[CleanHemi300S]

I had my 2013 300S For a little under a year now, and want to do some mods that actually GIVE me HP and that's NOT a WASTE of MONEY. I have the 5.7 Hemi. As of right now, I have a 180 degree thermostat, drop in K&N filter and the 93 octane diablo tune. Like the title says, I just want 425hp to the crank. Are there any mods that you guys (and gals) can think of that will help me reach that goal without wasting money?

 

[MADDOG]

It may be tough on the pistons, rings and rods but for a bolt on adder I'd go with a supercharger.

If you go over 6 - 8 psi on the blower I suspect the rings might fail so be warned you could have a rebuild in your future if you go with forced induction.

Good luck.

 

[magnuman]

A well selected cam, headers and a good cat. back exhaust will put you well on the way. As MADDOG said, forced induction would easily put you over the top and then some, but the cost (around $6000-7000) is a little steep. I am up about 120-130 hp. with the mods. I've done over the past 15 years or so.....see signature and showcase.

 

[CleanHemi300S]

A well selected cam, headers and a good cat. back exhaust will put you well on the way. As MADDOG said, forced induction would easily put you over the top and then some, but the cost (around $6000-7000) is a little steep. I am up about 120-130 hp. with the mods. I've done over the past 15 years or so.....see signature and showcase.

As of right now, I wasn't really looking to do a supercharger or anything too crazy. I was thinking more of simple mods like CAI, Shorty Headers, 85MM TB, and a pair of Flowmaster 40s hooked up to the stock exhaust. How much hp do you think that would add on top of what I already listed in description?

 

[magnuman]

The mods you've done and the mods you're thinking of doing probably will get you close. Your 2013 is starting with more horsepower from the factory than the early ones, so you're ahead of the game compared to us early 5.7 guys, and your Variable Valve Timing and better heads are a big help in this regard. I've advanced both of the aftermarket performance cams in my 5.7's to move the power curves to a slightly lower RPM. A well selected aftermarket performance cam will probably give you the biggest bang for the buck. On yours, because the engine is more efficient, you'll probably gain a bit less than 50 hp. On the early Hemi's, along with a good header back exhaust, these two mods. on the LX's were worth about 50-60 hp. On my 5.7 Jeep, with a super crappy stock exhaust system,, headers, a good straight through cat. back and a cam yielded about 75-85 hp over stock. . The biggest choke point on the Jeep 5.7's is the tiny exhaust log manifold. See pix below.....left to right, the stock 5.7 Jeep log, the stock early 5.7 LX log and, on the right, my first set of custom headers for the Jeep.

If your 2013 exhaust logs on the 5.7 are as good as the early (2005-2008) LX 5.7's, shorty headers (I have them on my 05), they won't give you more than about 10-15 horsepower. Good, straight through (no internal switchbacks) mufflers will give you maybe another 10 or so horsepower. An 85 mm throttle body probably won't give you anything other than maybe slightly better throttle response. With the mods on my 3 Hemi's (two 5.7's and one 6.1) I've run the stock 80 mm's, 85 mm ones and 90 mm ones. The only ones that do anything noticeable over the stock ones are the 90 mm ones, but only with a bunch of other mods.. The ONLY thing I can tell is they give slightly better throttle response......no noticeable increase in power. I recently took of the 85 mm one off my 6.1 and put the stock 80 mm one back on. I didn't notice any difference at all between the two.

Adding a K and N (I've tried this too) will give you some additional power, but it'll only be noticeable at WOT. Putting around town, you probably won't notice it. Back in July 2013, Mopar Muscle Magazine did dyno tests on the power lost by the various engine components......water pump, alternator, power steering, AIR FILTERS, and engine oil. The two we can really do something about are the air filters and the oil. On their tests, without any filter vs. a stock paper filter vs. a high flow filter, they found that, compared to no filter, the paper element robbed (at peak power)14.4 hp. and 10.4 lb. ft. of torque, and the high flow filter only robbed 5.9 hp. and 5.5 lb.ft. of torque. 20W-50 oil robbed 16.4 hp. and 12 lb. ft. of torque when compared to 5W-20 weight oil.

Bottom line, IMO, start with a good cat. back exhaust, and then do a fairly mild aftermarket performance cam, one with good street manners.

