Turbocharging
Postmaster
Joined: Oct 2009
Posts: 3,432
Likes: 7
Yes it can be done, and has been done. Have you got $6000.00 ?
Some have done mild boost, and then called it success, these engines fail prematurely becaused they were not designed for it.
A good machine shop can get you different pistons and stronger rods to lower the compression ratio and make the bottom end hold up to boost. The you need stainless steel valves and hardened nickel alloy exhaust seats so that those parts can handle the heat. Then you need larger injectors and a larger MAF and a way to tune for those parts. You can do away with the MAF if you convert to an aftermarket stand alone computer that uses speed density. Then you need a good turbo and a way to mount it and run the oil lines. This means either building a custom turbo manifold and bringing the opposing bank over into it, or mounting the turbo down lower which creates draining problems with the turbo. You could build two turbo manifolds and run twin turbos, but now your tubing and intercooler routing is far more complicated.
It is doable, but doing it right is very costly. Those who claim the stock parts can handle mild boost are neither knowledgable or experienced. Before we go further into that, lets lay down a few simple facts.
Not all 4.0L OHV are equal, some years use different heads and pistons, which affects the burn speed and compression.
The 4.0L OHV uses a cast iron head with flame hardened exhaust valve seats. These seats are know to wear down and crack frequently on these motors on stock fuel with stock compression. Add more heat from turbocharging and they fail even faster. Few motors with more than 120,000 miles are crack free.
The stock pistons are hypereutectic which means they are cheaper than forged pistons. When exposed to any pinging or preignition they are known to melt or shatter, even on stock compression ratios without boost. Please read this article for more information.
United Engine & Machine Co. Incorporated
Hypereutectic piston - Wikipedia, the free encyclopedia
The stock rods will take minor boost, but were not designed for it. If they fail, they tend to fail catastrophically, i.e. it will throw the broken rod out the side of the block, effectively destroying the entire engine. Replacing then with stronger rods is basically a must.
There are those that claim that with the right tuning you can get good boost out stock parts and that the tune is the magic secret. It is true that with a good yet conservative tune, you can improve the reliability of the parts. However, a good tune cannot compensate for the inevitable component failures. You get anything going wrong with the engine management, ranging from a failing fuel pump, a dirty injector, a plugged fuel filter, a dirty MAF sensor, a bad ECT sensor, pretty much anything, and the engine tune can get out of whack and cause serious engine damage. By using stronger components that are designed to handle the heat and stress of boost you get a much better margin of protection. Also instead of doing a "mild tune" that effectively limits the potential, you can run a "better tune" that takes advantage of the stronger components, so that even being safe and conservative you can produce impressive amounts of power.
Most people who cut corners and skip building the motor to handle turbocharging eventually grenade the engine.
Some have done mild boost, and then called it success, these engines fail prematurely becaused they were not designed for it.
A good machine shop can get you different pistons and stronger rods to lower the compression ratio and make the bottom end hold up to boost. The you need stainless steel valves and hardened nickel alloy exhaust seats so that those parts can handle the heat. Then you need larger injectors and a larger MAF and a way to tune for those parts. You can do away with the MAF if you convert to an aftermarket stand alone computer that uses speed density. Then you need a good turbo and a way to mount it and run the oil lines. This means either building a custom turbo manifold and bringing the opposing bank over into it, or mounting the turbo down lower which creates draining problems with the turbo. You could build two turbo manifolds and run twin turbos, but now your tubing and intercooler routing is far more complicated.
It is doable, but doing it right is very costly. Those who claim the stock parts can handle mild boost are neither knowledgable or experienced. Before we go further into that, lets lay down a few simple facts.
Not all 4.0L OHV are equal, some years use different heads and pistons, which affects the burn speed and compression.
The 4.0L OHV uses a cast iron head with flame hardened exhaust valve seats. These seats are know to wear down and crack frequently on these motors on stock fuel with stock compression. Add more heat from turbocharging and they fail even faster. Few motors with more than 120,000 miles are crack free.
The stock pistons are hypereutectic which means they are cheaper than forged pistons. When exposed to any pinging or preignition they are known to melt or shatter, even on stock compression ratios without boost. Please read this article for more information.
United Engine & Machine Co. Incorporated
Hypereutectic piston - Wikipedia, the free encyclopedia
The stock rods will take minor boost, but were not designed for it. If they fail, they tend to fail catastrophically, i.e. it will throw the broken rod out the side of the block, effectively destroying the entire engine. Replacing then with stronger rods is basically a must.
There are those that claim that with the right tuning you can get good boost out stock parts and that the tune is the magic secret. It is true that with a good yet conservative tune, you can improve the reliability of the parts. However, a good tune cannot compensate for the inevitable component failures. You get anything going wrong with the engine management, ranging from a failing fuel pump, a dirty injector, a plugged fuel filter, a dirty MAF sensor, a bad ECT sensor, pretty much anything, and the engine tune can get out of whack and cause serious engine damage. By using stronger components that are designed to handle the heat and stress of boost you get a much better margin of protection. Also instead of doing a "mild tune" that effectively limits the potential, you can run a "better tune" that takes advantage of the stronger components, so that even being safe and conservative you can produce impressive amounts of power.
Most people who cut corners and skip building the motor to handle turbocharging eventually grenade the engine.
Postmaster
Joined: Oct 2009
Posts: 3,432
Likes: 7
Turbocharging is a form of supercharging (the original full technical name for a turbo is 'turbosupercharger'. If you want to do forced induction you have to build the motor to handle it or internal engine damage will occur as a result.
The best way to turbocharge an Explorer is to either build the existing V6 (expensive) or to swap in a motor that was made to be turbocharged (2.3L turbo motor is a good option.).
The best way to turbocharge an Explorer is to either build the existing V6 (expensive) or to swap in a motor that was made to be turbocharged (2.3L turbo motor is a good option.).
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