buzzing sounds while deceletrating

slippery4678 · 05-17-2012, 03:00 PM

So I just got a 2010 (last week) and it came with a Stillen exhaust, nothing else. By the looks of the way it sits, flush with the bumper, it was professionally done. Anyway...I really like the sound of the Stillen, it would've been the one I put on anyway so it worked out but I've noticed a loud buzzing sound while decelerating in the lower gears. I really noticed it while city driving, having the sound echo off the buildings. Is this a normal thing with these exhausts or could it be a leak or something else?

cheshirecat · 05-17-2012, 04:20 PM

Sounds like it's vibrating against the rear crossmember. Either drop the crossmember with some washers or try to adjust the exhaust.

Footloose301 · 05-17-2012, 06:20 PM

If its more of a SWOOOOSSHHH sound then thats normal from our engines under deceleration.

slippery4678 · 05-18-2012, 10:44 AM

Thanks for the responses...I will have to wait until I can get to a garage to check....really don't feel like jacking it up on the street...lol. I'll let you know how it goes.

BuckeyeZ · 05-18-2012, 10:48 AM

Check the heat shields on the underfloor (between the exhaust and the floor pan). These are usually pretty flimsy and can be bent fairly easily if you are not careful. These will create a nasty buzz/rattle.

VDC_OFF · 05-18-2012, 10:54 AM

Quote:

Originally Posted by Footloose301

If its more of a SWOOOOSSHHH sound then thats normal from our engines under deceleration.

Ive been really noticing this. I have HFC's, ypipe and exhaust and it sounds like a blow off valve when i let go of the gas. Why does it do this?

MaDMaXX · 05-18-2012, 11:33 AM

HFCs can make that noise, but shouldn't really do it on decel, that's usually an exhaust leak.

OP, check the evap canister shield near the rear mufflers, that normally should be removed with most after market systems as they vibrate against it.

SS_Firehawk · 05-18-2012, 01:26 PM

Quote:

Originally Posted by BuckeyeZ

Check the heat shields on the underfloor (between the exhaust and the floor pan). These are usually pretty flimsy and can be bent fairly easily if you are not careful. These will create a nasty buzz/rattle.

This was definitely true for me. It gets worse the hotter they are. Mine would rattle at takeoff, at certain RPM's, and then constantly at freeway cruising speeds when it's hot. I took a bottle opener and stuck it between the body and heat shield and started prying it up some, it didn't need much.

scottIN · 05-19-2012, 06:03 AM

Quote:

Originally Posted by VDC_OFF

Ive been really noticing this. I have HFC's, ypipe and exhaust and it sounds like a blow off valve when i let go of the gas. Why does it do this?

I get that too. Best way to describe it is like a really loud aerosol can spraying.

reldas · 05-19-2012, 08:44 AM

Quote:

Originally Posted by scottIN

I get that too. Best way to describe it is like a really loud aerosol can spraying.

i get that on decel and hard accel, its the HFCs that do it. i need resonated ones.

scottIN · 05-19-2012, 11:27 AM

Quote:

Originally Posted by reldas

i get that on decel and hard accel, its the HFCs that do it. i need resonated ones.

I've got resonated 18" and it still does it.

reldas · 05-19-2012, 11:36 PM

i got 12" res but i dont have resonated HFCs. do you have resonated HFCs?

scottIN · 05-20-2012, 05:47 AM

Quote:

Originally Posted by reldas

i got 12" res but i dont have resonated HFCs. do you have resonated HFCs?

Yes, resonated HFC's.

VDC_OFF · 05-21-2012, 05:20 PM

someone was telling me this weekend that the flexible parts on the ypipe might also be making that noise because they are weak and they break. Or maybe its a blown exhaust gasket, but if you all say its the HFC's, then maybe I have nothing to worry about.

Footloose301 · 05-21-2012, 05:23 PM

It's the HFC's.... It's normal.... check around the forum.

