differential ratio's

willfish

been here since 2003
Apr 23, 2005
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Nick M;958228 said:
LSD was standard on the turbo, an option on the GE. I had 4 7MGE W58's, only one was an open diff.

3.91 is what percent of 4.3. Answer that and you know what percent your speedo is off. ( I only gave you that answer because I know a nuke is smart enough to figure it out)



a "nuke" ? :biglaugh:

Will
 

Nick M

Black Rifles Matter
Sep 9, 2005
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Well, if you pull the cover, you will see a clutch pack on the side gears. It makes the gears roll over with the axle. With an open diff, the gears will walk around each other.

What that does is give the open diff equal torque to both wheels. Which is why it will spin one wheel if it is slippery.

The diff is needed to achieve different speed of th wheels in turns.

gtsfirefighter;958249 said:
No because every single NA I've had and have looked at did not have one. I'm sure someone here can produce the numbers but IIRC LSD only came on sport models na's.

Already covered, but I bought four 7MGE's east of the Mississippi, and 3 of 4 had the LSD, none were the sport option.
 

too_stand

Supramania Contributor
Jul 27, 2005
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I parted dozens of MK3's, I would say 40% of na's had lsd .The 89 turbo could have 3.73 or 3.91 , depending on date it was made, just like an 89 can have either the rubber mounts or the older steel ones. I have also noticed that some of the 89+ lsd's especially on cars with better than 140K have lsd's that no longer act like lsd, I guess through wear.
 

Dan_Gyoba

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Aug 9, 2007
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FYI, all Canadian spec NAs had limited slip.

The amount that the speedo/odometer will be out can be compared directly from the ratios. I had a 3.909:1 (87T) differential in my '89NA for a long time, and the speedo was 10% out. (3.909 X 1.1 = 4.300) so if my speedo said I was doing 100 km/h, I was doing about 110. For every 100km I put on my odometer, I actually travelled 110km. (And my odometer now reads almost 461,000. Yikes.)

For the 3.727:1 going to a 4.3, the speedo would be out about 15%, so if your speeds says that you're doing 64mph, you'll be going about 55mph.
 

gtsfirefighter

SM Expert on White trash
Sep 26, 2006
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BorHor;958251 said:
Nope it was an option. Must be a cali thing to have an LSD then hahah.

Big Wang Bandit;958252 said:
And it was an option. My NA had an LSD, but was a sport model. Boris's has an LSD, but isn't sport model.

Most NA's ive seen are LSD as well. Must be a CA thing


It must be.:biglaugh: Open diff must be a Texas thing. I've looked a bunch and none of 'em had LSD. I wonder if it was tranny related. I always seem to find autos. The only stick I've looked at could make a right turn by itself so I never bothered to look under the rear to see what diff it had.
 

ZoomZoomZoom

On the road again..
Dec 9, 2007
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Dan_Gyoba;958689 said:
FYI, all Canadian spec NAs had limited slip.

The amount that the speedo/odometer will be out can be compared directly from the ratios. I had a 3.909:1 (87T) differential in my '89NA for a long time, and the speedo was 10% out. (3.909 X 1.1 = 4.300) so if my speedo said I was doing 100 km/h, I was doing about 110. For every 100km I put on my odometer, I actually travelled 110km. (And my odometer now reads almost 461,000. Yikes.)

For the 3.727:1 going to a 4.3, the speedo would be out about 15%, so if your speeds says that you're doing 64mph, you'll be going about 55mph.

Is there such a thing as an accurate speedometer on a Supra? :)

In my 90, the faster I go, the more the speedometer is off. At what I consider 70 mph, my speedometer will say 85 mph. I really need to confirm this number by pacing another vehicle, but for now, I just subtract 15 from the speedometer. No ticket yet..

My car has 16" stock-sized wheels on it. I was trying to figure out why the speedo was off so much. None of my other Supras were off this much. Is there an easy way to identify which LSD is in a car? Is it tagged in some way?
 

IJ.

Grumpy Old Man
Mar 30, 2005
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ZZZ: Even if you have it calibrated it'll only be accurate at that speed, the odometer should be accurate no matter what as it has a mechanical link to the cable the speedo doesn't.
 

Nick M

Black Rifles Matter
Sep 9, 2005
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ZoomZoomZoom;959339 said:
Is there an easy way to identify which LSD is in a car? Is it tagged in some way?

Yes. The placard on the firewall on the axle code. It is on the lower part, and ends in a 3 or 5. I think the 3 or 5 might be the ratio, but somebody else would have to verify thatl