There are dozens and dozens of Dyno runs on YOUTUBE of bone stock C7 autotmatics ---their RWHP ranges from 400 to 414--- So that's a drivetrain loss from 10% to 12% at it's worst---PLUS I have dynoed my own car which came in at BONE stock at 410 RWHP
( my car is from the 2nd release to dealers where GM has already updated the ECM's to a new operating system different and better than the 1st release)

 

Not true-----The NEW re-designed A6 is completely new as is the NEW A6 clutch to clutch TQ converter--Both mechanically and electronically
This is one article explaining the new A6

http://www.vetteweb.com/tech/1312_20...rack_mode.html

The drivetrain loss on ANY STOCK Trimec is known to be from 10-12 %
Now making the C7 A6's equal to a manual trans in RWHP compared to the C7 manuals and better than a C6 manual-----

 

I would contend the engines are underrated rather than the existence of a magical torque converter.

 

That, or inflated dyno numbers.

 

And I have also mentioned that the Tremec DCT(198#) weighs within a few pounds of the new A8(219# wet). Then you have to add the weight of the flex plate and torque convertor, whereas with the Tremec DCT, you have to add the weight of the flywheel. The weight of a flywheel for the DCT is around 25 lbs. Do you think the A8 will have a flex plate and convertor that only weighs 4 pounds, so to have the same weight as the DCT + the flywheel of 223 pounds? I doubt it. You add up the numbers and the mass of the A8 is substantially more than the mass of the Tremec DCT. Just the opposite of your opinion.

Oh, and I also mentioned that the Tremec DCT with hold 664 lb-ft of torque(the Z06 LT4 produces around 635 lb-ft) and is designed for the C7 application. It fits in the C7.

 

 

Yes, I realize that facts confuse you.

 

 

Sorry but on a Bicycle you count the teeth on the spockets.
To fiqure your gearing ratio's like a Motorcycle!

 

What if some teeth are missing or if it was a belt drive? HTF would you measure the ratio? Just can't be done I guess. I notice you did not comment on JoeC5's brilliant post.

 

Amuses me that people refuse to accept changes in technology--
Simple fact of the matter is that C6 and C5 owners are just pissed that someone with a non-Z51 C7 and a 2.56 rear ratio now is quicker and faster than their bolt on modded cars-

I spent $15k on my '98 A4 to get 475 crank HP--and now stock the C7 has 460----I was pissed too----But you either catch up to technology or fall behind---Just as in professional racing--
It's not magic --It's electronics
Get used to it----
GM has now with new tech. and new electronics-- given the ability for a 1st time Corvette owner with "0" experience and an automatic to run in the low 12's and a mid 4 second 0-60 time--and its making people mad---
On my C7 with 35 psi in the tires---on the street--set on touring mode and in drive--with FULL traction control on consistently ran a 4.5 0-60 time-------and yes on a sticky drag strip with TC turned off and some experience they easily will do the claimed 3.9 or better---
PS: after tuning my car---on the street--in Track mode I ran 4.1's 0-60 times---

 

That's nice... and totally irrelevant. An auto C7 doesn't have a 10% drivetrain loss. Period. End of story. The LT1 has torque for days, better tires, more advanced electronics... these things contribute very well to the performance of the vehicle. However, the 6L80E doesn't magically suck up less power simply because of "electronics". It is still a physical element of the drivetrain with parasitic drag on the power output, just as wheels, axles, brakes, tires, shaft, and other driveline components are.

 

 

The weight of the dual mass flywheel utilized in the C7 for dampening NVH going from V4 to V8 mode I assume, is ~39lbs and the pressure plate/discs are ~29lbs for a total of 68lbs. Do you know the weight of the new smaller torque converter and flexplate used in the A6 just for comparisons sake? Besides the rotational weight difference, the new auto also locks up extremely efficiently which helps limit drivetrain loss from slippage closing the gap on the manual as well.

 

I wasn't, your response to me was plenty.

Thanks, Chris

 

OMG I give up----You guys apparently won't read the post article and are stuck in the 90's keep telling yourself the HP#'s are overrated and that the drivetrain losses are bogus---have you read the forum's "fast list" for bone stock cars ?? all the fastest ones are A6's !!
maybe when the new Z06 8 speed A8 comes out and it will be quicker than the 7 speed manual you'll finally get the point--

 

the fast list is for drag racing. my race car has an automatic also. clearly you don't understand what makes an auto faster off the line than a stick....it isn't drivetrain losses. sure, it's fun to run the corvette at the drag strip because it is easy, fast, and cheap. but a corvette is not a drag car, it's designed for the road course. the auto, even the current one, can't even make it 5 laps without overheating.....yeah, what a step forward. read the posted article.... what a classic.

 

That has to do with ease/consistency of the launch, shift speeds and gear ratios more than anything else. The 6L80E has an incredibly low 1st gear ratio of 4.03:1 compared to the steepest manual gear ratio of 2.97:1.

I said the horsepower is UNDER-rated, meaning that the rear-wheel dyno numbers are higher than they should be for the rating, not to mention the variations in dynos and the differences between the factory SAE rating and the fact that many dynos are run STD, facts which preclude comparisons between chassis dyno numbers and factory power ratings. This point is moot unless you pull the engine and dyno it on an engine dyno before you install it and run it on an identically-calibrated chassis dyno under the exact same conditions..

You need to approach this with less passion and more objective logical analysis. The upcoming 8-speed Z06 should run consistent tens in the quarter-mile on stock tires with any driver who can stay on top of their launch, and that's awesome. I have no doubt that it will be the quickest combo ever offered in a factory Corvette. That still doesn't mean that the electronics make it sap less power; that's ludicrous and shows a fundamental ignorance of how physics work to reduce output. Electronics can't reduce parasitic loss on a drivetrain.

 

The DCT's weight of 198 pounds includes the weight of the two clutches as they are internal. You only add the weight of the flywheel to get the total weight. 198+25=223 pounds(or 198+39=237 pounds with a dual mass flywheel). GM has said the A8 weighs 8 pounds less than the A6(which weighs 227 pounds wet configured for the Corvette) thus it weighs 219 pounds. to that you have to add the weight of the flexplate and the torque convertor to get the total weight.

I don't know the weight of the flexplate an torque convertor used on the current A6 or the new A8, but I would guess that the combined weight would be at least 40-50 pounds(SWAG). 219+ 45=264 pounds(SWAG).

The TR6070 weighs 144 pounds + 68 pounds = 212 pounds. Not that much lighter than the Tremec DCT and quite a bit lighter than the A8.

I don't think you would need a dual mass flywheel with the DCT, but not sure, because of the AFM. Possible that on a limited production Z06 with a DCT, the AFM would not be standard thus would use the lighter 25# flywheel, vs the TR60670's dual mass flywheel/dual disc clutch.

I was addressing the weight comparison between the new GM A8 and the Tremec DCT. The DCT with it's flywheel weighs less than the A8 with it's flex plate and torque convertor.

With the DCT, I doubt that you will have the heat build up problems associated with an automatic transmission such as the A6/A8 hydramatic when tracking the car.

For your typical driver, that never tracks their car, the A8 should be an excellent street transmission with occasional WOT's and driving 8/10's on a twisty road. For the person that pushes his Z06, I feel the DCT will be a superior transmission to the A8. My opinion, of course.

 

I agree with this, but am eager to see how things work out with the new 8-speed before passing any sort of judgment. Since GM still has given no indications of bring a DCT to the street in any capacity, that's all we can do.

That said, my left knee still works for the time being, so I'll be sticking to three pedals