Why not 3:07?

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Oct 24, 2002 | 06:36 PM

aj1988

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From: The Colony Tx

Why not 3:07?

I have read a lot of posts about replacing the 2:59 (?) with another ratio. But the one number never mentioned is the 3:07. I seem to remember that this was supposed to be the performance axle for an automatic.

Also, you never read a discussion on the actual performance with 3:07. Anyone with an L98/auto have 3:07? How do they run? What are your 1/4 mile times and speeds?

:seeya

Oct 24, 2002 | 06:38 PM

chucks88

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From: Connectivette

Re: Why not 3:07? (aj1988)

I swapped from 2.73's to 3.07's and felt a diff. check out my page for times.

700R4/L98

Oct 24, 2002 | 06:38 PM

Springer's LT4

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From: Pinellas Florida Misfit

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Re: Why not 3:07? (aj1988)

The 3.07 is often recommended here as the perfect gear for the L98 cars... even cars running into the 11's work well with this gear. Anything more then 3.07 and you start to put the car out of it's power range to quickly.

Oct 24, 2002 | 08:56 PM

LT4BUD

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From: Hinckley Ohio

Re: Why not 3:07? (aj1988)

As I remember a magazine test comparing either '89 or '90 L98 vettes reported the auto with performance axle (3.07) ran 14.1 at about 100mph, the 6 speed just a tad faster at 14.0 at about 101 mph, and the auto with std axle (2.59) ran about 14.8 and I don't recall the speed. I need to go find this article as I know I have saved it somewhere. About the only test ever I recall that compared all the tranny/rearend combinations, usually the magazines only test the fastest version.

Oct 24, 2002 | 11:45 PM

vader86

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Re: Why not 3:07? (aj1988)

Quote:

3.07 is the perfect gear for L98, its the LT1s that really need the 3.54/3.73 switchover because their power band is at a little higher rpm.

I dont know if we've ever really compared the 2.73 L98 to 3.07, but i have seen people lose times when they go to 3.54s in a STOCK L98, and Beach Bum (i think) didnt gain any time with his Superram L98 when he switched gears from 3.07 to 3.45(?)

Oct 25, 2002 | 07:58 AM

1SLO POK

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From: Torrance California

Re: Why not 3:07? (aj1988)

On my 85 Auto I switch from 2:59 to 3:07. Now I can get MEAN 2nd GEAR CHIRPS :D :D :D :D With the 2:59....forget about it.....I couldn't even do a burn out from a dead stop :lol: :lol:

Oct 25, 2002 | 10:59 AM

smittyvette57

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From: Manchester MA

Re: Why not 3:07? (1SLO POK)

I have 2.59's in my 86 did you have to replace the carrier? My father might be getting gears for his 85 it has 3.07 now can I use these in my car?

Oct 25, 2002 | 11:17 AM

vader86

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Re: Why not 3:07? (smittyvette57)

Quote:

I have 2.59's in my 86 did you have to replace the carrier? My father might be getting gears for his 85 it has 3.07 now can I use these in my car?

Is his 85 a manual? Manuals have a D44 carrier, all A4s have a D36 carrier and those will just switch over.

But if you could switch over to a D44, itd be good. That rear can handle serious drag racing.

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Oct 25, 2002 | 11:34 AM

hz900

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From: The Black Hole LA

Re: Why not 3:07? (vader86)

Quote:

Is his 85 a manual? Manuals have a D44 carrier, all A4s have a D36 carrier and those will just switch over.

I have been told that there are two different kinds of D36 carrriers and the gears will not swap. Someone here on the forum replied to a post I had made a while back about a series 2 and series 3 D36. The 2.59 is the series 2. What he said is that he was trying to get new gears for his auto w/2.59 and ran into this problem. I myself have yet to research this though and can't remember who it was.

[Modified by hz900, 9:34 AM 10/25/2002]

Oct 25, 2002 | 11:38 AM

#10

vader86

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Re: Why not 3:07? (hz900)

Well they did change the D36 on later years, LT1 D36s are different.

On his years it will work.

Oct 25, 2002 | 11:42 AM

#11

scorp508

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From: Boston, MA

I'm debating going to a 3.73 to help avoid a slight bog on launch and since I've got about 6200 RPM to play with now. Not sure yet since nobody seems to show a gain.

Oct 25, 2002 | 11:47 AM

#12

vader86

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Re: (scorp508)

Have you tuned it yet?

Oct 25, 2002 | 11:48 AM

#13

scorp508

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From: Boston, MA

Quote:

Have you tuned it yet?

Nope, no decisions will be made until I do since I feel there is a crapload of torque to be found with leaning it out down low.

Oct 25, 2002 | 11:52 AM

#14

KyleBst264

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From: Rehoboth MA

Re: Why not 3:07? (aj1988)

My 85 is basically stock (has Automatic trans) w/3.07 gears and on street tires. Here are a some 1/4 mile numbers for you.

Sunday September 1, 2002 9:11 AM

R/T: .537
60': 1.922
330: 5.703
1/8: 8.915 @76.49 mph
1000': 11.693
1/4: 14.052 @ 95.54 mph

September 1, 2002 2:58 PM

Dial: 14.02
R/T: .514
60': 1.929
330' : 5.712
1/8: 8.911 @76.87
1000': 11.674
1/4: 14.017 @ 96.27 mph
(Other guy redlighted on this one, BTW)

On the way to and from the track, I'm getting approx. 22-24 mpg

Oct 25, 2002 | 11:59 AM

#15

smittyvette57

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From: Manchester MA

Re: Why not 3:07? (hz900)

Both of the cars are auto D36 and you confirmed what we thought. To be sure are there any distinguishing #'s to ID series 2 from 3, his is apart on the bench mine is in the car so we can't compare side by side, thanks.

Oct 25, 2002 | 01:03 PM

#16

Ron78Z&66Vette

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From: Derby Kansas

Re: Why not 3:07? (aj1988)

My times are below. Mine came with the 3.07's.

Oct 25, 2002 | 01:12 PM

#17

TIMSPEED

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From: Modesto CA

Re: Why not 3:07? (Ron78Z&85Vette)

I think the 3.07's MIGHT make a different, but not much of a difference to validate like a $300-$500 swap. Maybe like a $100-$200 swap, yeah. (I'm meaning swapping from a 2.73 to a 3.07. If you have a 2.59, DO A SWAP!) I had 2.73's in my 85, and bone stock it ran a 14.0@101. I think where the 2.73's help, is getting a high mph. With 3.07's in my 87, I've still YET to see a 101mph timeslip. (and I'm getting it to 13.5's)