Loud Rattle on Start up
04-09-2012, 02:27 PM
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Loud Rattle on Start up
I have a 2001 Honda Civic LX and when I start up my car for the first couple of minutes if I am accelerating I get a real loud almost drumroll sound coming from my engine compartment. I took my car in today to have the mechanics look at because I couldn't see anything but they couldn't get the problem to replicate itself since my car had already been running. Like I said it only happens during acceleration and only between 0 and 20 mph. It also only happens for the first few minutes of driving and then disappears. The mechanics said it was probably something loose but then it should rattle the whole time I am driving not just the first few minutes. Any body have any ideas as to what this could be? One of my friends said he thought it might be the power steering pump but it does seem to be coming from the block itself not from the components. Any ideas are much appreciated. Thanks.
04-10-2012, 10:45 AM
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Re: Loud Rattle on Start up
Standard Tranny RPM between 1500 (just above idle) and 3000. Only happens during acceleration up to 20 mph. I threw it into 2nd early and it does the same in second as long as I am feeding gas and between 0 and 20 mph. Sounds does not happen if running between 1500 and 3000 at a constant speed only during acceleration. Hope that helps.
04-10-2012, 03:12 PM
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04-10-2012, 03:17 PM
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Re: Loud Rattle on Start up
The exhaust shield I held onto while I gave throttle and the noise did not stop. Didn't check Cat. Shield but the noise is coming from the engine bay not from cat. location.
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04-10-2012, 03:19 PM
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04-11-2012, 08:27 AM
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Re: Loud Rattle on Start up
Here is a link to the video I made. The sound isn't that great but you can definitely here the rattle if you listen closely.
http://www.youtube.com/watch?v=2okKKnVyQmA
http://www.youtube.com/watch?v=2okKKnVyQmA
04-11-2012, 09:55 AM
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04-11-2012, 04:58 PM
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Re: Loud Rattle on Start up
If I am correct you have a crack in your manifold. As it heats up the metal expands and the noise goes away. It happened in my Nissan pathfinder. Drove me nuts, I ended up getting headers and the problem went away.
I'm not sure how prone these manifolds are to cracking, but the video you posted, sounds exactly like a leak in one of the manifold runners, hence the noise like a drum roll, its only making noise when that exhaust port opens up and lets the gasses out.
I'm not sure how prone these manifolds are to cracking, but the video you posted, sounds exactly like a leak in one of the manifold runners, hence the noise like a drum roll, its only making noise when that exhaust port opens up and lets the gasses out.
04-12-2012, 02:52 PM
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Re: Loud Rattle on Start up
Ok so if I need to get new headers should I replace with OEM or for the same or less go with performance parts. I know the performance parts don't have a cat. on them so that is probably part of the reason they are cheaper. Is this a major concern to not have a cat.? I live in a county that doesn't require emissions testing. Is there any other reason why I would need one? Thanks for the help guys.
04-12-2012, 07:58 PM
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Re: Loud Rattle on Start up
Ok so if I need to get new headers should I replace with OEM or for the same or less go with performance parts. I know the performance parts don't have a cat. on them so that is probably part of the reason they are cheaper. Is this a major concern to not have a cat.? I live in a county that doesn't require emissions testing. Is there any other reason why I would need one? Thanks for the help guys.
04-13-2012, 10:35 PM
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Re: Loud Rattle on Start up
Matt, all I'm running for an exhaust right now is stock muffler off, straight pipe off the resonator back out the rear with a tip. I think it sounds awesome. If I got headers, would the exhaust make that really unappealing "buzz"? I'm not looking for any buzz at all and I have NONE right now.
04-22-2012, 12:08 AM
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Re: Loud Rattle on Start up
Exhaust harmonics are dependent on a couple of factors including intake pulses and valve sizes. However the main factor involved is the pulse timing. An air pulse exiting the cylinder head creates a shock-wave that travels down the exhaust path and is follwed by a mometary vacuum pulse.
