Any comments on 3.73 gears would be cool to hear. I bought a DTE differential with 3.73s in it, its new in the box and im ready for install but before I do Id like to hear some comments. I have an 05 coupe automatic. Im runnin borla cat backs , dynotech headers , vararam , ported mani/TB, predator tune and a plethera of other suspension goods. My car has 3.15 gears right now which aint bad , it has plenty of power but it just doesnt have the launch im lookin for. I dont drag race but I would just like some better take off power so thats why I picked up this new diff. I dont think I need 4.10s and im pretty sure 3.42s would have been plenty but this deal came up and it was the 3.73's so I grabbed it. Am I making a good move? It seems like it would be a good split between 4.10s and a 3.15. Opinions please?

Thanx,
Pete

 

My 06 C6 has the stock 3.42 gears with the mz6 trans. , not bad..... also have an A4 98 Z28 that I put 3.73"s in. With some bolt ons, it runs high 12"s on street tires. You will like the neck snaping 3.73 gears.

 

Should I do a torque converter?. I read everything I could find on is forum and alot of that is mentioned along with getting the new rear. I am so ignorant in this area so this is all uncharterd waters. Should be very interesting learning this.

 

The 3.73s will make a nice extra kick for you. I personally think 3.90s are the perfect compliment for the auto, but you will be happier. The key to making the most of the launch is to get a good tune after the gear install. Chuck from Corvettes of Westchester does some amazing things with auto transmission Vettes. Ive driven in a few he has tuned that accelerate and shift faster than you could possibly imagine. Its like unleashing a beast...makes you rethink the manual vs auto argument all over again.

 

Sounds like you already have it? If so, run it and have fun. On a basically stock engine, 4.10's are nice, if you are adding a bunch of power, 3.73's. I have 4.10's and 4th gear feels like second did. Freaking rips!!!

 

Go for it I have 373 gears in my 05 a4 with a vigalante converter has the car is tons more fun to drive than the lame 315 gears I had before.If you can afford a converter nows the time to think about one because it is a lot cheaper to change now when when you do the gears.This mod is the best one I have done on any car and I have done a few.GARY

 

Yes, the 3.73s are a great gear for the A4 automatics, a lot of people go with the 3.42s in order to maintain that more daily driver friendly highway rpm but the punch of 3.73s is undeniable.


Yes, while it's all apart you really should consider even a mild (2800 - 3200) higher stall converter from say Precision Industries (Vigilante) or similar. It will in fact save you some labor costs over doing it later on for much of the same stuff has to come out again to install it.

 

I hav an 07 MN6. If you change your mind about the 3.73s that is what I am looking to do. Drop me a PM if you want 3.90s instead.

 

100%. IMO 3.90s and certainly 4.10s, are probably going to be too much in an A4 with 400hp. 3.73s and a good stall converter 2600-3200, Yank, Pro torque or Precision Industries (Vigilante) would be perfect.

A lot of emphasis is put on gears here. People going 3.90s, 4.10s in automatics and running the stock 1600-1800 stall torque converter. Waste of time and effort if you ask me. AMong other things take into account your traction and your gas mileage when you are considering such low gears as 3.90 or 4.10 in an automatic.

Its the selection of your torque converter, coupled with your gear selection, which is going to be the "crowning achievment" in the whole set up and will give you much more performance than the gears alone. If you are looking for launch, then the Pro Torque low stall 2600-2800 or similar, with a high stall torque ratio will give you what you are looking for in terms of launch. Torque convertors with a high STR tend to hit harder from a dig but sacrfice a bit when you hit them from a roll.

That torque converter is whats going to get you your performance from a dig or a roll, depending upon what you select in a torque converter, so select your torque converter after doing your research. You can almost say: Gears ain't $*** without a torque converter, so do them both at the same time instead of paying for labor twice. You'll save money on the install and the transmission tuning (it won't have to be redone after the install of the torque converter) and the car will not have dead spots if the converter is selected wisely. The car will just perform better.

Also, if you think you might be doing a cam later on, good torque converter selection is crucial.

Had 3.42s in my C5 with a Pro torque 2600 stall. Car had no "loosenes" to speak of, very little pedal to get it moving, but wished I had gone with the 3.73s in that car. When you stomped it it hooked and went. 3.73s would have given me a little extra and I could have gone with say a 2800 or 3200 stall and it still would not have felt loose.

Best advice here is go over into the C5 section. There is a ton of information on gear and torque convertor combos over there. Those cars are A4s just as yours. Granted their cars only make 350hp to our 400, its still worthwhile to read the posts of people over there whose cars have been modified to make in the 400hp range.

You will see very few of them over there with engines making in that 400hp + range, (which is where your car is right now) running 3.90 and 4.10 gears on a stock 1600-1800 torque converter, or even running gears that strong at all in an automatic.

 

This is all great information. Definitely confirms what I was thinking. Its nice to have a bunch of knowledgable folks like yourselves to share experience and info with me. Many thanx

Pete

 

Just went 3.90's in 05' C6 all I can say is phuking BEAST!!! needs more tuning though higher rpm limit by at least 500, plus shift point re-calibration, but serious power, ran into a brand new Gallardo the other day, ran light to light, pulled 1-to 1 1/2 lengths each time (2 lights) from 0-65mph manually shifted too!

Guy in Gallardo, waved me over to gas station he thought it was a Zo6 I told him nope! just cat-back C6 lol...he could drive that Gallardo too, and was freaking out when he saw it was an auto! it was the only way I could prove to him it wasn't a Z06! (I have Z06 wheels, red calipers, Z06 rear wide body NO badges, only blk's out C6 badge on rear) bad aszz yellow! I'd sell my soul for that