engine harness for $$$

-
HemiDenny

HemiDenny

HDK Suspension
FABO Gold Member
Joined
May 31, 2006
Messages
8,617
Reaction score
3,819
Location
NW Ohio
I might be new to the engine electrical management for the Gen III into out A body's, but who and what is the best to use? I believe I have read that the OEM harness that came with the engine has too many circuits that if left unconnected can confuse the computer.

for clarity, I am installing a 6.4 with a Whipple in a 73 Duster. not sure on trans yet, but it will be a stand alone (either an ATI Turbo 400 w/ gear vendor or 833 w/ gear vendor.

interested on any experience from those that have done it.

looking at these three options...so far

a)Mopar stand alone is around $1600 with an unlocked computer / PCM?

b)Holley stand alone harness Holley computer

c) OEM harness / computer / PCM that came with the 6.4 Hemi

Any advise or experience would be appreciated.
Thanks,
Denny

20220826_163018.jpg
 
Hi Denny,

I'm planning a conversion myself and am going to contact Bouchellon Performance as I have used them in the past.

Great service!

Here's a link on harness. Might not be what you are looking for but may be worth a phone call. I found these people very helpfull!

Here's their contact # 843-744-6559 ext.#1

Search Results - Bouchillon Performance Engineering

Hope this is of some help,

Cheers!!
 
great info.....anyone use anything above and recommend?

pros / cons helpful
 
Is this a Hellcrate? Is it drive by wire? Does it have VVT? There are some major differences between certain years. pass. car or truck variant, etc. You might want to think about how involved you want to get with controlling it and whether you want to spend time learning how to build a system on your own (MS3), be able to do some tuning/customization using aftermarket software (Holley) or just "make it work" (OE).

I have not done a Gen III swap myself but have been using Holley EFI stuff for a few years now. I'd wager the Holley is probably the most "efficient" choice since it's the largest brand with the most support. They have a complete package deal for $1,900. Not cheap for sure. The EFI software that comes with it is good though, I use it with the Sniper. You can get pretty deep with tuning if you wish. Holley makes it all pretty user friendly and the graphical interfaces are nice. Here's a link to their whole kit and kaboodle. Holley Terminator 2013+ Gen III ECU

Megasquirt has a stand-alone harness - MS3 Gen III wiring. If you like "DIY" and want to save some money then this might be a good choice. If it was me though, I'd be inclined to pay more for something I didn't have to engineer myself. MS3 info

I'm not up on what the OE or Mopar harness is about so I can't comment on it. Would you know if the "unlocked" PCM can be modified? You'd think that would be kind of limiting factor if you're stuck with a base tune, especially if it's from a truck.

If you use the OE PCM presumably you'll have to figure out how to make it work with your electrical system. You'd likely have to do something similar with the Holley/MS3 but my guess is they lay that out for you.

If you go with the stick that would pretty much alleviate the need for a trans controller. I'd want a Tremec over an 833 with a GV myself.
 
HemiDenny said:
great info.....anyone use anything above and recommend?

pros / cons helpful
Click to expand...
My experience falls far short of your Whipplecharged 6.4, I've only done a couple fairly stock 5.7s.
First was a modded stock harness and reflashed factory '04 ECM, other was 5.7 with a HotWire kit.
Hotwire's been at this for years, their stuff is pretty much seamless. Based on OEM.
Swap Specialties' stuff intrigues me, but have not used it.
DIYHemi is a wealth of information for various work-arounds and persnickety stuff.
I would think the user-tunability of the Holley setup (versus custom flashes in the OEM stuff) would be a major bonus for your setup, which is way beyond my Gen III experience.
 
Professor Fate said:
Swap Specialties' stuff intrigues me, but have not used it.
Click to expand...

Do a search on Swap Specialties, pretty sure there are a couple of threads on here of guys looking for help after they bought a harness from them and then got ghosted when the motor wouldn’t start. I think it might be the same place @Riddler sent his harness too and never got anything back.

I could be wrong, just suggesting someone looks into it.
 
I think the Holley stuff and MS3 has the best potential for things outside of running the motor, like traction control. And probably the easiest to tune.

The OEM stuff has probably 3 different options. If you want to use the VVT and SRV, I think you need to stick to at least ‘09-10 NGC. After that is the GPEC2 for 11-14 and then the 15+. The later ones (15+) are locked from the factory, but you can get a crate motor PCM from DIYHemi that is unlocked.

The OEM harness really isn’t a bad setup for a swap. The engine harness is really pretty self contained and just require some additional wires for things like power and fuel pump, ASD relay controls. DIYHemi sells a harness that plugs into the unmodified OEM engine harness and makes it a running setup.
 
Thanks for the replies. All good info.

not a Hellcrate... 6.4 (pulled from 2019 Charger) w/ Whipple, now non VVT . The SRV I believe is eliminated with the Whipple, but will need to re-read the instructions to verify). I have a cable to DBY adapter (RAM truck) to run the throttle body.
 
HemiDenny said:
Thanks for the replies. All good info.

not a Hellcrate... 6.4 (pulled from 2019 Charger) w/ Whipple, now non VVT . The SRV I believe is eliminated with the Whipple, but will need to re-read the instructions to verify). I have a cable to DBY adapter (RAM truck) to run the throttle body.
Click to expand...

