Is there any way to change the 4th gear ratio from .70(or .75?) to .50 like the m6s?

 

It's not that simple to do with a A4. I have heard of an after market planet that is out there but I personally have not seen it.

 

I too have heard theres one out there but apparently its only theoretically out there since all calls made attempting to get one came up not available

 

Thats gay. I was hoping maybe to install one

 

I wouldn't, going from 1:1 to .5:1 I'd imagine would kill fourth pretty quick.
I have 3.73's and 6th gear sucks unless you're going 80mph.

With 3.73's and a 4L60E with a .5 4th you'd be dropping 2000 rpm during the 3-4 shift.
And that would be 4000 rpm in 3rd to 2000 rpm in 4th at 80 mph.

 

I got his idea when I was looking at gas mileage for m6s and a4s. You could have the consistancy of an a4 with the mileage of an m6. 4th gear would only be used on the highways

 

Ok so you'd get the consistancy of an A3 with the advantage of a .5 OD.

Whoever were to build this needs to do a lot of R&D. Like I said my M6 car even with 3.73's is a pain to drive in 6th because it either lugs (low cruise rpm) and needs to downshift, or you need to drive above 70 on flat ground.

I can imagine a 2000 rpm upshift and downshift driving on a hilly road would kill gas mileage and your nerves.
Maybe if you ran higher (numerical) rear gears it might work in OD, but you're going to be revving pretty damn high before it hits OD so there goes the mileage.

 

I planned on originally getting 4.10s. To get to anywhere around here you have to take a 70mph parkway and my 323s are annoying as hell none the less. I was planning on just cruising around in town all the time in 3rd and when im going to go somewhere I could just throw her in D.

 

One thing you need to consider if your thinking you'll benefit from 0.50 overdrive Vs 0.70 with your rear end ratio is weight and COD of car/truck. Drop out of the engines power band thinking lower RPM will improve mileage will have the oppsite effect as you will have to use more throttle pedal to maintain speed.

You picked your rear end to try and get your lead sled to accelerate faster with it's 1st, 2nd, 3rd gear ratios. Have no idea if you can change 1-3 gear ratio's, but hopefully you can see from the data below is exactly what GM/Ford did with the 6sp auto GM desinated 6L80/90 transmission to get the weight moving yet get better gas milage too.

Depending on purpose, weight and COD of car/truck they just use higher or lower rear end ratio that provides best combination of acceleration and gas mileage.

What I've tried to show is 6sp manual vette with 3.42 ratio, compared to vette with 6sp auto with 2.56 stock ratio and 2.76 performance ratio, along with 3.07 ratio I'm using with trans and 2.97 ratio if I remeber correctly is what is ued in the GTO. Again if I remembered correctly due to the weight of the new G8 Pontiac they use a 3.27 ratio to get it moving yet still get decent mileage. If you look at numbers in RED at end of MM6 trans, that is the rearend ratio a manual 6 sp vette would need to in 1-6 to match what 3.07 ratio produces with the 6L80/90 in same gears. Then check out that the 6L80/90 1.15 4th gear ratio produces the same ratio as a 4L60/5 3th 1:1 ratio with 3.55 rear end, while 1 & 2 gears of the 4L60/5 with 3.55 can't match the 6L and it still has 3rd gear which is not that bad either compared to the 4L60/5 3rd gear with 3.55.

Gear ratios:MM6... 3.42.......3.07
First:......2.66...... 9.1109... 8.17848...2.66 X 4.64 =12.3610
Second:. 1.78...... 6.0979... 5.47381.. 1.78 X 4.06 = 7.2390
Third:.... 1.30...... 4.4528... 3.99714.. 1.30 X 3.61 = 4.7002
Fourth:.. 1.00...... 3.4200... 3.07....... 1.00 X 3.53 = 3.5300
Fifth:..... 0.74...... 2.5342... 2.27487.. 0.74 X 3.52 = 2.6083
Sixth:.... 0.50...... 1.7168... 1.54114.. 0.50 X 4.10 = 2.0532
Reverse:. 2.90
Final Drive Ratio: 3.42

Gear ratios:MYC.... 3.42...... 3.07........2.56.......2.76.......2.97
First:..... 4.03...... 13.7826.. 12.3721.. 10.3168..11.1228..11.9691
Second:. 2.36...... 8.0712... 7.2452.....6.0416....6.5136....7.0092
Third:.... 1.53...... 5.2326... 4.6971.....3.9168....4.2228....4.5441
Fourth:.. 1.15...... 3.9330... 3.5305.....2.944......3.1740....3.4155
Fifth:..... 0.85...... 2.9070... 2.6095.....2.176......2.3460....2.5245
Sixth:.... 0.67...... 2.2914... 2.0569.....1.7152....1.8492....1.9899
Reverse: -3.06
Maximum shift speed 6500 rpm

Gear ratios:4L60E.. 3.42...... 3.07.......3.55
First:......3.06...... 10.4652...9.3942....10.8630
Second:..1.63.......5.5746.....5.0041....5.7865
Third:.....1.00.......3.4200.....3.07.......3.5500
Fourth:...0.70.......2.3803.....2.13672...2.4708
Reverse: 2.29