diff problem please help
07-22-11, 07:19 PM
#16
first of all , i appreciate all the responses in this day and age i thought everyone was to themselves but neways the car is a 92 sc400, with a 1jz thats was making 440hp automatic on 15 pounds so it has boost, but converted to r154 5 speed and thr lower gears are short it revs so quick but doent go in boost at almost 6000 rpm so i really get nothing out of 1st and 2nd
07-22-11, 09:49 PM
#17
account2x
Quote:
Originally Posted by SC51 View Post
Lol not mine. Its more like a Jet that just keeps pulling
3.9 gave it a bit more torque (street fun), but I can sacrifice that for top end any day.
bit is an understatement
http://www.physicsforums.com/showpos...42&postcount=2
Gearing is all about torque manipulation. The JDM is rated 320 ft/lb of torque so I'll use that for this demonstration.
320 x 3.266 = 1,045
v160
3,999
2,466
1,761
1,371
1,045
829
r154
3,397
2,042
1,369
1,045
787
With 3.266 differential you'll lose 600 ft/lb of torque in 1st gear and 424 in 2nd gear.
Top speed is 155 mph @ 6800 rpm in 4th gear.
320 x 3.769 = 1,206
3,920
2,358
1,580
1,206
908
With the 3.769 differential you'll lose only 79 ft/lb in 1st gear and 108 ft/lb in 2nd gear compared to the v160.
Another way of looking is you'll gain 521 ft/lb in 1st gear and 319 ft/lb in 2nd gear compared to the 3.266.
Top speed is 134 mph @ 6800 rpm in 4th gear.
320 x 3.916 = 1,253
4,073
2,449
1,641
1,253
943
With the 3.916 differential you'll gain 74 ft/lb in 1st and and lose only 17 ft/lb in 2nd gear.
Or gain 674 ft/lb in 1st and 407 ft/lb in 2nd compared to the 3.266.
Top speed is 129 mph @ 6800 rpm in 4th gear.
Are you trapping higher 129 or 134 mph? If not the higher speed is compromising your acceleration. If so you're best off going with a v160 and 3.266 differential swap because of the inherent torque loss.
Quote:
Originally Posted by SC51 View Post
Lol not mine. Its more like a Jet that just keeps pulling
3.9 gave it a bit more torque (street fun), but I can sacrifice that for top end any day.
bit is an understatement
http://www.physicsforums.com/showpos...42&postcount=2
Gearing is all about torque manipulation. The JDM is rated 320 ft/lb of torque so I'll use that for this demonstration.
320 x 3.266 = 1,045
v160
3,999
2,466
1,761
1,371
1,045
829
r154
3,397
2,042
1,369
1,045
787
With 3.266 differential you'll lose 600 ft/lb of torque in 1st gear and 424 in 2nd gear.
Top speed is 155 mph @ 6800 rpm in 4th gear.
320 x 3.769 = 1,206
3,920
2,358
1,580
1,206
908
With the 3.769 differential you'll lose only 79 ft/lb in 1st gear and 108 ft/lb in 2nd gear compared to the v160.
Another way of looking is you'll gain 521 ft/lb in 1st gear and 319 ft/lb in 2nd gear compared to the 3.266.
Top speed is 134 mph @ 6800 rpm in 4th gear.
320 x 3.916 = 1,253
4,073
2,449
1,641
1,253
943
With the 3.916 differential you'll gain 74 ft/lb in 1st and and lose only 17 ft/lb in 2nd gear.
Or gain 674 ft/lb in 1st and 407 ft/lb in 2nd compared to the 3.266.
Top speed is 129 mph @ 6800 rpm in 4th gear.
Are you trapping higher 129 or 134 mph? If not the higher speed is compromising your acceleration. If so you're best off going with a v160 and 3.266 differential swap because of the inherent torque loss.