Steve White Motors sells/installs/tunes SC kits, so the OEM PCM might be an option. Might be worth reaching out to them. At the same time, might just be easier to go aftermarket.

Is the 6.4 built? Or are you limiting the boost? The 6.4 pistons are pretty fragile when boost is involved. Not that it can’t be done, but (as I understand it) tune is super important and boost is pretty limited.
 
DionR said:
Steve White Motors sells/installs/tunes SC kits, so the OEM PCM might be an option. Might be worth reaching out to them. At the same time, might just be easier to go aftermarket.

Is the 6.4 built? Or are you limiting the boost? The 6.4 pistons are pretty fragile when boost is involved. Not that it can’t be done, but (as I understand it) tune is super important and boost is pretty limited.
Click to expand...
I have heard of the results of too much boost especially with the OEM compression and the pistons w/ high ring glands....not good.

The 6.4 has the Extreme 10.1 / 1 drop in kit, features (.10 over) lower compression pistons and H beam rods. Bullet cam (w/ the new Mopar roller lifters) almost identical to the DSR. Timing cover / water pump from the Supercharged 6.2 to run the independent, wider supercharger belt. Butch is thinking around 12 lbs of boost.

thanks for your input
 
Last edited:
I think for the boost aspect alone the Holley should be your choice since those parameters are already built into the ECU and software. I hate to sound like a shill for them but it just seems to be the most logical way to go about this. No clue how other harness/ECU vendors handle supercharged applications but why make it hard on yourself trying to figure that out? No way other smaller vendors have the same resources Holley does either. Go to the drags and look at all the really fast power adder racers, they're basically all using Holley ECUs and software.

Yeah, it's an expensive initial buy-in but one would think that by going a cheaper route you'll be adding on stuff anyway and you'll end up in the same place. And think of all the extra aggravation you'll save yourself by not having to blindly piece things together and hope it all works.

"Built in 1bar MAP (manifold absolute pressure) sensor included - For Boosted applications – internal MAP sensor can be disabled and utilize external MAP sensor harness (kit includes a terminated connector for seamless installation)"

"Boost Control – boost vs. time, boost vs. gear, boost vs. RPM, boost vs. speed, and boost safeties"

BOOST BOOST BOOST!
 
I'm finally getting serious about my 5.7 swap. I've been collecting parts for 2 years and one of the first things I bought was the Mopar swap harness with ECM and Power Module. My plan was, and has been to run a basically stock 5.7. The ECM is unlocked and is comparable to a 2016 Challenger and can be tuned with HPtuners. It does not control a transmission which is ok with me because I have a Tremec 5 speed. One of the guys on FABO said a Diablo smoked his ECM and couldn't be saved but I don't know if that is common. Could've been operator error.

Since then, Holley has really stepped up with Mopar stuff and if I were to do it today, that's the route I would take. Especially since you are adding a supercharger. I hear that Holley has hired some ex-SRT engineers which may give them some good inside info.
 
Leaning towards Holley. we will see how it works out.

Thanks for all the input
 
Damm!! That looks awesome!

Is all that going to fit under a stock hood?
 
AAndrews said:
Damm!! That looks awesome!

Is all that going to fit under a stock hood?
Click to expand...


in mock up....see what is hiding under the former California Flash hood (damaged when the tent blew down at the 2019 Nats) ? answer: mock-up Whipple. Since the mock-up, I raised the nose 1/4" and moved the engine rearward 1/2" I will likely do a minor modification to the ribbing of the underside of the hood. If I can draw it on a cocktail napkin, the guy that does the HDK fabrication / welding (aka Fog) can make it happen.

The hard stuff gets done immediately, the impossible may take an extra day.

20220420_161102.jpg


20220420_151044.jpg


20220420_122633.jpg
 
Last edited:
HemiDenny said:
in mock up....see what is hiding under the former California Flash hood (damaged when the tent blew down at the 2019 Nats) ? answer: mock-up Whipple. Since the mock-up, I raised the nose 1/4" and moved the engine rearward 1/2" I will likely do a minor modification to the ribbing of the underside of the hood. If I can draw it on a cocktail napkin, the guy that does the HDK fabrication / welding (aka Fog) can make it happen.

The hard stuff gets done immediately, the impossible may take an extra day.

View attachment 1716007039

View attachment 1716007041

View attachment 1716007043
Click to expand...
Amazing work!

Very cool!!
 
HemiDenny said:
Leaning towards Holley. we will see how it works out.

Thanks for all the input
Click to expand...


