Supra Forums banner
1 - 17 of 17 Posts

·
Registered
Joined
·
2,141 Posts
Discussion Starter · #1 ·
I've got both a 3.133 USDM and a large 3.266 JDM diff on me right now and I need deciding which one I should keep.

By my math the v161 with the 3.27 diff will give me almost identical gearing to the v160 with the 3.13 diff in 1st and 2nd, taller 3rd gear and 4th gear, shorter 5th and 6th gear. If I keep 3.133 with the V161 it'll be taller in all gears besides 6th which will be shorter.

Has anyone driven both a 3.13 and 3.27, I doubt anyone has with a v161 but does everyone like the v160 gearing or would some of your guys prefer taller gearing?

Lastly which diff is more valuable?
 

·
Registered
Joined
·
1,510 Posts
I was just thinking the same thing but with the example of a V160 do people prefer 3.13 or 3.27
 

·
Super Moderator
Joined
·
11,529 Posts
How much power will you be making, and how tall are the tires you'll be running?

Just going by gearing alone is a bit arbitrary without knowing the whole picture.
 

·
Somebody's Watching Me!
Joined
·
1,875 Posts
I have had both actually all three auto, 3.13. 3.26 and i like the 3.26 the best but i'm not a drag racer or haven't done any racing as a matter of fact cause the car has been down last couple years anyways. The auto would take off like a bat out of hell but you have to switch gears every other second the 3.13 wasn't bad but it lagged off the line compared to the auto, and the 3.26 is the best of both worlds cause it takes off better off the line and you don't have to shift every second. Hope that helps I know I'm bias because i had the auto first and the 3.13 second and now the 3.26 and am loving it.
 

·
Registered
Joined
·
2,141 Posts
Discussion Starter · #5 · (Edited)
I think I am going to go with the JDM 3.266 diff.

JDM
49 (crown teeth) / 15 (pinion teeth) = 3.266...
195 mph at 6800 rpm

USDM
47 / 15 = 3.133...
204 mph at 6800 rpm

In theory the JDM "big" diff should be more stout because it has more contact area. I think the reason they went with the 3.13 diff for export specs was purely marketing. 'Top speed, over 200 mph' has a nice ring to it. But I do think they realized the v160 / 3.27 gearing was a bit short which is why they retooled the transmissions gears for the v161.
 

·
Registered
Joined
·
239 Posts
I would go with the 3.13 unless your drag racing. It will drop your rpms on the highway a little and if you dont need out of the whole power from a stop, then the 3.13 IMO is the way to go in a 6spd. with the auto, it may change depending on when your spooling.

CJG
 

·
Registered
Joined
·
1,069 Posts
Japanese Tuning in Plain English

Just going by gearing alone is a bit arbitrary without knowing the whole picture.
Agree... the only way to really know is to drive the with the gears in the conditions or environment that you will be driving in....

but... without considering the mathmatical aspect of gearing, you really wouldn't know whether it's worth trying out or not.

As ridiculous as this may seem... GranTurismo can be the perfect tool...

Choritsu-shi

View attachment 75475 V161 w/3.133
View attachment 75476 V161 w/3.266
 

·
Registered
Joined
·
790 Posts
Sell both and buy a TRD LSD.
He's asking about what gear ratio would work better with his tranny, not about the the LSD part of it, you can add a TRD or any other LSD to either of these housings. I would go with the 3.26 and the only reason I say that is because thats what I run and it works great for me.
 

·
Registered
Joined
·
2,141 Posts
Discussion Starter · #13 · (Edited)
I've done a ton of research over the last few days specifically on gear strength.




What I found was gears only make contact in very limited number of places. By distributing that force over a larger surface area you increase strength. You can increase surface area by making something larger or adding more teeth.

These are the crown teeth by pinion teeth ratios of all the differentials I know. Listed from most to least teeth.

220mm diffs
49:15 = 3.266
47:15 = 3.133
46:13 = 3.538

200mm diffs
49:15 = 3.266
49:13 = 3.769
49:12 = 4.083
47:12 = 3.916
47:11 = 4.273

The JDM 49:15 diff should be the strongest differential out there which is why I decided to use it.
 

·
adammackintosh.net
Joined
·
5,807 Posts
armed with this knowledge i would go with the larger JDM gear strictly based on potential longevity for a street car.


if its worth anything at all im running a v160 with jdm diff and ive always loved the gearing when it comes to gear vs. rpm on the street.

i can do 60mph in 2nd gear no prob.

speaking of which i just made a thread recently about the v160 vs. speed & rpm and someone linked a WICKED spreadsheet that i gaurantee you will enjoy.

you can plug in all parameters related to tire size, specify gear ratios, and it will tell you what speed you will be doing at what rpm.

you could use this to see some quantifiable numbers about what should happen in the real world.

[edit]

here it is, take a look.

http://www.supraforums.com/forum/showthread.php?640310-v160-speed-vs.-rpm-graph
 

·
Registered
Joined
·
37 Posts
These gears are helical, the contact point is not constant and moves along the tooth flank. The greatest addition of multiple teeth will reduce the average wear, the helix angle will determine how efficient either gear set. You will most likely find strength will be found from maintaining the differential to ensure it does not exceed the service specification.
 

·
Found E85 NOT in NJ!
Joined
·
5,252 Posts
For the ten thousandth time, the only time you break a ring and pinion is by wheel hop. At that point contact area or not, nothing is going to save you.

For someone that "reads" and does "research" you should have figured that out by now. You are the master of quoting things out of context, like the guy from "Trucks".
 
1 - 17 of 17 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top