V8 and 4-cylinders have pistons that rise up in perfect pairs at the exact same time. That explanes the deep note that you get from since they perfectly sinc exhaust pulses together. V6s on the other hand, usually have offset or split crank-pins to even out the firing sequence. So pistons are slightly off-sinc which in tern causes the exhaust pulses to slightly off. This leads to more raspyness because of gaps in the air-pulses.
Exhaust design utilizes one of three designs to control exhaust sound. The first type (and most common) is absorbsion. These mufflers use sound absorbstion material and internal channels to smother out noise. Although quiet, they are restrictive and they are the least desirable of the three.
The second type is deflection style mufflers. Mufflers of these type use internal baffles to bounce sound waves back at the incomming pulses and cause them to nullify each other. Flow-master (AKA choke-master uses this design)
The last, and best of the bunch are the "resonator" type. Resonators fall into one of two catagories. The first is "helmholtz" and the second is mesh type.
The mesh type mufflers are what you usuallt hear on most Imports. They utilize a flow-through design with a baffled pipe that passes through a cavity that is either filled with fiber-glass or stainless mesh to act as a silencer. "Cherry bomb" mufflers fall into this catagory.
The "helholtz" resonator uses a unique bulb shaped chamber which causes incomming air to suddenly expand over its inner surface area. As it enters the larger part of the bulb the shock wave slows down a bit. As the next shock-wave enters the chamber, the first wave exits through the other end, and speeds up as it leaves the bottle-neck. Both shock-waves mesh and causes the waves to mesh into one-another. A resonator gives a rich deep tone to your exhaust note while getting rid of unwanted "raspy" harmonics. That unique sound that you hear from a G35 can be attributed to this type of exhast design.
There are a few other factors like exhaust length, temperature and thermal expansion rates etc...
V8 and 4-cylinders have pistons that rise up in perfect pairs at the exact same time. That explanes the deep note that you get from since they perfectly sinc exhaust pulses together. V6s on the other hand, usually have offset or split crank-pins to even out the firing sequence. So pistons are slightly off-sinc which in tern causes the exhaust pulses to slightly off. This leads to more raspyness because of gaps in the air-pulses.
Exhaust design utilizes one of three designs to control exhaust sound. The first type (and most common) is absorbsion. These mufflers use sound absorbstion material and internal channels to smother out noise. Although quiet, they are restrictive and they are the least desirable of the three.
The second type is deflection style mufflers. Mufflers of these type use internal baffles to bounce sound waves back at the incomming pulses and cause them to nullify each other. Flow-master (AKA choke-master uses this design)
The last, and best of the bunch are the "resonator" type. Resonators fall into one of two catagories. The first is "helmholtz" and the second is mesh type.
The mesh type mufflers are what you usuallt hear on most Imports. They utilize a flow-through design with a baffled pipe that passes through a cavity that is either filled with fiber-glass or stainless mesh to act as a silencer. "Cherry bomb" mufflers fall into this catagory.
The "helholtz" resonator uses a unique bulb shaped chamber which causes incomming air to suddenly expand over its inner surface area. As it enters the larger part of the bulb the shock wave slows down a bit. As the next shock-wave enters the chamber, the first wave exits through the other end, and speeds up as it leaves the bottle-neck. Both shock-waves mesh and causes the waves to mesh into one-another. A resonator gives a rich deep tone to your exhaust note while getting rid of unwanted "raspy" harmonics. That unique sound that you hear from a G35 can be attributed to this type of exhast design.
There are a few other factors like exhaust length, temperature and thermal expansion rates etc...
04-22-2012, 12:20 AM
#21
Re: Loud Rattle on Start up
Exhaust harmonics are dependent on a couple of factors including intake pulses and valve sizes. However the main factor involved is the pulse timing. An air pulse exiting the cylinder head creates a shock-wave that travels down the exhaust path and is follwed by a mometary vacuum pulse.
