My 2011 Ram was seamless. If there was no light I would have no clue as to when it activated.
Death of the Hemi
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The Hemi in the 2005 Jeep WK my folks used to own was pretty good. You could tell it was doing the MDS thing, but only if you were really paying attention.
You can easily tell the change in displacement by the tone change in an opened-up exhaust if someone's running Flowmasters or similar.
You can easily tell the change in displacement by the tone change in an opened-up exhaust if someone's running Flowmasters or similar.
Originally Posted By: Hokiefyd
The Hemi in the 2005 Jeep WK my folks used to own was pretty good. You could tell it was doing the MDS thing, but only if you were really paying attention.
You can easily tell the change in displacement by the tone change in an opened-up exhaust if someone's running Flowmasters or similar.
It's a perfect illustration of OEM superiority. If a 5.7 Mopar with MDS in any platform goes into fuel saving mode there is no clue. That took some careful engineering, especially in the RAM trucks where the exhaust note is surprisingly peppy.
You should hear how a Magnum drones with an aftermarket exhaust!
The Hemi in the 2005 Jeep WK my folks used to own was pretty good. You could tell it was doing the MDS thing, but only if you were really paying attention.
You can easily tell the change in displacement by the tone change in an opened-up exhaust if someone's running Flowmasters or similar.
It's a perfect illustration of OEM superiority. If a 5.7 Mopar with MDS in any platform goes into fuel saving mode there is no clue. That took some careful engineering, especially in the RAM trucks where the exhaust note is surprisingly peppy.
You should hear how a Magnum drones with an aftermarket exhaust!
I drove a 2017 Charger in Detroit and the only indicator was the dash indicator, and a change in the tone of the engine. No giveaway at all, otherwise.
I noticed it in my CPO 2011 Chrysler 300C I purchased in October 2013. It was not too bad except right around 35-40 mph. I got a Diablo DCX Intune tuner and turned it off. It's been off ever since. My highway mileage went from around 26 to 23. In town I lost about 1.5 mpg. I now have 77K miles on it and runs perfectly. My wife purchased a new 2014 RAM Laramie in May 2014. Has the 5.7L with 8 spd trans and 3.21 rear qaxle. That truck is awesome. The MDS is seamless in it. If you pay attention you can notice a change in the exhaust tone at lower speeds but that's all. We get around 22 mpg on the interstate at 70 mph.
I've had arguments with people about this before. There is nothing that magical about a hemispherical combustion chamber. It's archaic and less efficient. A modern head should create quench as the GM engines do. It acts to create turbulence to get a better homogeneous mixture to burn. So the head should be flat and be within 40 thousands of the piston top at tdc.
GMs LS engines create plenty of power without being hemis. It just sounds macho. There are usually 20 of these in challengers at the show with their hoods open. I just walk right by as there is nothing to look at other than a huge plastic piece covering the whole thing.
GMs LS engines create plenty of power without being hemis. It just sounds macho. There are usually 20 of these in challengers at the show with their hoods open. I just walk right by as there is nothing to look at other than a huge plastic piece covering the whole thing.
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Yep. Hemi is no more than a marketing term these days. But they are not to be dismissed lightly. My Wife's is 395 HP, My sig car is 425 HP, and the hotter 6.4's now are 485 HP, all very conservatively rated numbers. Cheap to mod and extremely durable, everybody loves go. And one should not imagine cylinder head design to be so simple. It's not.
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Originally Posted By: SteveSRT8
Our 2014 RAM is absolutely perfect, you never feel a thing.
Exact same experience with my 2014 Ram as well. Engine and transmission combination is as close to perfect as I have ever owned (87 cars and trucks). With my 2016 Scat Pack, the transmission is programmed differently and you do notice the MDS in normal mode. Not a problem. If you don't like it, reach over to the dash and push the Sport Mode button and it deactivates the MDS. Out of all the toy cars I have owned, the 6.4L/485 HP Charger Scat Pack is by far the best (and that includes a 550 HP 2012 Shelby GT500 and a 460 HP 2015 Corvette Stingray). A truly awesome piece of machinery.
Our 2014 RAM is absolutely perfect, you never feel a thing.
Exact same experience with my 2014 Ram as well. Engine and transmission combination is as close to perfect as I have ever owned (87 cars and trucks). With my 2016 Scat Pack, the transmission is programmed differently and you do notice the MDS in normal mode. Not a problem. If you don't like it, reach over to the dash and push the Sport Mode button and it deactivates the MDS. Out of all the toy cars I have owned, the 6.4L/485 HP Charger Scat Pack is by far the best (and that includes a 550 HP 2012 Shelby GT500 and a 460 HP 2015 Corvette Stingray). A truly awesome piece of machinery.
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The remarkable thing to me is how much quicker these modern cars are compared to the musclecars of yore. I lived through that and I certainly wouldn't go back for any aspect of motoring (power, handling, NVH, you name it). Watching people drop big money at the auctions (Mecum this week included) for nostalgia mostly is understandable but THIS is the Golden Age of horsepower. Electrics may yet provide a Golden Age of torque but we'll all miss that V8 thrum. And don't get me started on 4-cyl Impalas......
