Caliber SRT-4
#11
01-18-2007, 07:57 AM
#14
01-29-2007, 08:15 AM
Legend
RE: Caliber SRT-4
The bad wheel hop issues with the Neon SRT-4 never stopped them why should they worry about it now with the Caliber, it's not something that can be easily solved on a FWD.
Wheel hop is a jackhammering type of action and feeling when taking off and the tires start to break loose, generally only happens when launching kinda aggressively in a FWD car (RWD cars can also experience wheel hop, but it caused by different yet similar actions). It's a result of several things going on at the same time, mostly it's the tires loosing traction and regaining traction repeatedly often caused by the rubber mounts on the engine and transmission allowing them (engine and transmission) to move and keep vibrations from transfering through the entire car. Have you ever noticed how when you rev the engine it moves, the same happens every time you take off.It's a seesaw effect throughout the entire drivetrain. The soft compound of the SRT-4's Z-rated tires grab fairly well transfering back through the drivetrain causing the engine and transmission to quickly reach their limit of movement allowed by the rubber mounts. Since they cannot absorb anymore torque being at their limit, it then transfers it back to the wheels and tires causing them to break loose and spin. When the tires loose traction from this the torque is no longer keeping the engine and transmission mounts flexed to their limit, this in turn starts the whole process over again by allowing the torque to transfer back from the tires as they once again get traction. It's kinda like the swinging steel *****, I forget what exactly they're called, where you pull the one back and it transfers it's moving energy through a few others on impact causing the one on the other end to be knocked away and once it reaches it's motionlimit and swings back it hits the others continuing the action back and forth. That isroughly the same kind of back and forth action that causes wheel hop.
The easiest and most common ways of lessening or eliminating wheel hop is by using inserts that fill in all the gaps in the rubber to greatly reduce the engine and transmission mounts ability to allow movement or replacing the rubber mounts with solid mounts that allow no movement at all, thus eliminating the back and forth energy transfer that causes wheel hop. These solutions will transfer the noise and vibrations from the drivertrain through the entire car which is why car manufacturers don't build cars with solid mounts.
Wheel hop is a jackhammering type of action and feeling when taking off and the tires start to break loose, generally only happens when launching kinda aggressively in a FWD car (RWD cars can also experience wheel hop, but it caused by different yet similar actions). It's a result of several things going on at the same time, mostly it's the tires loosing traction and regaining traction repeatedly often caused by the rubber mounts on the engine and transmission allowing them (engine and transmission) to move and keep vibrations from transfering through the entire car. Have you ever noticed how when you rev the engine it moves, the same happens every time you take off.It's a seesaw effect throughout the entire drivetrain. The soft compound of the SRT-4's Z-rated tires grab fairly well transfering back through the drivetrain causing the engine and transmission to quickly reach their limit of movement allowed by the rubber mounts. Since they cannot absorb anymore torque being at their limit, it then transfers it back to the wheels and tires causing them to break loose and spin. When the tires loose traction from this the torque is no longer keeping the engine and transmission mounts flexed to their limit, this in turn starts the whole process over again by allowing the torque to transfer back from the tires as they once again get traction. It's kinda like the swinging steel *****, I forget what exactly they're called, where you pull the one back and it transfers it's moving energy through a few others on impact causing the one on the other end to be knocked away and once it reaches it's motionlimit and swings back it hits the others continuing the action back and forth. That isroughly the same kind of back and forth action that causes wheel hop.
The easiest and most common ways of lessening or eliminating wheel hop is by using inserts that fill in all the gaps in the rubber to greatly reduce the engine and transmission mounts ability to allow movement or replacing the rubber mounts with solid mounts that allow no movement at all, thus eliminating the back and forth energy transfer that causes wheel hop. These solutions will transfer the noise and vibrations from the drivertrain through the entire car which is why car manufacturers don't build cars with solid mounts.
