Fancy Tech: How to Get Rid of Exhaust Drone, works great!

'10Anamoly · 08-04-2010, 11:41 AM

Here is the video of my setup with the side branch resonators and custom exhaust:

'10Anamoly's 2010 370Z - OEM Intakes, FI X-Pipe, OEM Resonators, Magnaflow 4" Race Mufflers, Side Branch Resonators, OEM Tips (1080P Available)

docaam · 08-04-2010, 12:21 PM

Quote:

Originally Posted by '10Anamoly

It really should not be the lack of flex pipes causing the drone, it has to do with standing wavelengths through long pipes. The length does matter a lot, what you need to know is the frequency of the drone. It should be close to what mine was.

Is the drone on your car heaviest between 2200rpms and 2800rpms? If so, you need around a 28" side branch resonator on each side, coming at a 90* angle off the area between the tips and the rear mufflers. That will kill off most of the drone. I had a local shop with a good welder make them for me for $100 and then I coated them in 2000* high temp flat black paint. They are tucked up behind the muffler so you cannot see them. Make sure to cover your rear bumper and the car undersides before you paint anything so you dont get spray paint on your paint job!

I have seen usually majority of aftermarket CBs are with flex pipes and someone said that this vibration might die with flex pipes

Anyways thanks for the reply, so 28" is the length of each pipe right and im not wrong then I should just weld these to the pipe behind the top without any hole or anything and then weld both of these pipe one behind the other right?

What should be the pipe diameter 2.5"???

For vibration I exactly havent noticed at what rpm it comes on, when you push the car hard it comes a bit early otherwise a bit late but within your mentioned range

m4a1mustang · 07-30-2010, 01:57 PM

Very nice!

People also need to note that you are using Magnaflow race mufflers and NOT the FI cans.

'10Anamoly · 07-30-2010, 01:59 PM

Yes, these are Magnaflow 4" stainless resonators (what Magnaflow called them on the box) also the same as race mufflers really since the diameter is smaller than 6". I much prefer them to the size of the FI cans from the rear view, although FI is not really bad looking to start with.

fairladyZ34 · 07-30-2010, 02:34 PM

sound clips?

'10Anamoly · 07-30-2010, 05:17 PM

One better, will have a video later tomorrow. We are making it at the TopSpeed grill out meet.

KEVTEX · 07-30-2010, 06:03 PM

Good solid technical info, plus 1 rep. I would have purchased an FI exhaust if it weren't for the drone problem. FI should offer this in their product line. Stillen and Berk avoid drone by having a longer exhaust path.

Highwind · 07-31-2010, 01:04 AM

Isnt this technology called the Hemholtz pipes?

ROC1ROB · 07-31-2010, 08:07 AM

I knew there was something wrong. That's not really a true FI exhaust. You still have stock cats?

'10Anamoly · 07-31-2010, 08:11 AM

I never said it was the FI exhaust, just the same style. I however have OEM resonators and the Magnaflow race mufflers instead of the FI setup, and yep they are stock cats. The x-pipe is actual FI back from the cats though to the x-crossover. The rest is custom.

KEVTEX is right, the extra bends and longer exhaust path move the frequency at which the exhaust resonates to eliminate drone. It is similar to a Helmholtz resonator but technically it is called a side brand resonator, running at a quarter the wavelength of the pipe resonance frequency. Similar though, much like the resonators on stock intake tubes!

kacz07 · 08-04-2010, 12:37 PM

This is exactly what Tony from Motordyne Engineering has done with the 350z. His are called Advanced Resonance Tuning pipes and they're integrated into the test pipe and DO create an HP gain.

'10Anamoly · 08-04-2010, 12:54 PM

If its a pipe vibration (not due to sound vibration) you have a different issue. If its that head thudding noise vibration in the cabin (resonance), then you want a 28 pipe coming off the pipe between your rear mufflers and tips.

1. First, use a hole saw to cut out a 2" to 2.25" opening on the pipe between your muffler and tips on each side (one hole per side of the car, hole should face towards the other pipe so the resonator you are welding on will extend into the area where the OEM muffler sat).

2. Next, have the exhaust shop weld a permanent cap (to seal one end of the pipe) on two pieces of 28" long, 2.25" pipes. Basically you want two 28" pipes, each has one open side and one capped side which reflect sound inside the pipe back at the open side.

