What part to replace to get rid of drone?
#31
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Helmholz chambers
The basis is flask resonance, calculating the reflective characteristics of a bottle-shaped container of which the cylinder is the body and a manifold runner is the neck - but not sure how that applies to an already-merged tailpipe? Don't you need to know the frequency of the wave you want to suppress?
The basis is flask resonance, calculating the reflective characteristics of a bottle-shaped container of which the cylinder is the body and a manifold runner is the neck - but not sure how that applies to an already-merged tailpipe? Don't you need to know the frequency of the wave you want to suppress?
#32
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I once had an HKS system on another car and that exhaust system had some pretty large Hemholtz chambers on it and the exhaust system was fairly loud but there was zero drone.
Last edited by Diesel350; 11-10-16 at 06:49 AM.
#33
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I'm going to cut the rubber weight off the stock catback and clamp it to the Borla today/tomorrow just for ****s and giggles.
I've already recorded lots of db readings on my iphone with the Borla catback + stock catted manifolds, so documenting any change should be easy.
Update: no need to cut it off, only need a 12mm wrench to un-bolt it from the factory muffler. Will clamp it to the borla and test tomorrow (wife took the car to work today)
I've already recorded lots of db readings on my iphone with the Borla catback + stock catted manifolds, so documenting any change should be easy.
Update: no need to cut it off, only need a 12mm wrench to un-bolt it from the factory muffler. Will clamp it to the borla and test tomorrow (wife took the car to work today)
Last edited by BLKLBL; 11-10-16 at 08:20 AM.
#34
#35
Racer
iTrader: (3)
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I'm going to cut the rubber weight off the stock catback and clamp it to the Borla today/tomorrow just for ****s and giggles.
I've already recorded lots of db readings on my iphone with the Borla catback + stock catted manifolds, so documenting any change should be easy.
Update: no need to cut it off, only need a 12mm wrench to un-bolt it from the factory muffler. Will clamp it to the borla and test tomorrow (wife took the car to work today)
I've already recorded lots of db readings on my iphone with the Borla catback + stock catted manifolds, so documenting any change should be easy.
Update: no need to cut it off, only need a 12mm wrench to un-bolt it from the factory muffler. Will clamp it to the borla and test tomorrow (wife took the car to work today)
#36
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Thread Starter
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Appreciate all the responses so far, and the initiative to find solutions. I think that I will keep the headers and have the stock exhaust re-installed and that should take of the drone, am I correct in thinking this? I will lose power but with the tune I am getting soon, it should be near the same power hopefully.
#38
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#39
Pole Position
#43
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Strapped the factory weight to the driver side pipe, close to the muffler.
no difference in db readings, no difference in drone. May have smoothed out the vibration in the exhaust pipes a little bit. My console buzzes on cold starts, but didn't do it this time
no difference in db readings, no difference in drone. May have smoothed out the vibration in the exhaust pipes a little bit. My console buzzes on cold starts, but didn't do it this time
#45
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I made a discovery today regarding this. I had done the intake mod where you disconnect the servo valve and cap the end so that the flap opens all the time instead of at 4,000rpm. This sounded great with the stock exhaust. I just installed a full borla and was surprised how loud it was relative to what people had said on the forums. It also had a very loud drone between 1500-2000rpm. I figured I would switch the intake back to stock to try and quiet the car back down as it was too loud for my taste. To my astonishment, the car has no drone now, and is significantly quieter. I am wondering if the droning is actually the intake making the exhaust sound louder, and that is why toyota put the flapper valve in. People with aftermarket intakes might try going back to stock, its much easier than messing with your exhaust.