TJ Hemi swap

[RockCity]

Has anyone swapped a 5.7L Hemi into a TJ?

[Bounty__Hunter]

It's done all the time in the magazines, many big-name shops are doing it. Namely American Expedition Vehicles - Brute Kit, V8 HEMI, Aftermarket Jeep Conversions, Suspension Systems, Products, Wheels, Accessories and Highline Kits for Jeeps (TJ, JK, WK, XK).

[SteelHeadz]

Avoid the MDS 5.7 Hemi commonly found on the 4WD durango's and later Dodge Ram pickup's.

[RockCity]

What's the issue with the MDS Hemi. It seems that would be the way to go if you were going to use it as a semi-daily driver.?

[SteelHeadz]

The MDS has a predermined threshold that has to be met before the sytem enables the 4cylinders to shut down and run the engine on the other 4 . With this, we found that the conditions changes with a different chassis and drivetrain and causes a constant surge from the MDS since the variables has changed..Other than that everything is just peachy.

[RockCity]

Good heads up, thank you. I quess if I want the power of a healthy V-8, I need not worry about fuel mileage.

[jps4jeep]

Originally Posted by SteelHeadz

The MDS has a predermined threshold that has to be met before the sytem enables the 4cylinders to shut down and run the engine on the other 4 . With this, we found that the conditions changes with a different chassis and drivetrain and causes a constant surge from the MDS since the variables has changed..Other than that everything is just peachy.

Can't you just use a Non MDS ECM.. Eliminates the whole system

[SteelHeadz]

Originally Posted by jps4jeep

Can't you just use a Non MDS ECM.. Eliminates the whole system

Yes you can. The problem with that is the hardware inside the engine is still there. Eventhough there's no software to actuate the hardware, the components may still fail and not be recognized by the non MDS PCM. The hydraulic lifters and solenoids on top of the engine is primarily a concern. The lifters has the ability to lock itself from firing on their respective cylinders to a total of four. If the mechanical failure occurs on any of these lifters, a catastrophic engine failure will be in order.. I don't know if replacing the lifters to a non MDS system will fix this but i think it's not worth the hassle rather than just finding the one without it.

[jps4jeep]

what about with a head swap?

[SteelHeadz]

It might work, i never tried it so i don't know. The only thing that will remain is the solenoids mounted on the top engine valley . I never really looked into what it would cause if it's just left there or replaced with a metal plug.

[ArmyDiver]

Just to give you some insight on the straight V8 swap, I just put a 350 small block in my TJ. I have loved every minute of it and it has some serious power, plus sounds redic. If you are worried about the gas mileage you might want to stay clear or go with the V8 with EFI, might get a little more mileage as far as fuel goes. I will say I turn some heads, so if that's what you want jump on the band wagon!

[jps4jeep]

I am just asking cause my wife drives a 06 hemi durango with the MDS and if it ever gets totaled and is still drivable, I want to swap the motor into something..


Actually.. If you use a LS series chevy motor froma pick up, 4.8 or 5.3, you will actually improve millage over the stock 6 cyl drive train. not sure about the 4cyl. A friend has qualified for KOH and we are taking out the TPI 350 from his buggy and swapping in a LQ9.. he is estimating that it will get better milage.

[RockCity]

I thought about a small block Chevy swap, but, I think I want to keep it all Chrysler. Plus the whole fact of having a "HEMI in it".

[SteelHeadz]

Originally Posted by jps4jeep

I am just asking cause my wife drives a 06 hemi durango with the MDS and if it ever gets totaled and is still drivable, I want to swap the motor into something..


Actually.. If you use a LS series chevy motor froma pick up, 4.8 or 5.3, you will actually improve millage over the stock 6 cyl drive train. not sure about the 4cyl. A friend has qualified for KOH and we are taking out the TPI 350 from his buggy and swapping in a LQ9.. he is estimating that it will get better milage.

I understand.. Don't get me wrong, it is a swappable engine and if you want it to function as it was intended to, then the best thing to do is swap all the electronics with it. From what i was told, the instrument cluster will also have to be swapped over due to it's communications thru the PCM inputs.That in itself made every aspect of a simple swap go really complicated. Just not worth the hassle in my opinion. I turned down a deal with a 4X4 durango Hemi for only $800.00 with under 30,000 miles on it for that reason.

[ArmyDiver]

like steelhead said, the cluster will have to go, probably regardless of when engine you put in. I know esp. for the tach that what ever engine you are running now it won't work with the hemi, I just had that problem with my V8 swap, I lost my mileage(odometer not trip for whatever reason) and my tach. I did however get a nice custom cluster out of it(being made now). Just something to think about

[RockCity]

Thanks for all of the info, I've got a lot to chew on. Doe's anyone know of a wiring "kit" for a Hemi swap, Painless, etc?

[SteelHeadz]

You can try Mopar Performance since they offer a generic PCM for hotrod applications.

[RockCity]

Good idea, thanks man! I'm still old school I guess, not used to the manufacturers having performance parts for swaps, and off the wall projects.

[volaredon]

why not do a 318 or a 360? They put them in the Grand Cherokees so why not a TJ??

[RockCity]

Originally Posted by volaredon

why not do a 318 or a 360? They put them in the Grand Cherokees so why not a TJ??

More power, better mileage, more reliable, less oil leaks. And this is bone stock, with a few mods for the swap.