2007 Silverado

[montanass]

I was scrolling through a magazine at the store today and I saw a pic of a 2007 Silverado being tested, the front end looks alot like the new(2007) Tahoe's. Anybody else hear/read/see anything one them?

[montanass]

http://www.detnews.com/2005/autosconsumer/.../F03-321678.htm

 

not much to look at yet, but it will be pretty sweet!

[6.0ss]

I wonder what "displacement on demand" Will be with the new engines!

 

I would love to see a 2007 SSS with the LS2 and a charger on it!!!

[diggler_d]

I wonder what "displacement on demand" Will be with the new engines!

 

I would love to see a 2007 SSS with the LS2 and a charger on it!!!

<{POST_SNAPBACK}>

 

it is on the new impala ss

it can use 8 cylinders under full power and then cut out cylinders as needed

to conserve fuel

from 8 -6- to 4 when crusing

actually pretty neat feature

[SuperDave]

Yeah, it sounds pretty neat, but I bet they have a lot of issues with it. Your valvetrain is still opening and closing valves, it justs cuts fuel delivery and spark to the selected cylinders. It will cause an inbalance in the exhaust pulses, making it less effective. Yeah, you'll save a little gas, but not what you'd expect.

 

And what about damage it will do to the flux capacitor?

[.justin.]

Yeah, it sounds pretty neat, but I bet they have a lot of issues with it.  Your valvetrain is still opening and closing valves, it justs cuts fuel delivery and spark to the selected cylinders. It will cause an inbalance in the exhaust pulses, making it less effective. Yeah, you'll save a little gas, but not what you'd expect.

 

And what about damage it will do to the flux capacitor?

<{POST_SNAPBACK}>

 

Actually, it doesn't. To overcome the parasitic pumping losses and actually achieve an increase in efficiency, they have some sort of valve in the lifters that stops them from opening the valve's when that particular cylinder is shut off.

 

Seems like a great idea, but the complexity of the system would kind of scare me away from wanting one until it's been proven to work well for a few years...

[Bruce Beaven]

I am not sure but the Hemi shown on TV shows piston movement stopped??

And that is how they call it varible displacement.

I have no idea how they could achieve this?

Sounds scary.

[SuperDave]

I would entertain the idea of the lifters bleeding off or however they limit valvetrain action(maybe the are electrically activated), but the idea of a Hemi that stops piston movement is downright ludicrous! No way that one will ever make it on this site! It sounds like a physical impossibility to me. The crankshaft rotates, and the connecting rod and piston just follow it around. To stop the piston you would have to stop the crank's rotation.... if the crank doesn't turn neither does the transmission or the wheels!

 

The DOD system has it's warrants, but seems like a desperate way to reduce the dependency upon fossil fuels. I would prefer to find another fuel to burn in our engines, like Hydrogen lets say. It's cheap to produce, would have an endless supply, and would cut out the damage to the ozone and reduce smog..... what's the thoughts on that?

 

[disguisedSS]

I dont know for sure guys, but what i heard is that there is no cam at all in the engine, in place are electronic triggers that open the valves?? If thats the case.....i wonder how tuning could go?

[SuperDave]

This is starting to get a little crazy guys.... that technology would never find it's way into a production Chevy or Dodge.... come on you GM guys with all the facts (that's FACTS) not I heards, or my cousin's baby sisters, momma told me's....we need someone with hard facts from GM to sound off here. No more BS rumors about no cams... electronic triggers, stop motion pistons etc...

 

I mean... get real here. This is GM and mass production!

 

[disguisedSS]

[trickmob]

[Bruce Beaven]

Miulti displacement????

 

 

 

http://www.chrysler.com/300/features/performance/

 

Displacement on demandThe 2005 Chrysler 300C and Dodge Magnum RT were the first high-volume, modern production vehicles in North America to feature fully-functioning cylinder deactivation; at Chrysler, they were followed by the 2006 Durango. The MDS (“multiple displacement system”) seamlessly alternates between fuel economy in four-cylinder mode, and power in V-8 mode. Owners receive the powerful benefit of the Hemi engine with the fuel economy that they would expect from a less powerful V6 engine. Most test drivers cannot tell the difference.

 

"The MDS was part of the engine's original design," said Bob Lee, Vice President Powertrain Product Team, Chrysler Group. "This resulted in a cylinder-deactivation system that is elegantly simple and completely integrated into the engine design. The benefits are fewer parts, maximum reliability and lower cost."

 

This system should triumph where the Cadillac 4-6-8 failed because of the speed of modern electronic controls, the sophistication of the algorithms controlling the systems, and the use of electronic throttle control. The HEMI will be able to transition from eight cylinders to four in 40 milliseconds (0.04 seconds).

 

 

 

The system deactivates the valve lifters. This keeps the valves in four cylinders closed, and there is no combustion. In addition to stopping combustion, energy is not lost by pumping air through these cylinders.

 

Fuel economy gains go up to 20 percent under various driving conditions, with a 10 percent (or so) aggregate improvement, without any change in customer experience—drivers will receive the benefit without changing their driving habits or losing power.

 

An LX engineer said that the Hemi was in part inspired by the slant six - in particular, the dual oiling circuit, with oil coming through the pushrods. This could maintain lubrication when cylinders are at rest.

 

Don Sherman's article in Automobile noted described a test of the MDS. They found that only four cylinders were used during 17% of the suburban traffic portion of the test, during a full 48% of the freeway test which included "over 70 mph" speeds. Overall, they found that the engine powered down to four cylinders about 40% of the time. Non-enthusiast drivers may experience even more savings. As with most testers (including us), Don was generally unable to detect the changes from four to eight cylinders and back again.

