C5 Differential question
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Joined: Dec 2014
Posts: 58
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From: Homosassa FL
C5 Differential question
I have a question and i'm curious what advice is out there.
I've got a 2003 with 2.73 gears currently. The car has a stock LS1 with a D1 supercharger and pushes 534 hp at the wheels. I'm going to do some upgrading to the driveline to include changing the rear differential, going with a new TQ and new transmission. Before I get back to the engine compartment. I've seen a lot of back and forth as to 3.15 or 3.42 and the value of 3 rib vs 1 rib. Im looking for an honest viewpoint as to gear size and case strength. 3.42 1 rib cases are going for much less money than 3 rib cases and 3.15 gears with the 3 rib are also very reasonable. So im just looking for real world experience. Mostly a weekend driver but it will see the track a couple times a year just to play with it.
I've got a 2003 with 2.73 gears currently. The car has a stock LS1 with a D1 supercharger and pushes 534 hp at the wheels. I'm going to do some upgrading to the driveline to include changing the rear differential, going with a new TQ and new transmission. Before I get back to the engine compartment. I've seen a lot of back and forth as to 3.15 or 3.42 and the value of 3 rib vs 1 rib. Im looking for an honest viewpoint as to gear size and case strength. 3.42 1 rib cases are going for much less money than 3 rib cases and 3.15 gears with the 3 rib are also very reasonable. So im just looking for real world experience. Mostly a weekend driver but it will see the track a couple times a year just to play with it.
Melting Slicks
Joined: Nov 2008
Posts: 2,938
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From: Rochester Hills MI
As you increase the gear ratio, more force is put on the differential carrier. In any case, I'd get a dte diff and trans brace with at least a poly trans mount with that much power. Definitely go with the 3-rib.
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Joined: Jan 2011
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From: Fort Wayne Indiana
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Joined: Dec 2014
Posts: 58
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From: Homosassa FL
Thank you for the responses, I figured the 3 rib was kind of the way to go. Im still curious as to the real difference between 3.15 or the 3.42 ? my understanding is that it is pretty imperceptible. Since I have to change the entire Differential anyway im a bit torn on the gears. I obviously need to change the 2.73's. I could go as high as 3.73 but im thinking the performance gain from 3.42 to 3.73 probably wouldn't be worth the fuel consumption for a car that wont regularly see the drag strip any thoughts on this. Thanks for all of the input this is truly a great site with some seriously knowledgeable people.
Heel & Toe
Joined: Mar 2016
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Thank you for the responses, I figured the 3 rib was kind of the way to go. Im still curious as to the real difference between 3.15 or the 3.42 ? my understanding is that it is pretty imperceptible. Since I have to change the entire Differential anyway im a bit torn on the gears. I obviously need to change the 2.73's. I could go as high as 3.73 but im thinking the performance gain from 3.42 to 3.73 probably wouldn't be worth the fuel consumption for a car that wont regularly see the drag strip any thoughts on this. Thanks for all of the input this is truly a great site with some seriously knowledgeable people.
Melting Slicks
Joined: Nov 2008
Posts: 2,938
Likes: 65
From: Rochester Hills MI
You need to find someone with around the same power you're making and see what they think about the ratio they are running. Go ahead and make a new thread and call it something like "What gear ratio for 534whp auto on street tires?". Be sure to mention what size/type of tires you are running and how you plan on driving the car. Also mention that you have an automatic.
I'm thinking with street tires and 534whp, you might start having some traction issues with higher gear ratios. Only experience will tell though. I'm only making around 385hp at the crank in a 6 speed, so my opinion on this matter isn't very valuable for your case. Good luck!
I'm thinking with street tires and 534whp, you might start having some traction issues with higher gear ratios. Only experience will tell though. I'm only making around 385hp at the crank in a 6 speed, so my opinion on this matter isn't very valuable for your case. Good luck!
