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So what's up everyone. I have been a charger owner for a long time. I started with a 2007 RT, swapped the intake out with a K&N and did a mid muffler delete back when I was keeping things extremely simple.

Loved the car. Then sold and bought the M11 charger. Added qtp cutouts for noise purposes and a JBA catback with an lmi hammer intake and Diablo tune to beef things up about with those stock 3.91 gears. Car hit almost 100K miles and decided to finally move on

Now it's time, 2015 charger RT road and track. Completely bone stock and this time around, A being much older and B having a much better job from my younger days to support such heavy mods, I want to make this RT scream. I didn't go with a scat pack because I personally feel the RT's are fantastic for me. Something feels great about working up an RT to me and I truly enjoying seeing the 345 really put down solid numbers on other builds I've seen. So, without further ado, I turn to the forums once again for thoughts and opinions.

One thing I'm letting the world know is I'm already working with pro charger, patiently waiting for the kit to arrive in March-April to boost this big guy with a supercharger. Extremely excited. I've already picked up the Diablo PCM and new I2 tuner from them. Extremely happy about that. What I need help with is exhaust and header choice. Having spent about 6000 total on the kit (money set aside waiting) I'd like to know what you folks think about supporting mods. My thought process is taking me towards kooks long tubes and just using the stock exhaust to save some cash and swapping the mufflers for the kooks muffler they produce for our cars. As well as delete the resonators.

Thoughts on this process? My end goal is to get around 480 to the wheel as if I had an srt but done my way.

FYI; I've already taken into account new rods springs gaskets etc etc for the super charger upgrade to promote longer engine life (only 3k now on the OD) had the car for only 3 months and it is a daily.

Throw me your thoughts on the headers idea and everything you can think of to help me promote team RT!
 

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3 chargers? Damn congrats you're a true fan lol. Im not sure on brands but i recommend going over to shophemi and seeing what they offer over there. And if you're putting all that money into it then maybe you should get a cam in there too as well. Anyways congrats on the new ride!
 

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I would invest in a 2 1/2 inch catback exhaust. Yours is a 2 1/4 inch. I have been told that you should have at least 2 1/2 inch piping when going over 450 rwhp. Longtubes IMO are not necessary if going with a blower but getting rid of the stock RT manifolds is a plus. I would get JBA Shorties with HF cats.

Why the rods (Pushrods?) and spring upgrade? Are you changing out the Cam?
 

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Possibly yes to the cam. I've been looking at a 270 comp cam for a while now. I also saw a 2015 RT throw down 380hp with just a mild cam and muffler delete for sound. So it captured my interest. So short ire vs long tubes has been a massive conversation piece for years upon years. Shorties are so much cheaper for sure and the 345 motor has horrible manifolds as is lol. So shorties an catback, do you believe the cost to owner gain would be beneficial?
 

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Shorty's and Catback vs cost when putting on a blower I do not know. I have just been told that there is very little gain to be made with Longtubes vs Shorties when going FI. You can always increase the boost. 1 lb of boost is probably equal to the gains you get with a set of Longtubes. An aftermarket catback IMO is beneficial because you are going to a bigger pipe from the motor to the tail end. Most all are 2 1/2 inch vs the 2 1/4 inch stock. Good for the sound also.

A spring package will be needed if you go with the 270. Pushrods are recommended while in the heads and only cost around $100. 6.1L lifters (4) called the MDS delete package to replace the mds lifters is also needed with that cam. A custom grind cam that does not provide that much lift will not require the head work but the gains are not going to be that much. Around 20-35 rwhp over the stock cam.
 

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Possibly yes to the cam. I've been looking at a 270 comp cam for a while now. I also saw a 2015 RT throw down 380hp with just a mild cam and muffler delete for sound. So it captured my interest. So short ire vs long tubes has been a massive conversation piece for years upon years. Shorties are so much cheaper for sure and the 345 motor has horrible manifolds as is lol. So shorties an catback, do you believe the cost to owner gain would be beneficial?
When doing anything such as boost or cam it is recommended to get the weak MDS lifters out. I personally went with Shorties bit the reason is because I have a straight pipe exhaust with the x pipe. The R/T exhaust is 2 1/4 from the exhaust manifold to the x pipe and 2 1/2" from the x pipe to the exhaust tips. Shorties help with low end torque and back pressure which was valuable with my setup but since you're boosting you shouldn't have an issue with low end torque and you're better off running Kooks LT headers since you'll spend more time in the mid-high RPMS range. Also I am getting 3.92 gears ratio on my car but since yours is the new 8 speed all you can do is wait for lower gears to be made, but you may not need cause I've heard great things with the way the 8 speed is geared. Ifor you go with a Cam the 270 would be perfect with the procharher since it is a mild cam. With the procharger, mild cam, upgraded internals and a tune you'll certainly see well over 500 hp to the wheels. Maybe then you'll think about slightly wider tires to hand that new found torque?
 

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Just re-read my previous post and want to say sorry for all of the typos lol. My phone hates me and it won't let me edit the post to correct ot.
 

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The myth about shorties retaining more low end HP/TQ has been proven to be false. Long tubes make more HP/TQ in all RPM ranges than shorties. Believe me I've been researching headers for over a year. Even the 1 7/8 Kooks long tubes that a lot of people say is way too big for a N/A bolt on 5.7 still made more HP/TQ than the 1 3/4 which most recommend. The more I read it really comes down to cylinder scavenging, which is related to the length, not so much the size, of the primary tubes. Kooks are equal length headers so they scavenge the exhaust pulses from the heads much better than unequal length headers, thus actually creating a vacuum effect from the heads. It's pretty amazing stuff. With that said though, shorties are still a great additions and will increase HP/TQ over the stock log manifolds, just not nearly as much as long tubes, especially equal length long tubes, will.
 

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I would invest in a 2 1/2 inch catback exhaust. Yours is a 2 1/4 inch. I have been told that you should have at least 2 1/2 inch piping when going over 450 rwhp. Longtubes IMO are not necessary if going with a blower but getting rid of the stock RT manifolds is a plus. I would get JBA Shorties with HF cats.

Why the rods (Pushrods?) and spring upgrade? Are you changing out the Cam?
Actualy the 5.7 hemi exhaust is 2.5 inch exhaust and the SRT's are 2.75
 

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Meh, back pressure. Back pressure is bad, and that myth started from dropping exhaust manifolds. An engine with no manifolds at all loses a ton of power because the exhaust tube length helps build power and an engine without manifolds has a tube length of about 2 inches, from the exhaust valve to the edge of the head. What people thought was backpressure building power was really the exhaust pulse scavenging, which I also saw mentioned here.

The 2.5 is really only needed up to the axle, after that a smooth transition to 2.25 to go over the axle will help keep exhaust velocity up after it cools down. This helps with the scavenging. Going for the mandrel bends is a plus here too. Forced induction, of course, would benefit from dual 3 inch exhaust.
 
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