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Old 11-30-2013, 02:18 PM   #29
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Old 11-30-2013, 02:48 PM   #30
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Removing 200 pounds of static weight would be noticeable by most folks on a track. Every day, it's doubtful. I actually enjoy the feel of our S4 compared to Mrs. Number 3's ATS and some of that is simply the rigidity and solid feeling of the Audi compared to the Cadillac. And the Audi weighs in about 300 pounds or so heavier.

I would like some clarity on how you think 100 pounds of wheel/tire/rotor(rotating unsprung mass) and caliper/lower control arm (unsprung mass) is going to save significant fuel. Yes it's directionally correct and in fact would do as much for wheel control by the chassis as anything else.

FE is rolling resistance, aerodynamics and powertrain.

If you have data, I wouldn't mind seeing it. What you suggest is interesting, I just think it would be so small as to not matter.

Besides, pulling 100 pounds out of the wheel/tire/rotor would be huge. I think the Z/28 with carbon ceramic brakes and 19" wheels didn't come close to the 100 pounds. That will be a very hard 100 pounds to get.



Mules will have the production intent architecture underneath. That means underbody, chassis and powertrain must be correct. You are correct, they've put some pretty strange stuff on top of those architectures i.e. recent photos of Chevy Caprice on top of what is rumored at least to be Omega.

Keep in mind, if the NG Camaro doesn't have a 4 cylinder then you can kiss outselling the Mustang goodbye. This suggests that Ford is 1) going global as 2.0 is a main tax threshold in most other countries 2) going after the total coupe market as I've suggested Chevy should do, meaning taking sales not just from Camaro, but also Nissan and Honda and 3) has a CAFE miracle up their sleeve. Not sure how you get to where the Camaro has to be for CAFE without a 4 cylinder. And please don't suggest that GM can get 6 MPG out of the current 3.6L. It's just not there. Look at the same 3.6L in the ATS. Rated at 28 in a much lighter car, 2 less than the Camaro.

I'm very skeptical GM would even want to pass up on a 4 cylinder solution unless they want to watch Mustang sales soar and not have anything to compete with.
Oh certainly someone out on the track with track experience could tell the difference in a 200 lb weight reduction, but for all the owners who never go on a track it's about the difference between driving by yourself and having a 200 lbs passenger with you; not very noticeable performance-wise.

The performance difference between a current Camaro, and a current one that has 100 lbs less unsprung and unsprung rotating weight is startling. You feel it the instant you press the gas pedal and start moving.

The fuel savings would come from not having to push the gas pedal as much to get the car moving, which is probably the majority of the type of driving most Camaro owners have to do. Unless you're driving long distances where you're cruising in 6th gear, most driving is around town with stop-and-go traffic. I barely have to push the gas pedal on mine to get moving and before I know it I'm at the speed limit without having to push the pedal any further. (I've done the weight reduction on mine). I've also done headers, cam, etc.... none of which are or were aimed at fuel economy. I'm pulling about 450 hp to the rear wheels. On the freeway at 70 mph in 6th gear I'm getting about 26 mpg. Around town with the way I like to drive I still get 14-15 mpg. If I was driving for economy that number could go up; and that's with all the performance mods I've done. I also have 19x10" wheels all-around which work against me for fuel economy.

Driving a stock SS it feels like I have to push the gas pedal 3 times farther to "try" and get it to go somewhat like mine does; and it's still not the same. It would be interesting to do the weight reductions on a current stock 1SS similar to what I've done and compare that to a stock non-modified car. The performance difference would seem like they aren't even the same type of car, even though nothing under the hood was modified. As for fuel economy, comparing both under the same around-town driving conditions I'm guessing you'd see an increase of maybe 2-3 mpg for the modified car. Not so much on the freeway at a steady speed where the extra weight on the unmodified car isn't that much a penalty once it's in motion.

Imagine though, if the new weight-reduced technology could be used across GM's product line, what adding 2-3 mpg could do for their corporate average. It might even be more than 2-3 mpg improvement on the bigger, heavier vehicles where the owners are pushing the engines harder to get them to move.

