thedoc302

My SC is currently at sound performance having a few odds n ends done before they tune it. The car has a r154 and once tuned it should make between 6-700whp. The problem is the car still has the stock open diff and i need to find something w/lsd. So i'm wondering what you guys think,what are my options? Thanks for you help.

2JZ4lyfe

Try to find a 3.77 open diff and install a 1.5/2 way lsd. (tomei, cusco, trd, kaaz etc..) I wouldn't bother with a torsen at that hp level.

Ali SC3

iTrader: (10)

what type of driving do you plan to do with the car? really need more info, there are a variety of gear ratios you could go with.

all of the following, the whole pumpkin will bolt into the SC chassis.
the most popular is the 2jzgte auto 3.76 as you can just buy that and drop it in and it has factory lsd.

the tt auto ones are getting hard to find in good shape at a reasonable price, so these days alot of people are just buying open diffs in the right ratio and installing an aftermarket like kaaz, cusco etc...
if you like closer gearing, the 92-96 sc400 diff's are available everywhere and have a 3.92.... on the other extreme if you like highway driving and want your pull to last longer, you can use a 97+ sc400 diff (also gs430) and its a 3.26. you can drop an aftermarket lsd into either of these. 3.92 is probably the safer bet though for street driving, most people use the 3.2 on 6 speeds but some people love the r154 3.2 combo once you get in boost it gets moving. the 3.76 on the tt auto is said to be quite well matched to the r154, but they are usually more expensive and have stock lsd, but if you can find a good one they are a drop in no fuss solution.

The only diff's that are different in the chart below, are the 2jzgte manual transmission diffs with the 3.1 ratio. they have a larger casing, ring gear, and lsd has more bolt holes, so they are not compatible with all the others ones.
All the other ones but the gte manual trans ones, you can drop an aftermarket LSD into.

also I changed the year range for the sc400, 98 is when it actually got vvti as far as I know it was not 97 like the other threads say.
the vvti one is the one that is 3.2 ratio as it has the 5 speed auto trans, basically if it has the 5 speed trans its going to be a 3.26 and is also found on the GS models too.

92-97 SC300
6 cyl, AT (4.27 ratio)
6 cyl, MT (4.08 ratio)

98-00 SC300
6 cyl, AT (4.27 ratio)

92-97 SC400
8 cyl (3.92 ratio)

98-00 SC400
8 cyl (3.266 ratio)

92-96 MKIV Supra

w/o turbo; (4.27 ratio) Limited Slip
w/o turbo; (4.27 ratio)
w/turbo, MT (3.133 ratio) Limited Slip
w/turbo, AT (3.769 ratio) Limited Slip

97-98 MKIV Supra
w/o turbo; (4.08 ratio) Limited Slip
w/o turbo; (4.08 ratio)
w/turbo, MT (3.133 ratio) Limited Slip
w/turbo, AT (3.769 ratio)
w/turbo, AT (3.769 ratio) Limited Slip

Deegee

iTrader: (1)

To piggyback on this thread, which LSD would be ideal for some drifting around 4-500HP range?

I've also heard that the Subaru BRZ diff would work in these cars, is that true? Welded isn't an option for me currently.

thedoc302

Thank you for the info, I want something i can drive daily but it won't be a drift car or anything. I'll probably take it to the 1/4 track once in a while but thats about it. It will be doing a decent amount of highway driving so i don't want my rpms super high. I'd like a direct replacement that can safely hold my power level and that doesn't kill my wallet. Now that you know a little more what do you recommend? Thanks agian

Ali SC3

iTrader: (10)

Deegee, power range wont come into play that much but you will want to pay attention to whether they are 1.5 way or 2 way. That will change how it acts when you start drifting, and also when you want to stop your drift.
The less expensive units are the 2 way which are more "aggressive" for drifting, the more expensive ones you can get in 1.5 way which I have read some people prefer for the street.
I have not run them so I couldn't tell you which one is right for you, but there are plenty of threads where people discuss it and a whole drifting section on SF, I would start reading all of those and asking questions.

thedoc, I would probably go for the 3.92 from a sc400 and drop an aftermarket unit in, unless you can find a TT auto that is 3.76 (getting harder to find).
you may find the 3.2 a little too low rpm wise for 1/4 mile, but then again with 700hp it could work.
I think Kahn (moderator on here) has run both the 3.9 and 3.7 with his r154 so maybe ask him what his opinion is on the matter.
you can ask 10 different people and get 10 different answers on gear ratios, everyone likes it a certain way so you will have to factor in what you prefer and availability.

