rear differential gear swap

[TeamRedLine23]

I have a 1991 z32 tt. I want to swap the 3.69 gear to a 4.10 gear. would I need to drop the whole diff.? how hard is it to the gear swap? how much would teh labor be? I live in San Diego CA, do you know of any shops around here. thanks

[Broke_as_****]

The only correct way to do it is to drop the rear end and take it to a shop. How much? Shouldn't be too bad, it's just the labor charge since you are providing the parts. Search www.twinturbo.net for members with the 4.10 gears for advice on the proper pre-load and placement of the gears, otherwise you'll get abnormal wear on the gears.

Anyway, from reading reviews by people who have them, it's right up there with turbo upgrades as far as the effect on power goes.

EDIT: The information about the installation was incorrect and has been corrected. You will now be returned to your regularly scheduled post. HAIL KORGOTH!

[longlivetheZ]

BUUUUUUUUUUUUUUT!!!!:

I think it should be known...mods like this are popular with the domestic guys and I laugh at them. Changing your gear ratio in this way makes your car get worse gas mileage on the freeway, subjects your engine to more wear and tear (as opposed to 2000 rpm at 60 mph, you're going at, say, 3000-4000 or whatever the case may be)...I would not personally recommend this mod to anyone, ever. Mod the engine to make more power. Don't try to cheat.

[Broke_as_****]

Originally Posted by longlivetheZ

BUUUUUUUUUUUUUUT!!!!:

I think it should be known...mods like this are popular with the domestic guys and I laugh at them. Changing your gear ratio in this way makes your car get worse gas mileage on the freeway, subjects your engine to more wear and tear (as opposed to 2000 rpm at 60 mph, you're going at, say, 3000-4000 or whatever the case may be)...I would not personally recommend this mod to anyone, ever. Mod the engine to make more power. Don't try to cheat.

First, if you laugh at someone for making their car faster through a revising of the gears for a better, sportier ratio, you're an idiot. It's one of the most effective upgrades you can do.

Second, the ratio is barely lower than the non-turbo Z32 (NA is 4.083 and Leader gears are 4.10). If you are going from 2000 rpm to 4000 rpm at 60 you would have to being going for EXTREME gear change, like from 2.8:1 to 5.8:1. You may lose one or two points off your miles per gallon count but fuck, who the hell drives a Twin Turbo for the fuckin gas mileage?

But this is besides the point BECAUSE:

At 60 mph at stock Twin Turbo is turning about 2300 rpm. With the 4.10 gears your only doing 2500 rpm.

Do the math yourself:

http://www.geocities.com/z_design_st..._300zx_tt.html

Third, there is no reason to stick with the hugely tall stock gearing (3.692) unless you plan trying to crack the 200 mph barrier, provided you can make 7600 rpm. Even as cool as it would be to say "How fast is it? Don't really know, the speedometer only goes up to 190 mph." I would much rather have the power down in speed ranges I'm actually going to be driving at.