Remember, a potential buyer who tests drive a car is basing their decision on their perception of how it feels; how it responds, not a number. If they go for a test drive and the car just sparkles; they just barely touch the pedal and it goes... RIGHT NOW... they will think it has power and performance regardless of the "numbers". The actual hp number doesn't mean much if they have to push the pedal halfway to the floor and it takes several seconds before they feel like it's starting to really move. GM needs to engineer and design for perception rather than just numbers and spreadsheets. And don't forget that 100 lbs of unsprung and unsprung rotating weight is also static weight so the "number" does improve on weight reduction.

You can find about 50 lbs of reduction just in the wheels and tires alone. The other candidates are brake rotors, axles, flywheel, clutch, driveshaft. Shocks, shock towers, suspension arms and components, brake calipers, hardware, etc. Collectively across all 4 corners of the car you can find that other 50 lbs of reduction quicker than you might think.

Another area of improving the driving perception is by improving the efficiency of the drivetrain. Better low-friction fluids in the trans and diff. Spend the extra money on an efficient 1-piece driveshaft. I gained 8 hp and 9 lbs of torque to the rear wheels just by replacing the factory 2-piece shaft with a carbon fiber 1-piece:

http://www.camaro5.com/forums/showth...t=45165&page=5

I imagine an aluminum 1-piece would produce very close to the same results. If I were GM I'd go on a mission to reduce the unsprung and unsprung rotating weights, and then start advertising the rear wheel horsepower as the "real" power you feel. If they dynoed a stock Mustang or other "competitor" cars and started comparing rear wheel horsepower to the rwhp of a new "mission-improved" Camaro and could show there's more power where it counts on a Camaro, that could be a genuine marketing/sales advantage. Imagine being able to free up 8-10 horsepower to the rear wheels without having to do a single thing to the engine, but being able to advertise last year's to this year's improved "power you can feel". (I should trademark that lol).

I'm not saying they should stop improving the engines, I'm just saying that's not the only area they can look at to help meet upcoming cafe standards. Engine improvements are bloody expensive along with the lengthy testing/certification procedures. The knowledge, design and techniques they would gain reducing the right kind of weight would help them across the board on every vehicle they make.

By the way; as for the data you wanted to see, look through my project thread link I posted just above; I documented everything with weights and dyno sheets as I went along. My current vehicle weight with a full tank of gas (no driver) is 3,700 lbs. And that's with the 19x10" wheels. Interior is completely stock; back seat and everything, so I KNOW the reductions can be done; and I did it without gutting the car. Going with the stock wheel sizes which would be even lighter, I know GM could do it too.
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Old 11-30-2013, 05:02 PM   #31
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Oh certainly someone out on the track with track experience could tell the difference in a 200 lb weight reduction, but for all the owners who never go on a track it's about the difference between driving by yourself and having a 200 lbs passenger with you; not very noticeable performance-wise.

The performance difference between a current Camaro, and a current one that has 100 lbs less unsprung and unsprung rotating weight is startling. You feel it the instant you press the gas pedal and start moving.

The fuel savings would come from not having to push the gas pedal as much to get the car moving, which is probably the majority of the type of driving most Camaro owners have to do. Unless you're driving long distances where you're cruising in 6th gear, most driving is around town with stop-and-go traffic. I barely have to push the gas pedal on mine to get moving and before I know it I'm at the speed limit without having to push the pedal any further. (I've done the weight reduction on mine). I've also done headers, cam, etc.... none of which are or were aimed at fuel economy. I'm pulling about 450 hp to the rear wheels. On the freeway at 70 mph in 6th gear I'm getting about 26 mpg. Around town with the way I like to drive I still get 14-15 mpg. If I was driving for economy that number could go up; and that's with all the performance mods I've done. I also have 19x10" wheels all-around which work against me for fuel economy.

Driving a stock SS it feels like I have to push the gas pedal 3 times farther to "try" and get it to go somewhat like mine does; and it's still not the same. It would be interesting to do the weight reductions on a current stock 1SS similar to what I've done and compare that to a stock non-modified car. The performance difference would seem like they aren't even the same type of car, even though nothing under the hood was modified. As for fuel economy, comparing both under the same around-town driving conditions I'm guessing you'd see an increase of maybe 2-3 mpg for the modified car. Not so much on the freeway at a steady speed where the extra weight on the unmodified car isn't that much a penalty once it's in motion.

