3.90's Anyone?
11 Second Club
Joined: Jun 2005
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From: Was New Orleans, but swam to Baton Rouge
Originally Posted by z062424
I'm looking for a little bit more low end torque. I don't feel i'm utilizing all my power with my stock 3.42's. Does anyone have any input on a 3.90?
On The Tree
Joined: Nov 2005
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From: Stillwater, OK
So the 3.90s are worth the change from 3.42? I take it you need a sticky tire to hook up 3.90 with the mn12 tranny, but you see a good gain? Also how is it installing gears in z06 as compared to an fbody or something? Thanks, I had 4.10s in my ls1 and my stang so I am used to steep gears anyways.
You need sticky tires to hook up with the stock gears. 3.90s just put you into the powerband sooner, they actually make the car easier to launch than with the stock gears. I had 3.90s in my C6, it made a nice difference.
11 Second Club
Joined: Jun 2005
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From: Was New Orleans, but swam to Baton Rouge
Originally Posted by okls1
So the 3.90s are worth the change from 3.42? I take it you need a sticky tire to hook up 3.90 with the mn12 tranny, but you see a good gain? Also how is it installing gears in z06 as compared to an fbody or something? Thanks, I had 4.10s in my ls1 and my stang so I am used to steep gears anyways.
Trending Topics
Originally Posted by Sigforty
I had the whole rear chukc swapped as I wanted hardened shafts as well. Sticky tires were required at the track stock now for the street I had to add them once I hit 450 rwhp. The car was not safe on anything but a drag radial at that power level on the street.
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11 Second Club
Joined: Jun 2005
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From: Was New Orleans, but swam to Baton Rouge
Originally Posted by okls1
can you buy the gears alone or has everyone bought the dte diff? I just dont know how I feel about spending 1300 on gears 
TECH Apprentice
Joined: Aug 2006
Posts: 348
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From: Atlanta
If you have an m12 (z06 tranny) your 3.42 is very close to a 3.90 in a standard vette (m6 tranny). I would suggest no more than a 3.73 for you cause a 3.90 is a crap load of gear changing. If you must have a 3.90 then expect frequent gear changes and forget road racing. If this is a daily driver I really would not go any more than 3.73. I would also not look anywhere other than DTE. They offer many different choices and all their rear diffs are THE BEST out there.
I have a 3.90 in a standard tranny and it is a handfull. I tach to red line in first at about 35 to 40 mph, so you see that the lower gears are not going to be used very long. I can easily start off in second and go right to fourth with no problem. That being said, sixth gear is no longer a cruse gear but something that has a little torque to it. You will also loose a little HP on the dyno with stronger gearing. Good Luck!
I have a 3.90 in a standard tranny and it is a handfull. I tach to red line in first at about 35 to 40 mph, so you see that the lower gears are not going to be used very long. I can easily start off in second and go right to fourth with no problem. That being said, sixth gear is no longer a cruse gear but something that has a little torque to it. You will also loose a little HP on the dyno with stronger gearing. Good Luck!
Last edited by Mr.427; Feb 9, 2007 at 02:04 PM.
Thread Starter
Staging Lane
Joined: Nov 2006
Posts: 88
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From: North Carolina
Hmm...Interesting thoughts about the 3.73. It's a weekend warrior but I am a road racer at heart. I grew up racing open wheel cars. I'm not so much of a drag racer but I sure do like to smoke people on a 3rd gear pull. It's hard to have the best of all worlds....
TECH Fanatic
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From: Elmhurst, IL (Chicago Suburb)
Get the 3.90s and don't even think twice about it. I had 4.10s in a stock bolt on C5 Z06 and it was a RIOT and I went road racing with no issues, except faster acceleration and faster shifting, which always makes more FASTER FUN!! 
With that big cam you have you are LOSING some low end grunt and the 3.90s will be JUST WHAT the Doctor ordered to make up for it and then some!! DO IT, DO IT!
With that big cam you have you are LOSING some low end grunt and the 3.90s will be JUST WHAT the Doctor ordered to make up for it and then some!! DO IT, DO IT!
Last edited by MTI 427 C5 Roadster; Feb 11, 2007 at 02:28 PM.
On The Tree
Joined: Dec 2006
Posts: 109
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From: Staten Island, NY
Originally Posted by z062424
Pewtavert...your car must move! Any video of it
The last time out at the track I ran a 11.96 @ 116 mph and that was before the Supercharger. I can't wait to see what she can do now. 
