afterfire or backfire?

JB1 · 12-30-2009, 07:45 PM

HFC's + Takeda intake = lots of burble...

MrBMW · 12-30-2009, 08:58 PM

Quote:

Originally Posted by gleonard

it's not any louder than the rest of the exhaust note, it just sounds out of place. It goes from a growl to a gurgle back to a growl.

As others have said it sounds perfectly normal. For myself i have the G3 Intakes, with the FI RTP's/18" Res and CF Muffler. To be honest it really is one of the best parts of the sound LOL. Especially accelerating hard in to a tunnel and then just lift off the accelerator. I absolutely LURVE it.

gleonard · 12-31-2009, 02:36 AM

Quote:

Originally Posted by MrBMW

As others have said it sounds perfectly normal. For myself i have the G3 Intakes, with the FI RTP's/18" Res and CF Muffler. To be honest it really is one of the best parts of the sound LOL. Especially accelerating hard in to a tunnel and then just lift off the accelerator. I absolutely LURVE it.

I have the FI TDX CBE 18"resonators w/polished mufflers. The rest of the exhaust sound is so exotic that the burble sounded a bit out of place. It doesn't bother me, however it isn't my favorite sound.

Minicobra1 · 12-31-2009, 03:56 AM

Yes, it is somewhat normal, Berk CBE + Berk HFC gets the burble too.

My Mini Cooper does it too, check out the video on this one:

A couple links on articles, not sure how accurate they are:

Exhaust Burble Causes | eHow.com

eBay Guides - Exhaust Pipe Diameters

Modshack · 12-31-2009, 10:45 AM

Quote:

Originally Posted by Minicobra1

A couple links on articles, not sure how accurate they are:

Exhaust Burble Causes | eHow.com

eBay Guides - Exhaust Pipe Diameters

Yeek...More bad info on the internet. I wouldn't put too much stock in either of those 2 links though there is a little truth in the second.

Most cars, due to emissions, now have complete fuel cuts when you close the throttle. This immediate transition to lean will cause the burble and snapping depending on exhaust design and back pressure. On my old ('08) Corvette you could tune this out with software by turning off the fuel cut and allow some fuel and combustibility into the system even on closed throttle. The more even burn did away with the burble and snap/crackle..It was all very tunable. Opening or closing the Exhaust flappers had an impact too.

Namir · 01-01-2010, 01:56 PM

Here's a good example of the 'burble' at 32 seconds. I think it sounds great.

Chupacabra · 03-09-2010, 04:26 PM

yeah i would like that in my car.

what about:

I saw a Supra on youtube once pull soemthing along those lines... Don't really care if its not good for the engine, it looks sweet.

Togo · 03-09-2010, 04:31 PM

My motorcycle does this all the time on decel only. It's normal. I wouldn't worry too much.

RCZ · 03-09-2010, 06:37 PM

I wish my Z gurgled more, its awesome when it does.

Hehe, I used to spit flames out of the STI. Check it out when I brake for the right hander. Lots of chirping BOV, I miss that car.

http://www.youtube.com/watch?v=B1TseDZbsrY#t=1m12s

bluestyle55 · 03-09-2010, 08:12 PM

I love the burble of my Invidia Gemini / ERZ combo

Red370 · 03-09-2010, 08:34 PM

Quote:

Originally Posted by RCZ

I wish my Z gurgled more, its awesome when it does.

Hehe, I used to spit flames out of the STI. Check it out when I brake for the right hander. Lots of chirping BOV, I miss that car.

YouTube - Passing and being passed.

ah man, you'll be carving apexes with that stillen supercharged Z i foresee in your near future

bluestyle55 · 03-09-2010, 09:06 PM

Quote:

Originally Posted by RCZ

I wish my Z gurgled more, its awesome when it does.

Hehe, I used to spit flames out of the STI. Check it out when I brake for the right hander. Lots of chirping BOV, I miss that car.

YouTube - Passing and being passed.

