Hemi swap questions

[CMC]

Luv the new SST plate with the 123>>
We r gonna try the 518 and see how minimal the tunnel modification thats needed will work out
behind the 5.7 HEMI---

Culinary Zest Dressing & Marinade - 2 (TWO 16 oz Bottles) w/ FREE Key chain LIGHT GIFT Pack FREE SHIPPING

 

[Buckminster]

I put mine together on a very low budget. Purchased what I could not build myself. I may be able to give some advice .

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I just bought a donor car. a 2006 Charger with a 5.7l and NAG1. What transmission did you use? I am in the process of doing all the research i can and there are some that say I need the ABS computer and wheel speed sensors for this transmission. Looking for some confirmation on that.

 

[Buckminster]

Done . Finally .

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Looks very very nice. well done

 

[Hubes71]

Looks very very nice. well done

Thanks.
I went with an original A833 4 speed so I can not give any input on requirements of the newer transmissions. Sorry I can not be of help.

 

[Buckminster]

Thanks.
I went with an original A833 4 speed so I can not give any input on requirements of the newer transmissions. Sorry I can not be of help.

All good. Thanks for responding!

 

[scar426]

I just bought a donor car. a 2006 Charger with a 5.7l and NAG1. What transmission did you use? I am in the process of doing all the research i can and there are some that say I need the ABS computer and wheel speed sensors for this transmission. Looking for some confirmation on that.

You do....But give Chris a call at HOTWIREAUTO.COM and discuss it with him. He has what ya need and can tell you more about the NAG-1 swap. Me personally, I switched to a 545RFE out of a 2wd truck or Durango. No "extra" donor vechicle parts required.

 

[Katfish]

Here is how I did mine, apologize it is on my Demon not my cuda. But same set of problems. And I went Dakota dash and never looked back.

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I'm loving that! Got more details on the process?
What metal did you start with?

 

[Buckminster]

You do....But give Chris a call at HOTWIREAUTO.COM and discuss it with him. He has what ya need and can tell you more about the NAG-1 swap. Me personally, I switched to a 545RFE out of a 2wd truck or Durango. No "extra" donor vechicle parts required.

I talked with Chris at Hotwire. Super knowledgeable with these sort of things. thank you for the tip!

Now I have to extract the NAG1 out of the Charger, sell it off and find a reasonably priced 8HP70. LOL. Chris did not advise against the NAG1 swap, he has a solution for this tranny, but finding a place for the TCU, ABS computer and adding the sensor wheel, is more "stuff" than I personally would like to re-package.

Also....
I did the math on the NAG1 with 3.73:1 rears. With its .86:1 OD ratio looks like I'll still be doing about 2,950 rpm at 70mph (I have 25.6" tall rear tires). Not enough of a reduction for me over the 727 I have in the car now. Plus I hear the NAG1 doesn't like tall rearend ratios without a lot of time spent reprogramming the TCU, or purchasing an aftermarket TCU that someone has already sorted out the programming on. Not my strength (programming a TCU).

if i can get an 8HP70 (.67:1 OD ratio), I can keep my 3.73's and turn about 2,300 rpm at 70, which is only slightly higher than I think I want, but probably do-able. From what I have read (not practiced yet), the early 5.7L Hemi's have a sweet spot as far as fuel efficiency is concerned at about 2,200rpm. The factory runs the engine at about 1,200 rpm in the stock setup for efficiency. these two peaks in the BSFC curve are where I would like to end up, the lower one, probably not practical, since I can only find 3.23 rearend gears for the 8 3/4 rearend I have. If I change from a 3.73 to a 3.53, I would end up at about 2,170 rpm at 70 mph. It should still accelerate smartly with the 3.53's. And get decent mpg while doing something like a Power tour (one of my bucket list goals).

Feel free to provide any and all feedback. It is appreciated.

 

[scar426]

I talked with Chris at Hotwire. Super knowledgeable with these sort of things. thank you for the tip!

Now I have to extract the NAG1 out of the Charger, sell it off and find a reasonably priced 8HP70. LOL. Chris did not advise against the NAG1 swap, he has a solution for this tranny, but finding a place for the TCU, ABS computer and adding the sensor wheel, is more "stuff" than I personally would like to re-package.

Also....
I did the math on the NAG1 with 3.73:1 rears. With its .86:1 OD ratio looks like I'll still be doing about 2,950 rpm at 70mph (I have 25.6" tall rear tires). Not enough of a reduction for me over the 727 I have in the car now. Plus I hear the NAG1 doesn't like tall rearend ratios without a lot of time spent reprogramming the TCU, or purchasing an aftermarket TCU that someone has already sorted out the programming on. Not my strength (programming a TCU).

if i can get an 8HP70 (.67:1 OD ratio), I can keep my 3.73's and turn about 2,300 rpm at 70, which is only slightly higher than I think I want, but probably do-able. From what I have read (not practiced yet), the early 5.7L Hemi's have a sweet spot as far as fuel efficiency is concerned at about 2,200rpm. The factory runs the engine at about 1,200 rpm in the stock setup for efficiency. these two peaks in the BSFC curve are where I would like to end up, the lower one, probably not practical, since I can only find 3.23 rearend gears for the 8 3/4 rearend I have. If I change from a 3.73 to a 3.53, I would end up at about 2,170 rpm at 70 mph. It should still accelerate smartly with the 3.53's. And get decent mpg while doing something like a Power tour (one of my bucket list goals).

