No K; I give up.
Except for counting gear teeth you can get only close by speedometer and tach.
Here is TBWilley's thread;https://g35driver.com/forums/drivetr...ms-80-mph.html

The diff gearbox stencil is not proven ID to the gearing numbers. The cast numbers on the diff gearbox neither.

Seems the gearing has never been clear-up according to the linked historical thread.

 

I LOVE this mod....def a must have for all 5at owners. 3.5 diff paired with tune = amazing

 

Nice!! Are you going to bring out to the track? I have a 3.5 also. There is going to be a track day aug 5th at Capitol if you can make it come out.

 

I actually might be able to make it out that day. we will see. I will need some tips from you guys prior to going the track lol

 

Hey guys, don't wanna jack anybodies thread, but I have 3.9s I'm looking to get installed in my 04.5 6MT. I can't seem to find anyone within an hour or two of Bel Air, MD that wants to do it. Local dealership said they didn't know how, and JTune said they aren't sure either because they have never changed gears. Anyone know a good place that has a good rate?

 

One of my friend got his 4.083 gears installed at this shop, he was very happy with everything.

http://www.swiftracing.com/SRT/default.aspx

Located in Beltsville, MD. Talk to Moe.

 

That's a little closer than AMS...thanks for the heads up. I'll give them a buzz. Anyone know/recommend anything closer?

 

Am I missing something here?

Couldn't you just take the pumpkin and rotate the input shaft and see how many times the output shaft rotates? I mean, if 3.5 rotations of the input shaft gives 1 full rotation on output, then it is 3.5:1. If you rotate input 3.3 times and you get 1 on the output, then it is 3.3:1. Also, if only one output rotates, it is an open diff.

(Granted, being able to decipher the code on the outside would be much nicer. But you don't have to take it apart.)

 

Wompem, you are right. The pumpkin itself can produce the answer of final gear ratio with hand turning the wheels, observing the drive shaft, using your sense of angular measurement and patience.

a) In this case 6 degrees of separation on the wheel.

driveshaft input 360 degrees of rotation (1 turn)= output 103 degree wheel rotation = 3.5
driveshaft input 360 degrees of rotation (1 turn)= output 109 degree wheel rotation = 3.3

B) like you say, in this case 72 degrees of separation on the drive shaft.
slightly easier to measure in a practical manner.

input 1260 degrees of rotation = output 360 degree rotation = 3.5 drive shaft turns
input 1188 degrees of rotation = output 360 degree rotation = 3.3 drive shaft turns
or why doesn't Nissan have the ratio noted in some way on the outside of the case, maybe a stencil painted on at the factory assembly.

I've got my VLSD determined by turning the rear wheel jacked up in neutral. Oh and burn-outs, more fun seeing the rubber on the road tell the story.
I'll count the rotations some time in future when I get the chance. Just to verify it is 3.3.

 

anything higher than 3.7? 4.5? i dont go over 70mph

 

Totally agree I can be cruising at 25 mph and get on it and break the back end free. That's with a 5AT.

Also I'm rolling 3200 RPMs at 80 on the 3.5 and 225/40/19-245/40/19 tires.

 

sorry for the noob question but which FD would my 06 5AT have?

 

3.3

 

Has anyone actually made the swap to a 3.5 pumpkin without vlsd? I have access to one for extremely cheap but i'm thinking it may not be worth the swap sense it doesn't have the limited slip

 

thanks for the quick reply blue dream...i read this thread and everybody seem to be in favor for the 3.5 FD where would i find that?