[ssmike]

So much for the Flowtie, made it worse!

[shaffe]

Originally Posted by torqueaddict

True, but they also allow better use of the powerband, so there is a performance benefit as well. For a performance car, performance will be the priority.

In the average family car, the TCU/ECU will try to get to the highest gear as possible as quickly as possible. For performance, that's the last thing to you want. You want the most appropriate gear to stay in the powerband, and you want to hold that gear as long as required. That will cost some mileage.

Sure, you can hold the gear in manual mode, but the computer will be a lot quicker at choosing the right gear. Just my rambling 2 cents.

Wouldn't the truck applications hold the same logic then? they would want to keep the engine in power band to make towing/hauling easier? The trucks saw improvement didn't they? Not trying to be argumentative, just seems odd it would lose. If no improvement I would have expected it to stay the same.

Originally Posted by ssmike

So much for the Flowtie, made it worse!

haha!

[Emoto]

Originally Posted by V8 Firebird

After I read this one, I think 19 Camaro could have more downforce that cause it get bad MPG, or it might have better MPG while driving.

httphttp://gmauthority.com/blog/2018/08/2019-camaro-ss-and-its-three-unique-aerodynamic-features/

Have they published the coefficient of drag (CD) of any of the model years? That would be good way to compare them.

[vtirocz]

Originally Posted by Emoto

Have they published the coefficient of drag (CD) of any of the model years? That would be good way to compare them.

Unless it's better than the current model, you'll never see those published!

[JamesNoBrakes]

More cooling=more drag.

[Need4Camaro]

Originally Posted by shaffe

Wouldn't the truck applications hold the same logic then? they would want to keep the engine in power band to make towing/hauling easier? The trucks saw improvement didn't they? Not trying to be argumentative, just seems odd it would lose. If no improvement I would have expected it to stay the same.

*Long Post Warning*

Before I give you my opinion on that let me explain a few things:

Time to break out the basics of a transmission and how / why it works in proportions to physics.

Okay, a transmission's objective is to leverage a mechanical advantage to achieve either a momentum goal or an acceleration goal in the most efficient means possible. Now note that I put "either" and "or" ...which means you cannot have both...you can only have one or the other in terms of peak efficiency.. Once again that means either you will have either an efficient speed OR all of your power will be efficiently transferred to produce peak acceleration / torque... you can't have your cake and eat it too...you get one or the other. That doesn't mean that one won't be good or acceptable while the other is at its peak..but it is to say, both cannot be at their peak potential for the vehicle, only one can be.

With that stated - Lets say you have a bolt and a ratchet and socket. It's the first time you've had to touch this bolt so its in there pretty tight. You have a small ratchet readily accessible to you, so you take it... and try to break the bolt loose... You cannot even budge it. For a car, this would be very similar as to trying to start off in Overdrive (smallest gear in the box) while the vehicle is sitting still...It stalls, much in the same way that you cannot budge that bolt with a small ratchet.. Not only however can you not move the bolt but in effort of trying, you are ALSO burning energy -- in the same principal, if the engine is trying to budge a car in a gear that is too small for the speed, you burn more fuel. That means..you need a torque multiplier. So you grab a breaker bar and attach it to that socket, and its probably what 7 times the size of your ratchet? This is very similar to starting off in first gear...

...POP...You broke it loose! Horrah!...but you're not out of trouble yet...

It turns out this bolt is a long mofo probably sinked in about 10 feet into the earth and although you can turn it, you can't unscrew it fast enough to make any sort of feasible progress... its taking too long -- for a car this is similar to revving to about 3k RPMS to achieve like 20 MPH in first gear when your destination is 50 miles away. You think...well...I'll just turn it faster and harder...well...you can...but you throw all you strength into it and although that bolt is easy to turn...you can't complete a revolution very quickly at all...and you're throwing EVERYTHING you have at it. For a car, this is like redlining first gear and only doing around 35 MPH. You're going to run out of strength and energy LONG before you get that bolt out, and also long before the car reaches its destination. You need another idea...