Thanks for the info, I'm not sure if I understand it all I kinda skimmed through it. I wasn't talking 1/4 mile times either. But I was just giving my personal opinion, being as Ive ran both of then and with my setup the 3.2 is faster. I just remember when I was running the 3.9 that there was like no 1st gear and 2nd just spun it was kinda un-fun. The other diff you can actually boost in 1st.
I'll have to post a vid as evidence once this disc is broken in
07-23-11, 01:57 PM
#18
I don't mean to doubt you but are sure you've actually driven with a 3.92 and you have a 3.27 right now? Your 1999 SC300 came with a 4.27 differential, are you sure you're not accidentally comparing? Are you also aware the differential needs to match the transmission with the further away you get the greater your speedometer error will be?
Top speed in 1st gear with the R154 3.92 would be 40 mph and with 3.769 41 mph. Top speed with the V160 3.27 in 1st gear would be 41 mph. As you can see the gearing is not dissimilar.
Top speed in 1st gear with the R154 3.92 would be 40 mph and with 3.769 41 mph. Top speed with the V160 3.27 in 1st gear would be 41 mph. As you can see the gearing is not dissimilar.
When I had the 3.26 diff installed it was completely the opposite almost to the point of being rediculous. The gears were far too tall and the car was a dog off the line. 3rd and 4th weren't bad although 5th was only good for highway cruising, but downshifts needed to do any passing or uphill driving.
07-23-11, 10:16 PM
#19
Pole Position
someone correct me if Im wrong...
4.083 is what you want if you are using a 1jz and a R154 to keep the speedo accurate (assuming you keep your Tire sizes to the same stock diamater as appropriate to the car the engine was pulled from)
the higher the number, the quicker the accelleration, but lower top speed,
the lower the number, the slower the accelleration, but higher top speed.
having the sc400 Diff is not all that far off from 4.083 and even the v8 guys notice a difference putting the Soarer TT diff (4.083) in their car and most enjoy it
4.083 is what you want if you are using a 1jz and a R154 to keep the speedo accurate (assuming you keep your Tire sizes to the same stock diamater as appropriate to the car the engine was pulled from)
the higher the number, the quicker the accelleration, but lower top speed,
the lower the number, the slower the accelleration, but higher top speed.
having the sc400 Diff is not all that far off from 4.083 and even the v8 guys notice a difference putting the Soarer TT diff (4.083) in their car and most enjoy it
07-24-11, 03:43 AM
#20
You are correct but the R154 came with multiple rear end ratios.
4.083 in the Soarer 1JZ-GTE R154.
4.100 in the Supra 1JZ-GTE R154. Closest equivalent is the SC300 4.083.
3.909 in the 87-88 Supra 7M-GTE R154. Closest equivalent is the SC400 3.916
3.727 in the 88-92 Supra 7M-GTE R154. Closest equivalent is the Supra Turbo Auto 3.769.
Unlike the Soarer no SC came with a limited slip differential. Putting a shorter differential can make a weaker vehicle slightly more powerful but it increases the chance of loosing traction. Coupled with the lack of LSD this is a big issue for anyone making good power. The decrease in RPM and increase in mileage is a nice secondary effect of lengthening the gearing.
4.27 is what all SC300 automatic come with.
4.08 is hard to find.
3.27 is cheap but far too tall.
3.77 is hard to find and expensive.
3.92 is the the most cost effective upgrade.
4.083 in the Soarer 1JZ-GTE R154.
4.100 in the Supra 1JZ-GTE R154. Closest equivalent is the SC300 4.083.
3.909 in the 87-88 Supra 7M-GTE R154. Closest equivalent is the SC400 3.916
3.727 in the 88-92 Supra 7M-GTE R154. Closest equivalent is the Supra Turbo Auto 3.769.
Unlike the Soarer no SC came with a limited slip differential. Putting a shorter differential can make a weaker vehicle slightly more powerful but it increases the chance of loosing traction. Coupled with the lack of LSD this is a big issue for anyone making good power. The decrease in RPM and increase in mileage is a nice secondary effect of lengthening the gearing.
4.27 is what all SC300 automatic come with.
4.08 is hard to find.
