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Cannot decide on gear ratio for rear end for Stalker XL


jevs

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3.23, 3.42, or 3.73

 

Here are some quick numbers and a couple stock comparison cars with LS3 motors also. This is shifting out at 6200. Of course it negates wind resistance etc. Numbers are in MPH.

 

3.23 3.42 3.73 Vette Camaro

1st 55 52 47 54 51

2nd 82 77 71 81 74

3rd 112 106 97 111 107

4th 145 137 126 145 153

5th 182 172 157 196 182

6th 231 218 200 289 269

RPM @70 MPH 1881 1992 2173 1504 1614

Edited by jevs
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If we compare to yours, we probably need to know the transmission and tire specs. This is what I based those numbers on above.

 

Model:TUET11009

Transmission:T56 Magnum Close Ratio

Engine:LS376/480

Gear

1st 2.660

2nd 1.780

3rd 1.300

4th 1.000

5th 0.800

6th 0.630

Reverse 2.900

 

Rear Tire Size 315/30R18

Wheel 18" x 10.5"

Tire Diameter 25.440"

 

 

So, is there anything much different about yours than this, and are you happy with the 3.42 ? 3.73 was recommended to me, but I am not so sure after looking at these numbers....???

Edited by jevs
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I have a T-56 out of a GTO

1st: 2.97

2nd: 2.07

3rd: 1.43

4th: 1.0

5th: .84

6th: .63

 

tires: 255/40ZR17, 25" diameter

wheels: 17X9

 

LS3 w/430hp, 424 lb. ft. storque

 

I am happy with the 3.42, but really have nothing to compare the car to as these cars are the most insane thing you will ever drive.

 

Traction, or the lack thereof, off the line really limits the potential of my car. 1st gear is unusable. 2nd gear works just fine 99% of the time, but it is super easy to break the tires loose under moderate acceleration. Tire spin in 3rd and up is not a problem.

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Okay, here’s sum more meat n’ taters :jester:

 

I’m running a Tremec TKO 600 geared as follows:

 

1st: 2.87

 

2nd: 1 .89

 

3rd: 1.28

 

4th: 1.00

 

5th: .82

 

My LSD gearing is 3.23. I’ll use two different tire sizes for examples; the smaller Avon slicks I used to run prior to stepping up to the larger Avon’s that I now run, and the Nitto NT01’s I currently run on the street.

 

Theoretical top end speeds are assumed using 6500 rpm and a nil drag coefficient.

 

Speed = RPM x Tire Circumference x 60 / (Differential Ratio x Transmission Final Drive Ratio x 12 x 5280)

 

Max Engine RPM: 6,500

 

Tire Circumference: 67.08 (Avon crossply slick: 10.7/21.5-15 with 21.85” OD)

 

Differential Ratio: 3.23:1

 

Transmission Final Drive Ratio: .82

 

6500 x 68.172 = 443,118

 

443,118 x 60 = 26,587,080

 

3.23 x .82 = 2.6486

 

2.6486 x 12 = 31.7832

 

31.7832 x 5,280 = 167,815.296

 

26,587,080 / 167,814.296 = 158.43mph

 

Speed = RPM x Tire Circumference x 60 / (Differential Ratio x Transmission Final Drive Ratio x 12 x 5280)

 

Max Engine RPM: 6,500

 

Tire Circumference: 77.7504 (Nitto tire: NT01 255/40ZR17 with 24.92”’OD)

 

Differential Ratio: 3.23:1

 

Transmission Final Drive Ratio: .82

 

6500 x 77.7504 = 505,377.6

 

505,377.6 x 60 = 30,322,656

 

3.23 x .82 = 2.6486

 

2.6486 x 12 = 31.7832

 

31.7832 x 5,280 = 167,815.296

 

30,322,656 / 167,814.296 = 180.69mph

 

Using the 3.23 gear ratio, 6500 rpm and the Nitto NT01’s from the above example, max theoretical speed for each transmission gear (sans overdrive, as discussed above) would be as follows:

 

1st: 2.87 51.97 mph

 

2nd: 1 .89 78.91 mph

 

3rd: 1.28 116.52 mph

 

4th: 1.00 149.14 mph

 

. . . . . . . . :svengo:

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I have a set of 2:73 gears for a S10 rear, may Shane could use these to help get traction :)

 

I wonder . . . . with the 2.73 (and enough motor) if the lack of aero could be overcome long enough to see 200 mph . . . . . :rofl:

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I have a T-56 out of a GTO

1st: 2.97

2nd: 2.07

3rd: 1.43

4th: 1.0

5th: .84

6th: .63

 

tires: 255/40ZR17, 25" diameter

wheels: 17X9

 

LS3 w/430hp, 424 lb. ft. storque

 

I am happy with the 3.42, but really have nothing to compare the car to as these cars are the most insane thing you will ever drive.