Feel free to provide any and all feedback. It is appreciated.

Yup Chris knows his stuff. My current swap is a 6.4l 8hp70 going into a 55 Chrysler Town and Country station wagon. It has 3.53 gears, so i'll see how that works out. Another source for the 8HP's is Russell at Sound German Automotive, I'm using his swap harness this time for the 8hp and a Mopar Perfomance engine harness. When you swap out the transmissions, I'm fairly certain the bushing in the end of the crank will have to be removed or swapped for another. When I did my last 6.4L it came with the NAG and I replaced it with a 545rfe and had to remove the bushing to fit the 545rfe converter. Not 100% sure there is a difference btwn the NAG and 8hps.

 

[Buckminster]

Yup Chris knows his stuff. My current swap is a 6.4l 8hp70 going into a 55 Chrysler Town and Country station wagon. It has 3.53 gears, so i'll see how that works out. Another source for the 8HP's is Russell at Sound German Automotive, I'm using his swap harness this time for the 8hp and a Mopar Perfomance engine harness. When you swap out the transmissions, I'm fairly certain the bushing in the end of the crank will have to be removed or swapped for another. When I did my last 6.4L it came with the NAG and I replaced it with a 545rfe and had to remove the bushing to fit the 545rfe converter. Not 100% sure there is a difference btwn the NAG and 8hps.

Thanks for the tip. I'll check that out when I get a hold of an 8HP70.

 

[Buckminster]

Also, I used a hydroboost system from a GM truck. Braking performance and feel is awesome . Highly recommend if you don't already have the factory set up.

did the booster hit the Hemi? is that why you used the Hydra boost?

 

[Hubes71]

did the booster hit the Hemi? is that why you used the Hydra boost?

I didn't have the original setup anymore and the hydro boost system was free. Also I liked the cleaner look.

 

[hpjunke]

If you guys want look in this section , I posted how I did my swap . Only thing I changed is to an 08 ecu (for tuning purposes) but it’s been a champ so far

 

[JpRngr]

Buckminster, something to consider with your rear gear ratio is 1st gear ratio. I have a 6.1L with the NAG1 in my 74 Challenger. I have 3.55's in the 8.8 rearend. I seriously would consider a bit higher gear, as taking off from a light, it very easily spun the tires. Before I supercharged it, I couldn't go to maybe half throttle before it just spun the tires. With the supercharger, it's quarter throttle. Also, with 3.55's I cruise down the highway at 80mph with ease. I have considered changing to 3.23 or even 2.92's To be quicker off the line and not spin so much.

Also, NAG1 has been a great transmission and finding a place for the modules up under the passenger side of the dash and kick panel wasn't difficult. You should have all the different modules, since you bought a full parts car. The ABS sensor wheel just bolted on with the driveshaft adapter and brackets for abs sensors were nothing.

 

[Buckminster]

Buckminster, something to consider with your rear gear ratio is 1st gear ratio. I have a 6.1L with the NAG1 in my 74 Challenger. I have 3.55's in the 8.8 rearend. I seriously would consider a bit higher gear, as taking off from a light, it very easily spun the tires. Before I supercharged it, I couldn't go to maybe half throttle before it just spun the tires. With the supercharger, it's quarter throttle. Also, with 3.55's I cruise down the highway at 80mph with ease. I have considered changing to 3.23 or even 2.92's To be quicker off the line and not spin so much.

Also, NAG1 has been a great transmission and finding a place for the modules up under the passenger side of the dash and kick panel wasn't difficult. You should have all the different modules, since you bought a full parts car. The ABS sensor wheel just bolted on with the driveshaft adapter and brackets for abs sensors were nothing.

This is part of the internal debate I'm having with myself. The ABS sensor wheel is what caused me some concern along from a packaging standpoint. I greatly appreciate you sharing your expertise!

 

[JpRngr]

This is part of the internal debate I'm having with myself. The ABS sensor wheel is what caused me some concern along from a packaging standpoint. I greatly appreciate you sharing your expertise!

The ABS sensor wheel I got from Hotwire was VERY easy to install. I bolted it in with the driveshaft off the output of the trans. Was fairly easy to bend up a couple backets to mount the sensors off the back of trans output housing, also.
BTW, I'm running 285/35R18's on the back.