...Well... you can take the breaker bar off, but then you'll be left with a small ratchet and the bolt is still so deep it will be very difficult and time consuming to turn that 7 foot bolt..even though its broken loose and you can probably turn it now...it would take forever... you need something thats smaller than your breaker bar but larger than your original ratchet. For a car...that answer is second gear...and for you...that answer is a larger ratchet which is smaller than the breaker bar and larger than your original ratchet... Now you're able to turn it again...and you're able to complete a revolution much faster than before...and its coming out faster but still not fast enough..but you DO find that your maximum effort (which is never increased) is more efficiently applied to removing that bolt ... well..you once again come to a point where you need that bolt out right gawd dam NOW ... you try to turn it as fast as you can but you reach those same limits you met with your breaker bar...only something is different this time.. With ALL of your strength applied, it IS is moving fast enough now but its taking way to much of your energy to keep it moving this fast... you need another idea because while you're close to your ideal speed...its taking too much of your strength to keep at this. For a car, that solution is third gear...and for you...a smaller ratchet...

Now that the ratchet is fairly loose...its much easier to turn, and for a vehicle now that it has sufficient inertia, a smaller gear can be used to continue accelerating. You're finding it much easier to turn that bolt at the same speed now, and much less of your strength is required to turn it faster and faster and faster.. until you reach the limits and switch to a smaller ratchet and ultimately into a ratchet so small that you can turn it so fast that your bolt is turning faster than your hand completes a revolution, and for a car - that is Overdrive... a point of which a vehicle can effortlessly maintain a high speed because the gear is literally turning SLOWER than the drive wheels..because of that, its taking the motor HALF the work to achieve the desired speed, thus why cars are able to save more fuel on the highway...

Now you probably had a pretty decent clue about all this and wondering how it pertains to your question by now...

Here is likely why the truck saw an improvement and why the camaro did not. Note that in either case -- NEITHER APPLICATION were designed to improve fuel mileage, for the truck it was a bi-product. For the Camaro, it was never intended.

Remember when I told you what happens when you turn a large ratchet on a bolt, that although you have more than enough power to move it, it takes all your strength to move it QUICKLY, causing you to switch to a smaller ratchet? Well this equation is radically magnified when you add LOAD to the equation, in terms of your ratchet, that would mean, a heavier bolt. Meaning everytime you switch to a smaller ratchet, the heavier that bolt is the more you will feel a difference between ratchets and the strength you have to exert to move that smaller ratchet until that smaller ratchet reaches a speed efficient enough to move it with as little effort as possible... In terms of cars... This means if you are talking about a heavy vehicle, the distance between two gears will temporarily put the engine in a less efficient range to MOVE that smaller gear to a point where it can efficiently transfer the weight of that vehicle...With a lighter car, this difference is quickly overcome AND is less noticable in the powertrain because the weight doesn't put as much of a shock against the drive train when moving to another gear (I dont mean shock as in damage but in terms of dropping from peak efficiency from the previous gear to much less efficiency in that next UNTIL a mechanical advantage is reached at that speed which in turn brings it back to peak efficiency), with a truck, not so quickly. How do you resolve that? More gears thus less space between gears so the engine is almost always running at peak efficiency even after changing gears so it doesnt feel as much of a "shock" from the weight.

Here's why that doesn't work so well on our cars...

For starters, we are curing a problem for the truck -- which gear ratios were unbalanced in proportion to their weight and towing capacity and by doing this we are reducing the amount of time the engine has to spend trying to reach an efficient speed.

For the car -- The car was already at a point where it was balanced to the extent of momentum efficiency. It doesnt take anywhere near as much effort gear for gear to move it right to its efficiency range nor does it take anywhere near as much effort to keep it there... We add 2 more gears and lets say for the sakes that we are doing it for the same reason as the truck, keeping the powerband together (because as many people misconceive just because you add gears doesn't mean that these new gears will make the vehicle more efficient, it all has to the with configuration.) We are at a point where we really can't gain anymore regardless of how much we throw at it, instead we may end up actually losing something... think of how much work it is to continuously change ratchets -- when its not necessary... you may get to your goal with less mechanical effort..but that doesn't mean you are saving energy by transferring to another gear unnecessarily. Then the converter as well - everytime you shift that converter has to unlock and let you accelerate - everytime that converter is unlocked you are nowhere near peak efficiency until it locks up again...

