995(?)ish LS400 3.615:1 ring and pinion should be usable as well if you harvest those parts and do a full differential rebuild with an SC diff housing and axles.
Your other available ratios are of course 4.272:1, 4.083:1, 3.916:1, 3.266 and even supposedly 2.937:1 from a 2007-2017 Lexus LS460 as the very lowest available ring and pinion that is compatible.
To be clear, the early LS400's 3.615:1 and the LS460's 2.937:1 are *only* possible by removing the ring and pinion from either. You can't use the full differential housings from those cars in your SC, only the R&P.
It has been said that the CD009's ratios are somewhat close to that of a V160's ratios. For Export Supra MKIV's 6-speed final drive ratio was 3.133:1 (with the 220mm "big diff") so the 3.266:1 ratio that is compatible with our 200mm SC diffs may be a similar match if you have a turbocharged JZ engine in your build.
A limited slip differential is recommended anyway if you have a turbo. A Supra MKIV TT Auto / Aristo / Soarer Torsen T-1 LSD is great (I run one myself at a mild 350hp) however if you'll be making 600whp+ out of the gate you should look at aftermarket diff options in a used TRD, Kaaz, Cusco, or OS Giken.
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KahnBB6 (12-31-21)
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