#15
01-29-2007, 01:04 PM
#18
01-30-2007, 02:14 AM
Legend
RE: Caliber SRT-4
Horsepower and torque are closely related even though they are different and both are plenty high enough in both versions of the SRT-4 to break all kinds of parts. The Neon SRT-4's wheel hop can be quite destructive and even when it isn't it feels like it is regardless. I have Prothane race motor mount inserts on my SRT-4 and it still beats the **** out of me and the car during hard launches just like it did before the inserts only not quite as badwhile my '88 Daytona Shelby Z never had any wheel hop, it would simply smoke the tires, but it also had plain Goodyear Wingfoot HP tires on it and not Z-rated or any other soft sticky kind of tires. My '99 Neon R/T had Rex motor mount inserts in the Mopar Performance stiffer motor mounts and bobble strut and it had problems with wheel hop still, but it too had good tires, Bridgestone Potenza RE950's.
If you launch hard enough, like doing a burnout,in the SRT-4 it will simply smoke the tires smoothly. I'm guessing in the Caliber SRT-4 it won't do that smoothly do to it's design/weight distribution and wheel hops even at the extreme, read: burnout, causing the destructive wheel hop.
Has there been any dynoproven numbers on the Caliber SRT-4 to show the power at the wheels? Going by how badly they underrated the Neon SRT-4 at the flywheel (215 for '03 and 230 for '04-'05) and with how much they actually put out at the wheels (between 223 for the '03 and 246 for the '04), based on what I've read so far on the Caliber SRT-4 with it'shorsepower rated at 300 andclose tothe same weight as the Neon SRT-4, maybe another hundred or two hundred pounds more, and it'slow 14 second 1/4 mile times, I'mguessing the actual power output is the same or only slightly morethan the previous version and all they did was rate it at what it's true flywheel horsepower is (the previous version is realistically around 260-285 at the flywheel). I really do want to know what the difference is between the two, to know how much they did or didn't do between the SRT-4versions.
If you launch hard enough, like doing a burnout,in the SRT-4 it will simply smoke the tires smoothly. I'm guessing in the Caliber SRT-4 it won't do that smoothly do to it's design/weight distribution and wheel hops even at the extreme, read: burnout, causing the destructive wheel hop.
Has there been any dynoproven numbers on the Caliber SRT-4 to show the power at the wheels? Going by how badly they underrated the Neon SRT-4 at the flywheel (215 for '03 and 230 for '04-'05) and with how much they actually put out at the wheels (between 223 for the '03 and 246 for the '04), based on what I've read so far on the Caliber SRT-4 with it'shorsepower rated at 300 andclose tothe same weight as the Neon SRT-4, maybe another hundred or two hundred pounds more, and it'slow 14 second 1/4 mile times, I'mguessing the actual power output is the same or only slightly morethan the previous version and all they did was rate it at what it's true flywheel horsepower is (the previous version is realistically around 260-285 at the flywheel). I really do want to know what the difference is between the two, to know how much they did or didn't do between the SRT-4versions.
#19
01-30-2007, 08:34 AM
RE: Caliber SRT-4
I hope this helps, it's a completely different all aluminum motor, (old SRT-4 had an iron block, I think) made in a different facility on a different line. I don't know how much else is different, just what I found.
Standout Powertrain
The all-new 2007 Dodge Caliber SRT4 is capable of a 0-60 mph time in less than six seconds.
The all-new 2007 Dodge Caliber gets its motivation from an all-new "World Engine" produced at the Global Engine Manufacturing Alliance (GEMA) facility in Dundee, Mich. The World Engine is a family of small fuel- and emissions-efficient aluminum four-cylinder gasoline engines co-developed by DaimlerChrysler's Chrysler Group, Hyundai Motor Company and Mitsubishi Motors Corporation.
"The all-new 2.4-liter turbocharged World Engine delivers a level of power you'd expect from a V-8," said Pete Gladysz, Senior Manager—Powertrain, SRT. "With the engine in the all-new 2007 Dodge Caliber SRT4, we were able to take advantage of tried-and-true performance improvements, such as increased cylinder-head flow and higher compression ratio, as well as newer technologies such as Variable Valve Timing (VVT)."
To achieve its high-performance Dodge Caliber SRT4 configuration, the aluminum 2.4-liter World Engine block is specially machined for increased water and oil flow. Unique cast pistons travel within iron cylinder liners, and are cooled by oil squirters and affixed to forged connecting rods for high-revving reliability.