Denny, the Terminator X would be a good choice if you don't need to control a bunch of other stuff not necessarily needed to run the engine. I.E. traction control. The terminator X will run a DBW throttle body, so you won't need to use that extra conversion component. If you want to get crazy with I/O, there's always the Holley Dominator, but the cost is significantly higher and I don't think they have a pre-made harness for that ECU. Speaking of harnesses, the Terminator harness may need some mods for the blower, like shortening or lengthening wires. While I'm typing this, I'm remembering the Hellcats have an electronic blow off valve that is essentially a small throttle body. Is that what this blower has? If so, I don't know if the Terminator X can control that. However, it does have trans control and if you aren't using that, perhaps some of that I/O could be used for the small bypass vale.
The holley will also require you use coil ignitors, which is an external component that goes in line with the harness. They should come with the terminator X. There are some smart coils out there for the hemi now which will negate the use of the ignitors. I'm not a fan of this because you're screwed if you have a coil failure driving down the road- the local stores won't have a replacement.
I don't personally have any experience using the stock computer, but I bet it would be harder to find a guy to tune the stock computer vs. the Holley. If you want to speak to someone about the stock computer option, I'd recommend you reach out to Sublime Technologies, previously DIY Hemi. They specialize is making take off harnesses and computers work in hot rods.
 
racerjoe said:
Denny, the Terminator X would be a good choice if you don't need to control a bunch of other stuff not necessarily needed to run the engine. I.E. traction control. The terminator X will run a DBW throttle body, so you won't need to use that extra conversion component. If you want to get crazy with I/O, there's always the Holley Dominator, but the cost is significantly higher and I don't think they have a pre-made harness for that ECU. Speaking of harnesses, the Terminator harness may need some mods for the blower, like shortening or lengthening wires. While I'm typing this, I'm remembering the Hellcats have an electronic blow off valve that is essentially a small throttle body. Is that what this blower has? If so, I don't know if the Terminator X can control that. However, it does have trans control and if you aren't using that, perhaps some of that I/O could be used for the small bypass vale.
The holley will also require you use coil ignitors, which is an external component that goes in line with the harness. They should come with the terminator X. There are some smart coils out there for the hemi now which will negate the use of the ignitors. I'm not a fan of this because you're screwed if you have a coil failure driving down the road- the local stores won't have a replacement.
I don't personally have any experience using the stock computer, but I bet it would be harder to find a guy to tune the stock computer vs. the Holley. If you want to speak to someone about the stock computer option, I'd recommend you reach out to Sublime Technologies, previously DIY Hemi. They specialize is making take off harnesses and computers work in hot rods.
Click to expand...

Thanks Tim, I plan on taking the Whippled Hemi / Big Red to BDS (lower Indiana, right outside the Cincinnati area) for initial tune. BDS does the tune on the DSR 1150 and that engine is almost a mirror of what we are putting together for Butch's new Duster. They already have a good baseline to start with and also recommended the Holley components.

I just discussed the different electronic blow off (Whipple calls it by-pass valve) that DSR has on the 1150. Because ours is not going in a late model but a resto-mod, our blow-off is actuated by vacuum. How that actually functions is a discussion I will have to have with Mike @ Whipple.

Now all I got to do is get my contact at Holley to pull the gear.

Thanks for your input.
 
it took me about 45 minutes to an hour to swap main harness in my 67. holley hp efi. i had to change a few connectors for non mopar parts on my car but this was included in that time frame. harness is like 500 bucks complete. i had 3 at one time and down to one on car and spare ive buchered that was my original harness. all cuz i wasnt finding solid trouble shooting leads to anything else.
 
racerjoe said:
Denny, the Terminator X would be a good choice if you don't need to control a bunch of other stuff not necessarily needed to run the engine. I.E. traction control. The terminator X will run a DBW throttle body, so you won't need to use that extra conversion component. If you want to get crazy with I/O, there's always the Holley Dominator, but the cost is significantly higher and I don't think they have a pre-made harness for that ECU. Speaking of harnesses, the Terminator harness may need some mods for the blower, like shortening or lengthening wires. While I'm typing this, I'm remembering the Hellcats have an electronic blow off valve that is essentially a small throttle body. Is that what this blower has? If so, I don't know if the Terminator X can control that. However, it does have trans control and if you aren't using that, perhaps some of that I/O could be used for the small bypass vale.
The holley will also require you use coil ignitors, which is an external component that goes in line with the harness. They should come with the terminator X. There are some smart coils out there for the hemi now which will negate the use of the ignitors. I'm not a fan of this because you're screwed if you have a coil failure driving down the road- the local stores won't have a replacement.
I don't personally have any experience using the stock computer, but I bet it would be harder to find a guy to tune the stock computer vs. the Holley. If you want to speak to someone about the stock computer option, I'd recommend you reach out to Sublime Technologies, previously DIY Hemi. They specialize is making take off harnesses and computers work in hot rods.
Click to expand...
I reached out to Holley about the harness options for the Hemi Terminator Vs Dominator. This was their response: "You can get the same harness for the Hemi that will plug into the Dominator. The Dominator will run a gen 3 Hemi no problem at all."

Fairly vague answer, but for my swap I really want traction control so I was concerned the Gen3 Harness they use for the Terminator wouldn't work for the dominator but that doesn't appear to be the case.

Mike
 
the termi harness will NOT work on a dominator. tbe dominator and hp use the same harness other than the i/o's. as the hp only has 4 inputs and 4 outputs. the dominator has 20 i/o's so much more wiring there.
terminator harness is different than the hp/dominator.
 
You must log in or register to reply here.
-

Back
Top