Quote:
Originally Posted by Cyber370
PS: Just be aware that aftermarket exhausts are usually louder than stock and that inevitably means some drone somewhere in the rev range.
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I would disagree, drone is a single resonant frequency that is dominant.
Volume is not drone. You can have an exhaust that is musical and loud everywhere, that is not drone. I had a really **** aftermarket exhaust on my R34 GT-T that had a god-awful drone at 125Hz or so, it was worst at about 2800RPM and above 3000RPM it rapidly got quieter. Above 4000RPM it sounded only slightly louder than a standard exhaust. But I couldn't tolerate going through that boomy zone. It almost rattled my teeth. I eventually found a Fujitsubo exhaust which was better but didn't get rid of the drone note entirely.
Drone happens because the vast majority of aftermarket exhaust manufacturers just bolt whatever on and call it a day. They don't actually understand the SCIENCE of exhaust noise management. Manufacturers do, that's why they have crazy complicated mufflers that suppress all the problem frequencies. Yes they usually go overboard in delivering an inoffensive note and make things too restrictive but they have different priorities.
The HKS team know their ****. The Helmholtz resonators are PERFECTLY designed. There is an exhaust note, but the note's pitch follows the revs (unlike drone which is a single note that just gets louder and quieter depending on revs) and the HKS is not in any way offensive. It is a very docile exhaust at light throttles but once you open the throttle a bit it comes to life. I'm an electronics engineer by trade but I can appreciate something in a different field that has had some proper effort put into it by talented people rather than just slapped together and pushed out the door with a dyno sheet to show it gains power.