Rumorpile: C7 Getting A Seven Speed Manual?

[William Maley]

Rumorpile: C7 Getting A Seven Speed Manual?

William Maley - Editor/Reporter - CheersandGears.com

September 26, 2011

Following the trail of a certain of German sports car manufacturer, General Motors could be adding a seven-speed manual transmission to the next generation Corvette.

Inside Line reports that a source on the C7 team has confirmed that seven-speed manual will be offered. This comes on the heels of Porsche making the announcement of the a seven-speed manual along with its seven-speed PDK dual-clutch transmission.

The added transmission cog will improve fuel efficiency and give engineers a chance to play with the lower gear ratios to improve lower end speed.

Source: Inside Line

[loki]

anything for the mighty mpg!

i envision lots of people that aren't racing this to skip shift, turning it into a 4 or 5 speed.

has under .5 ratios been made in a tranny? doesn't the "t56"(i know it's updated with a dif name) right now have a .5 ratio?

[Robert Hall]

Cool.

[Drew Dowdell]

it's not about mpgs expecially, it's about keeping current. If the C7 comes out without a 7-speed and all of it's competitors have them, yet again we'll hear about how behind the times GM is... and when will GM catch up...

[Robert Hall]

I wonder what the automatic will be...

[Z-06]

it's not about mpgs expecially, it's about keeping current. If the C7 comes out without a 7-speed and all of it's competitors have them, yet again we'll hear about how behind the times GM is... and when will GM catch up...

You should read comments on Insideline, people DO NOT like a manual transmission Corvette with 7 speeds, they say 6 speed is enough.

[dwightlooi]

anything for the mighty mpg!

i envision lots of people that aren't racing this to skip shift, turning it into a 4 or 5 speed.

has under .5 ratios been made in a tranny? doesn't the "t56"(i know it's updated with a dif name) right now have a .5 ratio?

In trying determine if a car can benefit from more speeds in the transmission, all you have to ask is three questions:-

• Does the car have enough torque to smoke the tires in 1st gear?
  
• Is the cruising rpm in top gear low enough?
  
• Between shifts, does the rpm fall too far below the torque peak?
  

If the answer to all the questions are NO. Then the car does not need more speeds in the transmission. In fact, more speeds in such instances will make the car slower with no benefits to fuel economy.

For the Corvette, the objective is for enough torque to break the tires lose in 1st, keep top gear rpms at around 1600~1700 rpm at 60 mph and make see to it that when shifted at the redline (6600 rpm) the rpm drops to within 800 rpm of 4,600 rpm. If it is already doing that, then giving it more gears just means more shifts during acceleration (slower), more smoke during launch (slower) or a top gear that cannot be used until you are seriously over the speed limit (pointless).

[hyperv6]

Well I am sure GM has it's reasons to do this. If they did not the money would be going else where. I am sure they have a engineering reason and they will also apply marketing here to keep current. This again is one of those big picture things and is not just a simple don't need it on paper issue.

Just be glad in a day when few Prancing Horses have gated shifters anymore you can still get a traditional stick in a Vette.

[Justin Bimmer]

7 speeds is no big deal. Try 18 speeds.

[Robert Hall]

7 speeds is no big deal. Try 18 speeds.

21 speeds like my bike would be cool..have 7 slots for the shifter, with a paddle shift to go up to 8-14 range and up to 15-21 range and down again...

[smk4565]

That is a lot of shifting, but I suppose the 6th and 7th gear wouldn't be used much unless on steady highway cruise. 7 or 8 speeds works when the computer does the shifting for you, but I don't know if manuals will be able to follow that trend when the driver has to do the work.

[A Horse With No Name]

anything for the mighty mpg!

i envision lots of people that aren't racing this to skip shift, turning it into a 4 or 5 speed.

has under .5 ratios been made in a tranny? doesn't the "t56"(i know it's updated with a dif name) right now have a .5 ratio?

Actually, having just the right gear on a road course or in an autocross is sweet....

Do you really think I'd trade a slick shifting 5 or 6 speed in a Vette, Miata, S2000, WRX STI, 911, or whatever....for an old fashioned three speed? Seriously...are you stoned?

That is a lot of shifting, but I suppose the 6th and 7th gear wouldn't be used much unless on steady highway cruise. 7 or 8 speeds works when the computer does the shifting for you, but I don't know if manuals will be able to follow that trend when the driver has to do the work.

If past vettes are any comparison, I'd take the manual over the autotrajic...

But automatics have their place. Calloway sells lots of supercharged automatic Vettes to people who don't want to row their own but want the power of a ZO6...

[Z-06]

That is a lot of shifting, but I suppose the 6th and 7th gear wouldn't be used much unless on steady highway cruise. 7 or 8 speeds works when the computer does the shifting for you, but I don't know if manuals will be able to follow that trend when the driver has to do the work.

Lot of shifting for what driving conditions?

What prevents a person to shift directly from 3rd to 7th once he gets on the interstate and sets the cruise on 70? Automatics do that - why cannot a human being?

