LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Stock 2.73 to ??

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Old Feb 13, 2012 | 08:26 PM
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Default Stock 2.73 to ??

Ok so i have a stock 93 Z and have the 2.73's how bad will switching to a 3.73 or even 3.42 affect top speed? ive heard stock LT1's with 2.73 are good for about 155mph, but ive only been to 140mph in my car. im looking for quicker acceleration. 0-60mph is claimed 5.7seconds about how much quicker will going 3.73 or 3.42 get me??
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Old Feb 13, 2012 | 08:35 PM
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Ive ran 343s, 373s, and 410s. My favorite was the 410s but the top of 3rd isn't much over 100. Id go with the 373s if you are worried about top speed. That said be careful, theres no need to go that fast.


EDIT: I ran the 410s on a cammed car shifting at 6200 rpms and a 2800 stall. They seemed to work well together, never took it to the track.

Last edited by IronOutlaw; Feb 13, 2012 at 08:43 PM.
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Old Feb 13, 2012 | 08:37 PM
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Wind resistance and horsepower become limiting factors in obtaining top speed before gearing in a stock f-body.

Gearing for top speed is ridiculous anyway considering the opportunities to reach your top speed are about 1% of the opportunities to stomp your car from a dig.

There's no magical number in determining your 0 to 60. If you're that concerned go out and buy a Gtech and see what happens. They're fairly accurate.

Also, slow down.
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Old Feb 13, 2012 | 08:38 PM
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I've got 4:10's and love em' get that pick up and on the expressway when I am at 70-75 mph i am at about 3k rpms. Ive haven't tried to see how fast i can max it at but i have hit 120.
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Old Feb 13, 2012 | 08:39 PM
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Ive hit 164mph in my 3.42 A4 car according to GPS...

0-60 times and top speeds are mostly for paper racing though.

A 2.73 to 3.73 will likely yield you a few .1's in the 1/4 mile, but gear upgrades aren't all they're cracked up to be. The most important part of picking gears is:

-Matching it to run most effectively with stall size and rear tire height
-Matching it to your 1/4 mile run to get you into desired gears by the end of the track (like trying to avoid hitting "the next gear" right before the end of the track/wasting time shifting)

That being said, it does effect acceleration some, but it feels more drastic than it actually is, like I said, usually just a few tenths at most. they also hinder your mpg (higher rpm cruising speeds) as mentioned above.


***Waits for the "I gained a full second in the 1/4 from my 4.10 gear swap" people to chime in***
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Old Feb 13, 2012 | 08:40 PM
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Even the 3.73's will not limit your top speed. In fact, they'll let you run faster, since the engine will be more in the meat of its powerband as you approach top speed. With your 2.73's you're too low in the powerband and thus power-limited, not rpm-limited.
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Old Feb 13, 2012 | 08:45 PM
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Originally Posted by bowtienut
Even the 3.73's will not limit your top speed. In fact, they'll let you run faster, since the engine will be more in the meat of its powerband as you approach top speed. With your 2.73's you're too low in the powerband and thus power-limited, not rpm-limited.
I didn't know this. cool
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Old Feb 13, 2012 | 08:46 PM
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Originally Posted by RamAir95TA
Wind resistance and horsepower become limiting factors in obtaining top speed before gearing in a stock f-body.

Gearing for top speed is ridiculous anyway considering the opportunities to reach your top speed are about 1% of the opportunities to stomp your car from a dig.

There's no magical number in determining your 0 to 60. If you're that concerned go out and buy a Gtech and see what happens. They're fairly accurate.

Also, slow down.

im not planning on going 140mph all the time, im just curious how bad itll affect top speed. and any experience with 3.42 or 3.73 4.10? oh and cruising rpms thats another question, is it really worth it?
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Old Feb 13, 2012 | 09:12 PM
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i've got 3:23's an have been 125 in my Ta and she had some left but was screaming pretty good. 3:73 is usually a pretty good all around gear. also, are you auto or stick? that makes a difference as well...

Last edited by Amazin1; Feb 19, 2012 at 09:15 AM.
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Old Feb 13, 2012 | 10:43 PM
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my 2cents is 3.73s for auto & 4.10s for manual Especially if you see any hwy time If its all city 4.10s are fun But goin from a 2.73 to 3.73 youll like it & itll still roll out over 140 lol
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Old Feb 13, 2012 | 11:33 PM
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I'm personally swapping to 3.42 gears in my A4 even though so many people have said it's pointless. Here's why:

-Some performance gain over 3.23's (not much but some)
-In the gear range for the stall Im going to run (SS3600)
-Cheap! Bought an oem set (higher quality than most aftermarket) for $40 with >20k mi.
-Stock 10 bolt isn't worth pouring hundreds into when its just going to explode eventually
-Better MPG over 3.73's
-Less RPM on highway (I have loud exhaust, drone would be worse with 3.73's)

Just my .02
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Old Feb 14, 2012 | 12:06 AM
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For the record I was getting over 20 miles to the gallon on the highway and 19+ city with 373s. I put in an ss3600 stall and it dropped to around 17 mixed. It got better gas mileage than my current M6 car, and better mileage than my older car with 273s in the city.
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Old Feb 14, 2012 | 12:10 AM
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When I first got my car I took it up to around 5k in 5th gear(3.73), that had me over 145 mph it sounded crazy with the top down. I haven't been up there since, now with the new motor I'm already over 115 if I top out 4th, it doesn't take much more than an on ramp to do that.
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Old Feb 14, 2012 | 12:58 AM
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i wouldnt worry too much about top speed unless your going to the salt flats or something. no race is worth going over 120 IMO.

i just went from 2.73 to 3.73 on my 97. BIG difference. worth it.
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Old Feb 14, 2012 | 01:46 AM
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Op if you have a stick get the 3.73s, the 93s have different gearing in the trans and 3.73s equal 4.10s
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Old Feb 14, 2012 | 02:19 AM
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3.73 =4.10 gears?
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Old Feb 14, 2012 | 08:21 AM
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That would be true if it was a stick car but its an auto. We went from 2.73s to 3.42s in my dads 95 ta a4. There was a huge difference in pickup as it would barely peel the tires before. Reason we stayed with 3.42s was to keep the rpms down on the highway as my dad doesnt really beat on and he cruises with it so he wanted the fuel economy. Just built a level 2 spec trans and that itself was a huge seat of the pants gain as i can only guess it was on its way out the door before we rebuilt it. If you beat on it and want all you can get out of it and sacrifice fuel economy go with 3.73s.
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Old Feb 14, 2012 | 08:36 AM
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2.73s in an Lt1 are terrible!
3.42s for simplicity and low $$$ spent get it from a 6 speed....
3.73s will be awesome and about all you would want with a bolt on or mildly modded Lt1 with or without Nitrous.......
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Old Feb 14, 2012 | 11:24 AM
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Originally Posted by IronOutlaw
For the record I was getting over 20 miles to the gallon on the highway and 19+ city with 373s. I put in an ss3600 stall and it dropped to around 17 mixed. It got better gas mileage than my current M6 car, and better mileage than my older car with 273s in the city.
Yikes, was this with a cam? My car gets about 27mpg highway.
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Old Feb 14, 2012 | 07:54 PM
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my car is an A4 and i do a lot of driving from (Orlando to Daytona) and will be visiting Miami in march, so what would the vote be a 3.42 or 3.73? what rpm~ is an A4 at 80mph with a 3.42 and what rpm~ is a 3.73 at 80mph, with the stock 2.73 its at about 2800rpm at 80mph and from orlando to Daytona is uses over a half of a full tank.
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