I've done all the calculations, played with all the numbers. I'm moving from a 3.23 to either a 3.73 or 4.11. My car is primairily for autocross but does get me back and forth to work too.

My question is this...

For a daily driver with an A4, what gear would you use and what gear are you happy with?

 

For a daily driven NA A4 car I'd go 3.73's.

 

Here's one more piece of the equation.

The plan is to yank the engine out, do a Lloyd Elliot head/Overton custom cam (LE2) before spring. With 400+ RWHP and an extended RPM range (over the now stock engine), does that change your opinion?

 

for a daily driven a4 car, I would go with 3.73's also. I had 3.73's in my car for awhile and loved them. I am switching my set up to two seperate rear end's now and i will have 3.23's for daily driving and 4.10's for racing. So that is also an option.

 

Anyone else that's maybe used both?

 

another vote for the 3.73s. actually for a daily driven car, 3.42s are an excellent ratio, but if you do alot of auto-crossing the '73s should keep your RPM up right where you want it.

4.10s are just overkill in my opinion for a street car. i've got a friend with a 4.10 geared 93 formula and on stock height tires, his motor screams away at a pretty ridiculous RPM for commuting back and forth.

 

It depends on your driving..... my car was a A4/2.73 setup converted to M6/3.73. My car is my primary transportation, and i do a LOT of interstate driving. OD in the A4/2.73 turned the same rpms the M6 in 6th did with 3.73s (~2000rpm at 75mph). Got about 26mpg regularly too with both setups. Well my T56 crapped out on me last week and i spent all of last weekend putting the A4 back in. I drove it for a day or two with the A4 and 3.73s... no traction in 1st and drove well around town. Didn't like how it turned ~2700rpm on the interstate. I don't like having the engine turning that many rpms cause i make about 6 or 7 130 mile and 2 or 3 200 mile trips a month, with regular trips during the week (yes i put a lot of miles on this car a year). I picked up a 3.23 rearend and installed it yesterday.... i can get traction in first and it only turns ~2300rpm on the interstate. Much more tolerable for my situation.

So it depends on what you want or need for your purposes. If the car isn't a daily like mine is or make many long trips, the 3.73s are for you. I loved how quick the car moved with the 3.73s, and if conditions were different i would buy better/bigger tires and keep them. But i gotta get around and mpg/engine longevity are my primary concerns.... so lower gears work better for me. Just my $.02

 

Thanks for the reply.

I currently have 3.23's but for autocross, it's not enough. I'm going to move up in class from ESP to SM which means engine, drivetrain, brakes, and rear end are pretty much open (to a limit). TO me going from a 3.23 to 3.42 isn't worth the effort. 3.73's seem to be a good middle ground between the 3.23's and 4.11's. I was thinking the 4.11's were going to be too much on the highway.

When I race I use 315 Kumho V710's so traction is less of an issue than with street driving.

Sounds like 3.73's for me...

Thanks again

 

I've had 4.10's in my car since May of this year, and I've been daily-driving my car about ~45 miles a day, just to work and back. I've done a few highway trips too, and I can get almost ~250 miles to a tank of fuel on the highway (turning ~2800 rpm's to do ~70 mph).

If you're going to build a high-revving engine for your car, and you really want it to perform on the track, I'd say go for the 4.10's / 4.11's. I had 3.73's in my car last year, and honestly, there's not much difference between the two on the highway (maybe ~200 rpm's difference at 70 mph ).....so if you want to go all out, then get the 4.10's.

FWIW, the best I ever got with 2.73's was 310 miles to a tank, so I've only lost about ~60 miles on a tank from 2.73's to 4.10's.