what SC do you have sc400 or sc300... if sc300 was it auto originally or manual?
most people want to be in the 3 something range with the r154 for what you described, so if you have a sc300 auto then you probably want to swap it out cause the 4.27 is going to rev pretty high on the highway.
for reference my sc300 manual has the 4.08 and the gear ratios between my w58 and the r154 are pretty similar, and I think that mine revs too high on the highway already... 3rd flys by pretty quick and 4th could def be longer... and I am only in the 4-500 range power wise.
if you have an sc400 then the stock 3.92 might be a good place to start with an lsd, drive it and see how you like it and if you do then drop an lsd in there.
The 3.76 is pretty much on the money if you can find one of those, I haven't anyone complaining about going with the 3.76 for all around usage.
The 3.2 you will need enough power to turn that and with 700hp you are in that range so its something to consider especially if you don't want to shift as much.

the good part is you can swap your lsd into any of the pumpkins above except for the 6speed gte manual one, so if you don't like a ratio its just labor cost to change it over.

Golden95SC

iTrader: (21)

Awesome information! the TT auto is definitely a good choice

KahnBB6

iTrader: (5)

^^^ This and everything Ali has stated above Especially regarding what ratios are available, what diff fits into what pumpkin and the power needed to drive them. That's pretty much it in a nutshell. Thanks Ali!! ^^

The Torsen T-1 (1.5-Way gear type LSD) found in Supra MKIV TT Automatic 3.769:1 differentials is generally good for up to 500whp. It can take a bit more but it is considered not as safely predictable beyond that power output. Above 500whp it should be upgraded anyway. There is a unicorn JDM-only Torsen T-2 (also 1.5-Way gear type) that later JDM MKIV's and JDM Soarer 2.5 GT 5-speeds came with which has an improved design but those are even harder to locate for sale than TT Auto Torsen LSDs.

Below the 500whp number and with respect taken with driving style in rainy conditions the Torsen is a great daily driver LSD. You hardly know it's there once you get used to it. It only needs regular diff oil changes as per the TSRM and SC300/400 or MKIV service schedule dictates.

This is actually not true, sorry. The FR-S and BRZ Torsen center is actually far more similar to the design used in the 2001-2005 IS300, 2006-2012(?) IS250, 1986-1992 MKIII Supra and last generation Toyota Cressida (~1992 last year). However even though there is this similarity between the rear diffs of those models the spline counts and possibly axle designs still have minor but nonetheless significant variances making it difficult to mix and match. This was explained to me by the guys at Driftmotion when I brought up the very similar diff design.

But none of the factory Torsen LSDs that came in those cars will fit the SC300 / SC400 / Z30-Soarer / GS (aka Aristo) / MKIV Supra NA & TT Auto & JDM TT/6 small diff / SC430 200mm pumpkins.

Further, there was a thread a while back that compared our common 200mm differential pumpkins to the rear diff and pumpkin that came in the first generation IS-F sedans. There are some very distinct similarities but as you'd guess it's still too different to use either the pumpkin or IS-F Torsen LSD.


What I have in my car is a Supra MKIV TT Auto 200mm rear pumpkin, the Torsen T-1 that it originally came with and a 4.272:1 ring and pinion I had the entire thing professionally rebuilt with. I ran this with my original W58 and now an R154. I use a Yellr YellowBox V4 speedo corrector at the VSS connector.

I did this back in 2011 because it's taken several years and counting to get a Cali-legal boosted engine finished to swap over and I am still running a bone-stock 225hp NA engine. I didn't like how the 4.083 gearing made for 2nd being too aggressive and 3rd being too lax when driving on mountain roads (this only changed so much once I swapped in the R154) and the 3.769:1 ratio would have made the car accelerate like a dog with no turbocharger boost. I have the 3.769:1 ring and pinion in storage to have re-installed once I have the new engine swapped in.

I made a thread on this a while back explaining the reasoning:
https://www.clublexus.com/forums/per...rset-swap.html

^^^ I agree with you, Ali. Though I have not yet been able to do it myself the consensus for turbo R154 SC's seems to be a 3.xxx ratio diff.

