EffWun

Hello all, I will be getting a double helmholtz resonator install with one or more of them possibly having a muffled can thing like some other helmholtz I've seen on here or elsewhere IF I can even find one by the weekend.

I forgot which HFC I'm running but was ordered from evasive. Either the evasive or the berk; anyways catback is the v1 greddy spectrum elite 2.75in piping with muffler packing pretty blown as the muffler rattles inside when I was shaking it before install.

The muffler fitment is on point so I'll leave it alone; probably subjectively the best looking backbox other than the OEM for the rear exit. I may opt to remove the resonator and have double or triple helmholtz. Thankfully the noise canceling phones I have reduce the drone by 80% I've driven it without headphones and could not last 5 minutes.

The helmholtz will not be "scientifically" done by frequency but will instead be random pipe sizings for reduction of all drone frequencies from interior and minimal change or somewhat quieter exterior noise levels. That's what I'm hoping for anyways.
Will report back after weekend.

GOGPWS2K

Just my experience. You will need to weld the helmholtz pipe on to your car. Even if you get it right, you will not completely eliminate drone. You will only eliminate the drone within a certain range.

Just to note, there are several factors that go into frequency cancellation.

1.The thickness of the steel
2. Length.
3. Piping size or chamber.

EffWun

Yes, that goes from my experience as well. Although one adjustable unit or multiple have also shown to have reduced the overall drone range as well so I'm basically going by previous experience but have had them on non 4 cylinder motors.

I will be having the first one where the OEM one would have been on this existing pipe. I've found a piece of older 16ga. 2.25" stainless steel that I can cap off. The other helmholtz pieces might need to be made with mild aluminium that norcal exhaust shops only seem to carry and will be placed either middle and or where the old resonator would be if removed.


edit: TWO 5.5-6" length piping of 2.25" 16ga piping side by side.

I maybe should extend one so it cuts drone at ALL range??

So far the drone seems more tolerable at light throttle and overall.
Better yet, I wear the NC headbuds and that was much more improved