SC300 W58 manual 4.08 to 4.27 gearset swap
11-11-11, 05:28 AM
#62
my car just has the stock sc300 auto diff. i believe its a 4.27 if i remember what u all typed correctly.
i am still in the process of completing the swap. im just down to little minor details. but many people from this board recommend using the 3.92 from a V8 SC400. because it matches the r154 and one guy said. "both" wheels spin...
i am still in the process of completing the swap. im just down to little minor details. but many people from this board recommend using the 3.92 from a V8 SC400. because it matches the r154 and one guy said. "both" wheels spin...
11-11-11, 10:27 PM
#63
A 3.92 is a good ratio for your car. The stock Soarer 1JZ diff ratio is 4.083 just like SC3 5-speeds, so, pretty close. An SC400 diff is open, though. I've heard of some open diff Lexus rear ends laying down two strips of rubber under certain conditions but they are still open differentials.
Another accepted ratio for 1JZ swap cars is the 3.769:1 that Supra TT Auto diffs have.
Your stock 4.27 will definitely not be what you want for your 1JZ application. I am only using it because I'm not going turbo and can use the extra revs for a modest improvement in drivability.
Another accepted ratio for 1JZ swap cars is the 3.769:1 that Supra TT Auto diffs have.
Your stock 4.27 will definitely not be what you want for your 1JZ application. I am only using it because I'm not going turbo and can use the extra revs for a modest improvement in drivability.
11-12-11, 09:52 AM
#65
EDIT: Theoretically with the 275/40-17's I have currently it should be 155mph at 6800rpm. With 255/40-17's it would be 151mph. On Supraforums the 5-speed NA people claim around 148mph realistically before you start hitting the rev limiter. I doubt I'll take it that high up anyway.
It won't suck any more than a stock Supra 5-speed sucks over 50mph. With the 4.083 in fourth it's a slug until you hit 65 mph. Downshifting to 3rd helps but I feel like it needs the 4.272 gears to pull better. My last car, a Prelude, ran at 3500rpm in 5th gear at 70mph. Yeah, I felt like it needed a 6th gear too but it had all of its pull on the highway and I loved that about it. I hated the low end acceleration, a problem the SC has to a far lesser degree due to its torque. Less aggressive gearing in that car would have been totally unacceptable.
As long as my car is NA I think it will be fine. Then again, I drive my SC like it's an old muscle car rather than a cruising luxury car if that is any indication as to why a 4.272 would appeal to me.
It won't suck any more than a stock Supra 5-speed sucks over 50mph. With the 4.083 in fourth it's a slug until you hit 65 mph. Downshifting to 3rd helps but I feel like it needs the 4.272 gears to pull better. My last car, a Prelude, ran at 3500rpm in 5th gear at 70mph. Yeah, I felt like it needed a 6th gear too but it had all of its pull on the highway and I loved that about it. I hated the low end acceleration, a problem the SC has to a far lesser degree due to its torque. Less aggressive gearing in that car would have been totally unacceptable.
As long as my car is NA I think it will be fine. Then again, I drive my SC like it's an old muscle car rather than a cruising luxury car if that is any indication as to why a 4.272 would appeal to me.
realized it before but just came back to me. My car red lines right after 6k, causing a lower rev limit. On 19's I'm putting my top right around 140 maybe 150 but with the information above it may be less. We shall see how the top speed factors in at the track for now it seems to pull well. The pull is definitely a fun factor as you said, I can roll into second and I'm really enjoying 3rd-4th gear
11-12-11, 04:34 PM
#66
It can be done I believe it has been. They all have the same rear(gs300 400 430) but I'm not sure on GR
6800 RPM redline realized it before but just came back to me. My car red lines right after 6k, causing a lower rev limit. On 19's I'm putting my top right around 140 maybe 150 but with the information above it may be less. We shall see how the top speed factors in at the track for now it seems to pull well. The pull is definitely a fun factor as you said, I can roll into second and I'm really enjoying 3rd-4th gear
6800 RPM redline
realized it before but just came back to me. My car red lines right after 6k, causing a lower rev limit. On 19's I'm putting my top right around 140 maybe 150 but with the information above it may be less. We shall see how the top speed factors in at the track for now it seems to pull well. The pull is definitely a fun factor as you said, I can roll into second and I'm really enjoying 3rd-4th gearTo me, from a seat of the pants perspective 6800rpm feels high on these engines. FEELS that way so I don't want to push it that far. I don't race mine on a track though so I'm biased. Yes, additional pull/response does have a strong factor in my project. My speedo will be off for a bit until I install a Yellow Box but I figure that the under-read from the 275's for a year of driving will make up for that on my odo. It's so marginal but I want to correct it.
