Starting a 6.4 Hemi swap

[gentlejax]

Welcome to the South!
Tennessee is much the same way and one of the reasons I love my home state, can't wait to see how your swap turns out, as I just finished mine recently through my shop.

What is your plan for skids for the new swap? The only ones that I found out the box that work with the 6.4L motor mounts are NextVenture, which is a great brand albeit pricey.

im in the South too. Shreveport ...you may have heard of. the place where the guy shot 8-10 kids 2 weeks ago. they get in shootout daily around here.

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[drewcnit]

what is your rig?

Someone else's thread and don't want to derail it much but 22 Gladiator on ECGS tons, RK long arms, and a 426 Hemi Stroker.
Motobilt armor all the way around.
Just because I run the brand from my friend's shop, doesn't mean I'm sponsored..
I funded this build.

 

[drewcnit]

im in the South too. Shreveport ...you may have heard of. the place where the guy shot 8-10 kids 2 weeks ago. they get in shootout daily around here.

Unfortunately Nashville joined the ranks of cities that have dealt with school shooters as well.

I'm still a firm believer that the only way to stop a bad person with a gun, is by having good people with even more guns. I personally am doing my part to raise the average of guns per person and own at least 5, that I'll talk about.


"The only thing necessary for the triumph of evil is for good men to do nothing"

 

[AZRubiX]

I believe the 5.7 and the 6.4 are the same weight. Someone check me on this...
From what (little) I know, the 5.7s experienced a price surge, while the 6.4s did not. The delta between those engines has narrowed, making it "easier" to just step up to the bigger displacement. There were some other factors, but having installed over a hundred 6.4s and tuned them, I think they're just a well-sorted, trouble-free swap. In either case, customers can choose to shop the 5.7 from other installers. I do think you can buy the 6.4 swap from my shop for less than a 5.7 from AMW...

The key difference being premium gas required. The gift that keeps giving. At $.8-$1 a gallon more expensive, that adds up fast. A 6.4 on regular would be a good option, if it was available.

 

[Flyin6]

The key difference being premium gas required. The gift that keeps giving. At $.8-$1 a gallon more expensive, that adds up fast. A 6.4 on regular would be a good option, if it was available.

I think part of the magic that makes the big Hemi work is it's higher compression ratio. We saw the lower CR in the earlier Hemi with a lot less power. I think it is what it is.
Currently, several dollars less per gallon for gas in KY. Personally, I'm good with fuel at any cost. Jeep is not my DD. I really only use it for "Adventures." When I'm out there having fun stuck on some rock on a mountainside, I couldn't care less about the cost of fuel.
I am wondering who would install a 500 hp motor in their daily driver anyway? For mundane things like driving to work, anything works...
All that being said, a premium-fuel 10-mpg Jeep is perfectly fine for me.

 

[Flyin6]

Welcome to the South!
Tennessee is much the same way and one of the reasons I love my home state, can't wait to see how your swap turns out, as I just finished mine recently through my shop.

What is your plan for skids for the new swap? The only ones that I found out the box that work with the 6.4L motor mounts are NextVenture, which is a great brand albeit pricey.

Copy all
Lived for 18 years in Clarksville (Stationed at Ft. Campbell)..Love Tennessee!

I'm going to purchase the ASFIR skids and "make 'em fit." ;-)

 

[AZRubiX]

I think part of the magic that makes the big Hemi work is it's higher compression ratio. We saw the lower CR in the earlier Hemi with a lot less power. I think it is what it is.
Currently, several dollars less per gallon for gas in KY. Personally, I'm good with fuel at any cost. Jeep is not my DD. I really only use it for "Adventures." When I'm out there having fun stuck on some rock on a mountainside, I couldn't care less about the cost of fuel.
I am wondering who would install a 500 hp motor in their daily driver anyway? For mundane things like driving to work, anything works...
All that being said, a premium-fuel 10-mpg Jeep is perfectly fine for me.

I get it, everyone has their own perspectives. I use mine to tow an overland trailer on long distance trips. So while not a daily driver, it is a long distance driver. A combo of 10mpg, even worse through the mountains, and $6 gas isn’t a good mix. Particularly for marginally increased usability and a $8,000 higher installed cost. I am willing to spend money to get improved performance for what I want to do, but not ok with pissing money away for no good reason.

 

[Flyin6]

Let me toss this out there:

Regarding gear ratio... I currently have 5.13

If I was turning the JT into a tow truck, I'd be there

I think I am going to stay in the 37"-39" tire size, so a change to either 4.88 or 4.56 is pending. If I were to have any chance at all of getting any decent fuel mileage, then 4.56 would be the best choice. The Hemi should be able to pull in 8th gear at 80 MPH. But 4.88 would work too and allow me to use high range climbing up things like Engineer Pass

Thoughts?

 

[Flyin6]

I get it, everyone has their own perspectives. I use mine to tow an overland trailer on long distance trips. So while not a daily driver, it is a long distance driver. A combo of 10mpg, even worse through the mountains, and $6 gas isn’t a good mix. Particularly for marginally increased usability and a $8,000 higher installed cost. I am willing to spend money to get improved performance for what I want to do, but not ok with pissing money away for no good reason.