In essence...adding gears only helps fuel mileage when its NEEDED...not when its for pleasure.

[shaffe]

Originally Posted by Need4Camaro

*Long Post Warning*

Before I give you my opinion on that let me explain a few things:

Time to break out the basics of a transmission and how / why it works in proportions to physics.

Okay, a transmission's objective is to leverage a mechanical advantage to achieve either a momentum goal or an acceleration goal in the most efficient means possible. Now note that I put "either" and "or" ...which means you cannot have both...you can only have one or the other in terms of peak efficiency.. Once again that means either you will have either an efficient speed OR all of your power will be efficiently transferred to produce peak acceleration / torque... you can't have your cake and eat it too...you get one or the other. That doesn't mean that one won't be good or acceptable while the other is at its peak..but it is to say, both cannot be at their peak potential for the vehicle, only one can be.

With that stated - Lets say you have a bolt and a ratchet and socket. It's the first time you've had to touch this bolt so its in there pretty tight. You have a small ratchet readily accessible to you, so you take it... and try to break the bolt loose... You cannot even budge it. For a car, this would be very similar as to trying to start off in Overdrive (smallest gear in the box) while the vehicle is sitting still...It stalls, much in the same way that you cannot budge that bolt with a small ratchet.. Not only however can you not move the bolt but in effort of trying, you are ALSO burning energy -- in the same principal, if the engine is trying to budge a car in a gear that is too small for the speed, you burn more fuel. That means..you need a torque multiplier. So you grab a breaker bar and attach it to that socket, and its probably what 7 times the size of your ratchet? This is very similar to starting off in first gear...

...POP...You broke it loose! Horrah!...but you're not out of trouble yet...

It turns out this bolt is a long mofo probably sinked in about 10 feet into the earth and although you can turn it, you can't unscrew it fast enough to make any sort of feasible progress... its taking too long -- for a car this is similar to revving to about 3k RPMS to achieve like 20 MPH in first gear when your destination is 50 miles away. You think...well...I'll just turn it faster and harder...well...you can...but you throw all you strength into it and although that bolt is easy to turn...you can't complete a revolution very quickly at all...and you're throwing EVERYTHING you have at it. For a car, this is like redlining first gear and only doing around 35 MPH. You're going to run out of strength and energy LONG before you get that bolt out, and also long before the car reaches its destination. You need another idea...

...Well... you can take the breaker bar off, but then you'll be left with a small ratchet and the bolt is still so deep it will be very difficult and time consuming to turn that 7 foot bolt..even though its broken loose and you can probably turn it now...it would take forever... you need something thats smaller than your breaker bar but larger than your original ratchet. For a car...that answer is second gear...and for you...that answer is a larger ratchet which is smaller than the breaker bar and larger than your original ratchet... Now you're able to turn it again...and you're able to complete a revolution much faster than before...and its coming out faster but still not fast enough..but you DO find that your maximum effort (which is never increased) is more efficiently applied to removing that bolt ... well..you once again come to a point where you need that bolt out right gawd dam NOW ... you try to turn it as fast as you can but you reach those same limits you met with your breaker bar...only something is different this time.. With ALL of your strength applied, it IS is moving fast enough now but its taking way to much of your energy to keep it moving this fast... you need another idea because while you're close to your ideal speed...its taking too much of your strength to keep at this. For a car, that solution is third gear...and for you...a smaller ratchet...

