Is it worth going from 3.27 to 3.45?

[Denis]

and thats what im sayin...its a street car 90% of the time. so im wondering if 3.45's are really worth the time or just go 3.91's. now it is an auto, and i hear that with 3.91's first gear is pretty much non-existant.

[Apex Motorsports]

For the kind of use you are describing I would recommend looking at 3.70s. That would give you the equivalent of an extra 62 lb.-ft. of torque across the entire RPM range and keep your 70 MPH cruising RPMs just over 2000. It is a really good gear ratio in the A6 cars.

[Denis]

Originally Posted by Apex Chase

For the kind of use you are describing I would recommend looking at 3.70s. That would give you the equivalent of an extra 62 lb.-ft. of torque across the entire RPM range and keep your 70 MPH cruising RPMs just over 2000. It is a really good gear ratio in the A6 cars.

this is true, but i can get the GM 3.91's for $290 or 3.73's for 650. so ill probably go with 3.91's for that reasn alone haha.

[H-E]

Originally Posted by Denis

this is true, but i can get the GM 3.91's for $290 or 3.73's for 650. so ill probably go with 3.91's for that reasn alone haha.

wont take long to eat up the difference in gas

[Nitroman28]

Originally Posted by Denis

i mean thats really all there is to the question.

for an A6 is it worth finding a cheep used set of 3.45? is that small of an increase really noticable?

I switched to 3.45's and cant tell any difference. Track times stayed the same. So I say it's a waste.

[Apex Motorsports]

Originally Posted by Denis

this is true, but i can get the GM 3.91's for $290 or 3.73's for 650. so ill probably go with 3.91's for that reasn alone haha.

This is true. I can help you some on the gears but there would still be a pretty good price difference. The thing you have to keep in mind is that the auto trans is geared more aggressively than the manual so a 3.91 in an auto is going to be pretty rowdy. Especially if a torque converter is in the cards. Rear suspension upgrades and drag radials would be a very good idea.

Originally Posted by H-E

wont take long to eat up the difference in gas

Actually, there probably wouldn't be much difference. You would only pick up an extra 100 RPM when cruising at 70 MPH versus the 3.70s and with the greater torque multiplication it would take less energy to get the car moving. In town economy would be slightly better and highway would be slightly worse.

[Padre]

Originally Posted by Nitroman28

I switched to 3.45's and cant tell any difference. Track times stayed the same. So I say it's a waste.

I would agree, except:

1) it does help if you add a torque converter to an L99, and

2) it helps if you're thinking about trap speeds, e.g. generally you don't want to be shifting into 5th going through the traps. It's better to be at the top of 4th. So it's a good choice for future big power.

Padre

[dekan513]

find someone close to u thats whats to do a gear swap in a ls3 car and figure something out.

[redneck89]

Good point y'all. I have come across a set of 3:91 gears for my L99. But still not sure about doing it as mine is a daily driver as well. But I do go to the track every weekend....
I'm running 13.02 with a 1.98 60' time on the pirelli tires. I do have a CAI, Long Tubes and no cats with a tune. My trap speed is 109.7....
Should I take the plunge with the gears or just a 3,000 stall?

[smokum]

I have done both. Gears first. Swapped a 3.45 set out of an ls3. Then did a 3200 stall when i did the cam. I have a vert weighing right at 4600 and i have run a best 60 ft at 1.83 with stock goodyears. If adding big power later too low of gear is useless. Stall is a good upgrade to get these things moving out of the hole.

[Nitroman28]

Originally Posted by Padre

I would agree, except:

1) it does help if you add a torque converter to an L99, and

2) it helps if you're thinking about trap speeds, e.g. generally you don't want to be shifting into 5th going through the traps. It's better to be at the top of 4th. So it's a good choice for future big power.

Padre

With the 3.45's I shift into 5th at 132mph. So you would need some big power. I run high 10's and trap 126. If I would have went cam, nitrous I would have went 3.91's. But with the Maggie I would never hook. I would go with a good 3200-3600 converter before gears.


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[Tampa Tuning]

Last week, I calibrated an pretty Stock 2013 A6 with 3.91 gears. The Camaro really jumped out of the hole, and the gears were great fun for his power level.

Add 150 RWHP to the package, and he's over geared never to see traction lol.


After my heads and cam package on my Corvette, I added 3.90 gears and it really balanced the Corvette.

I went from a fast Corvette to a quick and fast Corvette after the gear change.

On my Camaro, because of the weight, I can see losing the 3.27s

Changing gears is a great bang for the buck, but make sure you think long run and what you are going to do with your car.

[Denis]

And that's the idea...I want to think long term as a gear swap isn't just a bolt on per say. Nor is it cheep to have someone do it.

Cam, head work and a stall are all in the cards for the future so I don't want to be over geared.

Now, like I said this is 90% a street car with trips to the track a few times a year. So I want it street-able and useable. So I'm thinking 3.91's are a little much...but that price is hard to argue with. That's why I'm wondering about the 3.45's because they can be had for pretty cheap...but not if it's not even a noticeable jump.

And thanks for all the input guys, much appreciated!

[K32 Camaro]

They may not be noticable now, but with a cam and stall or FI the 3.45 will make a difference in feel.