2003 m45 3.69 gears

[viperatc1]

has anyone with an 03-04 m45 changed the rear differential?

[Bag302]

I am also interested in this

[viperatc1]

i'm guessing maybe 2-4 tenths in the quarter?

[szh]

It is certainly an interesting possibility for a modification ... although I do not know if anyone has actually done it.

Yeah, it might provide the 2-4 tenths gain ...

Z

[auditech10]

The pumpkins from the M/Q45 and 300ZX are identical except for the inpup flange. This is what I remember from the last few posts on this topic. Good thing is that the units from 300zx are posi diffs and ours are open, I believe, and they can be found pretty easily for a few hundred bucks.

[Q45tech]

Since the 60's it has been known that the best quarter mile times [around 100 mph with AT] are usually when 3 gears are used hitting the end at redline.

The oem 3.13 was updated to 3.31 in the later M45.

Unfortunately 300zx have 3.694 or 4.083 gears, Q45 [90-96] has a 3.538 even the Q set might force you to shift into 4th gear prior to end of quarter ADDING shift time!

Why not look at the current M45 gear set.

Lots of cost to gain 0.2 seconds at best.

[auditech10]

Good info. I wonder what the top speed in an M45 would be with a 4.083 rear gear? It would be so much better off the line though thats for sure!