Originally Posted By: DeepFriar
The remarkable thing to me is how much quicker these modern cars are compared to the musclecars of yore. I lived through that and I certainly wouldn't go back for any aspect of motoring (power, handling, NVH, you name it). Watching people drop big money at the auctions (Mecum this week included) for nostalgia mostly is understandable but THIS is the Golden Age of horsepower. Electrics may yet provide a Golden Age of torque but we'll all miss that V8 thrum. And don't get me started on 4-cyl Impalas......
I was in high school/college during the original muscle car era as well. By the mid 70's none of us would have thought we would reach the point we are at today. The Demon is the apex example. At that time could anyone have imagined a street legal production car with full warranty that developed 840 HP?? Not me for sure. You are right. This is the Golden Age of Muscle cars and horsepower. By the way, if you have never driven a 392 Charger or Challenger, I encourage you to do so. It is the best sounding stock exhaust system on a Muscle car I have EVER heard.
The remarkable thing to me is how much quicker these modern cars are compared to the musclecars of yore. I lived through that and I certainly wouldn't go back for any aspect of motoring (power, handling, NVH, you name it). Watching people drop big money at the auctions (Mecum this week included) for nostalgia mostly is understandable but THIS is the Golden Age of horsepower. Electrics may yet provide a Golden Age of torque but we'll all miss that V8 thrum. And don't get me started on 4-cyl Impalas......
I was in high school/college during the original muscle car era as well. By the mid 70's none of us would have thought we would reach the point we are at today. The Demon is the apex example. At that time could anyone have imagined a street legal production car with full warranty that developed 840 HP?? Not me for sure. You are right. This is the Golden Age of Muscle cars and horsepower. By the way, if you have never driven a 392 Charger or Challenger, I encourage you to do so. It is the best sounding stock exhaust system on a Muscle car I have EVER heard.
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Originally Posted By: SilverSnake
By the way, if you have never driven a 392 Charger or Challenger, I encourage you to do so.
Still trying to locate an SRT Charger near me that I could test drive. The closest one seems to be 100 miles away. Ugh...
By the way, if you have never driven a 392 Charger or Challenger, I encourage you to do so.
Still trying to locate an SRT Charger near me that I could test drive. The closest one seems to be 100 miles away. Ugh...
You guys are swooning over these Hemis. They are not so reliable with their infamous "TICK". I had a 2016 Challenger Scat Pack 6.4 six speed and it was nothing but trouble. Fast and fun, but a basket case otherwise
Originally Posted By: babyivan
You guys are swooning over these Hemis. They are not so reliable with their infamous "TICK". I had a 2016 Challenger Scat Pack 6.4 six speed and it was nothing but trouble. Fast and fun, but a basket case otherwise
Every car line has their issues. Neither of my current Hemis tick and both vehicles have been flawless. However, there are those that do have their problems. I had a 2015 Challenger R/T that never had a tick but the start up clatter on the 5.7L was terrible. Sounded like it had no oil in the engine for about 20 seconds. Could not stand it and dumped the car at 1300 miles.
You guys are swooning over these Hemis. They are not so reliable with their infamous "TICK". I had a 2016 Challenger Scat Pack 6.4 six speed and it was nothing but trouble. Fast and fun, but a basket case otherwise
Every car line has their issues. Neither of my current Hemis tick and both vehicles have been flawless. However, there are those that do have their problems. I had a 2015 Challenger R/T that never had a tick but the start up clatter on the 5.7L was terrible. Sounded like it had no oil in the engine for about 20 seconds. Could not stand it and dumped the car at 1300 miles.
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Originally Posted By: turtlevette
I've had arguments with people about this before. There is nothing that magical about a hemispherical combustion chamber. It's archaic and less efficient. A modern head should create quench as the GM engines do. It acts to create turbulence to get a better homogeneous mixture to burn. So the head should be flat and be within 40 thousands of the piston top at tdc.
GMs LS engines create plenty of power without being hemis. It just sounds macho. There are usually 20 of these in challengers at the show with their hoods open. I just walk right by as there is nothing to look at other than a huge plastic piece covering the whole thing.
The modern "HEMI" moreso resembles a pent-roof than a hemisphere. It has two quench areas (even the ones that "don't have a quench area" by nature of the shape of the chamber relative to the bore actually do) and canted valves that oppose each other. Unlike your GM LSx example, which is a traditional wedge, the HEMI and pent-roof designs offer more valve area. This was also the logic behind the Cleveland and BBC heads, which both feature canted valves, to allow for more area.
A quick look at the chambers of each:
6.4L Chrysler "HEMI":
Ford 6.2L SOHC head:
BMW M62 DOHC head:
GM LS3 "CNC" head:
Like with the SBF and venerable SBC, on the LSx both valves are on the same angle on the same side of the chamber, which limits valve area relative to bore diameter. The valves on opposing angles opposite each other like seen in the HEMI, SOHC and DOHC configurations offer more room for larger or more valves.