Now that the ratchet is fairly loose...its much easier to turn, and for a vehicle now that it has sufficient inertia, a smaller gear can be used to continue accelerating. You're finding it much easier to turn that bolt at the same speed now, and much less of your strength is required to turn it faster and faster and faster.. until you reach the limits and switch to a smaller ratchet and ultimately into a ratchet so small that you can turn it so fast that your bolt is turning faster than your hand completes a revolution, and for a car - that is Overdrive... a point of which a vehicle can effortlessly maintain a high speed because the gear is literally turning SLOWER than the drive wheels..because of that, its taking the motor HALF the work to achieve the desired speed, thus why cars are able to save more fuel on the highway...

Now you probably had a pretty decent clue about all this and wondering how it pertains to your question by now...

Here is likely why the truck saw an improvement and why the camaro did not. Note that in either case -- NEITHER APPLICATION were designed to improve fuel mileage, for the truck it was a bi-product. For the Camaro, it was never intended.

Remember when I told you what happens when you turn a large ratchet on a bolt, that although you have more than enough power to move it, it takes all your strength to move it QUICKLY, causing you to switch to a smaller ratchet? Well this equation is radically magnified when you add LOAD to the equation, in terms of your ratchet, that would mean, a heavier bolt. Meaning everytime you switch to a smaller ratchet, the heavier that bolt is the more you will feel a difference between ratchets and the strength you have to exert to move that smaller ratchet until that smaller ratchet reaches a speed efficient enough to move it with as little effort as possible... In terms of cars... This means if you are talking about a heavy vehicle, the distance between two gears will temporarily put the engine in a less efficient range to MOVE that smaller gear to a point where it can efficiently transfer the weight of that vehicle...With a lighter car, this difference is quickly overcome AND is less noticable in the powertrain because the weight doesn't put as much of a shock against the drive train when moving to another gear (I dont mean shock as in damage but in terms of dropping from peak efficiency from the previous gear to much less efficiency in that next UNTIL a mechanical advantage is reached at that speed which in turn brings it back to peak efficiency), with a truck, not so quickly. How do you resolve that? More gears thus less space between gears so the engine is almost always running at peak efficiency even after changing gears so it doesnt feel as much of a "shock" from the weight.

Here's why that doesn't work so well on our cars...

For starters, we are curing a problem for the truck -- which gear ratios were unbalanced in proportion to their weight and towing capacity and by doing this we are reducing the amount of time the engine has to spend trying to reach an efficient speed.

For the car -- The car was already at a point where it was balanced to the extent of momentum efficiency. It doesnt take anywhere near as much effort gear for gear to move it right to its efficiency range nor does it take anywhere near as much effort to keep it there... We add 2 more gears and lets say for the sakes that we are doing it for the same reason as the truck, keeping the powerband together (because as many people misconceive just because you add gears doesn't mean that these new gears will make the vehicle more efficient, it all has to the with configuration.) We are at a point where we really can't gain anymore regardless of how much we throw at it, instead we may end up actually losing something... think of how much work it is to continuously change ratchets -- when its not necessary... you may get to your goal with less mechanical effort..but that doesn't mean you are saving energy by transferring to another gear unnecessarily. Then the converter as well - everytime you shift that converter has to unlock and let you accelerate - everytime that converter is unlocked you are nowhere near peak efficiency until it locks up again...

In essence...adding gears only helps fuel mileage when its NEEDED...not when its for pleasure.

Thanks for the education. It makes sense when you explain it like that, I guess I just can't wrap my head around the fact that as far as I know every other application this 10 speed has been added too, has either improved fuel economy or remained the same. Silverado gained, F-150 gained, Mustang Gained, Camaro lost. Now I know that the fords went from A6 to A10 so that probably helped them there, but the Silverado 6.2 went from A8 to A10 and gained.

Your explanation makes sense, but seeing it compared to other applications and doesn't have the same effect is odd to me.

[S2K+1LE]

I feel like we should mention that modern DI motors will completely cut the delivery of fuel during off-throttle situations including transmission shifts... so... I'm not really perfectly clear on how shifting impacts economy.

There are many other factors not being discussed here, such as the overall gearing (is the spread of ratios CLOSER with the 10AT at the lower end and not in higher gears which impacts fuel economy), weight, final drive ratios, wheel/tire selections... I mean we're basically looking at one single thing and trying to pretend we're GM Powertrain engineers here.

