C5 A4 either comes with 2.73 or 3.15 (performance) gears.

 

Why does it seem like too much? The LS1, for a push-rod motor, is rev-happy, and the difference between the base and Perf gears is significant. I tested my wife's C5 auto w/2.73 gears (using GTech) and it was right around 1/2 second slower than the slowest of the magazine times. To give you an idea, it's virtually impossible to spin the *stock* rear tires on clean asphalt in her car. Every indication on various corvette forums is that with the Perf gears, it's quite easy to spin the rear tires. The two gear ratio's, as stated by 03EBZ06, are 2.73:1 and 3.15:1.

http://corvetteactioncenter.com/spec.../2004prod.html

 

Thank you. I knew it was something wierd like 3.15s. Why didn't GM just put in the 3.23s?

 

I would think more like 2-3 tenths faster with the 3.15s. But if you tested it then 1/2 second must be true. Testing is always better than bench racing. I never understood why GM and Ford put in these lame a** "economy" gears.

 

Were you talking about 0-60 or the 1/4 mile? I tested two bone stock Z28s (see sig.). One had 2.73s, the other had 3.23s. The 3.23 car did 0-60, 4 tenths faster than the 2.73 car. The 3.23 car also had about 220 extra pounds in it at the time. So that would mean how much faster 0-60 if both cars had the same weight? Maybe 5-7 tenths? How much faster in the 1/4 mile?

 

When your talking about jumping from 2.73 to 3.73 or even 4.10 then your gonna see a significant increase in 1/4 mile performance. But from 2.73 to 3.23 is only worth maybe 2 tenths in the 1/4 mile. As autos we don't need gears (they just increase our mpg). We need higher stall torque converters that bring with it higher shift extensions.

 

You might be right, and maybe there's just something wrong with my wife's car. I just know that it runs significantly slower than any mag times I've seen (or what I've seen at the track) for a C5.

 

Look what I wrote above: "I tested two bone stock Z28s (see sig.). One had 2.73s, the other had 3.23s. The 3.23 car did 0-60, 4 tenths faster than the 2.73 car. The 3.23 car also had about 220 extra pounds in it at the time." Both cars were bone stock and had all the same options. Gears really help. Do you think a stalled 2.73 car on stock tires would run as fast as a non stalled 3.23 car on stock tires?

 

Give it a tune up. Was it carrying any extra weight when you ran it? Does she run low octane gas in it? Was it a hot, low baro. day or at altitude when you ran it?

 

Absolutely it would. A stalled (2800-3500) 2.73 car would destroy a stock stalled 3.23 car if they don't blow the launch. Sorry Steve but the difference between a 2.73 car and a 3.23 car is small. I'm not even gonna debate 0-60 crap because it's 1/4 mile ET that I care about and the difference is still only about .2 between the standard gears and the performance (chuckle) gears.

 

You really think 5-7 tenths faster 0-60 is only 2 tenths faster in the 1/4 mile? The seat of the pants difference between a 3.23 and 2.73 car is huge! I've driven both cars hundreds of miles. Also from a rolling punch the 3.23 car has a lot better chance of taking off hard.

 

Go to ls1tech.com and ask in the tech section about what the difference is between 2.73 and 3.23 gears in the 1/4 mile. Your gonna find out like I did a long time ago when researching gears that the difference is minimal. If your gonna switch gears then 3.73's are the way to go but many say don't bother if you get the right torque converter.

You can debate with me all you want but I still don't believe you. I believe them.

 

I know guys that have that have shaved off as much as 4 tenths in the quarter . The average is probably 3 . But , do you realize how big a difference it is ? 3-4 tenths is a HUGE difference .
If you took the best time you could get out of your car. Added cam and headers " stock gears " You would likely see 3-4 tenths in the quarter.
Thats about how big the diff is between those 2 gears .
It simply makes the your cars HP and torque more usuable .

I have know many people in stock 2:73 LT1's running 14.2 and I know a people in stock LT1's with 3:23's running 13.8 .

Not trying to argue but this is what I have seen for the time I have spent around other F-bod owners and at the track So these are real world numbers.
And My formula had a few bolt on's adn I raced my best friends stock 3:23 car VS my 2:73" with some bolt ons " He whooped my A$$ and my car had WAY less miles and was like brand new.

 

I stand by my statement that .2 is the average gain for a 3.23 geared car vs 2.73 geared car. Maybe .3 but you guys that think it's worth .4, .5 or more are crazy or full of wishfull thinking. But add a 3500 2.5 str torque converter to both cars and the gain from gears may actually lessen since both cars now have a 3500 stall flash, 2.5 str for off the line grunt and 4700 rpm shift extenstion.

I believe you could gain .4 maybe .5 from going 2.73 to 3.73 gears. That's a healthy upgrade. But then you pay the price with really bad gas mileage which is fine for weekend warriors but some of us daily drivers might want to reconsider that one. Besides, after all my research I have found the 3.23 gear and 3500 stall are a very nice match and go real nice with N20

 

3:23's or 3:42's are both nice for an auto . I wouldnt get 3:73's cause the get HORRIBLE gas milage .unless like you said its nothing but a weekend car .