Imagine though, if the new weight-reduced technology could be used across GM's product line, what adding 2-3 mpg could do for their corporate average. It might even be more than 2-3 mpg improvement on the bigger, heavier vehicles where the owners are pushing the engines harder to get them to move.

Remember, a potential buyer who tests drive a car is basing their decision on their perception of how it feels; how it responds, not a number. If they go for a test drive and the car just sparkles; they just barely touch the pedal and it goes... RIGHT NOW... they will think it has power and performance regardless of the "numbers". The actual hp number doesn't mean much if they have to push the pedal halfway to the floor and it takes several seconds before they feel like it's starting to really move. GM needs to engineer and design for perception rather than just numbers and spreadsheets. And don't forget that 100 lbs of unsprung and unsprung rotating weight is also static weight so the "number" does improve on weight reduction.

You can find about 50 lbs of reduction just in the wheels and tires alone. The other candidates are brake rotors, axles, flywheel, clutch, driveshaft. Shocks, shock towers, suspension arms and components, brake calipers, hardware, etc. Collectively across all 4 corners of the car you can find that other 50 lbs of reduction quicker than you might think.

Another area of improving the driving perception is by improving the efficiency of the drivetrain. Better low-friction fluids in the trans and diff. Spend the extra money on an efficient 1-piece driveshaft. I gained 8 hp and 9 lbs of torque to the rear wheels just by replacing the factory 2-piece shaft with a carbon fiber 1-piece:

http://www.camaro5.com/forums/showth...t=45165&page=5

I imagine an aluminum 1-piece would produce very close to the same results. If I were GM I'd go on a mission to reduce the unsprung and unsprung rotating weights, and then start advertising the rear wheel horsepower as the "real" power you feel. If they dynoed a stock Mustang or other "competitor" cars and started comparing rear wheel horsepower to the rwhp of a new "mission-improved" Camaro and could show there's more power where it counts on a Camaro, that could be a genuine marketing/sales advantage. Imagine being able to free up 8-10 horsepower to the rear wheels without having to do a single thing to the engine, but being able to advertise last year's to this year's improved "power you can feel". (I should trademark that lol).

I'm not saying they should stop improving the engines, I'm just saying that's not the only area they can look at to help meet upcoming cafe standards. Engine improvements are bloody expensive along with the lengthy testing/certification procedures. The knowledge, design and techniques they would gain reducing the right kind of weight would help them across the board on every vehicle they make.

By the way; as for the data you wanted to see, look through my project thread link I posted just above; I documented everything with weights and dyno sheets as I went along. My current vehicle weight with a full tank of gas (no driver) is 3,700 lbs. And that's with the 19x10" wheels. Interior is completely stock; back seat and everything, so I KNOW the reductions can be done; and I did it without gutting the car. Going with the stock wheel sizes which would be even lighter, I know GM could do it too.
Doc, love your passion. But you won't get an EPA certified 2 to 3 mpg simply by reducing unsprung weight.

I absolutely agree that there are a ton of things you can do to simply make a car feel faster and quicker by simply adjusting throttle tip in. It can make a big difference in feel......................just not MPG.

Again, even assuming you are right, and I agree there is an element to how it "feels" in your point, it will be hugely expensive to get 100 pounds out of the car in this area. I can assure you that GM and every other OEM would literally kill for 2 to 3 mpg and if it were as easy as you suggest we'd see 13" tiny wheels and teeny tiny tires one every car. But you don't and there is a reason for that.
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Old 11-30-2013, 05:20 PM   #32
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Doc, love your passion. But you won't get an EPA certified 2 to 3 mpg simply by reducing unsprung weight.

I absolutely agree that there are a ton of things you can do to simply make a car feel faster and quicker by simply adjusting throttle tip in. It can make a big difference in feel......................just not MPG.