[vtirocz]

Originally Posted by S2K+1LE

I feel like we should mention that modern DI motors will completely cut the delivery of fuel during off-throttle situations including transmission shifts... so... I'm not really perfectly clear on how shifting impacts economy.

There are many other factors not being discussed here, such as the overall gearing (is the spread of ratios CLOSER with the 10AT at the lower end and not in higher gears which impacts fuel economy), weight, final drive ratios, wheel/tire selections... I mean we're basically looking at one single thing and trying to pretend we're GM Powertrain engineers here.

"I feel like we should mention that modern DI motors will completely cut the delivery of fuel during off-throttle situations including transmission shifts... so... I'm not really perfectly clear on how shifting impacts economy."

Certain conditions with 0% throttle will result in fueling being 0 (this is not new with DI vs. port), but transmission shifts aren't one of these conditions. The overall decel fuel cut-off strategy may be different with the new calibration. At any rate, they should be targeting a significant fuel economy benefit with the overall cal/hardware combo.

"There are many other factors not being discussed here, such as the overall gearing (is the spread of ratios CLOSER with the 10AT at the lower end and not in higher gears which impacts fuel economy), weight, final drive ratios, wheel/tire selections... I mean we're basically looking at one single thing and trying to pretend we're GM Powertrain engineers here."

None of this has changed on the manual transmission SS cars, which saw the largest reduction in fuel economy. The only possible contributing factors are the aero/drag less favorable, calibration changed (ie. traded off improved response for FE), or just run to run variation.

For the auto (specifically # of gears), I think they are just at about the point of diminishing returns from a fuel economy standpoint. Again, the only reason to go through the design/validation process ($$$) would be for an improvement in fuel economy, performance, or both. It doesn't look like the fuel economy is significantly better, so I really hope there's a performance benefit to the new trans.

[S2K+1LE]

They absolutely do cut fueling during shifts.

What is the percentage drop in the manuals vs the autos? That should tell the story about efficiency between these transmissions pretty easily, since it gives valid data points.

[torqueaddict]

Originally Posted by shaffe

Your explanation makes sense, but seeing it compared to other applications and doesn't have the same effect is odd to me.

You can have the same auto transmission on two identical models and get different mileage based on how it was programmed. If you think of that way, it's really not odd.

It's the same reason, with all else being equal, I can get better mileage on my M6 by changing the way I choose the ratios compared to someone else who likes to linger in the lower gears. The annoying skip-shift is proof of that.

And there are other variables to consider; among them are weight and drag. Are the vehicles that gained, lighter? Do they have less drag?

[vtirocz]

Originally Posted by S2K+1LE

They absolutely do cut fueling during shifts.

What is the percentage drop in the manuals vs the autos? That should tell the story about efficiency between these transmissions pretty easily, since it gives valid data points.

On the certification cycles (ie. FTP75 and HWFET)? Do you have a data log of this fuel cut on a part throttle upshift?

[Need4Camaro]

Originally Posted by S2K+1LE

They absolutely do cut fueling during shifts.

What is the percentage drop in the manuals vs the autos? That should tell the story about efficiency between these transmissions pretty easily, since it gives valid data points.

Actually I was more-less under the impression that alot of that has to do with auto's having cylinder deactivation and the manuals do not. While on the street its true you do spend alot of time shifting, or atleast more so than on the highway, with the fractions of a second it takes the car to shift its highly unlikely that they would save much if any fuel by cutting flow during a shift... even if it is going on, I kind of doubt that is helping anything.

[cellsafemode]

when you accelerate to the speed limit as fast as possible without the tires breaking loose at every light, your mileage isn't really reflected in the standard tests.

I still average double digits so I'm happy. And when I need the fuel to last, i have that option. Better than turbo 4's for sure. I'm sure the 2019's with the additional gears will be able to achieve better mileage over the same performance as prior years in the situations that matter to the largest portion of camaro owners. The fed tests just dont overlap that demographic as much as say, prius owners do.