I use to have an 07 STi....I do miss that car sometimes. In a perfect world were I had more money I would own my Z and a STi

JB1 · 03-09-2010, 08:43 PM

I have read through the thread but have not seen the answer to the question: what does cause the burble and gurgle? So I'll take a stab: As far as I know, the flames are unburned fuel getting into the exhaust and igniting/burning in the exhaust instead, resulting in popping/burbling noises. This is more present with high powered turbo engines due to running rich and the fact that the turbine housing and wheel get nice and hot and help to ignite the unburnt fuel. I had a friend with a Lotus Esprit turbo, carburetor + turbo= big flames and lots of popping on deceleration. I also once owned a car with a engine with carburetor myself, that car was running rich, lots of popping and burbling. At some point the popping turned into big explosions in the exhaust, getting big enough to blow a hole in the middle muffler

the muffler just split open like a coke can that had a lit firecracker inserted...

The other reason for burble is air being sucked into the engine, through the exhaust and exhaust valves on deceleration when the throttle is closed. Because there is no ignition and expansion of fuel and air on the 3rd stroke (or power stroke) there will be a slight vacuum in the cylinder when the piston reaches the end of the stroke. So when the exhaust valves open (to let the not present exhaust gasses out), air from the exhaust will be sucked in, resulting in a popping/burbling sound.

This is all AFAIK, please correct me if I'm wrong...

RCZ · 03-09-2010, 11:50 PM

Quote:

Originally Posted by JB1

I have read through the thread but have not seen the answer to the question: what does cause the burble and gurgle? So I'll take a stab: As far as I know, the flames are unburned fuel getting into the exhaust and igniting/burning in the exhaust instead, resulting in popping/burbling noises. This is more present with high powered turbo engines due to running rich and the fact that the turbine housing and wheel get nice and hot and help to ignite the unburnt fuel.

This is all AFAIK, please correct me if I'm wrong...

Bingo.

Chriz · 03-10-2010, 12:10 AM

Sometimes I wish the Z had more "burble" too. Someone I know owns a r32 with an aftermarket exhaust and it sound awesome.

Kind of like this but not as loud.

12-30-2009, 07:45 PM	#1 (permalink)
JB1 Track Member Join Date: Mar 2009 Location: Chicagoland Posts: 748 Drives: 09 Nissan 370Z sold Rep Power: 18	HFC's + Takeda intake = lots of burble... __________________ Black Fangs // Black rear Valance // Berk CBE // COBB post MAF tubes // K&N drop in filters // Setrab Oil Cooler // Stillen Sway bars // Z1 SS brake lines // Stillen brake cooling kit // Harness bar //

12-31-2009, 03:56 AM	#4 (permalink)
Minicobra1 A True Z Fanatic Join Date: Nov 2008 Location: Orange County, CA. Posts: 1,205 Drives: 370Z Tour, Spt, 6mt Rep Power: 645	Yes, it is somewhat normal, Berk CBE + Berk HFC gets the burble too. My Mini Cooper does it too, check out the video on this one: A couple links on articles, not sure how accurate they are: Exhaust Burble Causes \| eHow.com eBay Guides - Exhaust Pipe Diameters __________________ 370z Tour\| Spt Pack\|Navi\|BERK CBE\|Berk HFC's\| Eibach Springs\| Hotchkis Sway Bars\|SPC Camber Arms\|15mm Ichiba Wheel Spacers\| 19"Factory Nismo Wheels-Matt Black\|Stop Tech Rotors\|TWM Shifter\|3M Tint\|Black Fangs\|Black Rear Valance\|JDM Fog Light\| MY BAND-www.myspace.com/petroleum

01-01-2010, 01:56 PM	#6 (permalink)
Namir Track Member Join Date: Nov 2008 Location: OH and VA Posts: 627 Drives: 09 G37S 6MT Rep Power: 256	Here's a good example of the 'burble' at 32 seconds. I think it sounds great. __________________ Ambition is the path to success. Persistence is the vehicle you arrive in. G37S\|6MT\|PREM\|NAV\|Eibach\|Ichibia\|Injen

03-09-2010, 04:26 PM	#7 (permalink)
Chupacabra Enthusiast Member Join Date: Jan 2009 Location: Weston, Florida Posts: 477 Drives: 09 Nissan 370z s M6 Rep Power: 201	yeah i would like that in my car. what about: I saw a Supra on youtube once pull soemthing along those lines... Don't really care if its not good for the engine, it looks sweet. __________________ Where are my aluminum pedals? Last edited by Chupacabra; 03-09-2010 at 04:29 PM.

