Gears: 3.42 or >?
Thread Starter
Burning Brakes
Joined: Sep 2011
Posts: 764
Likes: 19
From: odessa FL
Gears: 3.42 or >?
Since it looks like rebuild time for the rear, considering upgrading to some C6 parts and possibly a ratio change. [01 m6 STS Turbo]
Anyone gone deeper and regretted it? With the .5 OD, the dif with 4.10 is ~300 RPM @70. Maybe 3.73/ 3.90? Traction might be worse but it would definitely turn on faster.
Is the 3 rib Zo6 case that much better?
OR: While the trans is out, upgrade to M12 with better ratios and stay with 3.42 or 3.73?
Thoughts?
Anyone gone deeper and regretted it? With the .5 OD, the dif with 4.10 is ~300 RPM @70. Maybe 3.73/ 3.90? Traction might be worse but it would definitely turn on faster.
Is the 3 rib Zo6 case that much better?
OR: While the trans is out, upgrade to M12 with better ratios and stay with 3.42 or 3.73?
Thoughts?
Melting Slicks
Joined: Jan 2009
Posts: 2,127
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From: Easley/Anderson South Carolina
There is a gut in Atlanta selling his M12 trans for $500. I think the gear ratio in the Z06 are quick enough and could not imagine changing my rear diff gear to something lower.
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I'm running 3.90's along with an RPM Level V configured as an M12. This set-up has totally transformed my mostly stock LS1. I love this combination. It makes 6th gear a driveable gear, meaning that I can pull out and pass someone at 70mph without downshifting.
Around town - I find myself in a higher gear than I used to, but that is not a bad thing. Overall - I am very happy with this set-up!
Around town - I find myself in a higher gear than I used to, but that is not a bad thing. Overall - I am very happy with this set-up!
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3.73s or 3.90s would be a good upgrade. 
Race Director
Joined: Mar 2007
Posts: 18,308
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From: Marlton. Increasing performance one speeding ticket at a time! NJ
I'm running 3.90's along with an RPM Level V configured as an M12. This set-up has totally transformed my mostly stock LS1. I love this combination. It makes 6th gear a driveable gear, meaning that I can pull out and pass someone at 70mph without downshifting.
Around town - I find myself in a higher gear than I used to, but that is not a bad thing. Overall - I am very happy with this set-up!
Around town - I find myself in a higher gear than I used to, but that is not a bad thing. Overall - I am very happy with this set-up!
I'd recommend staying with 3.42s or upgrading to 3.73s at most. The M12 gearing was designed to get the most out of the the higher RPM range of the LS6. Cammed M6 cars work great with 3.90 or 4.10.
But since you've gone the FI route, that extra torque in 1st gear could be insane with lower gearing and an M12. You have to decide if that's what you want.
Burning Brakes
Joined: Jun 2010
Posts: 769
Likes: 1
From: Columbia TN
I'm running 3.90s in my 04Z and along with that I've had a touch of head work done along with a mid range cam and bolt ons. My Nitto Invos CAN NOT hold traction. I can certainly drive in the city but I have to pay attention to my right foot at a stop light. It's made the car a little more difficult to drive since there is so much power so quickly. BUT I wouldn't change it at all. The small trade in ease of driving was worth it to me to get into the power band at an instant.
Overall I couldn't be more happy with the change, but since your turbo'd anything over 3.73 w/M6 could be interesting to drive to say the least.
Overall I couldn't be more happy with the change, but since your turbo'd anything over 3.73 w/M6 could be interesting to drive to say the least.
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Thread Starter
Burning Brakes
Joined: Sep 2011
Posts: 764
Likes: 19
From: odessa FL
The lag on the BW Bullseye turbos is not bad compared to a lot of complaints you hear about the STS kits, full 10# at 3500. Thinking that the gear or the lower ratios in the M12 [Not both!] would help it hit harder and faster. But yep, traction may be an issue!
I love the kick in the a$$ of lower gears and have always found them a great bang for the buck. But I have tended to go too far in the past. My Monza has 4.88s, a 700R4 4000 stall converter and small blower. Wonder why it wont hook...?
I love the kick in the a$$ of lower gears and have always found them a great bang for the buck. But I have tended to go too far in the past. My Monza has 4.88s, a 700R4 4000 stall converter and small blower. Wonder why it wont hook...?
