Bill17601

[QUOTE=JoesC5;1582922742]That's odd. When I do the math on a 2005 C6 with 285/35ZR-19 rear tires and the A4 with .7:1 overdrive 4th gear and the base 2.73:1 differential gear I come up with 1675 RPM at 70 MPH.

The optional 3.15:1 ring gear and pinion in a 20 equates to 1930 RPM at 70 MPH.

The 2006 A6 with it's .67:1 6th gear overdrive and standard 2.56 rear gear sees 1500 RPM at 70 MPH.

1450 RPM in a 2005 C6 with the A4 and base 2.73 rear gear equates to 60 MPH.

I sometimes wonder if you really do have a Corvette, or just pull crap off the Internet to post.

You can bet that a 8 speed auto will run at lower RPM at a given speed then your A4 or the newer C6's A6, while delivering better gas mileage.

My 505 HP 7L C6 will equal your 400 HP 6L C6 in highway gas mileage. But then I have a 6 speed with a higher final gear ratio(1.71:1) then your C6(1.91:1 or 2.45:1).

That's what a 8 speed auto will bring to the table over a 4 or 6 speed auto, plus the lower gears in 1 thru 5, will give better


Sounds good in theory but does not work as well in fact. BUT...as in all my post your opinion is your opinion and I respect that. It is not an argument about personalities...save the wave.

Parker Corvette

DRC---In your post number 36 you state that you can take your new Corcette to the drag strip and road race track and beat the crap out of it and your 100,000 mile warranty is still good. Did I understand that right? Can you expand on that statement.

Parker Corvette

Bill 17609. So you drag race on the streets. Not very smart.

BMW550XI

I have both a BMW 550 w/ 8 speed (2012) and BMW 550 w/ 6 spped (2008).

I was so excited about the extra two speeds prior to purchasing. Honestly...doesn't matter! Only difference is an extra 2mpg on the highway.

Both have paddle shifters, and the 8sp is just too many.

Bill17601

It's not but it is exciting. A lot has to do with the environment. Day light with no traffic. Actually a section of four lane which never got connected.
I guess risk is part of life. I do not say to anyone else you should try this. I do not drink or smoke so I guess it is my vice.

LT1_E85_Corvette

Not sure if you can do this in the C6 however, we just found out that GM is going to warrenty Corvettes that have track usage under the 5/100,000mile plan! Car has to be completely stock of course

Nitrous Oxide

Whoah! Is that an 8 speed premium Z4 I just saw???

BeaZt

That video always makes me want to go home and make sweet sweet love.............................. LOL

JoesC5

You are as bad as the guys that post on poor wear of the tires used on the GS and Z06, saying they get 30-40,000 miles out of their tires. Of course they don't have a GS or Z06 and the tires they brag about aren't the same tires as used on a GS or Z06.

This post was about automatic transmissions and you throw in your post about your great gas mileage, but fail to mention you aren't even talking about an auto transmission.

You were just trying to get your two cents in without contributing anything useful.

Since you are mathematically challenged, I'll run the numbers for you.

the C7 7 speed will run 70 MPH at 1260 RPM base, and 1440 RPM with the Z51 option.

A6 base C6 will run 70 MPH at 1500 RPM and the GS will run 70 MPH at 1600 RPM.

crabman

You have to consider both standing start acceleration and acceleration from any possible given road speed. The two primary selling numbers are 0-60 and the quarter both of which are obviously standing start numbers. Also the only numbers a lot of people seem to care about which shows a lack of understanding about a cars real world performance.

When C6 came out it was often compared to the 911s (also with a new iteration at the time) in road tests where by those two benchmark numbers it was very close with the 911 usually slightly besting the Vette in the 0 to 60 mark thanks to its traction advantage and better gearing and it being too close to call on the quarter. It was Automobile magazine that first pointed out the real world truth. The corvette felt faster and out on the road and at any given road speed the Corvette walked away from the 911s. How did it happen? It was not the gearing, the 911 had better gears. It was simply more power making itself known and allowing the Vette to overcome the 911s gearing advantage.

While it might not seem like its directly comparable my point is not just the obvious one; that a cars performance in terms of acceleration is primarily determined by its combination of weight, power, and gearing, but further that acceleration from any given speed is important. It matters because in the real world you accelerate from many speeds, not just a standing start. This is where more gears matter. The more gears you have the more likely you are at any given road speed to have a more advantageous gearing. More gears (can) make the car faster. This is physics and physics doesn't lie.

Where do we reach the point of diminishing returns turning into nothing more than bragging rights? I don't know. But I'm pretty sure out on the road the Vette would go faster with another gear or two and the better ratios they would then be able to choose. Like others it sounds to me like he is just making excuses till they get the next thing ready. Those with good memories will recall that they said the exact same stuff about the A4 when C6 came out and people here were also posting the same thing, that the cars engine didn't need more gears. Who here would make that argument for the A4 now? I'm thinking when they do get a better trans ready and get it in the car people are going to like it and soon enough the A6 will just be another memory of an older tech now left behind.

