Flux

I have had a vibration under tha car now for some time - especially when it is cold. I originally thought it was the heatshield on the Carsound cat - but that has been replaced and the vibration continues.

I put it up this morning determined to find out what is going on. It looks like there is a big vibration that runs from the engine through the header and most of the way down the exhaust at 1500rpms. When this bigger than normal vibration hits I am getting a fairly loud noise (vibration noise, not a rattle) from near the collector/cat area - which makes sense since that is where everything comes together.

It is not rubbing a heat shield and I have tightened everything down. Is it possible that I may have the header-to-cat bolts (with springs) to tight? Should those springs be fully compessed?

What else could be causing this? It is driving me a bit mad...
thanks

Ferrell

Could it be the header bracket? Maybe the 2 nuts backed off the screws?
happened to me and would make a loud vibrating noise...

Flux

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ferrell &raquo;</TD></TR><TR><TD CLASS="quote">Could it be the header bracket? Maybe the 2 nuts backed off the screws?
happened to me and would make a loud vibrating noise...</TD></TR></TABLE>

I wish that was the problem, because I think a header bracket would fix the problem. There is no bracket with the Spoon header...

rolow

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flux &raquo;</TD></TR><TR><TD CLASS="quote"> Should those springs be fully compressed?</TD></TR></TABLE>

No! the springs are there to act like a flex pipe so the motor/header and exhaust can move independently.

Sorry I can't help with the rest of your problem.

.RJ

If you have hte stock exhaust manifold, its probably the a-pipe.

Splat

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by .RJ &raquo;</TD></TR><TR><TD CLASS="quote">If you have hte stock exhaust manifold, its probably the a-pipe.</TD></TR></TABLE>

Reading for comprehension, y0!

He's got the Poon header.

scrap1ngsr

I think I have a similar problem , I did take off the heatsheild but tore it off so there are still bolts left . Its probally those bolts making that noise around 1.5 rpm

Rdriver

I would trash all heat shields first starting with the ones on the carsound cat. Or the cat itself could be broken loose inside. Carsound cats are known for that. Then check for loose motor mounts.

Flux

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rdriver &raquo;</TD></TR><TR><TD CLASS="quote">I would trash all heat shields first starting with the ones on the carsound cat. Or the cat itself could be broken loose inside. Carsound cats are known for that. Then check for loose motor mounts.
</TD></TR></TABLE>

I'll remove heatshields... will that have any other adverse effects? I'm convinced it is not the cat. I may loosen up the header - cat bolts, I may have gotten a little excited and over tightened those and the springs may not be doing their jobs...

Big Phat R

Check the motor mounts?

Rdriver

I have always tightened the exhaust springs bolts until they are fully compressed. Mine doesn't rattle. My car doesn't have any heat shields. The heat shields are really only for use with the stock exhaust.

Flux

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Big Phat R &raquo;</TD></TR><TR><TD CLASS="quote">Check the motor mounts?</TD></TR></TABLE>

Good suggestion - how do I go about checking those? What am I looking for?

Chris93Si

I'd say get rid of the heatshields, when I had my Spoon/T1R combo I couldn't see any places where it was touching the exhaust but after removing them no more rattles. No adverse effects from removing the heatshields, I've been w/o them for maybe 8-10 months and no problems.

Flux

I'll try that, but I honestly don't think that is it. I can visually see the header/exhaust get a nasty vibration at 1.5k rpms, the heatshields are not moving.

Flux

Anybody else?

Big Phat R

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flux &raquo;</TD></TR><TR><TD CLASS="quote">

Good suggestion - how do I go about checking those? What am I looking for?</TD></TR></TABLE>

Sounds like you have a bad motor mount - if your vibration problem is near or at idle RPM.

I found this re: checking motor mounts - since your car is getting older - probably you should check this out:

"A motor mount is made up of a piece of rubber sandwiched together by two plates of metal. These "rubber sandwiches" bolt the motor and transmission to the frame of the car. The vibration caused by the engine is absorbed by the rubber. It would be an extremely rough ride without these rubber cushions. The engine and transmission are constantly moving and flexing from the torque...when you give the engine gas you cause the motor and transmission to move or flex...and this movement is restricted by the motor mounts, otherwise the engine could pop out of the hood or fall on the ground. Most cars have three to six motor and transmission mounts depending on the model and year of the vehicle.

What causes the motor mounts to go bad? Rubber stretches and loosens with age and use. When the motor mounts start to loosen, they allow the motor and transmission to flex and move more than they should in the small confines of the engine compartment. When the engine moves, it also pulls on wires, hoses and other items that really should stay stationary. Excess movement of one mount will cause the other mounts to stretch more than they can withstand, thus breaking them. An oil leak that is allowing oil to collect on the rubber part of the mount will deteriorate the rubber as well.

