Datsun Roadster Forum-311s.org

I've seen mentioned a few times a 3.5:1 rear differential mostly by Mike young but I can't find any information on what car it came from and what not.
Anybody knows ?

I believe the ring and pinion come from a truck. The housing needs some modification as well.

I like the way a 3.5 drives more than a 3.7. It makes each gear really long, but at least it doesn't feel awkward like a 3.7.

Will

Gear ratios and part numbers.

3.364 38100-P0806
3.545 39/11 38100-P0706,38100-V7700
3.700 37/10 38100-77700,38100-A3800,38100-P0606/38100-P0607,38100-V7600
3.889 35/9 38100-61000,38100-A5300,38100-25600
38100-P0501/38100-P0506,38100-V7500
3.900 39/10 Not available (3.889 is quieter)
4.111 37/9 38100-61001,38100-P0306,38100-V7300
4.375 35/8 38100-37800/38100-22501/38100-23500,38100-26000
38100-B3300,38100-B5500,38100-P0206
4.625 37/8 38100-36800/38100-22600,38100-22901,38100-77500,38100-P0106,38100-C6200
4.875 39/8 38100-14901/38100-20600,38100-20659,38100-Y4006
5.125 41/8 38100-37000
5.143 41/8 [5.125] 38100-08700,38100-37000,38100-B4003
5.429 38100-T3003

Thanks

Mike mentioned this to me, as well. If I recall correctly, he said that the 3.5 center section from 1981-88 Maxima wagons fits right into our roadster diff housing.

Put me down for a couple 3.36 s ....ha ha ha

redroadster wrote: Fri Oct 08, 2021 7:14 am Put me down for a couple 3.36 s ....ha ha ha

Good luck finding one

funkaholik wrote: Fri Oct 08, 2021 12:45 am Mike mentioned this to me, as well. If I recall correctly, he said that the 3.5 center section from 1981-88 Maxima wagons fits right into our roadster diff housing.

77-84 Maxima Wagon and certain other imports , What he did not say is that's its almost impossible to find now
to give you and idea I just searched for a couple months to find a same generation Maxima Sedan 4:11 R180 differential for my Z and that was ultra hard to find

I'm not doubting you on they were made , but so rare
81thru 84 were rwd 85 up Fwd same ring & pinion?

And here I thought a 5.13 was the hot setup...

I think I have said it before, but I have an Excel spreadsheet (from Vic Laury, miss ya buddy) with graphs and the individual gear ratio listings for 25 different Nissan transmissions. Can send it along if anyone wants.

Also a separate file with Rpm vs Speed that you can enter your own tire/wheel sizes to determine accurate speed. (though it does need a bit of a factor, as it over estimates. I don't think it takes into account a tire not being perfectly round on the bottom, so effective radius is a bit smaller)

How do I know t is off? Most hybrids have a 1" or larger speed display on their dash, so when dark I just drive up next to them on the freeway and look in. (creepy, I know!)

I'd like to see that spreadsheet!

Let's se if this works.

I recently bought a 1969 1600 frame including suspension and differential. I will be having it painted or powder coated then have the original 1968 engine/body mounted on the upgraded frame. The differential looks like it has been pulled out and replaced, is there any way to determine the ratio and if it is stock to a 1600? I've been told that a 3.70 unit from a 2000 model will reduce the revs at highway speed. thanks for your assistance.

Spin it and count

Of course. It is easy. 3.7:1 means for each 3.7 turns of the drive shaft you get 1 turn of the wheel.

Chock one wheel so it can't turn (not necessary if limited slip) and lift the other wheel off the ground.

Put a sharpie mark or piece of tape on the DS and wheel to easily count rotations as they go by.

Get a helper to count wheel rotations while you count DS rotations. Tell your helper to tell you when he/she gets exactly 1 rotation.

If you turned 3.5 turns its a 3.5, 3.7 turns , its a 3.7, 3.9, its a 3.9, 4.11 its a 4.11....on down the line.

3.7 is stock 2000
3.9 is stock 1600

If it is too hard to approximate the fractional turn (not real difficult), have your helper count 10 wheel rotations

If you turned 35 turns its a 3.5, 37 turns , its a 3.7, 39, its a 3.9, 41 its a 4.11....on down the line.

If the diff is out, the ring gear has the ratio stamped on it, so that is even easier....