 

Bob Sheaves discussed why the system is almost always used on V8s and not V6s:

"An Otto cycle engine requires 2 full revolutions of the crankshaft to fire all the cylinders. Therefore: 2 x 360=720 degrees of rotation. Dividing that total rotation by the number of cylinders to have an even firing engine (naturally balanced) will give you 120 degrees, which means that you have a cylinder firing every 120 degrees of rotation. When you take out 3 of the cylinders, you have increased the firing rotation to 240 degreees (720/3), still balanced between each firing of a cylinder. The catch is that you have now increased the harmonic vibrations as the rpms increase. Deactivation of four cylinders in a V6 would mean losing the multiple of six cylinders that will keep the engine in primary balance. (The lack of natural balance is why balance shafts are often used in 90 degree V6s and larger inline 4 cylinder engines.)"

 

Chrysler engineer Cole wrote: "The modern HEMI always shuts off the same four cylinders. In our duarability test cycle (150,000 customer equivelant miles driven at the 95 percentile, meaning that only 5 percent of our owners are more abusive than our testing), we have not found any adverse wear patterns." (Chrysler PR materials boasted of “over 6.5 million customer-equivalent miles through development and durability testing.”)

 

[dneumannjr]

I can offer some insight from the drivers stand point. We bought my wife a 2005 Magnum R/T with the Hemi. We average about 16 - 17 strictly City and 21 - 22 with a combination of City and Highway and on longer trips when we have a chance to use the cruise religiously we saw about 24 - 25mpg. It's not a bad car pretty quick (14.5 Stock in 90 degree weather) As for the on and off, I can't tell when it's on or off then again I am not really sure what I am looking to see a difference in. Although it is smooth and quite when it does it no weird noises or anything to say it was part of.

 

As the article stated this was in place back in the 70's in Caddy's but they had so many issues with it that they where disabling the systems and it got shelved. But newer technology should prevail and I think that this will prove to be a good thing.

 

We shall see.

 

Miulti displacement????

 

 

 

http://www.chrysler.com/300/features/performance/

 

Displacement on demandThe 2005 Chrysler 300C and Dodge Magnum RT were the first high-volume, modern production vehicles in North America to feature fully-functioning cylinder deactivation; at Chrysler, they were followed by the 2006 Durango. The MDS (“multiple displacement system”) seamlessly alternates between fuel economy in four-cylinder mode, and power in V-8 mode. Owners receive the powerful benefit of the Hemi engine with the fuel economy that they would expect from a less powerful V6 engine. Most test drivers cannot tell the difference.

 

"The MDS was part of the engine's original design," said Bob Lee, Vice President Powertrain Product Team, Chrysler Group. "This resulted in a cylinder-deactivation system that is elegantly simple and completely integrated into the engine design. The benefits are fewer parts, maximum reliability and lower cost."

 

This system should triumph where the Cadillac 4-6-8 failed because of the speed of modern electronic controls, the sophistication of the algorithms controlling the systems, and the use of electronic throttle control. The HEMI will be able to transition from eight cylinders to four in 40 milliseconds (0.04 seconds).

 

 

 

The system deactivates the valve lifters. This keeps the valves in four cylinders closed, and there is no combustion. In addition to stopping combustion, energy is not lost by pumping air through these cylinders.

 

Fuel economy gains go up to 20 percent under various driving conditions, with a 10 percent (or so) aggregate improvement, without any change in customer experience—drivers will receive the benefit without changing their driving habits or losing power.

 

An LX engineer said that the Hemi was in part inspired by the slant six - in particular, the dual oiling circuit, with oil coming through the pushrods. This could maintain lubrication when cylinders are at rest.

 

Don Sherman's article in Automobile noted described a test of the MDS. They found that only four cylinders were used during 17% of the suburban traffic portion of the test, during a full 48% of the freeway test which included "over 70 mph" speeds. Overall, they found that the engine powered down to four cylinders about 40% of the time. Non-enthusiast drivers may experience even more savings. As with most testers (including us), Don was generally unable to detect the changes from four to eight cylinders and back again.

 

Bob Sheaves discussed why the system is almost always used on V8s and not V6s:

"An Otto cycle engine requires 2 full revolutions of the crankshaft to fire all the cylinders. Therefore: 2 x 360=720 degrees of rotation. Dividing that total rotation by the number of cylinders to have an even firing engine (naturally balanced) will give you 120 degrees, which means that you have a cylinder firing every 120 degrees of rotation. When you take out 3 of the cylinders, you have increased the firing rotation to 240 degreees (720/3), still balanced between each firing of a cylinder. The catch is that you have now increased the harmonic vibrations as the rpms increase. Deactivation of four cylinders in a V6 would mean losing the multiple of six cylinders that will keep the engine in primary balance. (The lack of natural balance is why balance shafts are often used in 90 degree V6s and larger inline 4 cylinder engines.)"

 

Chrysler engineer Cole wrote: "The modern HEMI always shuts off the same four cylinders. In our duarability test cycle (150,000 customer equivelant miles driven at the 95 percentile, meaning that only 5 percent of our owners are more abusive than our testing), we have not found any adverse wear patterns." (Chrysler PR materials boasted of “over 6.5 million customer-equivalent miles through development and durability testing.”)

 

<{POST_SNAPBACK}>

[diggler_d]

 

to put this into comparsion

the dodge hemi ram truck get 11 mpg city 16 highway

pretty big difference in fuel economy!!!!