As a person who has had the same vehicle for track and daily driving - I in fact like the idea of 7 speeds stick. The car gets a dual character, use lower gears for tracks with a better spread for optimal torque usage and higher ones for slow highway cruising.

[Justin Bimmer]

7 speeds is no big deal. Try 18 speeds.

21 speeds like my bike would be cool..have 7 slots for the shifter, with a paddle shift to go up to 8-14 range and up to 15-21 range and down again...

[regfootball]

because the feds want unrealistic cafe, is why you get and have to pay for a 7 speed tranny

[loki]

anything for the mighty mpg!

i envision lots of people that aren't racing this to skip shift, turning it into a 4 or 5 speed.

has under .5 ratios been made in a tranny? doesn't the "t56"(i know it's updated with a dif name) right now have a .5 ratio?

Actually, having just the right gear on a road course or in an autocross is sweet....

Do you really think I'd trade a slick shifting 5 or 6 speed in a Vette, Miata, S2000, WRX STI, 911, or whatever....for an old fashioned three speed? Seriously...are you stoned?

did you miss the (revised)bolded part? aren't racing...turning it into an (effective) 4 or 5 speed. starting in 2nd, go to 3rd or 4th, then 5th, 6th, and maybe 7th for getting on the highway... or just using 2nd and 4th around town, just cruising.... (these are just guesses, i don't know where the rpm-speed range for these gears would be.)

e.g. on flat parts of town around here, i can start in 2nd, go to 3rd and then cruise in 5th in my dad's 4.3L '95 c1500.

why would you shift more in everyday driving if you don't need to?

[A Horse With No Name]

Because GM doesn't want to build one transmission for enthusiasts and one for people like Z06 and myself who beat on their crs.

Nothing says you can't shifutmn l,kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkfrom third to seventh...

Sorry, cat got on the computer...

[Robert Hall]

It probably will have the skip shift thing like they have for years on Corvette manuals.

[Drew Dowdell]

anything for the mighty mpg!

i envision lots of people that aren't racing this to skip shift, turning it into a 4 or 5 speed.

has under .5 ratios been made in a tranny? doesn't the "t56"(i know it's updated with a dif name) right now have a .5 ratio?

In trying determine if a car can benefit from more speeds in the transmission, all you have to ask is three questions:-

• Does the car have enough torque to smoke the tires in 1st gear?
• Is the cruising rpm in top gear low enough?
• Between shifts, does the rpm fall too far below the torque peak?

If the answer to all the questions are NO. Then the car does not need more speeds in the transmission. In fact, more speeds in such instances will make the car slower with no benefits to fuel economy.

For the Corvette, the objective is for enough torque to break the tires lose in 1st, keep top gear rpms at around 1600~1700 rpm at 60 mph and make see to it that when shifted at the redline (6600 rpm) the rpm drops to within 800 rpm of 4,600 rpm. If it is already doing that, then giving it more gears just means more shifts during acceleration (slower), more smoke during launch (slower) or a top gear that cannot be used until you are seriously over the speed limit (pointless).

Do we have details on what gear is being added? Can they be putting an even more over, overdrive in?

[Camino LS6]

Seven is just one too many.

[dwightlooi]

Do we have details on what gear is being added? Can they be putting an even more over, overdrive in?

We don't know if this rumor is even true. But in general, a 7-speed transmission will have a ratio spread of around 6.5~7.0:1 compared to 5.9~6.1:1 for a typical 6-speed or 5.0~5.5~1 for a 5-speed. So, yes, that can mean more overdrive. Or, it can mean a lower 1st.

The problem with putting more speeds on a big displacement Corvette in the 430 hp/lb-ft class (probably even higher with the C7) is that the car really does not need a shorter 1st (you'll just melt the tires more) and you really don't need closer ratios (shifting itself always slow you down, what they do is perhaps make you accelerate faster in between shifts). The same can be said of fat torque bi-turbo V6es in the same power class. At the end of the day, MOST 7 or 8-speed transmissions end up starting in 2nd, or skipping one or two gears during "normal" driving, or both. This is why I have been saying that 7 or 8-speeds is a low priority for big V8 powered Vettes or Caddys. They are much more useful for less powerful motors. In a big V8 powered Vette or Caddy, if you want better mileage, just put in a taller final drive. Sometimes, that actually makes the car faster because it makes 1st gear wheel spin is easier to manage -- either manually or with less intervention from traction control.

[A Horse With No Name]

Which is why I enjoy autocrossing with a 5 speed rather than a six speed Miata...the ratios work out better. it tops out at about 62 in second, which is plenty fast for an autocross....but I do hit third once in awhile...

[hyperv6]

Life was just fine with my Muncie M21 and Hurst then the goverment had to make my like better.

At least we will finally get the duel disc clutch....At least I hope. For those who have not driven one it is a great improvment. I have driven street and race cars with them and I think most will be plesently suprised on their first drive.

We sell a lot of retro duel disc for muscle cars from Ram. They have gotten the price down and many people are jumping on them.

Edited September 27, 2011 by hyperv6