3.27 is cheap but far too tall.
3.77 is hard to find and expensive.
3.92 is the the most cost effective upgrade.
07-24-11, 07:51 AM
#21
account2x I don't mean to doubt you but are sure you've actually driven with a 3.92 and you have a 3.27 right now? Your 1999 SC300 came with a 4.27 differential, are you sure you're not accidentally comparing? Are you also aware the differential needs to match the transmission with the further away you get the greater your speedometer error will be?
Top speed in 1st gear with the R154 3.92 would be 40 mph and with 3.769 41 mph. Top speed with the V160 3.27 in 1st gear would be 41 mph. As you can see the gearing is not dissimilar.
Top speed in 1st gear with the R154 3.92 would be 40 mph and with 3.769 41 mph. Top speed with the V160 3.27 in 1st gear would be 41 mph. As you can see the gearing is not dissimilar.
But ya some of your info is wrong 98-00 vvti SC300's come with 3.9 rear. And for those who didn't know 98-00 vvyi SC400's come with a 3.2. Top speed in first gear is no where near 40mph when I had it in. And thats with 20" wheels which would make the ratio even longer. And the speedo is always 100% correct on my car and all 98+ SC's. It uses separate wheel sensors and ecu for the dash. 40mph in first seems more like my current setup. And I'm 100% its a 3.26.Like I said I'll just have to get some vids together.
07-24-11, 01:13 PM
#22
CARRIER ASSY, DIFFERENTIAL, REAR Manufacture notes: *FGR=47:11=4.272
SC300 came with 4.27. 98-04 GS300 came with 3.92.
I'll look into the ABS speed sensor. Count the differential ratio.
07-24-11, 04:12 PM
#23
Pole Position
You are correct but the R154 came with multiple rear end ratios.
4.083 in the Soarer 1JZ-GTE R154.
4.100 in the Supra 1JZ-GTE R154. Closest equivalent is the SC300 4.083.
3.909 in the 87-88 Supra 7M-GTE R154. Closest equivalent is the SC400 3.916
3.727 in the 88-92 Supra 7M-GTE R154. Closest equivalent is the Supra Turbo Auto 3.769.
Unlike the Soarer no SC came with a limited slip differential. Putting a shorter differential can make a weaker vehicle slightly more powerful but it increases the chance of loosing traction. Coupled with the lack of LSD this is a big issue for anyone making good power. The decrease in RPM and increase in mileage is a nice secondary effect of lengthening the gearing.
4.27 is what all SC300 automatic come with.
4.08 is hard to find.
3.27 is cheap but far too tall.
3.77 is hard to find and expensive.
3.92 is the the most cost effective upgrade.
4.083 in the Soarer 1JZ-GTE R154.
4.100 in the Supra 1JZ-GTE R154. Closest equivalent is the SC300 4.083.
3.909 in the 87-88 Supra 7M-GTE R154. Closest equivalent is the SC400 3.916
3.727 in the 88-92 Supra 7M-GTE R154. Closest equivalent is the Supra Turbo Auto 3.769.
Unlike the Soarer no SC came with a limited slip differential. Putting a shorter differential can make a weaker vehicle slightly more powerful but it increases the chance of loosing traction. Coupled with the lack of LSD this is a big issue for anyone making good power. The decrease in RPM and increase in mileage is a nice secondary effect of lengthening the gearing.
4.27 is what all SC300 automatic come with.
4.08 is hard to find.
3.27 is cheap but far too tall.
3.77 is hard to find and expensive.
3.92 is the the most cost effective upgrade.
You can also just grab a 10Bolt Torsen centre and have it installed in your current Diff..
07-24-11, 04:45 PM
#24
The American non-turbo JZA80 Supra's came with 4.27 up until 97. The next model year 1998 was the final year. Not all differentials are limited slip.
Currently a 4.083 is on eBay for 349.99 + 170 shipping. $520 is a big risk to take for a differential that may not be limited slip. I can find a SC400 differential locally for half the price easily and a quarter with some luck.