I made an inquiry thread about this on SF also:
http://www.supraforums.com/forum/sho...ch-well-or-not

4.083:1 (4.08) was used in the SC300 5-speeds because it was sporty but not quite as racy as 4.272:1 in the near identical Supra MKIV NA 5-speeds. More suitable for a "Lexus". Also, since it's the same ratio 5-speed 1JZ Soarers came with from the same assembly line it was both a no-brainer for Toyota to carry over and also a better match for the 2.5L higher revving 1JZ-GTE engines which saw *most* of their driving around town or below 70mph on Japanese highways. The Soarers get away with it in terms of acceleration due to their turbo(s) and they get away with slightly better fuel economy due to the lower displacement. I got the impression that people like the 4.083/1JZ-GTE/R154 factory combination up through BPU power levels. For USDM SC's getting the turbo treatment with our 3.0L engines it's not as ideal.

4.272:1 (4.27) was only ever used in naturally aspirated Auto and W58 applications. That's why I used it. For now. I can attest that it will work fine with an R154 but without boost you do feel that you are driving much beefier gears that are overkill for NA 225hp. The lighter W58 is much better suited to this ratio against an NA engine especially on the highway.

3.916 (3.92) was used in both the SC400 and JDM 4.0L Soarer but also in the JZZ30 Soarer 1JZ-GTE Automatics. Due to it being more available than a TT Auto (or JDM Aristo V300 2JZ-GTE cars) 3.769 diff and a little more aggressive I considered using this. I think it is a popular budget option for turbocharged A/T or M/T SC300's be they NA-T or GTE swapped.

3.769 (3.77) was only used in the Supra MKIV TT Auto (USDM/UK/JDM) and JDM Aristo V300 2JZ-GTE's).

3.26 is only found in 4.0L VVT-i cars (GS430, SC430) and in the "6-speed small diff" (same 200mm casing as ours) ratio used in JDM MKIV 6-speeds for certain years. I think it's far too low a ratio unless you have a V160/161 or as Ali SC3 says are in the 700whp ballpark. It's definitely not an around town gear if you use it with an R154.


^^ This is generally what I've heard as feedback from others as well: 4.083 works and it *IS* a good ratio (also for people considering the Grannas Tremec Magnum 6-speed transmission) but with a W58 or R154 turbocharged car it revs too much on the highway.

...when you have a turbo.

For NA use I feel it's an acceptable tradeoff with only five forward gears: you get better around town acceleration, 1st is very aggressive but still useable for its purpose, 2nd, 3rd and 4th are all pulling more RPMs through each gear than before, it can still be driven in a very docile "Lexus-like" manner when desired, and highway pulling in 3rd, 4th and in some cases 5th is improved. Highway passing power is improved. With only 3.0L naturally aspirated and 225hp at the crank it turns the SC300 from a slow dog to an adequately quick car. Not in a million years like a turbo car... just better all around. The price you pay of course is cruising RPMS. After you have run the speedo corrector 5th gear in the R154 @ 70mph is right about 3,000 RPM. 5th gear @ 80 mph is right about 3,500 RPM. 5th gear @ 90 MPH is 4,000 RPM on the dot. On long highway trips it is best to stay at 80mph or even 70mph for better fuel economy.

1993.5-1996 Supra NA 5-speeds all came with 4.27 ratios from the factory so it is a legitimate combination from Toyota.

For turbo with a 5-speed I really feel 3.92 and 3.77 are probably going to be the best unless you are pushing a very big turbo and a lot of power. Although I'd love to try a 1JZ-GTE VVT-i and R154 with a 4.08.

....

Now as for 1.5-Way LSD's you only have Toyota factory Torsen T-1's, unicorn JDM factory Torsen T-2's and OS Giken's Super Lock. AFAIK.

2-Way TRD LSD's have been discontinued but are out there for sale occasionally. In the past they have been the recommended upgrade for 500whp+ JZ cars. Very good track record.

2-Way's are also available from Kaaz, Cusco, OS Giken and... I'm not sure who else...?

....

thedoc302, since you say you'll be running a 700whp engine I think it's a toss-up between an ideal 3.77 ring and pinion and a GS 3.26. If you are building a highway pulling monster with the best engine response above 3500-4000rpm for high speed then the 3.26 may be best. If you do a mix of daily and technical track driving with your car then the 3.77 may be the best choice.

