Rear Gears

**ls1speedster** · 06-28-2007, 02:57 PM

I seen a post for 3.73

im 02 t/a bone stock ls1 A4

if i was to go to the 3.90 gear or the 4.10 gear...
- im taching 2100 at 80 how much would gears raise the rpm..

- how much would top speed suffer...not realy worried tho...

- what would the shift points do since with stock 2.73 it shifts about 5.900 would everything be fine there or would they have to get moved...

- how much would gas milage suffer

im thinking gears after i get a slp lid which is on order..
any help would be appreciated...
thanks

**autoxr** · 06-28-2007, 08:12 PM

Do you have a high stall torque converter yet. I would go that route before changing rear gears. Ask some of the auto guys what stall you should get.

The gears will kill your gas milage. You can gain performance and gas milage if you do it right.

**SStriker** · 06-28-2007, 08:18 PM

i wouldnt go lower then 3.73 for a street car. It sounds like you have some pretty tall gears as it is right now. 3.73s will be a crazy difference for you.

**ls1speedster** · 06-29-2007, 08:42 AM

I have stock 2.73 and would like to go to 3.90 or 4.10...

i have no stall that would be the next thing....i would go with 3000...
as of right now im looking for gears more rather than stall..

thanks

**slims00ls1z28** · 07-01-2007, 07:46 AM

I have 4.11's in mine and 75 is around 28-2900 RPM with the converter in lockup. Gas mileage dropped with my car but not near as bad as I expected provided I don't play around too much. I still drive it to work on the weekends and it uses right at 15$ in gas whereas it used to use about 12$ a dayand that is with a 3600 stall. Over a 40 mile streatch the useage went up about a 1/16th over what it used to. According to my own calculations I went from about 28-29 to 20-21 MPG most of which is highway but Its a little lower in a bunch of stop and go traffic. Shift points would be the same once you get the speedo recalibrated to match. As of right now mine isn't and it bounces of the limiter everytime if I leave it in gear becaue the MPH is not right according to the computer.

**Proud2bSS** · 07-08-2007, 07:06 PM

wow.....my 70 Cuda with a 3 speed auto (1, 2, D) and 4.30's was a real beotch. 4.11's with an A4 (which has over drive) is cake.

**TwiSSter418** · 08-01-2007, 07:09 PM

I have an auto with 4.10s and love it. I went from 3.23 to 3.73 and didn't feel a difference at all. Got 4.10s with the new rear and the car finally feels snappy. I also have a 3200 stall torque converter. I would personally recommend a larger stall than 3000. The 3200 I got was barely noticeable until you mashed it and THEN you could feel it. Overall one of the most effective mods I've ever done BTW so I highly recommend getting a stall even if you go with the smaller one.

As for RPMS at a certain speed, i've always used this website:
http://www.f-body.org/gears/