trilkb

iTrader: (4)

Was sitting there thinking about stuff, Gears came to mind. Alot of people say go to a 3.42 rear end for an A4 car. Thats nice and all but i was wondering if anyone has done a 3.45 9 bolt?

In my eyes the 9 bolt is a stronger rear end. Its also 2-4 inches narrower though. since a 4th gen rear bolts into a 3rd gen, a 3rd gen rear sould bolt into a 4th gen right?

Just hypothetically speaking, a 3.45 borg warner 9 bolt could be found for the same price as a 3.42 10 bolt but be a better rear end, plus being more narrow you could possibly run a wider rim (if you want) or just one with a bigger lip.

thoughts?

CRAZZ28

iTrader: (13)

A guy i work with has one in his 3rd gen. Its held up to a couple of pretty stout motor combos so i guess it would work. His only complaint is the lack of options as far as gearing.

Young Maro

iTrader: (5)

That's a pretty low gear ratio... unless you are going to be cranking out very high HP I'd step it up some more.

trilkb

iTrader: (4)

well from what i hear the 3.42 10 bolt is kind of a good street/strip rear end. so i figured the 3.45 would be as well.

I see they now make a 3.70 9 bolt kit.

I had a 3.27 borg warner in my old GTA, that rear end gave me no issues, and always left 2 marks lol. Both 10 bolts ive had like to only spin 1 tire alot of the time

LSWHO

iTrader: (1)

trilkb

iTrader: (4)

For an A4 Car.

my car now has 3.23's

Puck

iTrader: (17)

A street/strip A4 should be looking at 3.73s if running modest FI and at least 4.10s if NA.

I wouldn't run 3.42s unless I was making a ton of power sprayed or turbo'd.
3.42s are fine for a daily driver but not really an upgrade unless you are coming from crappy 2.73s.

LSWHO

iTrader: (1)

Currently running 3.42s in my A4. Was a step up from 2.73s.

Again...

MasterTomos

iTrader: (15)

3.42's are a nice street gear for an A4 that sees occasional track duty, better than any factory A4 gear and not as aggressive as 3.73's. 3.73's hurt gas mileage more and make loud exhaust setups annoying on the highway sometimes for a primarily road driven car...

Young Maro

iTrader: (5)

Man 373's are the best gear all around. You will notice little to no gas mileage difference, MAYBE 1-2 mpg tops only on the freeway. I had gone from 323's to 410's with only a 1 mpg loss on the hwy.


If you aren't going to be supercharged/turbo'd making 600+ hp, go with at least 373's. You won't regret it.

SexyTransAm

iTrader: (6)

i went from 2.73s to 3.42s (swapped in a M6 rear) for round 100 bucks. and i love the 3.42svsthe 2.73s. but if i could have got the 3.73s for 100 i would have done that and said to hell with 3.42s. now when the good ol 10 bolt takes a **** the least ill do is 3.73s and might do 4.10s in my auto car

MasterTomos

iTrader: (15)

I geuss it's all preference, I've been in several 3.73 gear swapped auto cars and I know a handful of people who would've prefered 3.42's if they could do it again.

pancho toco loco

iTrader: (8)

Wondering if it can be done also.

trilkb

iTrader: (4)

it can be done, just wondering if its been tried. People swap 10bolts into 3rd gens every other day. Im sure it works the other way too.

T/ALT1

iTrader: (3)

Well the 3.42's work great in auto F-bodys but you need to have some HP. My car ran 11.20@120mph N/A and low 10's on n2o with 3.42's in the 10bolt.

robsquikz28

iTrader: (246)

3.73 at minimum

MasterTomos

iTrader: (15)

Everyone can go back and fourth on this subject but there's really no right or wrong answer, it really varies from people's goals, preferences, and what they use the car for.

pancho toco loco

iTrader: (8)

I like the idea of running a 3.70 with the 9 bolt. like said befor you can run a wider wim or bigger lip with less issues. How do the lt1 brakes bolt up to the 9 bolt? Straight swap?