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A4 with 3.73's

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Old Nov 2, 2008 | 02:23 PM
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Default A4 with 3.73's

alright guys im thinking of doing 3.73 in a a4 02 z28.last week it ran a 12.48@112.36 with a 1.98' on 2.73 gears.stock stall

1.how much et can I drop with a gear swap/mph

2.are you happy with your 3.73's if you could pick a gear again what would it be.

3.how long did your 10 bolt last.what kind of 60'.is it holding up or did it break.

thanx guys let me know the good,bad,and the ugly
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Old Nov 2, 2008 | 02:49 PM
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Jusy had mine installed about two weeks ago. Haven't taken it to track yet but it feels a lot quicker down low. Very hard to find any traction tho with my set up. I'd do it if I were you. I came from 2.73 also and I didn't like them at all
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Old Nov 2, 2008 | 02:51 PM
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i swapped out my 2.73 to 3.73. but i also did a 3200 stall, and a cam. it definitely woke up the car big time. i think alot of guys will tell you 3.73 are the way to go with an A4. i think the 10 bolt will hold up for awhile from what i have always read on 10 bolts in autos. just as long as you dont put slicks and stuff like that.
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Old Nov 2, 2008 | 06:31 PM
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3.73's seem like a all around good gear for me,I plan on trapping 127mph on a 150 shot.Right now I want to hit 115mph stock internal.

any reason not to put 3.73,maybe go with 3.42?
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Old Nov 4, 2008 | 10:20 AM
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anyone else?
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Old Nov 4, 2008 | 12:29 PM
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I've got 3.73s in my 10 bolt. Had a 1.50 60 foot time last month. I run a 28 inch M&H DR, though. Trapped 137. I lock my TC in top gear which knocks the rpm down. I go through the lights @ 6000, I think. I don't watch the tach @ 137 mph
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Old Nov 7, 2008 | 12:00 PM
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Originally Posted by fly pantera
3.73's seem like a all around good gear for me,I plan on trapping 127mph on a 150 shot.Right now I want to hit 115mph stock internal.

any reason not to put 3.73,maybe go with 3.42?
im going with 3.42 cause my car sees the expressway often.
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Old Nov 7, 2008 | 02:17 PM
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3.73 is a good ratio for an automatic.
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Old Nov 7, 2008 | 03:21 PM
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Love my GM 3.73's! Great upgrade!
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Old Nov 7, 2008 | 03:35 PM
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good choice..see my sig.
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Old Nov 7, 2008 | 04:14 PM
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Unless you use the car just for the track or the track and in town driving you will be much happier going with a 3.42. Sustained highway speeds with a 3.73 is not pleasant, I went from 2.73 to 3.73 and less than a month later went to the 3.42. Much happier now.
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Old Nov 7, 2008 | 04:26 PM
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Originally Posted by OEM_TA
Unless you use the car just for the track or the track and in town driving you will be much happier going with a 3.42. Sustained highway speeds with a 3.73 is not pleasant, I went from 2.73 to 3.73 and less than a month later went to the 3.42. Much happier now.
3.73 on the hwy are not that bad. I drive a lot of hwy miles during the summer and it's not bad at all. I would say if you drive a butt load of hwy to go 3.42. If it's more track/around town and hwy every so often 3.73 without a doubt.

Last edited by Elliott's94Z; Nov 7, 2008 at 04:47 PM.
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Old Nov 7, 2008 | 05:12 PM
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I always figured that gears were fine but the only thing that makes hwy driving unpleasant if you do allot of it is a high stall. .... I.E.: 4000 stall
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Old Nov 7, 2008 | 11:03 PM
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If you're worried about highway rpm, just get taller tires. I run 70 mph @ 2000, give or take with my 28s and 3.73s. I even get 20 mpg on the highway.
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Old Nov 8, 2008 | 07:25 AM
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I'm going to put 3.73s in mine next week. Just bought the car and one of the bearings in the rearend is making noise, so that was all the reason I needed. The difference between a 3.73 and a 3.42 is probably only like 200 rpm at highway speeds. I know I changed the gear in my 4x4 this summer and went back and forth on it and decided with a 4.56 and my tires measure like 33.5(suppose to be 35). So other than the traction I don't see anything wrong with the gear because these motors love rpms.
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Old Nov 8, 2008 | 08:29 AM
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I like my 3.73 gears. I daily drive my car on the highway.
You should pick up .2 to.3 in the 1/4.
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Old Nov 8, 2008 | 07:43 PM
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3.73 gear is ideal for A4 street/strip. Stoplight to stoplight, 4.10's. in my opinion.
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Old Nov 8, 2008 | 09:04 PM
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what would you pick up going with 3.42' from 2.73 ?
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Old Nov 9, 2008 | 12:46 PM
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the car rarely sees the highway,but when it does its only like 30miles.im leaning towards the 3.73.

thanks for all the opinions
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Old Nov 9, 2008 | 12:49 PM
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I have 3.73's and they're great.. actually thought about bumping up to 3.90's when I rear end swap but kind of decided against it.

I'd almost just tell you to save the money and put it in your new rear end fund. The 10 bolt isn't much but an oversized paper weight IMHO. So throwing money into it for temporary fun isn't solving the long term problem of an inferior part. But it's your decision and you have to pay to play either way..
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