Tri-metal bearings are used for the connecting rods and crankshaft for high-performance durability. A unique oil pump/balance shaft module keeps the reciprocating assembly well-lubricated and running smoothly. An external cooler keeps oil temperatures within a safe range.
The aluminum cylinder head is equipped with unique high-temperature exhaust valves. VVT uses computer mapping to open and close intake and exhaust valves at optimal points for efficient combustion and flow. The camshaft and micro-alloy steel crankshaft, shared with the non-turbocharged 2.4-liter World Engine, are fully capable of high-horsepower loads.
Free-flow induction begins with an all-new air cleaner assembly that draws through an opening in a front crossmember for proximity to cool air. The air is then compressed in a TD04 turbocharger specially configured for the engine's inlet and outlet packaging requirements, and sent through an intercooler to a 57mm throttle body.
Fuel is provided by a high-flow pump feeding injectors developed specifically for the 2007 Dodge Caliber SRT4. An all-new engine management system designed by Siemens—the Global Powertrain Engine Controller—keeps the powerplant running at maximum efficiency and power.
On the exhaust side, spent gas exits through a free-flow system that features two catalytic converters—one immediately downstream from the turbo, and another further along the 3-inch single-pipe exhaust system. Using two catalytic converters in this way provides significantly better "light-off" for decreased emissions. As with the previous-generation Dodge SRT4, the exhaust is tuned for maximum performance while meeting federal noise regulations.
Power is transferred through a dual-mass flywheel to the six-speed manual transmission. The dual-mass flywheel consists of two flywheels sandwiching internal springs that are specially tuned to reduce noise and vibration. The GF DMT-6 six-speed transmission, equipped with a limited-slip differential for uniform side-to-side power transfer, is capable of handling up to 300 lb.-ft. of torque.
Torque is sent to the Dodge Caliber SRT4's wheels through equal-length halfshafts sourced from Chrysler Group mid-size cars for their larger size and power-handling capability.
Standout Powertrain
The all-new 2007 Dodge Caliber SRT4 is capable of a 0-60 mph time in less than six seconds.
The all-new 2007 Dodge Caliber gets its motivation from an all-new "World Engine" produced at the Global Engine Manufacturing Alliance (GEMA) facility in Dundee, Mich. The World Engine is a family of small fuel- and emissions-efficient aluminum four-cylinder gasoline engines co-developed by DaimlerChrysler's Chrysler Group, Hyundai Motor Company and Mitsubishi Motors Corporation.
"The all-new 2.4-liter turbocharged World Engine delivers a level of power you'd expect from a V-8," said Pete Gladysz, Senior Manager—Powertrain, SRT. "With the engine in the all-new 2007 Dodge Caliber SRT4, we were able to take advantage of tried-and-true performance improvements, such as increased cylinder-head flow and higher compression ratio, as well as newer technologies such as Variable Valve Timing (VVT)."
To achieve its high-performance Dodge Caliber SRT4 configuration, the aluminum 2.4-liter World Engine block is specially machined for increased water and oil flow. Unique cast pistons travel within iron cylinder liners, and are cooled by oil squirters and affixed to forged connecting rods for high-revving reliability.
Tri-metal bearings are used for the connecting rods and crankshaft for high-performance durability. A unique oil pump/balance shaft module keeps the reciprocating assembly well-lubricated and running smoothly. An external cooler keeps oil temperatures within a safe range.
The aluminum cylinder head is equipped with unique high-temperature exhaust valves. VVT uses computer mapping to open and close intake and exhaust valves at optimal points for efficient combustion and flow. The camshaft and micro-alloy steel crankshaft, shared with the non-turbocharged 2.4-liter World Engine, are fully capable of high-horsepower loads.
Free-flow induction begins with an all-new air cleaner assembly that draws through an opening in a front crossmember for proximity to cool air. The air is then compressed in a TD04 turbocharger specially configured for the engine's inlet and outlet packaging requirements, and sent through an intercooler to a 57mm throttle body.
Fuel is provided by a high-flow pump feeding injectors developed specifically for the 2007 Dodge Caliber SRT4. An all-new engine management system designed by Siemens—the Global Powertrain Engine Controller—keeps the powerplant running at maximum efficiency and power.