Aside, at that power level you really should have your R154 built and upgraded with Marlin Crawler and Driftmotion parts. You'll also have an easier time at 700whp if you have a tripod R154. Monitor your rear tailshaft seals and shifter seals especially if you have an early version from a '91-'93 Soarer or MKIII Supra Turbo. Remember that the general ceiling for R154's is about 700-750whp before you should be careful. Currently there is no replacement for 3rd gear assemblies if something should go wrong even with a built R154.

You might also want to consider the Nissan 350Z CD009 6-speed or especially the Grannas conversion kit to run a Tremec Magnum 6-speed (a VERY beefed up version of the Tremec TR6060 found in the Mustang GT500, Camaro ZL1, Cadillac ATS-V, old CTS-V and Viper among others that is rated for a minimum 700ft-lbs of *constant* torque) if you are going to run at those boost levels regularly.

RXRodger

iTrader: (2)

Will drop in with one significant change, you have to swap the input flange from your diff. They are very close, so don't just look at them and assume they are the same, there is only like 1/2" difference in bolt circle.

KahnBB6

iTrader: (5)

^^^ Yes!! Thank you for mentioning this, RXRodger! I forgot about that.

IIRC the difference should be that the spread between the driveshaft bolt holes for the SC/Soarer flange is 101mm. The MKIV flange has a spread of 111mm between those bolt holes.

The MKIV diff companion flange should also be the same as the GS/Aristo diff companion flange (111mm) so this would also apply to swapping a GS430 3.26 pumpkin into an SC.

To swap over the flanges there is a specific torque setting required by using a dial torque wrench (you don't want to use a normal torque wrench)... and you can't just slap it on without proper torque. The reason for this is so as not to potentially upset the precise alignment depth of the pinion gear and ring gear tooth engagement inside the differential. Not a hard procedure but it still has to be done right. It is the same procedure in the TSRMs for the SC300, SC400 and MKIV Supra NA & TT Auto models (but excluding the MKIV 6-speed models).

Ali SC3

iTrader: (10)

Yeah my recommendations in the 3.xx range were assuming a turbo charged 2jz.
If you don't have a turbo then the stock 4.08 is pretty nice or go with the 4.27 for even better acceleration, these motors can handle being revved that high even on the highway.

oh and yes I did forget to mention you have to swap the companion flange at times but that is not difficult.

76mmturbo

iTrader: (6)

What's the best diff for the cd009 swap. Would the same for the R-154 be recommended for this also? I'm looking to pick up a 3.26 with a 1.5 lsd for my cd009 swap. Will be used for road course and highway runs for the most part not to much drag.

Ali SC3

iTrader: (10)

cd009 is basically geared like a v160, so you would want the 3.2 ratio and it would be like a stock supra tt gearing. That is the only ratio I would use with the cd009 or v160, unless you drop some $$ on the larger 220mm gte manual 3.13 diff.

the 5 speeds like the w58/r154 are spaced more appropriate for a higher rear end ratio, and the 6 speeds like cd009/v160 are spaced more appropriate for the lower rear end ratio.

There are exceptions, like the magnum t56 6 speed is spaced differently, its gearing is lower than a v160 so to make them act similarly, you would go with a higher rear end ratio with this transmission, something like the stock 5 speed rear end or the auto rear end.

scblackout

iTrader: (2)

Was the TRD only available in a 2 way configuration? I'm asking because while I have the stock 200mm torsen, it is known to not work so well above 500hp which is not going to work for me. So, I am going to swap it out for either a TRD or Giken. I've read obviously great threads on the TRD and if it is indeed only a 2 way, I would have expected to hear lots of complaints for street use, but really there aren't any, seems everyone loves it. While I have never driven a 2 way setup, I have driven with a welded diff and hated it. As to the Giken, I have found very little info in the sc/supra community, although there is plenty of great info on the bmw and miata forums. Seems they are quite popular on those platforms.

Given the choice of a 2 way TRD, vs. a 1.5 way Giken, which would be the best for an 80/20 track use car? -- assuming no 1.5 way TRD was never available....

Ali SC3

iTrader: (10)

it seems like the most affordable option for a new lsd is the Kaaz 2 way, anyone here with first hand experience of these or other aftermarket units..