Gilla81

I'm curious how big of a difference there is between a 2005 auto and the newer 2006 and above automatic transmission C6 vettes? If I'm not mistaken in 2005 it was a 4 speed auto and in 2006 until now it is a 6 speed, right? Is the A4 much slower? How big of a difference are we talking about? Are their any other benefits to the newer A6 vettes? Thanks!

RicK T

Yes, you are correct.

The A4 is not inherently slower than the A6. The benefit of the A6 is a smaller spread between gears and the 2 overdrive gears for hwy cruising gas economy, and of course the paddle shifters if that interests you. The A4 is a good trans and isn't inferior to the A6, just different.

dennis50nj

LS1LT1

Stock versus stock, on average, the A6 LS2 cars are probably ever so slightly quicker than the A4 LS2 cars (can't really compare the more powerful LS3 cars as they only came with the A6), especially if the A4 car has the standard 2.73 rear gears as opposed to the optional 3.15 gears that were available in the 2005s.
If I were starting from scratch to build a car for fast 1/4 mile duty I would likely start with a 2005 A4 car and upgrade the rear to one of the newer/stronger units as there are just more options for strengthening/building up the 4L65E (A4) trans right now.
In time the 6L80 (A6) might prove better for racing but right now I don't think it is.

pmj341

In time the 6L80 (A6) might prove better for racing but right now I don't think it is.

the time is getting closer, more manufacturers are doing R&D
to help make it a more reliable trans under high HP usage.

LS1LT1

True, there are quite a few builders working on/strengthening them as we speak. Though I'm hoping that I won't need their skills/services for my A6 any time soon LOL.

And as mentioned above, the highway fuel economy benefits of the A6 over the A4 are a bonus as well.

BSSN

More gears mean a tighter rpm-band under WOT means more average hp during acceleration. If parasitic loss is the same, A6 will be faster.

LS1LT1

True, providing that the PCM/TCM (and the dreaded Torque Management intrusions) all cooperate. More gears + more electronics = more potential complications but the A6 has a lot of great qualities about it as well.

BSSN

No dead-zones. I have only owned one slushbox sports car, it was a 95 Trans Am with a 4L60E. Bad dead-spots. Same with my roommate's C5, but not so bad. Still, A6 is better, stock/stock imho.

Gilla81

Thanks everyone for your feedback. Reason I was asking is because I am looking to buy a 2005-06 vette and was under the impression if I was going to get an automatic I should only buy a 2006 becuase of the different A4 to A6 trannsmission. So in 2005 they offered an optional 3.15 gear? Were their any other gearing options in the 2006 and above vettes? I'm not nearly as knowledgeable as everyone on here. So any advice or questeions I should ask as I go on my search for a C6 would be greatly appreciated.

Also, do any of you know how the temp tags would work if I bought a vette from a forum member in a different state then I live in? If I flew there to drive it back, how would I have a temp tag to put on for the drive home? I wouldn't be able to register it until I get back to FL, where I live. I know this is a small detail that can be easily figured out, but thought I would ask. I'm guessing someone on here has done this before. Thanks again in advance for eveyrone's advice.

RicK T

Just so you know, the '05 A4's had a standard final drive of 2.73 (RPO GU2). The optional final drive was 3.15 (RPO G90) that was available as a stand alone option for all A4 cars and standard on Z51 equipped cars.

For the '06 and '07 A6, there was only 1 final drive, 2.56. There were no options.

For the '08 and '09 A6, the standard final drive was still 2.56 but they offered the 2.73 as a stand alone option on all A6 cars and standard on Z51 equipped cars.

For the '10 and '11 A6, they returned to only the 2.56 with no options for the base coupe and convertible. The 2.73 is only available in all A6 GS's with no options.

Hope that helps.

revo1059

Another thing to consider in the 2005-2006 equation is the 06 has the stronger differential casing (I believe).

Vito.A

More trans gears does not necessarily make a car faster in a 1/4 mile drag race, (especially if it is not a dual clutch design). Most purpose built drag cars are using a modified 2 speed Powerglide.

If the price is right, I would not hesitate to buy a 2005 with the 4L65 Auto trans. It is actually more durable than the newer 6L80. The 6L80 paddle shifters are almost not usable because of the delay problems.
The 2005 rear differential is not as strong, but can be easily upgraded.

Some of the fastest C6 Corvettes have 4L65 transmissions. Several Z06 cars have been converted and they are running unbelievable times/speeds.

JoesC5

Actually, the two speed powerglide acts as a three speed transmission because of the 2:1 torque converter. A powerglide with a 1.92 first gear actually has a 3.84 first gear and it transitions to the 1.92 without actually changing gears.

The same reasoning that makes a 4-speed Muncie a car accelerate quicker then a 3-speed Borg Warner also works for an automoaric transmission.

Gearhead Jim

FWIW, we had a 2006 A6 and a friend has a 2005 A4.

Even with two people in our A6, it was always equal to or slightly faster than his A4 3.15 with one person, depending on speed. It also got slightly better MPG because of the higher 6th gear, and the paddles were nice for running the twisties.

But for the way he uses his car (Daily driver, road tripper) his A4 does just fine.

Craigster05

And wont that be a happy day for you with the land rocket of yours...

lgm118icbm

When I was shopping for Vettes, the a6 felt confused when driving around. It was always doing something, always shifting. Felt similar to a CVT. The a4 knows what it wants to do and DOES it!

I love my a4.

Darwin11

Love my A4 also.......Cant go wrong...:-)

jpee

I'm right there with both of you..... LUV my A4 ! AND... it runs very consistent 1/4 mile times!

Gilla81

Thanks again everybody for the feedback and all your opinions. After reading everything here, I feel much differently about the A4.