6.4L

[Scorch95]

This is probably a very stupid question and I'm very new to Dodge/Ram/FCA, but I haven't found an answer to it or a discussion on it. Is the 6.4L related to the 5.7L with the exception of the larger bore/stroke? By this what I'm trying to understand is if the motors are the same besides a different set of heads and intake but everything else would still attach and work as normal from a 5.7L? Would you be able to one day drop a 6.4L and get the 5.7L etorque to work with it?


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[Fatherof3]

I believe they share blocks and some hardware but the electronics are different . I don’t think the 6.4 uses MDS and the 5.7 does . If I’m wrong someone will let us know .

 

[79 300]

The 6.4 in my Challenger has MDS.

 

[Moparian]

6.4 has MDS unless you opt for the Tremec. As far as what will bolt on to the 5.7, the intake manifold and I am pretty sure the heads will as well. If you were really ambitious the Hellcat blower will bolt on with an adapter plate although the inlet points the wrong way for the airbox, havent seen the TRX version to see if it points the other way.

 

[Scorch95]

My curiosity is mainly would you be able to drop a 6.4L truck motor in our 1/2 ton trucks and be able to still utilize the etorque setup. I wasn't sure if the systems were so different that there would be no hope of an integration as they currently sit without some form of etorque being offered in the 3/4 and 1 ton trucks from the factory. I have no immediate plans for a project of this magnitude but I do plan on keeping my truck for the long haul and was curious of the possibilities.


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[devildodge]

The 6.4l BGE in the Truck is a completely different engine it has more In common with the Hellcat line. In 2018 the 6.4L SRT also went to the hellcat block.

So it is really going to depend on what you plan to do.

I am sure there is some way to do what you ask. There are plenty of people making their 5.7l a 426 and such. So the info is out there.

 

[Moparian]

My curiosity is mainly would you be able to drop a 6.4L truck motor in our 1/2 ton trucks and be able to still utilize the etorque setup. I wasn't sure if the systems were so different that there would be no hope of an integration as they currently sit without some form of etorque being offered in the 3/4 and 1 ton trucks from the factory. I have no immediate plans for a project of this magnitude but I do plan on keeping my truck for the long haul and was curious of the possibilities.


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I can almost 100% say you wouldnt be able to retain etorque if you swapped a 6.4 into your truck. I have a feeling Ram will give us a 6.4 1500 at some point in the next few years seeing as how they finally put one into the Wrangler. At that point it would likely be easier/cheaper to trade your truck in.

 

[WXman]

The truck 5.7 vs 6.4 reminds me of how Ford did the 5.0 and 6.2 in the F-150. Both engines were so similar in HP and torque that it was pointless.

 

[Willwork4truck]

The truck 5.7 vs 6.4 reminds me of how Ford did the 5.0 and 6.2 in the F-150. Both engines were so similar in HP and torque that it was pointless.

From tfltruck.com: “The big Ram comes with FCA’s tried and true 410 hp 6.4-liter HEMI V8 that makes 429 lbs-feet of torque.”

Our 5.7 hemi is 395 horsepower; 410 lb.ft. of torque so a bit more but not really enough difference unless the 6.4’s torque is generated at a lower rpm. I didn’t research that.

See the article entitled “Chrysler 6.4L Hemi 392 Engine Review” from website motorreviewer.com for a good description and summary of the 6.4.

 

[Scorch95]

I had a feeling your points were going to be the truth of the issue but figured I'd ask the questions. This was more of a down the line if I ever needed to replace a motor for whatever reason would it be feasible or even possible much less worthwhile. Thanks for everyones input.


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[Moparian]

The truck 5.7 vs 6.4 reminds me of how Ford did the 5.0 and 6.2 in the F-150. Both engines were so similar in HP and torque that it was pointless.

If we are talking about the HD 6.4 then yes it would be pointless but if we are talking about the SRT 6.4 with 485 hp then thats a significant bump and what I'd expect them to put in the 1500(similar to the Wrangler).

 

[SD Rebel]

They won't simply due to CAFE concerns for a high volume vehicle like the 1500. The Wrangler 6.4L is a near $80,000 vehicle, essentially a low production "Halo" vehicle to drive sales of more mundane versions. They could have put a 5.7L and priced it similar to how RAM does the 3.6L vs 5.7L, but that would create a high-volume low mpg scenario that FCA cannot afford in regards to corporate mpg requirements. They are already buying millions in carbon credits from Tesla.