Again, even assuming you are right, and I agree there is an element to how it "feels" in your point, it will be hugely expensive to get 100 pounds out of the car in this area. I can assure you that GM and every other OEM would literally kill for 2 to 3 mpg and if it were as easy as you suggest we'd see 13" tiny wheels and teeny tiny tires one every car. But you don't and there is a reason for that.
Are you absolutely sure about that? I never said it was easy; it wasn't easy for me but I was only modifying my one car. It would be "easier" to some degree for GM because they can actually make the technology they need; I had to wait and research like crazy to put together what I did. But based on my actual experience I can say it would be worth GM's time and money to do more research in this area. Yes it will be expensive initially, but what isn't in order to meet cafe standards?? The problem with pouring millions into certifying one engine is it's only good for that one engine; they have to do it for every new or modified engine if I understand it correctly. The tech they would develop for reducing unsprung I believe would actually be cheaper in the long run as it can be used across many vehicle product lines and can be carried over year to year. And there wouldn't be expensive certification tests involved.

I don't know how they go about getting an epa certified rating but I firmly believe it would be worthwhile to create one "mission modified" test car that's only had a reduction in unsprung to see what the actual results are. My car is modified for the track with appropriate cam and everything and I STILL get pretty decent gas mileage; especially on the freeway. If I was just modifying for street/daily driver I have no doubt I could get better mpg out of a stock SS without engine mods and it would be a noticeable improvement in performance. And that's just me modding an already manufactured car. If I had the backing and resources of GM behind me I'm absolutely positive I could improve the performance and mpg WITHOUT modifying the already-certified engine.

It would be an investment on GM's part but a worthwhile one that would pay off for years and years.
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Old 11-30-2013, 06:16 PM   #33
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I just hope that GM doesnt screw up the 6th gen
Oh they won't - believe me, just wait...
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Old 11-30-2013, 07:31 PM   #34
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I hope GM doesn't push the Camaro to meet European style and engine sizes. They need to keep the Camaro an American car. That's the only concern I have for the Camaro future.
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Old 12-01-2013, 01:34 PM   #35
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Are you absolutely sure about that? I never said it was easy; it wasn't easy for me but I was only modifying my one car. It would be "easier" to some degree for GM because they can actually make the technology they need; I had to wait and research like crazy to put together what I did. But based on my actual experience I can say it would be worth GM's time and money to do more research in this area. Yes it will be expensive initially, but what isn't in order to meet cafe standards?? The problem with pouring millions into certifying one engine is it's only good for that one engine; they have to do it for every new or modified engine if I understand it correctly. The tech they would develop for reducing unsprung I believe would actually be cheaper in the long run as it can be used across many vehicle product lines and can be carried over year to year. And there wouldn't be expensive certification tests involved.

I don't know how they go about getting an epa certified rating but I firmly believe it would be worthwhile to create one "mission modified" test car that's only had a reduction in unsprung to see what the actual results are. My car is modified for the track with appropriate cam and everything and I STILL get pretty decent gas mileage; especially on the freeway. If I was just modifying for street/daily driver I have no doubt I could get better mpg out of a stock SS without engine mods and it would be a noticeable improvement in performance. And that's just me modding an already manufactured car. If I had the backing and resources of GM behind me I'm absolutely positive I could improve the performance and mpg WITHOUT modifying the already-certified engine.

It would be an investment on GM's part but a worthwhile one that would pay off for years and years.
You are correct that the responsiveness of a car with less rotating unsprung mass will be better. The rotational moment of inertia of a larger and/or heavier wheel tire combination will take more to spin. So from a real world standpoint you would be absolutely correct.

If you look at the Cruze ECO, you will see that it comes with what I believe are lower weight aluminum wheels. But this is only a part of the equation.

So I am agreeing that you are correct in your assumption. Reducing the rotational inertia of the wheel/tire/rotor will make a difference. Just not as big as you are suggesting.

All I am suggesting is that if it were simply a matter of reducing rotational mass you would see a much different set of wheels and tires on cars today.

GM and every other OEM would pay dearly for the 2 to 3 MPG you are suggesting is possible and if all it took was 12 or 13" aluminum wheels...............you'd see every car come standard with those. You wouldn't see some base models coming with steel wheels and hubcaps either.