03-09-2010, 04:31 PM	#8 (permalink)
Togo A True Z Fanatic Join Date: May 2009 Location: E. Northport, NY Posts: 7,597 Drives: Stuff Rep Power: 657	My motorcycle does this all the time on decel only. It's normal. I wouldn't worry too much. __________________ This will decimate all after you put about fifteen grand in it or more, and if we have to, overnight parts from Japan. Joe Clem and Koeppel Nissan

03-09-2010, 06:37 PM	#9 (permalink)
RCZ A True Z Fanatic Join Date: Nov 2008 Location: Miami Posts: 6,403 Drives: '09 370Z Rep Power: 1119	I wish my Z gurgled more, its awesome when it does. Hehe, I used to spit flames out of the STI. Check it out when I brake for the right hander. Lots of chirping BOV, I miss that car. http://www.youtube.com/watch?v=B1TseDZbsrY#t=1m12s

03-09-2010, 08:12 PM	#10 (permalink)
bluestyle55 Premium Member Join Date: Apr 2009 Location: Pa Posts: 194 Drives: 09 Nissan 370z B 6M Rep Power: 16	I love the burble of my Invidia Gemini / ERZ combo __________________ 2009 370z 6MT Touring w/ Sport Pkg \| Invidia Gemini CBE\| Stillen G3 CAI \| ERZ HFC's \|X-Pel Clear Bra \| 20% Tint

03-09-2010, 08:43 PM	#13 (permalink)
JB1 Track Member Join Date: Mar 2009 Location: Chicagoland Posts: 748 Drives: 09 Nissan 370Z sold Rep Power: 18	I have read through the thread but have not seen the answer to the question: what does cause the burble and gurgle? So I'll take a stab: As far as I know, the flames are unburned fuel getting into the exhaust and igniting/burning in the exhaust instead, resulting in popping/burbling noises. This is more present with high powered turbo engines due to running rich and the fact that the turbine housing and wheel get nice and hot and help to ignite the unburnt fuel. I had a friend with a Lotus Esprit turbo, carburetor + turbo= big flames and lots of popping on deceleration. I also once owned a car with a engine with carburetor myself, that car was running rich, lots of popping and burbling. At some point the popping turned into big explosions in the exhaust, getting big enough to blow a hole in the middle muffler the muffler just split open like a coke can that had a lit firecracker inserted... The other reason for burble is air being sucked into the engine, through the exhaust and exhaust valves on deceleration when the throttle is closed. Because there is no ignition and expansion of fuel and air on the 3rd stroke (or power stroke) there will be a slight vacuum in the cylinder when the piston reaches the end of the stroke. So when the exhaust valves open (to let the not present exhaust gasses out), air from the exhaust will be sucked in, resulting in a popping/burbling sound. This is all AFAIK, please correct me if I'm wrong... __________________ Black Fangs // Black rear Valance // Berk CBE // COBB post MAF tubes // K&N drop in filters // Setrab Oil Cooler // Stillen Sway bars // Z1 SS brake lines // Stillen brake cooling kit // Harness bar // Last edited by JB1; 03-09-2010 at 08:53 PM.

03-10-2010, 12:10 AM	#15 (permalink)
Chriz Track Member Join Date: Dec 2009 Location: Houston TX Posts: 626 Drives: '10 370z PW 7AT Rep Power: 17	Sometimes I wish the Z had more "burble" too. Someone I know owns a r32 with an aftermarket exhaust and it sound awesome. Kind of like this but not as loud. __________________ PW 7AT w/Sports Pkg Hook Em!

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