If anyone claims significant power gains from these changes, ask to see the dyno before/after results to prove it. The subconscious mind often makes things feel better that you've spent money on and expect happy results. As I have with other vehicles, if I changed either it would be for the sound. It is possible to improve power slightly if you replace a restricted intake or exhaust, but ask for proof.

3...2...1... until someone responds to the contrary.

 

Exactly why I asked!! I have seen some decent gains on restrictive turbo cars in the past with adding some "breathing" bolt on's, but it seems these big motors pushing big HP out of the factory don't get the same gains. I figure you might, maybe, get a better throttle response and some decent sound to go along with a few % gain which is pretty much negligible when tacked onto the stock output.

Thanks for your response.

 

big difference between HP adders for NA motor vs turbo/supercharged...the former is more placebo the latter is real power....

 

If you don't need to tune the vehicle after a bolt-on install then the gains are minimal....so 10-25 hp.

 

There are slight gains if VVT is tuned for performance but other than that you are not going to see much gain without a tune. Just remember at part throttle operation the PCM uses an algorithm to maintain stoich. WOT fueling and spark (triggered by accelerator pedal voltage) is all based off tables that use aircharge and RPM to determine correct spark/fueling. So if you do add long tube headers, there is risk that WOT fueling/timing will not be optimal to take advantage of the improved scavenging.

VVT in 123

You're ready to tune your Hemi, or you already have your Hemi tuned. All is great, but what about that cam phaser thing? What is it? What does it do? How can you use it to your advantage? When Dodge started utilizing Variable Valve Timing (VVT), it was for various good reasons, and during our...

thetuningschool.com

 

Some of us want better sound and longevity of the exhaust. Not propelled by noise.