5.7 Hemi MDS Delete

What does the MDS delete do?

MDS- Multi-displacement system by Chrysler is a variable displacement technology for automobile engines. Debuted in 2006, the 5.7L modern Hemi has four separate mufflers. Among them two large central ones are for V8 mode, the other two ones are smaller and for four-cylinder mode. MDS or multi-displacement system is a cylinder deactivation system as a measure for fuel economy.

Whenever an engine reaches highway speed it comes to the rescue. Among the eight, MDS then deactivates four cylinders and thus ensures that the engine is using less fuel. MDS delete is disabling the system with a kit by a tuner or the gear. This will stop MDS on your Hemi.

5.7 Hemi MDS delete tune

As for now, we know that MDS is a multi-displacement system that deactivates cylinders to ensure fuel economy. After you have installed an MDS kit on your Hemi you are going to need a tune for disabling your MDS.

Tuning your MDS is necessary, if you do not tune your MDS your PCM will think that the MDS solenoid circuits are not disabled and they are in function. If the lifters are non-MDS the engine will not run correctly but still, the PCM will attempt to manage it as it thinks the MDS is there.

So, you need to tune your MDS delete kit. You can use tuners for this function. Another reason for tuning is if the cam in the non-MDS profile is different from the factory MDS cam. You will need to tune out your MDS for that too.

Hemi MDS Delete Benefits

MDS or multi-displacement system is a form of cylinder deactivation technology. This is quite popular as it ensures fuel economy. Though it saves your engine still sometimes you might want to delete MDS on your Hemi because of the disturbing sound it makes or the sudden speed changes. Now here Hemi MDS Delete benefits:

● Eight of your cylinders will be active and you will be able to drive smoothly. 

● It will guarantee you optimum power delivery.

● The valve lifters will not collapse or reactivate consistently and save you some money.

● It will help you prevent the ticking sound which you may find loud and annoying.

● Downshift will become quicker, throttle response will enhance and it will eradicate durability issues.

● Shuddering will be eradicated and you will be able to drive in all terrains.

5.7 Hemi MDS Delete Plugs

Most of the 5.7L Hemi engines from 2003-2008 have MDS in them that shut the cylinders down to give gas mileage. But in the case of non-MDS expansion plugs are used. These plugs are also known as Hemi block plugs or Solenoid block off plugs. These are mostly used in engines that don’t have MDS. Four of these plugs are mainly used with two sets of tappets to convert a 5.7L Hemi engine to non-MDS. So these plugs (such as 1409 KMT) are MDS delete plugs.

5.7 Hemi MDS Delete Problems

Having MDS on your hemi will ensure your fuel economy for sure. But it is not always as you wanted. You might face some problems because of your MDS and want to delete it. There are some common problems for which users want to disable their Hemi MDS. This can be the loud ticking noise, lifter problems, and MDS problems.

Moreover, there can be, dropped valve seat or vibration making you want to delete your MDS. But once you delete your MDS you can also face a few problems such as-

● Loss of gas mileage. As MDS deactivates cylinders once the vehicle reaches high speed, gas mileage increases. But once you delete MDS with a tuner or in another way, it will not work anymore and you will end up spending more fuel.

● Expensive deletion is another problem. If you want to delete MDS with a tuner it might cost you a lot like 300 USD or more. So, disabling MDS with a tuner will be expensive for you.

Gen 3 Hemi VVT Delete

VVT or variable valve timing does a stellar job for the gearheads. The VVT system advances and retards the timing of the cam to suit the speed of the engine. If you want a cam swap for turning more horsepower, VVT is what you need. Gen 3 Hemi VVT is one of the most common and popular ones. But if you want more than good there are reasons you might want to delete your VVT. It means you might remove your VVT if you want more power. 

Hemi MDS Delete Meaning

MDS means Multi displacement system. This is a kind of cylinder deactivation technology to ensure fuel economy. So, whenever any vehicle reaches high speed and the engine reaches a high temperature, MDS turns off four of the eight cylinders so that you can use less fuel. MDS delete is when you shut your MDS down through a tuner or using any other way. If you are not satisfied with the service you can turn it off by turning it out.

5.7 Hemi MDS Delete Cam Kit

Hemi MDS can be lifesavers for engine fuel. It saves your fuel and gives you gas mileage. If you install a cam kit it will also work as an MDS delete.

Along with the cam kit you also have to use a custom tune. Here, the custom tune will disable your MDS. It doesn’t matter if you change your lifters or not, the MDS will get removed. In this case, the MDS lifters will not collapse.

And after the lifter is working as a non-MDS you have to replace it. In this step, you may also replace the solenoids with delete plugs. The plugs will seal the oil. 

5.7 Hemi MDS Delete Tuner

You can delete MDS on a 5.7 Hemi through several methods. It can be disabled or eliminated either through tuners or using the gear. But most people prefer tuners as it is hassle-free. Deleting MDS with a tuner is like using software programming.

There are a few tuners such as Diablosports, Jay green, Hemi fever, etc. Among them, Diablosport is the most popular one. After you get your tuner, plug it into the OBD2 port and work as your manual guides you.

MDS is healthy for increasing fuel economy, but it comes with some cons too. So, for some reason, you might want to delete it and you can use a tuner for it. 


How do you turn off MDS Hemi?

You can turn off your MDS Hemi through a tuner or a gear. 

● With a tuner, you can turn off your MDS by software programming by modifying several factory settings.

● If you don’t want to modify your settings you can turn it off using your gear.

Can I use non-MDS lifters on 5.7 Hemi?

No, you can’t use non-MDS lifters on 5.7 Hemi MDS. If you want to, then first you have to find a non-MDS lifter and turn off your MDS with a tuner. 

Is MDS bad for Hemi?

No, MDS is not bad for Hemi. It helps the users to minimize their fuel usage and gives them gas mileage. If anyone wants to change or turn MDS off, it depends on their will or any disturbance they feel. But it does not harm your Hemi. 

Is MDS Bad for Engines?

The 5.7 Hemi engine with the MDS (Multi-Displacement System) often experiences issues with the system’s operation, including rough idling and engine noise. Some vehicle owners opt to have the MDS system deleted to improve the engine’s performance and longevity.

Deleting the MDS system in the 5.7 Hemi engine results in several benefits, such as:

  1. Improved throttle response: Without the MDS system, the engine delivers a more immediate and responsive throttle.
  2. Increased horsepower: The deletion of the MDS system can result in a horsepower increase for the 5.7 Hemi engine.
  3. Better engine sound: The engine produces a more aggressive, performance-oriented sound without the MDS system.
  4. More consistent performance: The MDS system’s operation can cause fluctuations in engine performance, but deleting the system results in a more consistent, predictable performance.


Here, we have briefly discussed the methods of 5.7 Hemi MDS delete. The users can get ideas about the process if they want to disable or get rid of this fuel-saving MDS. Before setting up your mind consider some factors such as your driving habit. If you drive on smooth highways most of the time you might not want to delete it. But if you drive on rough terrains more often then it will be easier for you to delete MDS on your Hemi. Finally, the process of deleting is not that tough and it is quite fast too.


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