SC A4 w/ 2.73: Upgrade to 3.42 only, or 3.15 w/ stall
 

As the title suggests, I have a 2001 A4 with an A&A supercharger kit. I also am running headers and full exhaust. The car came with 2.73 gears.

I am wanting to upgrade the rear and have 2 options I am considering. I could go with a 3.42 rear only, or, I could go with a more price-friendly 3.15 rear and an inexpensive 2800-3000 stall from Phoenix Transmission in Texas. I will be doing the installation myself.

All I have read is "just save up and do the 3.42 gears instead" but pretend that is not an option. I am worried that 3.42 rear with a 3000+ stall would make traction very expensive. The car is wide body and will run 325 Super Sports on the street. It is daily driven. I don't track the car but I don't want someone to pull me on the street either.

Is it feasible to get traction on a street tire with 3.42 gears and a stall? Would I be better off going with 3.15 gearing and a 3000 stall? From what I have seen, I could expect to pay $600 for a 3.42 unit. I have seen 3.15 units in the ~$300 and Phoenix Torque Converters in the 2800-3000 range prices around $400. My budget is ~$600-$700.

Opinions are appreciated.

I run 3.15 with a 3500 stall and 305 tire. Traction sucks. I rebuilt my trans and changed the 1 and 2 gear ratio. Also changed the shafts and clutch packs in the diff to handle more power. What if you install the stall and see how you like it with what you have now?

So you are saying that I might be happy sticking with 2.73 gears and just adding a converter? What type of tire are you running? I was debating keeping the 2.73s for a while and then thought 3.15s would be a good compromise, but all the threads I searched are full of people raving about the 3.42 rear. I'm just concerned about not having any traction on the street. Any other opinions?

I run the Michelin Pilot Super Sports. They work well for what they are but I have too much power. I believe they are 305/30-19. The stall gets you into a better power range and closer to boost so it does help. I would say find someone with the other gear ratios and supercharger that you can ride with and see what you think. I guess I am around 650 at wheels.

Thanks Chris, those are some healthy numbers!

I'd like to hear what some other supercharged members are running gear/stall wise and if they are happy with it's street manners.

I wouldnt buy a stall from phoenix. I would buy a reputable Circle d, PI, Yank or the like.

They are usually easy to find on this site used for decent money. And most times, you can send them back to the manu for a free "re-stall". I just did that with a 3800 PI that i purchased used.

I have 3.42 gears. Traction sucks. For the street, i limit my downshifts so it doesnt downshift and break traction. I will be going to 28" tall tires next to see if that helps. I was at 650+ rwhp before, should be closer to 900 after recent rebuild and YSi.

My opinion for you is to wake up that beast with a 3200-3800 stall converter and then see how you like the 2.73. If you still dont like it, then change gears.

3.42 rear ends are readily available. I bought mine with 15k miles for 300.00. had a shop swap stock 2.73 for the 3.42 and it was great. be careful on automatic donwshifts because it will go into boost etc... that would be the most economical change.

I bought a 3.42 rear with 22,000 miles on it. I got under the car today to plan out the removal of the stock unit. Although I was told by the original owner the car came with 2.73 gears, I can see "3.15" plain as day on the rear. Now I have a conundrum. Should I go ahead and install the 3.42 set with 22,000 miles or sell them, and keep my 3.15 set with 75,000 miles. Is the upgrade worth the cost ($600) of the differential, or would I be better of selling the 3.42s and using the extra funds for a higher quality converter and shift kit??

Weather its gears or power. The more you add, the more tire you need. It gets to a point where tires like Michelins or Goodyears are not going to be enough. You have to step up to a drag radial like a nitto, then if you have more power you are up to a Mickey Thompson and then you have to change to a smaller wheel and tire combo and go with 15" wheels and big tires.