Putting a 6.4L of either HD or SRT in a production 1500 would be a no go due to the hit to CAFE. The high priced halo option is already taken up by the TRX. I can see them doing a 6.4L SRT in a TRX package as a lower cost alternative, but it will still be low production.

As for the OPs original question, I can't see why not, you can engineer anything, people were already putting in HC motors before the TRX came about, I think a 6.4L should be fine. Though probably not worth the cost if it's the HD version. Though having it work with the E-Torque system would likely be very difficult.

 

[Dragonmaster13]

I would just take the 5.7 block and get it bored out with new cylinder liners and call it a day. Much easier and WAY, WAY cheaper than trying to mate electronics/replace/reprogramming and troubleshoot for years on end when something goes wrong.

 

[devildodge]

You can not compare the 6.4l BGE to the 5.7l Hemi in the 1500.

The BGE is designed for HeavyDuty use.

The 5.7l Hemi has many different ratings. The RAM 1500 gets the highest.

For 2 showings. The charger has 370 and 395 where as the RAM has 395 and 410. This is mainly due to cooling and exhaust.

The 6.4l BGE has 410 and 429. Not much more than 395 and 410...but the 5.7l HD that the 6.4l sent to pasture was only rated at 383 and 400.

Even in the HeavyDuty level...the 6.4l BGE in a chassis cab is again rated different at 370 HP And RPM is dropped from 5600 to 4600 to achieve this.

The engines are specifically designed to complete a task. Not to necessarily beat ratings.

 

[Scorch95]

Is there a torque curve difference that is meaningful between the two motors?


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[devildodge]

I have not been able to find a factory torque curve for the 6.4l BGE.

But yes. The torque comes on lower and climbs faster and remains flat to peak.

That is what makes the difference.

 

[silver billet]

For all you 6.4L doubters; I test drove the one my brother got from a rental, and that thing moves. Just a BigHorn trim, no fancy options, but it would undoubtedly smoke my 5.7. Not just from a stop either.

There is always more to the story than one specific measurement (peak HP/Torque). You can't judge an engine by how it performs at one spot in time.

It would have course have a higher gear ratio (3.73?), but again, how it performed at speed makes me think it's significantly more powerful.

 

[SD Rebel]

For all you 6.4L doubters; I test drove the one my brother got from a rental, and that thing moves. Just a BigHorn trim, no fancy options, but it would undoubtedly smoke my 5.7. Not just from a stop either.

There is always more to the story than one specific measurement (peak HP/Torque). You can't judge an engine by how it performs at one spot in time.

It would have course have a higher gear ratio (3.73?), but again, how it performed at speed makes me think it's significantly more powerful.

I think it feels that way due to the torque curve, but performance times don't bear that out. The few recent 0-60 of the 2500 6.4L published is about 7.2-7.3 seconds, which is about 1 second slower than a 1500 with a 5.7L, quarter mile is about 15.6 seconds, which is about .5 second slower than a 1500 with a 5.7L.

This is comparing similar crew cab, 4x4 configurations.

 

[Willwork4truck]

They won't simply due to CAFE concerns for a high volume vehicle like the 1500. The Wrangler 6.4L is a near $80,000 vehicle, essentially a low production "Halo" vehicle to drive sales of more mundane versions. They could have put a 5.7L and priced it similar to how RAM does the 3.6L vs 5.7L, but that would create a high-volume low mpg scenario that FCA cannot afford in regards to corporate mpg requirements. They are already buying millions in carbon credits from Tesla.

Putting a 6.4L of either HD or SRT in a production 1500 would be a no go due to the hit to CAFE. The high priced halo option is already taken up by the TRX. I can see them doing a 6.4L SRT in a TRX package as a lower cost alternative, but it will still be low production.

As for the OPs original question, I can't see why not, you can engineer anything, people were already putting in HC motors before the TRX came about, I think a 6.4L should be fine. Though probably not worth the cost if it's the HD version. Though having it work with the E-Torque system would likely be very difficult.

Yep, now with the change in Wash DC coming guess what is going to happen to CAFE standards... better enjoy your hemi cause it may be getting legislated away or penalized as not earth friendly...

 

[WXman]

Yes, at the end of the day torque curves don't matter if performance (speed) is your goal. Horsepower is horsepower, and 15 more horsepower in a truck that weighs 1,900 more lbs. is going to result in a slower truck, period.

You could put the 6.4 in the 1500 and you might gain 0.3 seconds in a 0-60 sprint with a loss of 5-15% of the fuel economy. What's the point?

Again, Ford tried this several years ago and realized quickly that it was pointless. So they dropped the 6.2 option after only a model year or two.