How do you know you need to replace the motor mounts? The only clue you may have as a driver is a rough vibration, especially at idle. You usually can't feel the vibration caused by a bad motor mount while you are driving the car. Switching between drive and reverse may cause a change in the vibration felt as the torque changes direction. If you notice a change in the vibration of the engine as you switch gears, the vibration is more than likely a bad motor mount as opposed to an engine miss or the need for a tune-up. If the rubber is cracked in two, you may also hear an occasional thump as the loosened motor bangs against the body of the car.

When do you replace the motor mounts? If you notice a strong vibration at idle, get the motor mounts checked right away. Neglecting this repair can cause other damage as the too-mobile engine or transmission puts undue stress on belts, hoses, and other connected parts. The motor mounts on most cars are not easily visible, and it's even harder to tell if they are worn or broken by sight, so it's not an item that you can inspect as part of your regular maintenance schedule. Your mechanic probably won't check your motor mounts unless you indicate a possible problem, or unless he notices symptoms of a bad motor mount during a test drive.

For older cars, it is certainly reasonable for your car to have a bad motor mount. This repair does tend to be expensive because it is such a labor-intensive job. The mechanic will have to take several parts off of the car to get to the motor mount, and some motor mounts are expensive parts depending on the make and model of the car. "

BPR - hope this is helpful

Flux

BPR - you rock with some great information.
It doesn't sound like this is something I can check myself so I'll take it in. This may very well be the problem.

So, this leads to the next question (and yes, I will search too) - if it is the mounts what are good replacements?

Eric R

Flux, why don't you do something, get the car to a place like a muffler shop or aligment place and put the car on the lift. Let it cool down and start the engine.
Get underneath and try to hear where the vibration is coming from. Some times, a piece of hose is a good help to detect noises.

Flux

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Eric's R &raquo;</TD></TR><TR><TD CLASS="quote">Flux, why don't you do something, get the car to a place like a muffler shop or aligment place and put the car on the lift. Let it cool down and start the engine.
Get underneath and try to hear where the vibration is coming from. Some times, a piece of hose is a good help to detect noises. </TD></TR></TABLE>

Dude, I was under that car for 1.5 hours today checking and double checking everything before I asked for opinions in here. It isn't a matter of locating the noise - the entire exhaust system is vibrating more than it should at a certain rpm.

J_Edwards

If you find that it is the mounts that are bad, there are a few things that you can do. You can replace the entire mount setup, meaning the housings and the bushings. Or you can just replace the inner bushings. I know that Energy Suspension makes motor mount inserts which replace the stock rubber pieces. Mugen makes a set also which is considerably stiffer than the stock pieces. You will have less driveline loss of HP due to less motor shift under acceleration, it will just be a little big rougher at idle due to the stiffer bushings inside the motor mounts.

J N

Tommy_Gunns

Get a set of ES inserts if you don't have them already. At a cost of $40, even if it does not fix the rattle it is a good upgrade.

The ES inserts do NOT replace anything, they just get sandwich in-between the gap on the stock mounts. The stock mounts have gaps to allow for flexing and absorb vibrations from the motor to the chassis.

Which brings up the next problem, if you can't stand the vibration, maybe you should get a ride in a car with ES inserts before you decide on installing them.

Flux

I'll look into the ES inserts as well.

It isn't the vibration that I can't stand, it is the noise....

vtec.dc2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flux &raquo;</TD></TR><TR><TD CLASS="quote">I have had a vibration under tha car now for some time - especially when it is cold. I originally thought it was the heatshield on the Carsound cat - but that has been replaced and the vibration continues.

I put it up this morning determined to find out what is going on. It looks like there is a big vibration that runs from the engine through the header and most of the way down the exhaust at 1500rpms. When this bigger than normal vibration hits I am getting a fairly loud noise (vibration noise, not a rattle) from near the collector/cat area - which makes sense since that is where everything comes together.

It is not rubbing a heat shield and I have tightened everything down. Is it possible that I may have the header-to-cat bolts (with springs) to tight? Should those springs be fully compessed?

What else could be causing this? It is driving me a bit mad...
thanks</TD></TR></TABLE>

whats your header/exhaust setup? i've had 2 types of very annoying rattles:
1. carsound cat heatshield - solved after placing 2 metal clamps around the cat
2. bottom heatshield for jdm4-1 header hada crack near one of the bolts, i couldn't even notice the crack the way the dirt aligned until all the parts got removed.