On the exhaust side, spent gas exits through a free-flow system that features two catalytic converters—one immediately downstream from the turbo, and another further along the 3-inch single-pipe exhaust system. Using two catalytic converters in this way provides significantly better "light-off" for decreased emissions. As with the previous-generation Dodge SRT4, the exhaust is tuned for maximum performance while meeting federal noise regulations.
Power is transferred through a dual-mass flywheel to the six-speed manual transmission. The dual-mass flywheel consists of two flywheels sandwiching internal springs that are specially tuned to reduce noise and vibration. The GF DMT-6 six-speed transmission, equipped with a limited-slip differential for uniform side-to-side power transfer, is capable of handling up to 300 lb.-ft. of torque.
Torque is sent to the Dodge Caliber SRT4's wheels through equal-length halfshafts sourced from Chrysler Group mid-size cars for their larger size and power-handling capability.
#20
01-31-2007, 08:56 AM
Legend
RE: Caliber SRT-4
Thanks, but I already knew everything except the dual mass flywheel thing, which doesn't sound any different or not much different than the previous modualr clutch which is a one piece clutch and flywheel assembly. Several (most all) of the items they list are already on the Neon SRT-4, the only different parts I know ofare the VVT, all aluminium block, 6-spd. transmission (the Neon SRT-4 was 5-spd. only)and 3" exhaust single pipe with 2 catalytic converters. I like how they list all these great things they're doing just for the Caliber SRT-4 when most every part was already on or done to the Neon SRT-4 such as the equal length halfshafts, limited slip differential, free flow induction, external oil cooler, etc.
I only refered to the Neon SRT-4 as such to eliminate any possibility for confusion, the Neon SRT-4 is actually just the Dodge SRT-4 and has been since it's debut as a concept car when it was called the Dodge SRT and was supercharged instead of turbocharged. From the beginning it was always considered a completely seperate and new model called the SRT-4 and not Neon SRT-4. Even though it's base was obviously the Neon it was never to be called a Neon, it doesn't have Neon anywhere on them or the owners manual,and many times whenmagazines did an article on the SRT-4 they even include in the article how Dodge specifically told them not to refer to it as or call it a Neon and it's the media, magazines included,that always called it a Neon SRT-4. The SRT-4 uses just the shell/frame of the Neon which is one of the reasons why it's a completely seperate and different model all together, the PT Cruiser shares more with the Neon than the SRT-4and no one calls the PT a Neon PT Cruiser. I don't know what all the Caliber SRT-4 will have different than all the other versions of the Caliber, but if it's as far removed from the Caliber as the SRT-4 was from the Neon, then it too should only be called the Dodge SRT-4. The only problem with this is that Dodge is calling it the Caliber SRT-4 as is everyone and that will just mean that it's a trim level or option package, which it may just be and it depends on how much or little it shares with the Caliber.
I only refered to the Neon SRT-4 as such to eliminate any possibility for confusion, the Neon SRT-4 is actually just the Dodge SRT-4 and has been since it's debut as a concept car when it was called the Dodge SRT and was supercharged instead of turbocharged. From the beginning it was always considered a completely seperate and new model called the SRT-4 and not Neon SRT-4. Even though it's base was obviously the Neon it was never to be called a Neon, it doesn't have Neon anywhere on them or the owners manual,and many times whenmagazines did an article on the SRT-4 they even include in the article how Dodge specifically told them not to refer to it as or call it a Neon and it's the media, magazines included,that always called it a Neon SRT-4. The SRT-4 uses just the shell/frame of the Neon which is one of the reasons why it's a completely seperate and different model all together, the PT Cruiser shares more with the Neon than the SRT-4and no one calls the PT a Neon PT Cruiser. I don't know what all the Caliber SRT-4 will have different than all the other versions of the Caliber, but if it's as far removed from the Caliber as the SRT-4 was from the Neon, then it too should only be called the Dodge SRT-4. The only problem with this is that Dodge is calling it the Caliber SRT-4 as is everyone and that will just mean that it's a trim level or option package, which it may just be and it depends on how much or little it shares with the Caliber.
