Jared's 2015 Challenger Hellcat Build

[Unholy707]

Ye

It's been a wild couple weeks.

Due to time constraints and the fact that my buddy had a brand new Trackhawk 8HP95 kicking around we decided what we would do is gut the HP95 and put everything in my HP90 case. Easy enough, right? Wrong. There are case differences, and the the front pump/housing/clutch assembly (I'm not a trans guy, I'm not sure what it's called) doesn't fit as it's just a touch larger than the HP90 assembly and gets hung up on the case.

At that point, we had ten days to get the TH400 in and make the event. That day we test fit the trans, found out we had the wrong bellhousing, and got all the parts we needed ordered rush delivery. A few days later, we got back to it with all the parts, decided to go the David Freiburger motto of "don't get it right, just get it running" for the event, and swapped in a Hellcrate harness and PCM.

My tuner was on Vacation so with hours left before we had to leave for the event I just copied my tune over from my pcm to the hellcrate PCM and we got the car up and running. Went out to try the transbrake and bump box and under full throttle the car just closes the throttle blade to 17% and opens up the supercharger bypass.

We ended up deciding to leave the car at the shop and go out and support our friends in the drag and drive, as opposed to bring the car and start fighting with it. I think that was the right call and allowed us to enjoy the event and just hang with friends.

I'll have to figure out what's going on with the car, I'm sure copying the tune right to the hellcrate PCM probably wasn't the best way to go but I didn't have a ton of options at the time. We are swapping manual harnesses into the car and I'll have to get my PCM bench flashed to a manual OS. Eventually I still want to go with a Holley dominator setup but I'm having a hard time opening my wallet for it knowing just how much other stuff the car needs as well. I am definitely playing with fire with the stock bottom end and I don't feel great about it.

Yes, that’s the right way to do it. But that’s not all you need to do to make the th400 work.

 

[Unholy707]

Need to reconfigure the BCM, you need the engine harness and headlamp to dash harness, the clutch pedal slave cylinder (it’s a switch), AND THE MOST IMPORTSNT PART - the reverse lockout solinoid from a tr6060. Then the th400 is plug and play and the car will function as an m6 with everything working with the th400 in it. Or just hellcrate harness and have everything lit up like a Christmas tree lol. M6 os as far as I know is a must

 

[Jroc]

Need to reconfigure the BCM, you need the engine harness and headlamp to dash harness, the clutch pedal slave cylinder (it’s a switch), AND THE MOST IMPORTSNT PART - the reverse lockout solinoid from a tr6060. Then the th400 is plug and play and the car will function as an m6 with everything working with the th400 on it.

Yeah we have all that stuff on the way. Actually, swapping every single harness on the car over to new harnesses. I bought the car already modified and while we were working on it we kept finding wires and stuff cut everywhere we looked, behind every interior panel with other wiring spliced in like shit. The original shop that built the car for the previous owner was a complete hack job, hell the added PWM for the second fuel pump was wrapped in bubble wrap and thrown in a trunk cavity, and all the wiring they did was a mess.

No wonder I've been fighting with this car the past 2 years.

 

[Unholy707]

Hellcrate harness will work with the car if you don’t care about nothing else working and stuff lit up like a Christmas tree, but the m6 os is needed so you don’t have any of the weird torque management stuff. Unless there’s some creative tuners out there, I know OST offers the swap for A8 but only in house and not sure if they bench flash the pcm to an m6 OS

 

[Unholy707]

Yeah, my car is (was) an m6 from the factory. I swapped everything over and it’s now a factory grade A8 swap.

 

[Unholy707]

In hind sight I probably should have left it for the ease of a th400 swap 😂 but I know everything I did/removed so putting it back would be simple.

 

[Jroc]

Hellcrate harness will work with the car if you don’t care about nothing else working and stuff lit up like a Christmas tree, but the m6 os is needed so you don’t have any of the weird torque management stuff. Unless there’s some creative tuners out there, I know OST offers the swap for A8 but only in house and not sure if they bench flash the pcm to an m6 OS

I’ll have to return the hellcrate harness and pcm to the car we robbed it from just to get it going. Also I want all the factory integration, having it set up the way it is right now is a pain in the ass.

 

[Unholy707]

A built Zf8hp90 will hold more than enough for 8s and even 7s

 

[Unholy707]

Bill gamble (factory m6) spilt the beans about the reverse lockout being needed. He pushed in the clutch pedal and starts the car, didn’t have to do anything fancy (th400)

 

[Unholy707]

So, m6 configuration with all factory wiring, clutch master cylinder (switch behind the clutch pedal, it DOES have an electrical connector), and the reverse lockout solinoid from a tr6060. All you need, besides reconfiguring bcm /bench flashing m6 os. And then the TH400 just works like it came from the factory that way

 

[Jroc]

A built Zf8hp90 will hold more than enough for 8s and even 7s

It's too late now I've got too much money tied up in this TH400 business. Also, I like the idea of the transbrake and bump box.

Another way to do it is to build a can box to trick the car into thinking it still has an A8. Then, you could leave all the A8 stuff in it. My friend who's doing the work has a 2019 Ram 1500 with a 24-valve Cummins and G56 manual in it, and as far as the truck is concerned, it's still a 5.7 Hemi and 8-speed auto.

 

[Jroc]

So, m6 configuration with all factory wiring, clutch master cylinder (switch behind the clutch pedal, it DOES have an electrical connector), and the reverse lockout solinoid from a tr6060. All you need, besides reconfiguring bcm /bench flashing m6 os. And then the TH400 just works like it came from the factory that way

Perfect, I appreciate the info, it sounds like we are on the right track.

 

[Unholy707]

Old probably figure out the resistance that the reverse lockout solenoid gives off and fab something up with some resistors and plug it into the harness, but it is needed. A shame I sold all my m6 wiring harnesses for my 2015 when I did the a8 swap

 

[Unholy707]

You have to program said box, and it’s not that easy. Car needs to see the 12v signal and signals from the tcm along with canbus messages and correct crc check byte

It's too late now I've got too much money tied up in this TH400 business. Also, I like the idea of the transbrake and bump box.

Another way to do it is to build a can box to trick the car into thinking it still has an A8. Then, you could leave all the A8 stuff in it. My friend who's doing the work has a 2019 Ram 1500 with a 24-valve Cummins and G56 manual in it, and as far as the truck is concerned, it's still a 5.7 Hemi and 8-speed auto.

 

[Jroc]

 

[Unholy707]

Looking good! You’ll get it sorted, just do what I said. Few places can bench flash it for you - trick is for them to bench flash it with an OS that’s already been unlocked for HPT (bench read of already unlocked pcm)

 

[Unholy707]

Talk to Tapped, demon performance, or AMP

 

[Jroc]

Looking good! You’ll get it sorted, just do what I said. Few places can bench flash it for you - trick is for them to bench flash it with an OS that’s already been unlocked for HPT (bench read of already unlocked pcm)

Good point, I didn't consider that it should be flashed with an already unlocked PCM OS. I'm tempted to just buy a 2018 manual PCM and have that flashed so the PCM will actually see more than 17 pounds of boost. I swapped to 3 bar maps, and when logging the computer won't see anything above 17 PSI, apparently a restriction of 2015-2017 PCMs.

 

[jonx96]

Big 3 racing just came out with a plug n play module for the hellcats and turbo 400.

 

[Jroc]

Big 3 racing just came out with a plug n play module for the hellcats and turbo 400.

The RACE Gate-way, or something else?