Just look at the Camaro. Do you think GM would love to have the same or higher EPA highway number as the Mustang???? YES in as big a font as I can come up with. I know the effort that went into getting 30. And if all they had to do was put the aluminum wheels on as standard to get even 1 MPG do you think they would have done that? Again, YES in as big a font as the last yes. I believe the aluminum wheels save something in the neighborhood of 30 to 50 pounds, half of your suggestion.

So I am pretty sure that rotating unsprung mass won't get the MPG you are thinking. For highway numbers it truly is Aero, Tire Friction and Powertrain. Mass of the vehicle highly impacts the tire friction. For City, it's less Aero and more Mass. Much more to the art and science of it and there is a bunch that can impact "real world" FE as well compared to the EPA cycles.
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Old 12-01-2013, 01:46 PM   #36
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Oh they won't - believe me, just wait...
Believe you eh??

You have some sort of connections??
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Old 12-01-2013, 01:49 PM   #37
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I hope GM doesn't push the Camaro to meet European style and engine sizes. They need to keep the Camaro an American car. That's the only concern I have for the Camaro future.
I just hope they decide to keep giving the car it own style and attitude. Don't just make it look like part of the fleet and feel like they have to give it the current corporate grille or something like that.

Corporate styles come and go, and they are trendy and eventually they fade away.

The 5th gen and its styling will never fade away because there is nothing else out there like it. That again is a key they need to nail when designing the new beast.

Ford decided to make the next Mustang resemble some of the other cars in the line up. That's fine I guess....not saying that automatically makes the car look bad. It just doesn't make it unique.
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Old 12-01-2013, 06:43 PM   #38
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Mules will have the production intent architecture underneath. That means underbody, chassis and powertrain must be correct. You are correct, they've put some pretty strange stuff on top of those architectures i.e. recent photos of Chevy Caprice on top of what is rumored at least to be Omega.

Keep in mind, if the NG Camaro doesn't have a 4 cylinder then you can kiss outselling the Mustang goodbye. This suggests that Ford is 1) going global as 2.0 is a main tax threshold in most other countries 2) going after the total coupe market as I've suggested Chevy should do, meaning taking sales not just from Camaro, but also Nissan and Honda and 3) has a CAFE miracle up their sleeve. Not sure how you get to where the Camaro has to be for CAFE without a 4 cylinder. And please don't suggest that GM can get 6 MPG out of the current 3.6L. It's just not there. Look at the same 3.6L in the ATS. Rated at 28 in a much lighter car, 2 less than the Camaro.

I'm very skeptical GM would even want to pass up on a 4 cylinder solution unless they want to watch Mustang sales soar and not have anything to compete with.
What would you say to LGX + eAssist in a Camaro? That might help bump the V6 FE up a few notches (even if it pisses off the purists).

Going off ATS specs, I really don't see a way to avoid using the LTG as a base engine to beat Mustang FE-wise.

Just anecdotally, the rumored ATS powertrain MCE includes a 2.0T + eAssist + 8 speed automatic and a 2.0T manual + Start/Stop.
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Old 12-01-2013, 07:06 PM   #39
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Removing 200 pounds of static weight would be noticeable by most folks on a track. Every day, it's doubtful. I actually enjoy the feel of our S4 compared to Mrs. Number 3's ATS and some of that is simply the rigidity and solid feeling of the Audi compared to the Cadillac. And the Audi weighs in about 300 pounds or so heavier.
You shouldn't be surprised that you prefer the "solid feel" of Audi's highest performance (US) 4 series sport sedan to a middle-of-the-pack commuter ATS that costs significantly less.

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Look at the same 3.6L in the ATS. Rated at 28 in a much lighter car, 2 less than the Camaro.
The ATS is rated higher city/highway/combined than the Camaro, while offering significantly more passenger and cargo volume.
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Old 12-01-2013, 08:39 PM   #40
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You are correct that the responsiveness of a car with less rotating unsprung mass will be better. The rotational moment of inertia of a larger and/or heavier wheel tire combination will take more to spin. So from a real world standpoint you would be absolutely correct.

If you look at the Cruze ECO, you will see that it comes with what I believe are lower weight aluminum wheels. But this is only a part of the equation.