 

Traction, or the lack thereof, off the line really limits the potential of my car. 1st gear is unusable. 2nd gear works just fine 99% of the time, but it is super easy to break the tires loose under moderate acceleration. Tire spin in 3rd and up is not a problem.

 

I can see where 1st gear would be pretty bad for you :) That jump from 3rd to 4th is pretty big too.

 

Here is your car plugged into my initial post so you can compare.

 

1st 42

2nd 60

3rd 87

4th 124

5th 147

6th 197

RPM @70 MPH 2027

 

25.03" Diameter Tire

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Interesting thread as I'm getting ready to order my Stalker XL and was wondering the same thing. I was also kicking around the tranny choices, 6 speed vs. 5 speed. In all these cases, 6th gear is only used while crusing on an interstate wanting to keep low revs. Since I don't plan on "cruising around" with this car, I wondering the wisdom of a 6th useless gear. However, as Scott at Brunton explains, the T56 Magnum is a beast of a tranny when properly prepared and will give long life.

 

I'm leaning towards the 3.42 but am also concerned about uncontrollable wheel spin. Point being if your wheels are spinning, you aren't moving very fast. I don't plan on ever drag racing the car, strictly road racing. Has anyone run a paddle shift automatic in one of these ?

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The 3.42 is the best deal price wise.

The 3.73 is also hard to find right now. Only 2 in the country available at the moment and you would have to buy them from those dealers, and they most likely won't match these prices. I know one won't for sure. I did not ask the other yet because I want to figure out which ratio I want for sure.

 

Ratio P/N ~Price

3.73 25873497 $804.57

3.42 25873500 $696.76

3.23 25978162 $736.65

 

The 3.23 would put my gearing pretty darn close to a stock C6 Z06.

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Interesting thread as I'm getting ready to order my Stalker XL and was wondering the same thing. I was also kicking around the tranny choices, 6 speed vs. 5 speed. In all these cases, 6th gear is only used while crusing on an interstate wanting to keep low revs. Since I don't plan on "cruising around" with this car, I wondering the wisdom of a 6th useless gear. However, as Scott at Brunton explains, the T56 Magnum is a beast of a tranny when properly prepared and will give long life.

 

I'm leaning towards the 3.42 but am also concerned about uncontrollable wheel spin. Point being if your wheels are spinning, you aren't moving very fast. I don't plan on ever drag racing the car, strictly road racing. Has anyone run a paddle shift automatic in one of these ?

 

There is one out there, but I don't think it is done yet?? A GM paddle shifted auto would not be like a Ferrari or Lamborghini. Its just an automatic with a torque converter and paddle shift controls (slower shift). I have read they can be sped up a little with programming. The paddle shift cars that use an automated clutch are actually faster around the track than a manual, but they eat clutches fast and they are expensive and not as friendly on the street.

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Wow, heck of a deal for a brand new diff. Are there any gears in this one ? (Just kidding). I agree with you, the 3.42 is the best compromise. By the way, the wife's 07 Vette has the paddle-shift tranny and it does shift slowwwwwly. New Vette trannies are supposed to be quite fast, and the new Z06 will be available with it. Claims made are that it is as fast as any DPK tranny out there. Time will tell.

Edited by Klasik-69
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I'm late to the party. FWIW I went 3.23.

 

When I road raced my old 02 Z-28, it had the LS1/T-56, 275/40/17s, and a 3.42. Launch was an issue and 1st gear was already a tire burner. So, I actually wanted the 3.23 gear set the auto's had. There were a few corners I would just run out of 3rd gear, and only need 4th for a second. I figured w all the V-8 torque, I could pull a higher (numerically lower) gear and do less shifting.

 

I have yet to fire mine (hopefully soon!), but I'm guessing all the Z-28s issues will be quite exaggerated having more power and 1/2 the weight. So, the less shifting, the better.

 

I am also curious to see what the top end will be. I realize the aero is not ideal, but I still want to do a standing mile event just to see how it fairs.

 

Mike, that video was cool. Have you considered running a drag radial? I may run one on the street, but Brunton doesn't like that idea much.

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What tire size are you going to run with the 3.23's? Are you using the same transmission as me?

 

Edit: I see from your build that your using a different trans, so our ratios will be a lot different (aside from the diff ratio).

Edited by jevs
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