stock exhaust - it's unbelievably quiet! Why?

Cyber370

Be careful about what you hear on YouTube. The sound is always misleading because you can never gauge the drone and loudness levels by watching videos. Believe me, I have gotten burned several times before learning my lesson. The only real way to know how an exhaust sounds and whether it is too loud for you, is by hearing it in person. Of course this is not easy so you need to trust your instincts and do a little bit of engineering analysis. Any exhaust with straight pipes, no mid pipe resonators, and tiny mufflers will be loud and most likely have drone. Systems with Helmholtz chambers tend to have lower drone levels but can still be extremely loud at WOT. Systems that resemble the stock setup having proper crossover, resonators and mufflers close to the stock locations will most likely be acceptable. Again, it’s still a crap shoot as to finding the Goldilocks sound we all look for. Good luck.

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"That’s when you know you’ve found somebody special. When you can just shut the f*ck up for a minute and comfortably enjoy the silence.”-Mia (Pulp Fiction)

370zBoyz

Not familiar with the ARK exhaust systems but usually anything buzzing comes from our interior being vibrated by the louder exhaust

Going back to my nismo muffler with test pipes I don't hear any buzzing or rattling any more

Maestro666

The rear hatch locking mechanism is a source of rattle. There is a youtube video somewhere of some guy who searches for ages and ends up finding it and filling it up with lube.

I had this issue once my exhaust got loud enough and I just stuck a chunk of sound deadener over the metal where it's screwed in. That fixed it!

Geoff-AU

HKS Hi-Power

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There is a post on here by a fussy bastard who's almost as particular as me and he said the HKS Hi-Power has zero drone at any load or RPM point. He's right. HKS have done some brilliant engineering on this one.

This exhaust is perfect for me - I want something quiet when just cruising (and at light throttle below 3000 RPM it sounds almost as quiet as stock) but if you stomp on it then it gets a really nice sound (which is also what I want). A friend drove mine on the weekend and said he was "changing gears just for the sake of it" so he could listen to the exhaust.

JARblue

And this is why everyone gets worse gas mileage after a new exhaust install despite the fact that a freer flowing exhaust should get better gas mileage all other variables being equal.

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dave11

Isn't that the truth!

Geoff-AU

Only true at light throttle / load.

At full throttle you have more airflow, which means more fuel gets injected, and your economy will be worse. Often, because you're flowing more air than a stock car, you hit new map cells that are tuned very conservatively because the stock engine doesn't normally go there. Those cells are usually richer and more retarded than normal, which also hurt economy.

Unlikely to happen in an NA car where bolt-ons are only worth a few percent but turning up the boost in a 90's turbo Nissan absolutely does this "Rich & Retard" effect on the stock ECU.

JARblue

No one cares about gas mileage at full throttle though

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