05dsom

2009-2013 all had GG tax

speedlink

All the OP's that have chimed in already are correct.
Not sure what the purpose of the post is?
Maybe he's just late to the dance. Another troll?
Maybe niels007 needs to consider something else. His comments don't make sense. Clearly doesn't understand the reasons why it was done that way, and the capability of the car.

niels007

The purpose is to show the somewhat odd decision at Chevy to keep the gearbox of the C7 Z51 exactly the same as the C6 Z51 / GS, only add *another* super tall gear. It had one already!

It is a FACT that for performance / circuit driving, you could just as well have the old 6 speed as the ratios are exactly the same.

I feel this is odd and I didn't expect it at all.

If you'd show the gearing chart I posted earlier to any engineer in the performance driving world he'd frown.. It doesn't take away from the fact that the C7 is, just like the C6 and C5 were at the time, an awesome car, but just that this gearing doesn't make sense when you look at it from an objective distance with a performance eye. Again, have the 7th gear as a tall economy gear but at least use 6 for performance!

Torque is great, but the more optimally you can multiply it through the gearing, the more of it will arrive at the rear wheels when you need it. The C7 has amazing torque, but more of it would arrive at the rear wheels at certain speeds if the gearing was better.

I'm into vehicle dynamics, sadly not into a real Corvette. As much as I love the Vette, it seems I have a somewhat more objective point of view here than some of the lucky owners here.

Forums are a great place to disagree, but I can't see why an engineer type guy making a qualified observation is considered to be trolling or not making sense.

I think GM is well aware of the gearing and just saves nicer ratios for the future Z06 / ZR1 type models

SharkDiverZ06

Generalize much?

coupeguyz51

Hey, what's all the complaining about?
I drive mostly 80mph commute on interstate...
at the price of premium gas, I am more than happy
to be doing 80 at 1300 rpm on 4 cylinders....

PAmotorman

emissions are rated in parts per mile so turning less RPMs means less parts per mile.

RocketGuy3

What do you mean by "the gaps grow"? The difference between the gear ratios steadily decreases as you go from 1->2 to 6->7.

Do you mean that the rev range increases for the gears as you go up when you shift at/near redline? That seems unlikely to me, but I don't know the exact numbers, and I've never tracked or driven a manual C6 (or C7, obviously).

SCM_Crash

The irony of calling 97% of scientists "idiots".

/Fail

niels007

This is the approx. gearing chart of the C6 GS, C6 Z51 (up to 6th gear) and the new C7 which only adds a 7th gear.

You can see that each gear you go up has to cover a greater speed before you reach the next one. That is what I mean with the 'gaps grow':

http://www.h-engineering.nl/pics/c7_z51gears.png

Kappa

In a vacuum, more aggressive gearing makes sense. But, we don't. The Corvette engineers obviously wanted to reuse the current gearset, while still improving FE and setting it apart from some of its competitors. The C7 still outaccelerated the equivalent C6 models while achieving better FE. I don't see the downside.

Calling it 5 speed doesn't make sense.

The 8 speed auto everyone is clamoring for will most likely have 2- 3 of gears as well. As long as the LT1 has the lowend torque to pull those gears, it'll work fine in a world with compromises like 99% of us live in.

PAmotorman

with 4th gear still 1 to 1,direct drive like a std 4 speed it is a 4 speed trans wirh 3 overdrives.

hig4s

Gearing from 1 through 6 on a C6 and C7 are identical, the C7 out accelerating the C6 is not because of gearing.

Minkster

Not understanding the rigors and principles of disciplined science and following the rest of the morons over the cliff…

Quintessential fail

zr-1 guy

what the hell are you talking about?

they added ANOTHER tall eco gear to have ANOTHER TALL ECO GEAR. Fuel economy standards are going up, that's why they added ANOTHER tall eco gear. additionally, i don't think there's EVER been a 5 SPEED vette!

rgamache

That is how I read the story from Harlan Charles at LimeRock.

SCM_Crash

Let me get this straight...

97% of scientists say climate change is man-made; scientists that are far smarter than we are in a field they've chosen to spend their life researching; who have data that comes from around the world, from places you nor I would or could ever go (due to funding or lacking the skills to get there); who've spent decades studying this particular issue.

But you with your infinite wisdom and (taking a guess here) Fox News, simply say they're morons and going over a cliff?

I'd like to see the data and research you've done to counter my point. I'll give you decades too.

Until then, I'll believe the world's population of smart people over the tiny group of nay-sayers who are likely people that don't believe we landed on the moon.

RedLS6

He would frown, and then he'd go ahead and build it this way anyway, when he was shown the budget he had to work with in further developing this transmission.

The downside to tightening the ratios and using the first 6 as performance gears would be that drivers would be shifting more often around town, unless they elected to skip gears like a lot of us do now anyway.

The upside would be that the area under the rear-wheel-horsepower curve would be increased "a little". As it is now, shifts 1-2, 2-3, 3-4, and 4-5 on the 7-speed manual drop the LT1 out of the flat part of its horsepower curve, and take it down to under 5000rpm where it's making 410-ish hp. The acceleration advantage of tighter ratios would then be partially offset by the increased number of shifts.

It probably makes more sense to compress these ratios in the next version of the automatic.



.

0WildVettes

I can afford a C7, I am not jealous, my C7 will be delivered next month hopefully, and Ibwill have three other Vettes including a C3,C5,and C6.

I was disappointed in the ratios and that dual 6-7 fuel mileage gear is silly. They should have made 1st gear good until 60 and 2nd a little taller. 3rd to fourth on my C5 and C6 are the same and have a big rpm drop. I would have liked to see 5th gear the 1:1 and top speed from 6th with a fuel gear for seventh.

I can assure you this will change later in the line and is probably being held for Z06/ZR1 models. The current gear ratios is illogical and was likely done to merely make it a "seven speed" Corvette. At least I have another gear I can swap out in the tranny later on

SCM_Crash

I disagree.

I liked the gearing in my C5 Z06. The only thing it needed was a gear for highway driving. Otherwise it was perfect. There was never a time I felt I was out of the powerband and I always knew exactly where I needed to be. I just always wished there was one more gear to help quiet the engine and gain a couple MPGs when I was driving to Vegas.

I think going the route you've suggested would throw it all off. What you're suggesting is even taller gears to start with a ridiculously close ratio for the rest. If first gear went to 60MPH and then 5th was 1:1, that'd mean that 1-2, 2-3, 3-4 and 4-5 would be super short. You'd have to use 5 speeds to go from 2.45:1 to 1:1. That's a LOT of shifting. I might see how that would work on the track, but this car is meant to be a compromise between track and street. I don't want 2nd-5th gears only lasting 1 second at the most before being required to shift. Even skipping gears would be too short.

Big Dan 427

Does anyone know what the .09 difference in ratio will increase the gas mileage by? I mean if it's one mpg was it really worth the R&D and extra expense in the tranny? I know it would help the CAFE too but again is it make or break?