When I eventually switch down to 255's I'll have a 5.16% inaccuracy, which is about 5-6mph so I want to have it corrected by then.
Are you also running a 4.272?
Last edited by KahnBB6; 11-12-11 at 04:38 PM.
11-12-11, 04:52 PM
#67
i only ask. because i have yet to confirm whether those GS430 diffs came with LSD since they are a bit newer than the older 400 diffs out there.
as a lower cost option, getting a diff from one of those with LSD versus the over priced diffs that those greedy used imported part resellers ask for them.
feel me?
as a lower cost option, getting a diff from one of those with LSD versus the over priced diffs that those greedy used imported part resellers ask for them.
feel me?
11-12-11, 06:25 PM
#68
i only ask. because i have yet to confirm whether those GS430 diffs came with LSD since they are a bit newer than the older 400 diffs out there.
as a lower cost option, getting a diff from one of those with LSD versus the over priced diffs that those greedy used imported part resellers ask for them.
feel me?
as a lower cost option, getting a diff from one of those with LSD versus the over priced diffs that those greedy used imported part resellers ask for them.
feel me?
http://www.varioustopics.com/lexus/9...l-is-lame.html
To my knowledge, the only USA model Lexus cars that had factory Torsens are certain IS300's (optional on M/T and A/T) and on later model IS-F's. The LF-A may use a Torsen or more likely something electronic.
Your best bet will still probably be finding a Supra TT Auto Torsen or full pumpkin. Alternatively, you could go with a TRD LSD which is a 2-way but which will be brand new and so I hear will be easier to drive with than a Kaaz 2-way LSD. OS Giken 1.5-way is the best one I've heard of for its drivability in road and track/course conditions but it's about $1800 just for the part. None of those will be cheap options but they're the only alternatives to an already expensive one.
If you're set on a Torsen, you have to be patient and pay attention to our classifieds here and on Supraforums. They DO show up but they go quickly. Unfortunately the prices are not cheap but sometimes they will go for less than the usual $1k. It really depends on the seller.
On newer vs older diffs. For what it's worth, these Lexus differentials are quite tough. They will not be LSD but the gear sets themselves are very strong. It turned out that the SC300 Auto 4.272 open pumpkin that I had cannibalized had better side carrier bearings than the TT Auto pumpkin I had worked on. That is probably due to the TT pumpkin having taken more abuse than the Lexus pumpkin ever saw.
Both, however, are extremely durable.
Based on that link and having already done a lot of scouring already, I don't believe any GS430 had LSDs standard or as an option. The upcoming GS350 may but that will be a first.
EDIT: It won't be easy to find or cheap but the LSD rear ends from JDM Toyota Aristos (same as GS300 only with 2JZGTE's) would also bolt up. I don't know the gear ratios on those but they only came in automatic. Also, Soarers had T-2 Torsen LSDs on some models but those are quite rare and pricey if even available.
Last edited by KahnBB6; 11-12-11 at 06:53 PM.
11-12-11, 07:08 PM
#69
^^ I just emailed you, JDMparts.
Gear oil will be my next small project after actually installing the diff. Supra TT guys apparently like Redline Heavy Shockproof gear oil in their cars so I plan to follow suit. I believe it's 80W-90. There is even a handy writeup for it with pictures:
http://www.supraforums.com/forum/sho...+HD+Shockproof
ADDENDUM: I've just been informed that, based on the recommendation of Curt Aigner of Elmhurst Toyota, people running factory Torsen LSD's use standard Toyota or other equivalent 75w-90 gear oil. Redline HD Shockproof is not needed. GM LSD modifier is not needed either. Other types of LSD's likely would require non-standard oils or additives.
EDIT: And yet another installation guide from Planetsoarer.com:
http://planetsoarer.com/diff/diff.htm
Now I just need to find 2-3 quarts of the stuff for my dry diff...
Gear oil will be my next small project after actually installing the diff. Supra TT guys apparently like Redline Heavy Shockproof gear oil in their cars so I plan to follow suit. I believe it's 80W-90. There is even a handy writeup for it with pictures:
http://www.supraforums.com/forum/sho...+HD+Shockproof
ADDENDUM: I've just been informed that, based on the recommendation of Curt Aigner of Elmhurst Toyota, people running factory Torsen LSD's use standard Toyota or other equivalent 75w-90 gear oil. Redline HD Shockproof is not needed. GM LSD modifier is not needed either. Other types of LSD's likely would require non-standard oils or additives.