Bill Dearborn

For highway driving that is pretty wound up if you are running those kind of rpms at 70 mph. Any Vette produced since 97 will run in the range of 1600 to 1800 rpms depending on the transmission gear ratios (M6/M12, etc) at that speed. My current C6Z loafs along at 1600 rpms at 70. In town I can run it in 5th gear at 32 mph with the rpms down around 1200 or basically just off idle. However, there is a big difference between running the car at a max fuel economy setting and running at max power. You do need more gears to keep a peaky engine like yours near the HP peak if you are pushing it hard. An engine with lots of low to mid range torque doesn't need as many gears to whomp butt.

Bill

crabman

You have to consider both standing start acceleration and acceleration from any possible given road speed. The two primary selling numbers are 0-60 and the quarter both of which are obviously standing start numbers. Also the only numbers a lot of people seem to care about which shows a lack of understanding about a cars real world performance.

When C6 came out it was often compared to the 911s (also with a new iteration at the time) in road tests where by those two benchmark numbers it was very close with the 911 usually slightly besting the Vette in the 0 to 60 mark thanks to its traction advantage and better gearing and it being too close to call on the quarter. It was Automobile magazine that first pointed out the real world truth. The corvette felt faster and out on the road and at any given road speed the Corvette walked away from the 911s. How did it happen? It was not the gearing, the 911 had better gears. It was simply more power making itself known and allowing the Vette to overcome the 911s gearing advantage.

While it might not seem like its directly comparable my point is not just the obvious one; that a cars performance in terms of acceleration is primarily determined by its combination of weight, power, and gearing, but further that acceleration from any given speed is important. It matters because in the real world you accelerate from many speeds, not just a standing start. This is where more gears matter. The more gears you have the more likely you are at any given road speed to have a more advantageous gearing. More gears (can) make the car faster. This is physics and physics doesn't lie.

Where do we reach the point of diminishing returns turning into nothing more than bragging rights? I don't know. But I'm pretty sure out on the road the Vette would go faster with another gear or two and the better ratios they would then be able to choose. Like others it sounds to me like he is just making excuses till they get the next thing ready. Those with good memories will recall that they said the exact same stuff about the A4 when C6 came out and people here were also posting the same thing, that the cars engine didn't need more gears. Who here would make that argument for the A4 now? I'm thinking when they do get a better trans ready and get it in the car people are going to like it and soon enough the A6 will just be another memory of an older tech now left behind.

CaryBob

The March 2012 issue of Vette Magazine contained a lengthy interview with Rich Mardeuz (ACE for Corvette Automatic Transmissions) and Gabe Gibson (Clutch-control calibration engineer) about what they called the "Staged Upshift" changes made to the Corvette A6 for 2012, mainly in the TEHCM to affect clutch fill and torque transfers.

Bottom line is that paddle up-shifts were cut in half or a bit less. At WOT, upshift times dropped about 65%. For the 1-2 shift it went from about 350ms to about 120ms. For a WOT 2-3 upshift it went from about 400 milliseconds to under 200 milliseconds.

The change only affects 1-2, 2-3, and 3-4 upshifts.

jkcam6017

Would you check my math for me? I calculated that putting 10K miles on the car annually, I will save $2.47 in fuel costs each year.

CaryBob

So in a sense the C7 will include a "free" dollar-menu item every five months?

Parker Corvette

BMW550xi I guess my only comment would be why not be happy with the extra 2 mpg? You aren't paying any extra for the 8 speed trans. In this day of stiffer CAFE requirements, mpg is important. I want better milage, doesn't everybody? The auto manufactures are sure interested in better milage. They reduce weight. Offer cyl deactivation. Why not just return to the old powerglide 2 speed. I had a few of those. LOL

rcallen484

Yeah but it runs like a Singer sewing machine

Raitzi

http://www.gizmag.com/gms-tapshift-t...ogy-zl1/21568/

JoesC5

Gladly, if you will tell me the cost of the fines to GM if GM doesn't meet the EPA regulations. Or how about a gas guzzler tax if the Corvette doesn't get the minimum as specified by the EPA.

Your $2.47 number could be well off if GM fails to get the gas mileage needed to make the EPA happy, and a bunch of fines are then added to the cost of your new C7, because GM didn't give a **** about the gas mileage on their cars, including the Corvette.

The A8 will be used in other GM vehicles, not just the Corvette, thus helping GM meet CAFE across the board.

While $1.24(5,000 miles annually) won't break my piggy bank, across the millions of cars GM sells, it adds up. Under Obama, the EPA is a monster, and you don't want the monster pissed off.

BlueOx

I meant the C7's 6spd auto, that is what we are talking about.

I think my simplistic point about relative Corvette rpm-to-speed vs the Z4 was made whether it is an auto or a manual. As I said, the Z4 is running 2200 rpm at 70 mph with an 8 speed, that seems high to me.

Your whining about whether I own a Vette or not is pretty funny to me. You've demonstrated that think you own the joint because you have a Z06. After all, if some of us just own 'base' C6's, we don't really count, right?

BTW, it's my thread - apparently that is useful even for you, since you came all the way over here to hassle me.