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Discussion Starter #1
Hey guys,
I posted a thread earlier when trying to decide between a rear for my 2019 Charger RT 5.7 and decided to go with the 3.09's. Is anyone currently running them and can report on how much of a difference they make? More specifically - differences in 1/4 mile times. Thanks in advance.

Joe
 

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Did you get a rear with the limited slip option? Might as well since the labor will be the same. Going from 2.65 to 3.09 will get you into the engine's power band bit quicker. You'll also see a few hundred more rpms while cruising at highway speeds. As I mentioned in your other post, it's a shame there isn't an option to go a bit deeper, say 3.20, 3.30, or 3.40.
IMO, 3.70 would be the max for a street car, and 3.90 kind of makes the first couple of gears on the 8 speed worthless.

When I swapped the 2.73s out for 4.11s for my then '72 Camaro, it really woke the car up, but around town 1st gear was almost useless, and cruise rpms for the TH-350 with no overdrive was around 3200 at 60.

Don
 

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Discussion Starter #3
Did you get a rear with the limited slip option? Might as well since the labor will be the same. Going from 2.65 to 3.09 will get you into the engine's power band bit quicker. You'll also see a few hundred more rpms while cruising at highway speeds. As I mentioned in your other post, it's a shame there isn't an option to go a bit deeper, say 3.20, 3.30, or 3.40.
IMO, 3.70 would be the max for a street car, and 3.90 kind of makes the first couple of gears on the 8 speed worthless.

When I swapped the 2.73s out for 4.11s for my then '72 Camaro, it really woke the car up, but around town 1st gear was almost useless, and cruise rpms for the TH-350 with no overdrive was around 3200 at 60.

Don
I appreciate the info Don! I did go with the LSD option and plan to do the install myself. I’m hoping the 3.09 wakes it up a bit and improves 1/4 mile time and 0-60. I plan to go forced induction eventually so I figured 3.70 would be too much for all that, especially in a street car. I agree—I wish there was a 3.30 to 3.55 option.
 

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I just had my anti-spin diff (3.09) installed..upgraded from the 2.65 open diff. Still a big difference. It drives more like a muscle car....especially with traction off and in sport mode. It does drive one gear above (in full auto) on my normal routes, but manual shifting remedies that. I installed the getrag LSD on my 2007 RT myself....never again. It was worth the $700 bones....I love it. It digs deep off the line. Hope you love it too 🤙
 

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Had mine installed almost a year now. Honestly I don't see that much of a difference. I was expecting more maybe. I don't do racing. No where to race here.
As someone said it gets to speed quicker, but again it's not earth shattering of a difference. HW RPM's I dont care about, gas mileage I don't care about or follow. Was it worth the grand I spent for the unit & install? Not really, for me anyway.
You may pickup a tenth or 2 on a track.
 

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Since you say you are adding power with forced induction eventually, I think it makes sense to swap in the Scat Pack 3.09 since you'll probably have around Scat Pack power or a little higher depending on what else you do.

A good comparison is the 2015 and 2016 R/T R&T cars, they came with an open diff but it was a 3.07. It was dropped in 2017 and didn't return on the Super Track Pak cars. I think it might have shaved a tenth off your 0-60 but it wasn't an earth shattering difference.

If you are tracking the car the limited slip should obviously help you launch and get around corners better.
 

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6 psi and 3.06 open diff.
295288
 

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The 3.70 and 3.90 LSD are intended for the 6M equipped cars. This is simple math, The 8HP70 has a 4.71:1 first gear 3.14 Second, and the TR 6060 has a 2.26 first for Hellcats, and 2.97 for scat and R/T The NAG-1 is 3.59

Someone made an excel sheet posted here


So if you go beyond 3.09 you essentially delete 1st on the Auto. I have the 3.07 open and even then it starts in second sometimes in traffic.
 

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Since you say you are adding power with forced induction eventually, I think it makes sense to swap in the Scat Pack 3.09 since you'll probably have around Scat Pack power or a little higher depending on what else you do.

A good comparison is the 2015 and 2016 R/T R&T cars, they came with an open diff but it was a 3.07. It was dropped in 2017 and didn't return on the Super Track Pak cars. I think it might have shaved a tenth off your 0-60 but it wasn't an earth shattering difference.

If you are tracking the car the limited slip should obviously help you launch and get around corners better.
I have a 3.09 LSD waiting to install, and I have the 2016 29R R&T. My best track times stock were 5.6 0-60 13.7 @103. With the original goodyear RSA-2 you could hook somewhat but push a bit more and it spun and literally didn't move, I had to hit the brakes and get the car off the line ended up with an 18 second the next pass after 2 13.7 runs
I have the AZ-850 on Hellcat 20x9.5 now but only one track visit so far. Now it hops and skips, didn't crack 6 sec 0-60 Only got 3 runs never got a chance to get dialed in. Same traction issues on the street with the tires aired up, the Goodyears also would not move the car at times on the street trying to pull out etc similar to my track experience I let the air down to 29 psi cold on the AZ-850 which did seem to help but that's too mushy for me driving.

I still get over 80 mph at 2000 rpm in 8th gear, but I bet CAFE comes to play with all those 2.62 equipped cars.
 

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I have a 3.09 LSD waiting to install, and I have the 2016 29R R&T. My best track times stock were 5.6 0-60 13.7 @103. With the original goodyear RSA-2 you could hook somewhat but push a bit more and it spun and literally didn't move, I had to hit the brakes and get the car off the line ended up with an 18 second the next pass after 2 13.7 runs
I have the AZ-850 on Hellcat 20x9.5 now but only one track visit so far. Now it hops and skips, didn't crack 6 sec 0-60 Only got 3 runs never got a chance to get dialed in. Same traction issues on the street with the tires aired up, the Goodyears also would not move the car at times on the street trying to pull out etc similar to my track experience I let the air down to 29 psi cold on the AZ-850 which did seem to help but that's too mushy for me driving.

I still get over 80 mph at 2000 rpm in 8th gear, but I bet CAFE comes to play with all those 2.62 equipped cars.
What 0-60 times do you get on the Performance Pages? I've gotten a couple of 5.2 to 60 and those were just launched on the street from a stoplight. I haven't had a chance to take it somewhere with a stickier pavement.

It's amazing how the 8 speed works so much quicker than the 5 speed in my 2006 R/T R&T.
 

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Discussion Starter #12
Traction won’t be a problem for me with the 3.09. I have 17x10.5 race stars with 305/45/17 Mickey Thompson Street SS.
 

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Traction won’t be a problem for me with the 3.09. I have 17x10.5 race stars with 305/45/17 Mickey Thompson Street SS.
Any update on your diff install? How did you like it? Be honest do you wish you went with 3.70?

I’m looking at getting a rear diff here pretty soon and am curious what you think.
 
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