V8 and 4-cylinders have pistons that rise up in perfect pairs at the exact same time. That explanes the deep note that you get from since they perfectly sinc exhaust pulses together. V6s on the other hand, usually have offset or split crank-pins to even out the firing sequence. So pistons are slightly off-sinc which in tern causes the exhaust pulses to slightly off. This leads to more raspyness because of gaps in the air-pulses.
Exhaust design utilizes one of three designs to control exhaust sound. The first type (and most common) is absorbsion. These mufflers use sound absorbstion material and internal channels to smother out noise. Although quiet, they are restrictive and they are the least desirable of the three.
The second type is deflection style mufflers. Mufflers of these type use internal baffles to bounce sound waves back at the incomming pulses and cause them to nullify each other. Flow-master (AKA choke-master uses this design)
The last, and best of the bunch are the "resonator" type. Resonators fall into one of two catagories. The first is "helmholtz" and the second is mesh type.
The mesh type mufflers are what you usuallt hear on most Imports. They utilize a flow-through design with a baffled pipe that passes through a cavity that is either filled with fiber-glass or stainless mesh to act as a silencer. "Cherry bomb" mufflers fall into this catagory.
The "helholtz" resonator uses a unique bulb shaped chamber which causes incomming air to suddenly expand over its inner surface area. As it enters the larger part of the bulb the shock wave slows down a bit. As the next shock-wave enters the chamber, the first wave exits through the other end, and speeds up as it leaves the bottle-neck. Both shock-waves mesh and causes the waves to mesh into one-another. A resonator gives a rich deep tone to your exhaust note while getting rid of unwanted "raspy" harmonics. That unique sound that you hear from a G35 can be attributed to this type of exhast design.
There are a few other factors like exhaust length, temperature and thermal expansion rates etc...
V8 and 4-cylinders have pistons that rise up in perfect pairs at the exact same time. That explanes the deep note that you get from since they perfectly sinc exhaust pulses together. V6s on the other hand, usually have offset or split crank-pins to even out the firing sequence. So pistons are slightly off-sinc which in tern causes the exhaust pulses to slightly off. This leads to more raspyness because of gaps in the air-pulses.
Exhaust design utilizes one of three designs to control exhaust sound. The first type (and most common) is absorbsion. These mufflers use sound absorbstion material and internal channels to smother out noise. Although quiet, they are restrictive and they are the least desirable of the three.
The second type is deflection style mufflers. Mufflers of these type use internal baffles to bounce sound waves back at the incomming pulses and cause them to nullify each other. Flow-master (AKA choke-master uses this design)
The last, and best of the bunch are the "resonator" type. Resonators fall into one of two catagories. The first is "helmholtz" and the second is mesh type.
The mesh type mufflers are what you usuallt hear on most Imports. They utilize a flow-through design with a baffled pipe that passes through a cavity that is either filled with fiber-glass or stainless mesh to act as a silencer. "Cherry bomb" mufflers fall into this catagory.
The "helholtz" resonator uses a unique bulb shaped chamber which causes incomming air to suddenly expand over its inner surface area. As it enters the larger part of the bulb the shock wave slows down a bit. As the next shock-wave enters the chamber, the first wave exits through the other end, and speeds up as it leaves the bottle-neck. Both shock-waves mesh and causes the waves to mesh into one-another. A resonator gives a rich deep tone to your exhaust note while getting rid of unwanted "raspy" harmonics. That unique sound that you hear from a G35 can be attributed to this type of exhast design.
There are a few other factors like exhaust length, temperature and thermal expansion rates etc...
Post #4 by Driver_10 looks awfully familiar.
In case you don't want to click the link.
Originally Posted by Driver_10 on 01-03-2010 @ 12:25AM
Exhaust harmonics are dependent on a couple of factors including intake pulses and valve sizes. However the main factor involved is the pulse timing. An air pulse exiting the cylinder head creates a shock-wave that travels down the exhaust path and is follwed by a mometary vacuum pulse.
