anyone now what gear ratio a 2000 z28 A4 comes with???

**00maroz28** · 03-26-2007, 04:48 PM

323... right?

**2001NBMZ28** · 03-26-2007, 04:52 PM

Could be either 2.73 (GU2) or 3.23 (GU5).

**00maroz28** · 03-26-2007, 04:53 PM

thanks.

**00maroz28** · 03-26-2007, 05:00 PM

now i just checked and mine says gu2 meanindg they are 273...will 342's from an m6 fit ...

**67CamaroRSSS** · 03-26-2007, 05:57 PM

Originally Posted by 00maroz28

now i just checked and mine says gu2 meanindg they are 273...will 342's from an m6 fit ...

You will need the posi unit also. IDK about your car but my Z28 had 2.73's with an open diff.

**ATCharming** · 03-26-2007, 06:00 PM

so how do u know which one ur car has? is that why some stock zs are faster than other stock zs?

**tommyjt2006** · 03-26-2007, 06:13 PM

You have 2.73's and in order to install gears bigger than 3.08 you will need the larger carrier. I swapped my 2.73's with 3.73's and had to purchase the Auburn Carrier that allows up to 4.11's. The total installation costs with parts will be $900 if you know a friend that will cut you a deal. Otherwise it will run you around $1K. Good Luck with the swap. You will never see 160 MPH ever again if you go higher than 3.42's. You should try swapping the converter with one from an SS Trailblazer and get Vette servo installed. Also disable the torque management from the PCM and get some BFG's. Take care.

**67CamaroRSSS** · 03-26-2007, 07:41 PM

I bought a complete 3.42 rear end from a wrecked 99 M6 car, rebuilt it and ran .35 seconds faster at the track.

**Mjolnir** · 03-27-2007, 12:22 AM

I just got my 373's installed for 700 (new carrier, posi, gears)

**ATCharming** · 03-27-2007, 10:30 AM

Originally Posted by Mjolnir

I just got my 373's installed for 700 (new carrier, posi, gears)

u told me on aim already

i get the in scoop b4 anyone. lol anyways, so how big of a difference do u notice with them? i think i asked u already but i 4got

**2001NBMZ28** · 03-27-2007, 11:25 AM

Originally Posted by 00maroz28

now i just checked and mine says gu2 meanindg they are 273

Not necessarily, my car came with 2.73 - GU2 still on the door - but replaced it with a complete 3.42 rear out of an M6 car.

**doctorslp** · 03-28-2007, 08:47 PM

yes 2.73s is what ur car came with. if u want something better 4 daily driver get 3.73s but for drag and stuff go with 4.10s but make sure u also upgrade ur complete rear end. 10 bolt, 12 bolt.