I have a 99 Z/28 a4 with 2.73's. I really want to get those slow gears out now. lol The plan is to get 3.73's. What do I need for the gear swap? I know the gears and install kit. Anything else? These will be going into the stock 10 bolt. Will the car be faster with the 3.73's? Thanks guys!

 

yeah just get the ratech kit or similiar and gears thats it. make sure you get the gears for the two series carrier. and yes the car should scat with those new gears. you are gonna be holding a lot higher cruising rpms though. its gonna be a big jump but worth it in my opinion.

 

^ Cool! Thanks for the info. The 2.73 gears are worthless. Not sure why gm would put those in a LS-1 car.

 

google CAFE. (coporate average fuel efficiency) you will understand in the big scheme of things.

 

The LS1 makes enough power and torque to put down some decent acceleration numbers even with the 2.73 gears, and fuel economy is pretty respectable too. My best run when all stock was 13.5, enough to lay it down on a steeper-geared Mustang of the same year. [/hijack]

 

tricky thing about gears is that some of the fastest LS cars are still running factory gear ratios. it all plays into the whole package/right combo thing

 

ya, your car will accelerate quicker if you get good traction. you will need gear oil and limited slip additive. i would recomend getting "Strange" aka "u.s. gear" 3.73 gears. they are great quality. i used their 4.10 ring and pinion in my 10 bolt and they made NO noise while driving and never had any metal shaving when i would change the fluid. i also recomend changing all your seals and bearings in your rearend. i also changed my ring gear bolts to be safe. good luck man.

 

This is common with turbo cars. In fact, a lot of Turbo Buick guys (3.42 gears are standard) will put in 3.23 or even 3.08 gears because they work better with the setup.