V8 and 4-cylinders have pistons that rise up in perfect pairs at the exact same time. That explanes the deep note that you get from since they perfectly sinc exhaust pulses together. V6s on the other hand, usually have offset or split crank-pins to even out the firing sequence. So pistons are slightly off-sinc which in tern causes the exhaust pulses to slightly off. This leads to more raspyness because of gaps in the air-pulses.
Exhaust design utilizes one of three designs to control exhaust sound. The first type (and most common) is absorbsion. These mufflers use sound absorbstion material and internal channels to smother out noise. Although quiet, they are restrictive and they are the least desirable of the three/
The second type is deflection style mufflers. Mufflers of these type use internal baffles to bounce sound waves back at the incomming pulses and cause them to nullify each other. Flow-master (AKA choke-master uses this design)
The last, and best of the bunch are the "resonator" type. Resonators fall into one of two catagories. The first is "helmholtz" and the second is mesh type.
The mesh type mufflers are what you usuallt hear on the rice burners. They utilize a flow-through design with a baffled pipe that passes through a cavity that is either filled with fiber-glass or stainless mesh to act as a silencer. "Cherry bomb" mufflers fall into this catagory.
The "helholtz" resonator uses a unique bulb shaped chamber which causes incomming air to suddenly expand over its inner surface area. As it enters the larger part of the bulb the shock wave slows down a bit. As the next shock-wave enters the chamber, the first wave exits through the other end, and speeds up as it leaves the bottle-neck. Both shock-waves mesh and causes the waves to mesh into one-another. A resonator gives a rich deep tone to your exhaust note while getting rid of unwanted "raspy" harmonics. That unique sound that you hear from a G35 can be attributed to this type of exhast design.
There are a few other factors like exhaust legnth, temperature and thermal expansion rates, but thats really the jist of it.
V8 and 4-cylinders have pistons that rise up in perfect pairs at the exact same time. That explanes the deep note that you get from since they perfectly sinc exhaust pulses together. V6s on the other hand, usually have offset or split crank-pins to even out the firing sequence. So pistons are slightly off-sinc which in tern causes the exhaust pulses to slightly off. This leads to more raspyness because of gaps in the air-pulses.
Exhaust design utilizes one of three designs to control exhaust sound. The first type (and most common) is absorbsion. These mufflers use sound absorbstion material and internal channels to smother out noise. Although quiet, they are restrictive and they are the least desirable of the three/
The second type is deflection style mufflers. Mufflers of these type use internal baffles to bounce sound waves back at the incomming pulses and cause them to nullify each other. Flow-master (AKA choke-master uses this design)
The last, and best of the bunch are the "resonator" type. Resonators fall into one of two catagories. The first is "helmholtz" and the second is mesh type.
The mesh type mufflers are what you usuallt hear on the rice burners. They utilize a flow-through design with a baffled pipe that passes through a cavity that is either filled with fiber-glass or stainless mesh to act as a silencer. "Cherry bomb" mufflers fall into this catagory.
The "helholtz" resonator uses a unique bulb shaped chamber which causes incomming air to suddenly expand over its inner surface area. As it enters the larger part of the bulb the shock wave slows down a bit. As the next shock-wave enters the chamber, the first wave exits through the other end, and speeds up as it leaves the bottle-neck. Both shock-waves mesh and causes the waves to mesh into one-another. A resonator gives a rich deep tone to your exhaust note while getting rid of unwanted "raspy" harmonics. That unique sound that you hear from a G35 can be attributed to this type of exhast design.
There are a few other factors like exhaust legnth, temperature and thermal expansion rates, but thats really the jist of it.
04-22-2012, 04:31 PM
#23
Re: Loud Rattle on Start up
Matt, all I'm running for an exhaust right now is stock muffler off, straight pipe off the resonator back out the rear with a tip. I think it sounds awesome. If I got headers, would the exhaust make that really unappealing "buzz"? I'm not looking for any buzz at all and I have NONE right now.
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