05-17-2012, 03:00 PM	#1 (permalink)
slippery4678 Base Member Join Date: Jul 2010 Location: S. Jerz/Arlington VA Posts: 58 Drives: 2010 370z PG + sport Rep Power: 15	buzzing sounds while deceletrating So I just got a 2010 (last week) and it came with a Stillen exhaust, nothing else. By the looks of the way it sits, flush with the bumper, it was professionally done. Anyway...I really like the sound of the Stillen, it would've been the one I put on anyway so it worked out but I've noticed a loud buzzing sound while decelerating in the lower gears. I really noticed it while city driving, having the sound echo off the buildings. Is this a normal thing with these exhausts or could it be a leak or something else?

05-17-2012, 06:20 PM	#3 (permalink)
Footloose301 A True Z Fanatic Join Date: Apr 2010 Location: Naples, FL Posts: 2,659 Drives: 40th Rep Power: 21	If its more of a SWOOOOSSHHH sound then thats normal from our engines under deceleration. __________________ 2010 40th Anniversary 370Z

05-18-2012, 10:44 AM	#4 (permalink)
slippery4678 Base Member Join Date: Jul 2010 Location: S. Jerz/Arlington VA Posts: 58 Drives: 2010 370z PG + sport Rep Power: 15	Thanks for the responses...I will have to wait until I can get to a garage to check....really don't feel like jacking it up on the street...lol. I'll let you know how it goes. __________________ Stillen CBE \| Berk HFC's \| Intake Plenum \| AAM UpRev Tune \| Swift Spec-R Springs \| H&R 15/20 Spacers \| 265/285's \| Stillen Sways \| 20% tint

05-18-2012, 10:48 AM	#5 (permalink)
BuckeyeZ Enthusiast Member Join Date: Dec 2010 Location: Music City Posts: 291 Drives: 370Z BMW M4 Rep Power: 65	Check the heat shields on the underfloor (between the exhaust and the floor pan). These are usually pretty flimsy and can be bent fairly easily if you are not careful. These will create a nasty buzz/rattle. __________________ Stillen \| EVO-R \| HPS \| K&N \| Hotchkis \| Modshack Oil Cooler \| SPL

05-18-2012, 11:33 AM	#7 (permalink)
MaDMaXX Enthusiast Member Join Date: Jan 2012 Location: Oregon from England Posts: 292 Drives: 350z Rep Power: 13	HFCs can make that noise, but shouldn't really do it on decel, that's usually an exhaust leak. OP, check the evap canister shield near the rear mufflers, that normally should be removed with most after market systems as they vibrate against it. __________________ '04.5 350Z - Very Motordyne.

05-17-2012, 04:20 PM	#2 (permalink)
cheshirecat A True Z Fanatic Join Date: Jan 2009 Location: Florida Posts: 1,428 Drives: N54 135i Rep Power: 292	Sounds like it's vibrating against the rear crossmember. Either drop the crossmember with some washers or try to adjust the exhaust.

05-19-2012, 11:36 PM	#12 (permalink)
reldas Base Member Join Date: Aug 2011 Location: Sydney Posts: 144 Drives: 09 Nissan 370z auto Rep Power: 14	i got 12" res but i dont have resonated HFCs. do you have resonated HFCs?

05-21-2012, 05:20 PM	#14 (permalink)
VDC_OFF A True Z Fanatic Join Date: Aug 2011 Location: Houston (Pearland) Age: 44 Posts: 1,205 Drives: 2011 370Z M6 Rep Power: 17	someone was telling me this weekend that the flexible parts on the ypipe might also be making that noise because they are weak and they break. Or maybe its a blown exhaust gasket, but if you all say its the HFC's, then maybe I have nothing to worry about. __________________ DRIFTING JOURNAL \| Follow me on Instagram \| Facebook \| Houston Halos

05-21-2012, 05:23 PM	#15 (permalink)
Footloose301 A True Z Fanatic Join Date: Apr 2010 Location: Naples, FL Posts: 2,659 Drives: 40th Rep Power: 21	It's the HFC's.... It's normal.... check around the forum. __________________ 2010 40th Anniversary 370Z

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