3:27 rear end ratio with w58
09-13-09, 03:58 PM
#16
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The LSD unit should be independent of the LSD differential so you shouldn't have a problem as long as they make a unit that is compatible with the rear end that you are purchasing.
12-20-09, 04:21 PM
#19
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Im pretty sure im going to be putting in the 3.26 gears from a 98+ sc400 in my sc3 5spd soon and i wanted to know what i have to do to have the speedometer accurate to the new gears
12-20-09, 06:59 PM
#20
I did a few calculations to get the relative differences with tranny and/or diff swap. Here is what I came up with on stock 92-96 SC400 as baseline.
SC400 with auto and 3.92 diff = 0% 83.14 at 3000 rpm
SC400 with auto and 3.76 diff = +4.08% 86.68 at 3000 rpm
SC400 with W58 and 3.92 diff = -9.96% 74.86 at 3000 rpm
SC400 with W58 and 3.76 diff = -6.12% 78.04 at 3000 rpm
SC400 with W58 and 3.62 diff = -2.50% 81.06 at 3000 rpm
SC400 with w58 and 3.26 diff = +7.64% 90.01 at 3000 rpm
So if you want as close to stock as possible the 3.62 from a 90-97 LS400 would be the closest. The 3.26 seems a little long. Definitely need boost to make that work. For me the question is can I get LSD in the 3.62 or 3.26?
SC400 with auto and 3.92 diff = 0% 83.14 at 3000 rpm
SC400 with auto and 3.76 diff = +4.08% 86.68 at 3000 rpm
SC400 with W58 and 3.92 diff = -9.96% 74.86 at 3000 rpm
SC400 with W58 and 3.76 diff = -6.12% 78.04 at 3000 rpm
SC400 with W58 and 3.62 diff = -2.50% 81.06 at 3000 rpm
SC400 with w58 and 3.26 diff = +7.64% 90.01 at 3000 rpm
So if you want as close to stock as possible the 3.62 from a 90-97 LS400 would be the closest. The 3.26 seems a little long. Definitely need boost to make that work. For me the question is can I get LSD in the 3.62 or 3.26?
Has anyone ever swapped in an LS400 rear gear set into an SC3/400 housing? I actually just turned down a 3.62 entire rearend because it was not a direct replacement, is it just a simple ring and pinion swap and check the shim?
Turbos build boost based upon engine load dude.
The taller the gears the quicker and harder boost hits and you can stay in boost longer.
If you're only boosting to 12psi or something then you're not worried all that much about spool. But if you're boosting to 30... then you'll want to load that engine up for all it's worth.
The taller the gears the quicker and harder boost hits and you can stay in boost longer.
If you're only boosting to 12psi or something then you're not worried all that much about spool. But if you're boosting to 30... then you'll want to load that engine up for all it's worth.
For flat out accelreation, the shortest possible gears for the distance required is the best, now most of our SC's are not solely 1/4 mile cars so this may not apply to everyone.
For a good understanding of "too tall a gear" just think way back when you had a 10 speed bike, for some of us a 3.26. 3.31, or 3.13 would be like starting off in 10th gear nit was hard as hell to get going but once you did it was okay. the only worry is when you do get going will the race be over?
Also too long of a gear isnt too great for boosted cars as EGTs and tuning becomes a critical issue as time increases. We all have been told "dont boost 5th" as the gear is too tall and long, but if you lengthen your gears its almost as if 4th became 5th or worse.
I have a TH400 and i have only 3 gears, i currently have my stock 4.08(w58 car) and the gear is a tad too short, I have the choice of stretching out the gear or going to a larger tire(possibly a 28 in) I want to stay with my 26in mickey thompsons so i really wanna do a 3.77 or 3.62 to achieve the mph that is needed for my elapsed time.
12-26-09, 08:14 AM
#26
This is what I'm planing on using.
http://www.yellr.com/
I've got the R154/3.76/1JZ combo. I've contemplated swapping to the 3.92 ring gear as I think it'd be more fun on the street.
http://www.yellr.com/
I've got the R154/3.76/1JZ combo. I've contemplated swapping to the 3.92 ring gear as I think it'd be more fun on the street.
Last edited by RyanV; 12-26-09 at 08:20 AM.
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