Cincinnati is a long way from Arizona, but the shop I'm using has that 6.4 kit priced closer than an $8K delta...

 

[drewcnit]

Let me toss this out there:

Regarding gear ratio... I currently have 5.13

If I was turning the JT into a tow truck, I'd be there

I think I am going to stay in the 37"-39" tire size, so a change to either 4.88 or 4.56 is pending. If I were to have any chance at all of getting any decent fuel mileage, then 4.56 would be the best choice. The Hemi should be able to pull in 8th gear at 80 MPH. But 4.88 would work too and allow me to use high range climbing up things like Engineer Pass

Thoughts?

Very smart to consider this as well.
My setup is probably heavier than yours, I'm on 42s as well but running 5.38s.
Put her in 4L for the first time yesterday and climbed the shops ramp for the first time. She crawled up the ramp with no gas pedal and almost wanted to push through the brakes...
Even with a sport TCase, the torque pushing her is insane.
So definitely a gear ratio swap might help that as well, but I'm leaning towards a hydro boost brake setup.

 

[Freems]

When he was just getting here, some stupid teens broke into an old man's home. The old timer dumped an entire magazine of .22 into them. One dead in the house, one dead a mile down the street. The police came, looked it over, and gave him a pat on the back.

…So no crime in Kentucky huh?

 

[AZRubiX]

Very smart to consider this as well.
My setup is probably heavier than yours, I'm on 42s as well but running 5.38s.
Put her in 4L for the first time yesterday and climbed the shops ramp for the first time. She crawled up the ramp with no gas pedal and almost wanted to push through the brakes...
Even with a sport TCase, the torque pushing her is insane.
So definitely a gear ratio swap might help that as well, but I'm leaning towards a hydro boost brake setup.

I am putting in 4.88 gears as step one. Then will decide next steps. A 5.7 conversion is on the table. Unfortunately I bought an Rubi X so if I make the conversion will need to “downgrade” to a standard Rubi transfer case to avoid the On Demand clutches of the X transfer case.

 

[drewcnit]

A buddy of mine, that built up his JKU, said this -

I would 100% recommend hydroboost brakes. I had the same issue with lack of braking power. I looked into locating the J8 setup, but they never seem to be in stock. Plus I’ve heard even the J8 did not effectively create enough PSI for GM and Ford factory calipers. Evidently Fusion, Dynatrac, & I believe ECGS use a smaller caliper on their axles to accommodate the PSI demands. Hydroboost was simple to install, I paired it with the compact willwood MC and only had to shift my ABS pump slightly. I retained the factory brake petal and just had to modify/bend the metal bracket that holds the brake switch so that my brake lights worked.

You will need to swap out your PSC res to the three port, PSC and WOD do not recommend tapping into a low pressure return. And of course run new lines. My pump goes to my brakes first and then my steering.

I’ve had zero failures and even if you lose power you will still have three good manual pumps to come to a stop and engage the E brake.

Ram 2500/3500 come with hydroboost from the factory. So it’s reliable and safe. With all the work you have had done, hydroboost would be a no brainer for me.

For anyone else that decides to go Hemi and needs more stopping power.

 

[Flyin6]

Very smart to consider this as well.
My setup is probably heavier than yours, I'm on 42s as well but running 5.38s.
Put her in 4L for the first time yesterday and climbed the shops ramp for the first time. She crawled up the ramp with no gas pedal and almost wanted to push through the brakes...
Even with a sport TCase, the torque pushing her is insane.
So definitely a gear ratio swap might help that as well, but I'm leaning towards a hydro boost brake setup.

So...4.56 then???

 

[Flyin6]

A buddy of mine, that built up his JKU, said this -

I would 100% recommend hydroboost brakes. I had the same issue with lack of braking power. I looked into locating the J8 setup, but they never seem to be in stock. Plus I’ve heard even the J8 did not effectively create enough PSI for GM and Ford factory calipers. Evidently Fusion, Dynatrac, & I believe ECGS use a smaller caliper on their axles to accommodate the PSI demands. Hydroboost was simple to install, I paired it with the compact willwood MC and only had to shift my ABS pump slightly. I retained the factory brake petal and just had to modify/bend the metal bracket that holds the brake switch so that my brake lights worked.

You will need to swap out your PSC res to the three port, PSC and WOD do not recommend tapping into a low pressure return. And of course run new lines. My pump goes to my brakes first and then my steering.

I’ve had zero failures and even if you lose power you will still have three good manual pumps to come to a stop and engage the E brake.

Ram 2500/3500 come with hydroboost from the factory. So it’s reliable and safe. With all the work you have had done, hydroboost would be a no brainer for me.

For anyone else that decides to go Hemi and needs more stopping power.

I'll broach the subject with the builder at the shop. Personally, I've used hydro-braking systems on other builds, even a Tundra on which I installed a SAS.
After my last trip down Corkscrew Pass in Colorado, my brakes were hot. Actually boiling the fluid, and stunk! I upgraded to a better brake package, which has worked OK, but, yeah, with the low torque of this 6.4 and my 4:1 Rubi T-case, that motor may well overrun the brakes.

I do know they are doing something different with the brakes in this swap, removing the electric brake shenanigans and going belt-driven, but with some alternative pump. Whether that will handle the additional demands of hydro brakes, I do not know.

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