So I am agreeing that you are correct in your assumption. Reducing the rotational inertia of the wheel/tire/rotor will make a difference. Just not as big as you are suggesting.

All I am suggesting is that if it were simply a matter of reducing rotational mass you would see a much different set of wheels and tires on cars today.

GM and every other OEM would pay dearly for the 2 to 3 MPG you are suggesting is possible and if all it took was 12 or 13" aluminum wheels...............you'd see every car come standard with those. You wouldn't see some base models coming with steel wheels and hubcaps either.

Just look at the Camaro. Do you think GM would love to have the same or higher EPA highway number as the Mustang???? YES in as big a font as I can come up with. I know the effort that went into getting 30. And if all they had to do was put the aluminum wheels on as standard to get even 1 MPG do you think they would have done that? Again, YES in as big a font as the last yes. I believe the aluminum wheels save something in the neighborhood of 30 to 50 pounds, half of your suggestion.

So I am pretty sure that rotating unsprung mass won't get the MPG you are thinking. For highway numbers it truly is Aero, Tire Friction and Powertrain. Mass of the vehicle highly impacts the tire friction. For City, it's less Aero and more Mass. Much more to the art and science of it and there is a bunch that can impact "real world" FE as well compared to the EPA cycles.
If you read my posts in detail and took the time to examine my project thread you should be able to see I'm not saying just replacing the wheels is the magic bullet to gaining 2-3 mpg. There is no magic bullet. It's a combination of several things; wheels and tires being part of that equation.

I don't know how cars are EPA certified; are they tested in a lab by a machine or out on the road with real drivers? I know that people push the gas pedal as far as they feel is necessary to get the feeling they're "moving" at a rate they feel is acceptable. That "feeling" depends on acceleration response and how quickly they reach that "feeling". The farther they push the gas pedal to get going, the worse the gas mileage. If you take the same driver and put them in a car with more "pep" so that they get to that "feeling" quicker and only have to push the gas pedal half as far or even less, then they are using less gas to get going and will get better mileage as a result. How far they push the gas pedal depends on their perception of how the car is responding to their throttle input. If they feel the car is sluggish, they're pushing the pedal down pretty far to get it going. If it feels like they barely push it at all (like mine; I can push the pedal no more than an inch at the most and in a couple of seconds I'm at the speed limit on the street) then they're using less fuel; especially for around-town stop-and-go driving. Freeway driving is very different; there it's rolling and wind resistance you have to overcome more than anything else. Unsprung reduction would have little effect on that unless the freeway traffic is heavy and you're having to speed up and slow down a lot.

It would have to be a total approach; drivetrain from the flywheel through the clutch/trans, driveshaft, differential and axles, as well as unsprung rotational in the wheels, including using low-rolling-resistance tires and lighter brake rotors. Any of that mass you can reduce means less power is required to get moving which means less gas is used. Just changing the wheels isn't enough; you need the total package, but that's something GM can certainly do.

The reason why manufacturers haven't so far I'm guessing is because they're also focused on making the parts as cheaply as possible, so the idea of putting what they would probably perceive as racing grade engineered parts in a mass-manufactured street vehicle would seem cost prohibitive and be nixed by the bean counters.

Times have changed though. With new materials and manufacturing techniques what was once highly custom engineered is now reasonably possible with computerized manufacturing. And again, they need to recalibrate their focus on targeting to the performance perception of the customer. When a customer does a test drive it's not the numbers that impresses them, it's how the car makes them feel when they drive it. Aim for that. A car could literally have less horsepower than a competitor's car, yet feel better when driving because of how it responds to the driver. Aim for the perception because to the customer, perception is reality.
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Old 12-01-2013, 11:17 PM   #41
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Originally Posted by MEDISIN View Post
The ATS is rated higher city/highway/combined than the Camaro, while offering significantly more passenger and cargo volume.
The LFX?
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Old 12-02-2013, 08:17 AM   #42
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The LFX?
According to fueleconomy.gov

http://fueleconomy.gov/feg/Find.do?a...VWTYoWiw.gmail

2014 Cadillac ATS: 18/22/28
2014 Chevrolet Camaro: 18/21/27

I see Chevrolet advertises the 2LS at 30hwy, so maybe that's the difference.
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