3. Next, weld each straight piece of 28" to the area of the pipe that you cut the hole out of. You are basically t'ing off the stock exhaust with a 28" piece of pipe at a 90 degree angle, per side. This lets the sound go down that pipe and back and cancels out that annoying droning frequency.

4. End results should be that you have tee'd off of both side with a 28" capped extension pipe, each extension going up into the area where the OEM muffler sat.

Check my pics and this should all make better sense.

CAN-ZED · 08-04-2010, 01:11 PM

has anyone pinged Tony from FI on this, be interesting to see what his take is?
what kind of power loss would you get if doing this, and im sure it also impacts your warranty

'10Anamoly · 08-04-2010, 02:05 PM

The resonator pipes are back by the tips and meet the exhaust at 90 degrees. As they are capped and are perpendicular to exhaust flow, there is no power loss.

I know this because I had the same exhaust before and after the pipes and have noticed absolutely zero loss with them off, just much more comfort due to the reduced drone.

docaam · 08-04-2010, 02:22 PM

Quote:

Originally Posted by '10Anamoly

The resonator pipes are back by the tips and meet the exhaust at 90 degrees. As they are capped and are perpendicular to exhaust flow, there is no power loss.

I know this because I had the same exhaust before and after the pipes and have noticed absolutely zero loss with them off, just much more comfort due to the reduced drone.

Just to clear I dont have to make any hole in the FI exhaust or have to make hole where these new pipes will connect

08-04-2010, 11:41 AM	#1 (permalink)
'10Anamoly Track Member Join Date: May 2010 Location: GA Posts: 882 Drives: 2010 370Z BS M6 Rep Power: 17	Here is the video of my setup with the side branch resonators and custom exhaust: '10Anamoly's 2010 370Z - OEM Intakes, FI X-Pipe, OEM Resonators, Magnaflow 4" Race Mufflers, Side Branch Resonators, OEM Tips (1080P Available) __________________ 2013 Ford Mustang GT 374rwhp, 360rwtq SAE / GT500 Axle-Backs / Brembo Pack / Track Pack / Recaros / 6spd

07-30-2010, 01:57 PM	#3 (permalink)
m4a1mustang A True Z Fanatic Join Date: Feb 2009 Location: Northern VA Posts: 55,385 Drives: on two wheels Rep Power: 6963	Very nice! People also need to note that you are using Magnaflow race mufflers and NOT the FI cans. __________________ - Steve Zs & Coffee - Saturdays at 10AM in Fairfax, VA and Columbia, MD (Click the banner!) LIKE us on Facebook!

07-30-2010, 01:59 PM	#4 (permalink)
'10Anamoly Track Member Join Date: May 2010 Location: GA Posts: 882 Drives: 2010 370Z BS M6 Rep Power: 17	Yes, these are Magnaflow 4" stainless resonators (what Magnaflow called them on the box) also the same as race mufflers really since the diameter is smaller than 6". I much prefer them to the size of the FI cans from the rear view, although FI is not really bad looking to start with. __________________ 2013 Ford Mustang GT 374rwhp, 360rwtq SAE / GT500 Axle-Backs / Brembo Pack / Track Pack / Recaros / 6spd

07-30-2010, 02:34 PM	#5 (permalink)
fairladyZ34 A True Z Fanatic Join Date: Aug 2009 Location: Central NJ Posts: 1,577 Drives: 08 G37S Black M6 Rep Power: 19	sound clips? __________________ From Z to G to BMW and back to a G! Nismo for life

07-30-2010, 05:17 PM	#6 (permalink)
'10Anamoly Track Member Join Date: May 2010 Location: GA Posts: 882 Drives: 2010 370Z BS M6 Rep Power: 17	One better, will have a video later tomorrow. We are making it at the TopSpeed grill out meet. __________________ 2013 Ford Mustang GT 374rwhp, 360rwtq SAE / GT500 Axle-Backs / Brembo Pack / Track Pack / Recaros / 6spd

07-30-2010, 06:03 PM	#7 (permalink)
KEVTEX Base Member Join Date: Nov 2009 Location: Montgomery, TX Posts: 119 Drives: 2010 370Z 7at sp pg Rep Power: 16	Good solid technical info, plus 1 rep. I would have purchased an FI exhaust if it weren't for the drone problem. FI should offer this in their product line. Stillen and Berk avoid drone by having a longer exhaust path.

