rickssz

I am trying to pick a ratio to replace my stock TA a4 rear gears. I usually see people make the comment dont bother or its not worth it when someone wants to go from 342 to 373. Does that mean 342s give about the same performance and benefit of 373s and the difference isnt worth going after which to me says take your pick you wont notice or feel or see much improvement. Any M6 replies wont help and can you give reason or experience for your answer? Thanks!

Black02SLPSS

iTrader: (5)

Most of the time when people say that going from 3.42s to 3.73s isnt worth it is because that is a pretty small jump in ratios. However you since you dont have 3.42s because that was stock in the m6 cars you either have 2.73s or 3.23s and going from either of those two to a 3.73 would be a pretty big jump, especially from 2.73s. What gear ration do you currently have. Look on your door jam for a GU2 or a GU5 code and let us know. A GU2 code means you have 2.73s and a GU5 means you have 3.23s

rickssz

I have 273 A4 and like the sound of the deeper 373 but am worried they will just spin on the street without some sticky MT DR etc so the extra kick or torque Im expecting wouldnt be felt due to the spinning.

MattIROC

iTrader: (19)

the 3.73's dont spin THAT much on the street. It is well worth doing the swap from 2.73's. I went that route, and I picked up half a second at the track (actually 7 tenths, but 20 degree drop to me means 2 tenths for air change). To top it off, I only spent $356 total on everything including installation. I only bought the ring and pinion, new fluid, and new posi additive (even though they say its not needed for the torsen). I've driven over 10k miles so far, and no problems. I went with the Motive 2 series, and they do whine, but they were setup by the same guy who set up my gears and spool in my Moser 9", and no whine there.

Here's where I started at the track when I first got the car till I got the gears.

Stock - 14.14 @ 100 (90 degree weather)
Lid only - 14.04 @ 101 (80 degree weather)
Lid/3.73's - 13.31 @ 104.9 (60 degree weather)

And my car is a 98 A4 with 133k miles now. Everything else is stock.

Also to top everything off, my gas mileage hasn't changed when I drive fairly normal. Before with the 2.73's I was getting about 19 mpg. When I went with the 3.73's, I've averaged 18-22, depending my city/hwy variations.

rickssz

Thats what Im asking. Your comment suggests there isnt enough of a performance improvement over 342 to bother changing them.

rickssz

Thanks for the real world answer it helps.

jessedale98

iTrader: (16)

Why do you care if you dont have 342s?

rickssz

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Cap'n Pete

iTrader: (2)

1 - 3.73's behind an A4 don't automatically mean you have no traction! I ran 4.10's behind my A4, and had no problem cutting 1.9xx 60' times at the track, and on the street, the thing was fine!

2 - why NOT go from a 3.42 to a 3.73? Or a 3.23 to a 3.42? Or a 3.73 to a 4.10?! ..... well, small increments may not be worth it to SOME PEOPLE, while to others, it's totally worth it. If you have a performance goal in mind, then correct gearing means everything. Running the wrong gear can be leaving performance on the table. If you're just looking for a nice street/strip setup? Then you have to weigh out the benefits vs. cost. Don't know what more I can say, but I guess it's personal preference/situation/goals that will decide whether ANY gear change is necessary or "worth it" .

rickssz

Did you switch to 323 while you were still an A4 and can you describe the change from your 273?

9000th01ss

iTrader: (10)

2.73's suck unless you want gas mileage. I swapped from an A4 to M6 and did the gear swap first to be sure if there was a problem I wouldn't need to guess if it was the rear or trans.

I went from 3.23 to 3.73 with an A4. It had a noticeable seat of the pants feel- more acceleration, more tire spin. Noticable higher rpm on the highway without looking at the tach. Normal city driving was hard to tell anything changed.
If you go from 2.73 to 3.73 you WILL notice a difference.
You will also need a different series diff carrier when you go to anything numerically higher than 2.73.

Cap'n Pete

iTrader: (2)

I only drove the car with A4/3.23's for about ~2 weeks, so I can't say much about them, other than I didn't really like the overall feel?? This was after I just broke my 4.10's! Dunno, the 3.23's weren't anything special off the line (but compared to 4.10's, they wouldn't be), and all the in between spots, I guess I wasn't used to their shift points, and I just found them ... boring? I honestly preferred 2.73's to the 3.23's! (maybe I was just used to them?!)

Overall, I ran with 2.73's and 4.10's the longest in my car, with 3.73's for a couple of months one summer, and like I said, 3.23's for about ~2 weeks (until I swapped to the 6-speed, which I have now).

4.10's and 2.73's actually have very similar shift points, except that they're 1 gear apart from each other (and 2.73's have a super long 1st gear). I never had any worse traction running 4.10's than I did the 2.73's. Maybe that was just me though? And that was on street tires, not DR's or anything!

FWIW, my average mileage (city/hwy mix) has always been about the same, no matter which tranny or gears I've had. Typically around ~230 miles to a tank (whatever that works out to MPG). That's probably due to my driving style I guess?

That is incorrect. The factory 2.73's ride on a 2-series carrier. If you want 3.73's, you can buy them specific for a 2-series carrier. You don't need a new carrier! If you already have a 3-series carrier (they come in 3.23 and 3.42 geared cars) then buy for the 3-series.

Irocem99

Going from 2:73 to 3:73 and there is a huge difference.It makes the car so much more fun to drive.If your just going to street it and not strip it,3:42's or 3:73's are the way to go.It's almost like driving a diff car..

SREETRACEGUY

iTrader: (13)

i swapped from 3.42s to 3.73s and i'd say it was worth it

02silvaZ

iTrader: (12)

if you have 2.73's the 3.42's are a nice upgrade that will net you a little more gas mileage over the 3.73, but if you have 3.23 then def go to 3.73, the 3.23 to 3.42 isnt worth it

rickssz

Thanks but I was lookin for A4 comparisons.

rickssz

Money doesnt come into play since I didnt purchase yet so when you say 323 to 342 or 343 to 373 isnt worth it given the choice which would you choose personally and why? Just noticed if you are an M6 I dont think that helps me.

keliente

iTrader: (22)

The 3.42 to 3.73 seems to be a heated topic in this section. The simplest way to put it is that the difference between 3.42 and 3.73 is minimal. In my opinion, it is usually not worth swapping from 3.42 to 3.73 unless you are doing it for a specific reason. The cost of the upgrade (~$400) is often not worth the end result.

If however you are coming from a 2.73 or a 3.23, you generally want to get the most gain for your buck, which usually translates to 3.73s. It's pretty much the ol' standby choice for the automatic gear upgrade.

If this is one of your first mods, or you never seriously plan to build your car, go with 3.73s. If you have a specific goal in mind (big hp and you want to hit up the track a lot) then you will want to consider things like transmission gearing (if you don't keep it stock), what tire size you'll be running, where you'll make peak power, whether you want to race 1/8th or 1/4th; and from there decide what gear you need to be in and thus derive what rear end gears to go with so you're not replacing them later to accommodate your setup.

Clear as mud?

rickssz

What gears do you use now and before and why? And how are they on the street on street tires?

05MBMLS2

iTrader: (34)

Holy cow dude...you have 2.73's now...why are you asking about the diff between a 3.42-3.73
When it comes down to it the 3.73 gear is going to be a very noticable improvement from your 2.73 set.