Currently a 4.083 is on eBay for 349.99 + 170 shipping. $520 is a big risk to take for a differential that may not be limited slip. I can find a SC400 differential locally for half the price easily and a quarter with some luck.
07-25-11, 04:49 AM
#26
Lexus Test Driver
iTrader: (44)
Join Date: Jan 2007
Location: Maryland /Germantown
Posts: 5,139
Likes: 0
Received 7 Likes
on
7 Posts
I don't mean to doubt you but are sure you've actually driven with a 3.92 and you have a 3.27 right now? Your 1999 SC300 came with a 4.27 differential, are you sure you're not accidentally comparing? Are you also aware the differential needs to match the transmission with the further away you get the greater your speedometer error will be?
Top speed in 1st gear with the R154 3.92 would be 40 mph and with 3.769 41 mph. Top speed with the V160 3.27 in 1st gear would be 41 mph. As you can see the gearing is not dissimilar.
Top speed in 1st gear with the R154 3.92 would be 40 mph and with 3.769 41 mph. Top speed with the V160 3.27 in 1st gear would be 41 mph. As you can see the gearing is not dissimilar.
And for your information 99 sc300 came with 3.92 just like the old SC400.
You still haven't prove me or anyone wrong here , you are just qoting what we talked about maybe 2-3 years ago.
You don't have any first hands experience so please stop posting on this thread .
Like i said till i see you driving or owning an SC with swap, i don't believe nothing you say sorry.
OP do not listen to this dude he doesn't know what his talking about
have a nice day..
07-25-11, 07:04 AM
#27
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
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
Don't worry about me, worry about yourself. I'll post what I have when I'm good and ready. Just you wait.
P.S. : Just because you say that [have a nice day] doesn't mean you get to say whatever you want to say to me. Ricky Bobby
07-25-11, 08:12 AM
#28
Lexus Test Driver
iTrader: (44)
Join Date: Jan 2007
Location: Maryland /Germantown
Posts: 5,139
Likes: 0
Received 7 Likes
on
7 Posts
Again i don't believe none you say, all do you is tell people don't do this , do this, don't do 1jzgte, do 1uzvvti, i have 1uz, do 2jzgte vvti what do you have or what are you doing we like to see and i know i am not the only one that like to see what your are working on or working with.
i don't beleive everything i read on here because we have alot people like you that thinks it's their job to spread wrong info on here without first hand experience.
You know everything, you answer for everything please be humble and just chill.
I can say whatever i want (That's what they call freedom of speech) what are you going to do? nothing so
that's you right there always quoting someone esle's reply what if scott made a mistake ? then what?
How about you get the diff and take it apart and maybe some people on here will believe you...
i am done feeding to your garbage peace..
i don't beleive everything i read on here because we have alot people like you that thinks it's their job to spread wrong info on here without first hand experience.
You know everything, you answer for everything please be humble and just chill.
I can say whatever i want (That's what they call freedom of speech) what are you going to do? nothing so
that's you right there always quoting someone esle's reply what if scott made a mistake ? then what?
How about you get the diff and take it apart and maybe some people on here will believe you...
i am done feeding to your garbage peace..
07-27-11, 10:04 AM
#29
Driver School Candidate
Thread Starter
so thanks guys I did actually learn something from everyones post, and im deciding to stick to the sc400 diff that i have,ill try it out and see ,n im tuning n dynoing this friday
07-27-11, 02:03 PM
#30
Lexus Test Driver
iTrader: (44)
Join Date: Jan 2007
Location: Maryland /Germantown
Posts: 5,139
Likes: 0
Received 7 Likes
on
7 Posts
Yes the SC400 diff works fine unless it was replaced by an SC300 diff maybe it went bad in the past before you owned the car .. who knows maybe that's what happen if your gears are too short.
I used 3.92 rear on my car 500rwhp and it was great for me i can cruise in 3rd with my R154.
I used 3.92 rear on my car 500rwhp and it was great for me i can cruise in 3rd with my R154.