07-31-2010, 01:04 AM	#8 (permalink)
Highwind Base Member Join Date: Oct 2009 Location: IRVINE Posts: 44 Drives: Pearl White 370z Rep Power: 16	Isnt this technology called the Hemholtz pipes?

07-31-2010, 08:07 AM	#9 (permalink)
ROC1ROB Base Member Join Date: May 2010 Location: AZ Posts: 201 Drives: 09 MT BS Base/Sports Rep Power: 16	I knew there was something wrong. That's not really a true FI exhaust. You still have stock cats?

07-31-2010, 08:11 AM	#10 (permalink)
'10Anamoly Track Member Join Date: May 2010 Location: GA Posts: 882 Drives: 2010 370Z BS M6 Rep Power: 17	I never said it was the FI exhaust, just the same style. I however have OEM resonators and the Magnaflow race mufflers instead of the FI setup, and yep they are stock cats. The x-pipe is actual FI back from the cats though to the x-crossover. The rest is custom. KEVTEX is right, the extra bends and longer exhaust path move the frequency at which the exhaust resonates to eliminate drone. It is similar to a Helmholtz resonator but technically it is called a side brand resonator, running at a quarter the wavelength of the pipe resonance frequency. Similar though, much like the resonators on stock intake tubes! __________________ 2013 Ford Mustang GT 374rwhp, 360rwtq SAE / GT500 Axle-Backs / Brembo Pack / Track Pack / Recaros / 6spd

08-04-2010, 12:37 PM	#11 (permalink)
kacz07 Base Member Join Date: Nov 2008 Location: EB,NJ Posts: 42 Drives: 06 350z SS 6mt Rep Power: 0	This is exactly what Tony from Motordyne Engineering has done with the 350z. His are called Advanced Resonance Tuning pipes and they're integrated into the test pipe and DO create an HP gain.

08-04-2010, 12:54 PM	#12 (permalink)
'10Anamoly Track Member Join Date: May 2010 Location: GA Posts: 882 Drives: 2010 370Z BS M6 Rep Power: 17	If its a pipe vibration (not due to sound vibration) you have a different issue. If its that head thudding noise vibration in the cabin (resonance), then you want a 28 pipe coming off the pipe between your rear mufflers and tips. 1. First, use a hole saw to cut out a 2" to 2.25" opening on the pipe between your muffler and tips on each side (one hole per side of the car, hole should face towards the other pipe so the resonator you are welding on will extend into the area where the OEM muffler sat). 2. Next, have the exhaust shop weld a permanent cap (to seal one end of the pipe) on two pieces of 28" long, 2.25" pipes. Basically you want two 28" pipes, each has one open side and one capped side which reflect sound inside the pipe back at the open side. 3. Next, weld each straight piece of 28" to the area of the pipe that you cut the hole out of. You are basically t'ing off the stock exhaust with a 28" piece of pipe at a 90 degree angle, per side. This lets the sound go down that pipe and back and cancels out that annoying droning frequency. 4. End results should be that you have tee'd off of both side with a 28" capped extension pipe, each extension going up into the area where the OEM muffler sat. Check my pics and this should all make better sense. __________________ 2013 Ford Mustang GT 374rwhp, 360rwtq SAE / GT500 Axle-Backs / Brembo Pack / Track Pack / Recaros / 6spd

08-04-2010, 01:11 PM	#13 (permalink)
CAN-ZED Base Member Join Date: May 2009 Location: h Posts: 132 Drives: h Rep Power: 17	has anyone pinged Tony from FI on this, be interesting to see what his take is? what kind of power loss would you get if doing this, and im sure it also impacts your warranty

08-04-2010, 02:05 PM	#14 (permalink)
'10Anamoly Track Member Join Date: May 2010 Location: GA Posts: 882 Drives: 2010 370Z BS M6 Rep Power: 17	The resonator pipes are back by the tips and meet the exhaust at 90 degrees. As they are capped and are perpendicular to exhaust flow, there is no power loss. I know this because I had the same exhaust before and after the pipes and have noticed absolutely zero loss with them off, just much more comfort due to the reduced drone. __________________ 2013 Ford Mustang GT 374rwhp, 360rwtq SAE / GT500 Axle-Backs / Brembo Pack / Track Pack / Recaros / 6spd

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