wondering what gears to run was thinking of 373 slp has a ring & pinion 7.5 and 7.625 differential kit what do you guys think of this set up? anyone have this what do you think 373 or 411 whats the pros and cons of both thanks

 

m6 4.11's A4 3.73's......I have 4.11's in my A4 but don't do much driving. I had 3.73's in before and they were good as well but 4.11's for 1/4 all the way.

 

3.73 will be nice in a auto car. What other mods do you have?

 

PLEASE post on the correct forum. Questions about "gears" do not belong on "LT1/LT4 Engine Tech". Moving to "Drivetrain".

 

Depends on the power band of the motor, intended use, etc. 3.42's are great in my M6, for example.

Rich

 

1993 lt1 auto trans k&n cold air kit 1le elbow 52 mm throttle body and air foil throttle body bypass mac headers and off road y-pipe no cats chip from madz28 slp loudmouth 8.5mm msd wires bosch plugs shift kit i think thats it just looking for some lower gears what should i go with ?

 

3.73

Rich

 

From LS1Tech:

Stock Gear Ratios:
M6: 3.42
A4 Standard: 2.73 (GU2 code on the door sticker)
A4 Performance Axel: 3.23 (GU5 code on the door sticker)
WS6 and SS models came with 3.23s.
Your A4 did not come with 3.42s.
If your sticker is gone you tell which gears you have by your highway rpms:
3.23s @ 2000 rpm = 67 mph; 2.73s @ 2000 rpm = 80 mph
3.15s were available in A4 Vettes

The attached file has the mph & rpm for the most popular gear ratios for F-bodies:

M6:
3.73
3.90 (requires aftermarket rear)
4.10

A4:
3.42
3.73
4.10

The mph assume a stock 245/50/16 F-body tire. Those on 17" wheels will find this pretty close since your tires are a narrower aspect ratio. If you run ET Streets, they are generally larger than stock tires. Depending upon which tire you select, you can add 2% - 5% to the mph numbers to estimate your rpm for a given trap speed.

A stock A4's converter is unlocked at WOT. Therefore when you cross the line your rpms will be higher than shown in the chart. While the amount slip will vary by converter, you should figure an extra 5 - 8% above the rpm shown in chart when looking at the high rpm numbers where you are likely to be at WOT.

If you want to play further with tire sizes and gear ratios go here:

http://www.f-body.org/gears/


Additional Info for A4's:

Swapping from 3.23s to 3.42s is a waste of money. There is barely enough gain to justify the cost of a bottle of gear oil and additive, no less buying the gears. If you have 3.23s your next move is to 3.73s.

If you don't have a high stall torque converter, you really should look at that first. The big gains come from a converter, not from gears. You'll be amazed what a 3000 stall converter will do to the launch of a 2.73 geared car. Look in the automatic transmission forum for more info on them.