This doesn't make a huge difference in stock engines, but does, generally, facilitate greater flow for a given bore diameter in high performance applications. This becomes particularly relevant when dealing with engines that are bore-diameter limited and was evident with the Chevrolet 305 that could not accommodate larger valve heads like its 4" bore sibling the 350 and was subsequently of limited potential when compared to GM's previous 302 (4" bore) or its Ford counterpart (302HO).
I've had arguments with people about this before. There is nothing that magical about a hemispherical combustion chamber. It's archaic and less efficient. A modern head should create quench as the GM engines do. It acts to create turbulence to get a better homogeneous mixture to burn. So the head should be flat and be within 40 thousands of the piston top at tdc.
GMs LS engines create plenty of power without being hemis. It just sounds macho. There are usually 20 of these in challengers at the show with their hoods open. I just walk right by as there is nothing to look at other than a huge plastic piece covering the whole thing.
The modern "HEMI" moreso resembles a pent-roof than a hemisphere. It has two quench areas (even the ones that "don't have a quench area" by nature of the shape of the chamber relative to the bore actually do) and canted valves that oppose each other. Unlike your GM LSx example, which is a traditional wedge, the HEMI and pent-roof designs offer more valve area. This was also the logic behind the Cleveland and BBC heads, which both feature canted valves, to allow for more area.
A quick look at the chambers of each:
6.4L Chrysler "HEMI":
Ford 6.2L SOHC head:
BMW M62 DOHC head:
GM LS3 "CNC" head:
Like with the SBF and venerable SBC, on the LSx both valves are on the same angle on the same side of the chamber, which limits valve area relative to bore diameter. The valves on opposing angles opposite each other like seen in the HEMI, SOHC and DOHC configurations offer more room for larger or more valves.
This doesn't make a huge difference in stock engines, but does, generally, facilitate greater flow for a given bore diameter in high performance applications. This becomes particularly relevant when dealing with engines that are bore-diameter limited and was evident with the Chevrolet 305 that could not accommodate larger valve heads like its 4" bore sibling the 350 and was subsequently of limited potential when compared to GM's previous 302 (4" bore) or its Ford counterpart (302HO).
Yep, I see it. It's more of an oblong chamber so the piston will come real close to the head on both sides. The dual spark plugs must help too. With valves that big you'd think they would out power the ls engines.
Another neat engineering feature is the straight port design. Unobstructed by the pushrod tubes or snaking around head bolts. It took GM many years to finally go with offset rockers to allow a straighter port on their newest LS variants. Ford tried the old tunnel ports, and there were some other neat ideas that were floating around. I think Chrysler was using offset rockers in wedge head as well, thinking W2?
I agree that in stock, street level settings there is not much advantage for the hemi style heads. But you turn up the boost, fuel, heat and they really shine. How many top fuel cars are running a wedge set up?
I always admired the engineering put into those heads. Straight ports, spark plug location (2 in the newest variants), opposed valves that allowed big diameters, shaft mounted rockers and the idea that the exhaust and intake ports are separated for heat rejection.
I stray a little now but I still think the best looking valve covers were on the BOSS 429.
I agree that in stock, street level settings there is not much advantage for the hemi style heads. But you turn up the boost, fuel, heat and they really shine. How many top fuel cars are running a wedge set up?
I always admired the engineering put into those heads. Straight ports, spark plug location (2 in the newest variants), opposed valves that allowed big diameters, shaft mounted rockers and the idea that the exhaust and intake ports are separated for heat rejection.
I stray a little now but I still think the best looking valve covers were on the BOSS 429.
Originally Posted By: babyivan
You guys are swooning over these Hemis. They are not so reliable with their infamous "TICK". I had a 2016 Challenger Scat Pack 6.4 six speed and it was nothing but trouble. Fast and fun, but a basket case otherwise
The tick is annoying, yes, but it doesn't make the engine any less reliable. It is usually from poor maintenance. Chrysler thinks going 10,000 miles on conventional oil per the OLM is perfectly fine, while many of these engines see abuse and heavy towing. My father's 2013 Grand Cherokee with the 5.7L is approaching 95k miles and the engine has no ticks of any kind. He tows almost every weekend with it. I use Pennzoil Platinum synthetic and change it every 8,000 miles.
The first few oil changes were with conventional, but that was because the dealer told us they were using synthetic when the work order showed conventional.
What issues did you have with your 2016?
You guys are swooning over these Hemis. They are not so reliable with their infamous "TICK". I had a 2016 Challenger Scat Pack 6.4 six speed and it was nothing but trouble. Fast and fun, but a basket case otherwise
The tick is annoying, yes, but it doesn't make the engine any less reliable. It is usually from poor maintenance. Chrysler thinks going 10,000 miles on conventional oil per the OLM is perfectly fine, while many of these engines see abuse and heavy towing. My father's 2013 Grand Cherokee with the 5.7L is approaching 95k miles and the engine has no ticks of any kind. He tows almost every weekend with it. I use Pennzoil Platinum synthetic and change it every 8,000 miles.
The first few oil changes were with conventional, but that was because the dealer told us they were using synthetic when the work order showed conventional.
What issues did you have with your 2016?
I guess there can be a lemon with anything, but everyone I know with a Hemi likes it.
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