 

[CleanHemi300S]

The mods you've done and the mods you're thinking of doing probably won't quite get you there. Your 2013 has more horsepower from the factory than the early ones, so you're ahead of the game compared to us early 5.7 guys, and your Variable Valve Timing is a big help in this regard. I've advanced both of the aftermarket performance cams in my 5.7's to move the power curves to a slightly lower RPM. A well selected aftermarket performance cam will probably give you the biggest bang for the buck. On the early Hemi's, along with a good header back exhaust, these two mods. on the LX's were worth about 50-60 hp. On my 5.7 Jeep, with a super crappy stock exhaust system,, headers, a good straight through cat. back and a cam yielded about 75-85 hp over stock. The biggest choke point on the Jeep 5.7's is the tiny exhaust log manifold. See pix below.....left to right, the stock 5.7 Jeep log, the stock early 5.7 LX log and, on the right, my first set of custom headers for the Jeep.

If your 2013 exhaust logs on the 5.7 are as good as the early (2005-2008) LX 5.7's, shorty headers (I have them on my 05), they won't give you more than about 10-15 horsepower. Good, straight through (no internal switchbacks) mufflers will give you maybe another 10 or so horsepower. An 85 mm throttle body probably won't give you anything other than maybe slightly better throttle response. With the mods on my 3 Hemi's (two 5.7's and one 6.1) I've run the stock 80 mm's, 85 mm ones and 90 mm ones. The only ones that do anything noticeable over the stock ones are the 90 mm ones, but only with a bunch of other mods.. The ONLY thing I can tell is they give slightly better throttle response......no noticeable increase in power. I recently took of the 85 mm one off my 6.1 and put the stock 80 mm one back on. I didn't notice any difference at all between the two.

Adding a K and N (I've tried this too) will give you some additional power, but it'll only be noticeable at WOT. Putting around town, you probably won't notice it. Back in July 2013, Mopar Muscle Magazine did dyno tests on the power lost by the various engine components......water pump, alternator, power steering, AIR FILTERS, and engine oil. The two we can really do something about are the air filters and the oil. On their tests, without any filter vs. a stock paper filter vs. a high flow filter, they found that, compared to no filter, the paper element robbed (at peak power)14.4 hp. and 10.4 lb. ft. of torque, and the high flow filter only robbed 5.9 hp. and 5.5 lb.ft. of torque. 20W-50 oil robbed 16.4 hp. and 12 lb. ft. of torque when compared to 5W-20 weight oil.

Bottom line, IMO, start with a good cat. back exhaust, and then do a fairly mild aftermarket performance cam, one with good street manners. View attachment 175549

Thanks for the info. I'm doing my build slowly, due to budget. Just buying one thing at a time lol. Another question for you with all of that info. You said from factory my 2013 300S has more hp. If the crank is quoted for 363hp, how much to the wheels is that really?

 

[magnuman]

I hear you on the "slow build". I've been working off and on with my 05 LX for almost 16 years now, the 06 Jeep Grand Cherokee for almost 11 years and the LX SRT8 for a little over two years. The early 5.7's had around 330-340 hp. and the Daytona Charger had about 10 more due to the SRT type airbox and a straight through "suitcase" muffler. IIRC, the early LX 5.7's would put about 270-300 hp. to the wheels, depending on engine condition, tune, etc. My guess is that yours would probably put down 300-330 to the wheels, probably closer to the high end because of your 93 octane DS tune.

If this is your daily driver, IMO, you need to be focusing more on low to mid range power than the amount of power it'll put out at 6000+ RPM. Since most aftermarket cams rob some from the bottom end in favor of the mid and top ends, that's why I said, "well chosen" cam, if you go that route. Even my SRT, when stock had a good low/mid range and a better top end, but when I installed the mild aftermarket performance cam, the bottom and mid range RPM got somewhat better with not too much loss on the top. That was mainly due to the 4 degree lower Lobe Separation Angle on the performance cam. Because of the VVT on yours, your power curves wil be better than those of us that have "fixed", non variable cam timing. I'll also say, that with aftermarket cams on VVT engines, you'll probably need to either use a phase limiter, or a phase lock which will make it like a non variable cam. This is necessary when higher lift, longer duration cams are used with VVT to avoid piston to valve collisions.