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pops and gurgles !


yokomo

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Exhaust Burble on Acceleration

 

Some cars' exhaust systems will produce an odd burble or bubbling noise. For the most part this is deliberate when it occurs in vehicles upon acceleration, but not always. Many "street racers" and similar cars have undergone a few modifications to give them better fuel efficiency at higher RPMs. In order for this to occur, the lifters and timing mechanism for the sequence of combustion in the engine's cylinders is altered. This means that, while the engine timing will work well at much higher RPM, the combustion process at lower speeds is slightly off. The burble is in actual fact a series of lean misfirings caused by this timing which rumble out through the exhaust system. It causes no serious damage to the engine, and soon disappears once the vehicle has reached high speeds.

 

Exhaust Burble on Deceleration

 

An exhaust burble, or throaty popping noise which could be likened to a babbling brook, is has a different cause if it only occurs when suddenly backing off on a vehicle's throttle. Essentially, the sudden easing off the throttle causes an immediate decrease in exhaust emissions to the degree that atmospheric pressure surrounding the exhaust pipe pushes cool air up into the exhaust system. This air collides with the warm exhaust gasses and creates a rumbling not unlike thunder. Normally this will only happen if the tailpipe has too wide a diameter to maintain equalized air pressure, or there is a seam in the exhaust pipes which is not air tight.

 

Repairs

 

Some people like having the throaty noise of an exhaust burble; some do not. For those who do not want this sound, there are ways of fixing it. For an exhaust burble on acceleration, the engine must undergo a professional tune-up including resetting the timing mechanism and lifters; keep in mind this will decrease high speed engine performance, but increase the quality of performance at low speeds. For exhaust burbles upon deceleration, the seams of the exhaust pipe must be sealed against unwanted air entry, or the pipe must be swapped out for one of a smaller diameter to maintain equalized pressure between exhaust and the surrounding atmosphere.

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pops are un burnt fuel being ignited

 

burbles, not so sure about :shrug: need to have a think

ah so running a little rich on the lift off , makes sense.

always loved the sound of your single Ian , just dont think i could handle the volume.

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pops are un burnt fuel being ignited

 

burbles, not so sure about :shrug: need to have a think

ah so running a little rich on the lift off , makes sense.

always loved the sound of your single Ian , just dont think i could handle the volume.

 

As a daily I don't think I could either :headhurt:

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pops are un burnt fuel being ignited

 

burbles, not so sure about :shrug: need to have a think

ah so running a little rich on the lift off , makes sense.

always loved the sound of your single Ian , just dont think i could handle the volume.

 

from what i found on the goole i was wrong, :blush:

 

full explanation above

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Interesting read thatyou found there... not sure re deceleration being a problem with the seams on the exhaust... mine has that with the haltech in line and without it I don't so in my case it's more the timing/fuelling thats causing it... I LOVE it so it's staying B)

 

Mine sounds a bit loud in a sharp way no rumble really... Ian yours is loud :headhurt:

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Pretty sure its when a car is running a little richer than stock. I think excess fuel hits the hot exhaust and explodes which is less muffled by an aftermarket exhaust, thus usually more noticeable.

 

I live down a hill and if I put the car in second and let the cars weight pull itself down the hill without throttle it pops and bangs all the way down :teeth:

 

Personally I LOVE IT :lol:

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i love it to, but my zed just doesn't compare in that respect to my old roadster. that thing was awesome.

 

am hoping the plenum and a retune may have some effect on the exhaust note.

 

the one thing i have noticed is that the zeds cabin is surprisingly well insulated. well in the coupe it is anyway.

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Pretty sure its when a car is running a little richer than stock. I think excess fuel hits the hot exhaust and explodes which is less muffled by an aftermarket exhaust, thus usually more noticeable.

 

I live down a hill and if I put the car in second and let the cars weight pull itself down the hill without throttle it pops and bangs all the way down :teeth:

 

Personally I LOVE IT :lol:

damn you ian dont give me ideas of roling down hils just to make noise !

havent manged to get any tasty over run noise as yet but dont really run in low gears very often , till now !

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  • 3 weeks later...

Mine pops aswell, its loud now i have the manifolds on, feels quicker at the top of the rev range too, would be interesting to have it dyno'd again.

Still isnt anything like as loud as yours Ian, but i do daily drive mine. I do have solid engine mounts now though, which adds a little something to the cabin noise!

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Mine pops aswell, its loud now i have the manifolds on, feels quicker at the top of the rev range too, would be interesting to have it dyno'd again.

Still isnt anything like as loud as yours Ian, but i do daily drive mine. I do have solid engine mounts now though, which adds a little something to the cabin noise!

 

Really? I thought you would be louder than me with headers :) My car "gained" 13hp with headers :)

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