EDIT: And yet another installation guide from Planetsoarer.com:
http://planetsoarer.com/diff/diff.htm
Now I just need to find 2-3 quarts of the stuff for my dry diff...
Last edited by KahnBB6; 11-13-11 at 10:42 AM.
11-13-11, 10:21 AM
#70
^^ I just emailed you, JDMparts.
Gear oil will be my next small project after actually installing the diff. Supra TT guys apparently like Redline Heavy Shockproof gear oil in their cars so I plan to follow suit. I believe it's 80W-90. There is even a handy writeup for it with pictures:
http://www.supraforums.com/forum/sho...+HD+Shockproof
EDIT: And yet another installation guide from Planetsoarer.com:
http://planetsoarer.com/diff/diff.htm
Now I just need to find 2-3 quarts of the stuff for my dry diff...
Gear oil will be my next small project after actually installing the diff. Supra TT guys apparently like Redline Heavy Shockproof gear oil in their cars so I plan to follow suit. I believe it's 80W-90. There is even a handy writeup for it with pictures:
http://www.supraforums.com/forum/sho...+HD+Shockproof
EDIT: And yet another installation guide from Planetsoarer.com:
http://planetsoarer.com/diff/diff.htm
Now I just need to find 2-3 quarts of the stuff for my dry diff...
.+1 on redline shockproof its thick and works great, the best part is pumping it in!
11-13-11, 10:53 AM
#71
Yes I'm running the 4.27 as well, only because I'm not focusing on my rear ATM. I have a 4.08 as well and might pick up a 3.26 but not sure if I need that... The last time I put my diff in it took 3 people, I tend to do work in my garage so i haven't tried to mess with it since.
+1 on redline shockproof its thick and works great, the best part is pumping it in!
.+1 on redline shockproof its thick and works great, the best part is pumping it in!
11-13-11, 11:04 AM
#72
I can't believe people don't do the MKIII 8.0" LSD carrier, in the SCXX Pumpkin.
Toyota put the 8" into every RWD vehicle they made. Except the V160 MKIV, that is a 8.7" Diff.
The Turbo MKIII Diff comes in either 3.90 or 3.73, and you can get them for $150 all over the place.
Two birds, one stone.
That's what I'm going to do at least.
Toyota put the 8" into every RWD vehicle they made. Except the V160 MKIV, that is a 8.7" Diff.
The Turbo MKIII Diff comes in either 3.90 or 3.73, and you can get them for $150 all over the place.
Two birds, one stone.
That's what I'm going to do at least.
11-13-11, 11:23 AM
#73
Neat! I think it will be easy to figure out what ratio you like based on (I am assuming) what turbo setup you'll eventually be going with. Also consider the 3.769 ratio. A TT Auto Open pumpkin will have that and be far cheaper to buy than an LSD version. 3.26 is probably going to be better suited to a Getrag since it's so close to the Supra 6-speed ratio.
I can't believe people don't do the MKIII 8.0" LSD carrier, in the SCXX Pumpkin.
Toyota put the 8" into every RWD vehicle they made. Except the V160 MKIV, that is a 8.7" Diff.
The Turbo MKIII Diff comes in either 3.90 or 3.73, and you can get them for $150 all over the place.
Two birds, one stone.
That's what I'm going to do at least.
Toyota put the 8" into every RWD vehicle they made. Except the V160 MKIV, that is a 8.7" Diff.
The Turbo MKIII Diff comes in either 3.90 or 3.73, and you can get them for $150 all over the place.
Two birds, one stone.
That's what I'm going to do at least.
11-13-11, 11:25 AM
#74
I wasn't aware the MKIII LSD would fit our rear pumpkins. Something about the length of it not being the same despite both cars technically using "8-inch" LSD's. I have, on the other hand, heard of Lexus IS300/IS250 owners using the MKIII LSD's because their cars apparently use the same or similar rear carrier.
Keep in mind too that only certain year MK3's actually used Torsens, and I don't know whether or not they were used on Turbos or Sport Package NA's. Most MKIII Turbos used clutch-type LSDs that tend to wear out quickly, warranting service or replacement with a TRD style unit.
Keep in mind too that only certain year MK3's actually used Torsens, and I don't know whether or not they were used on Turbos or Sport Package NA's. Most MKIII Turbos used clutch-type LSDs that tend to wear out quickly, warranting service or replacement with a TRD style unit.
11-13-11, 11:27 AM
#75