Engine noise exaggerated from 1500-1800rpm

I

ijbrekke

Member

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2015 Mazda 6

• Jul 22, 2011

• #1

I have an odd problem/annoyance that's developed lately: I get excessive engine noise from 1500-1800rpm, but ONLY in that range. It seems to be a very low resonating frequency, like loud bass buzzes through a car trunk. It bothers me because that's essentially the rev range I use at every launch of the car, so I hear it a lot around town. It's loud enough for friends to notice.

I visually inspected the exhaust system with a friend revving the engine in that range, and couldn't find any leaks or rattles. I suspect motor mounts, maybe? The front is cracked, that I'm sure of.

Any thoughts?

 

J

JiggaBro

Member

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Mazda Protege5

• Jul 22, 2011

• #2

a sound clip would be really helpful

 

J

jtlinna

Member

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mazda protege 5

• Jul 23, 2011

• #3

Sounds like the engine needs to be under a load for it to make noise.. Find someone you trust. Have them brake torque the engine. Go around the car and see if you can hear it.
I have a noise in your RPM range. But im 99% its my trow out bearing.. Cuz it goes away when the clutch is pushed in when i have the car in neutral...

JT

 

R

RABID_MP5

Member

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2002 Protege5

• Jul 23, 2011

• #4

yeah motor mount is a good guess. Kinda like when you get rigid AWR mounts you'll also get RPM sensitive vibes.

 

I

ijbrekke

Member

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2015 Mazda 6

• Jul 24, 2011

• #5

I tried to take a video, but the vibration/ear pounding isn't really coming through except for an associated dash rattle at 1600 rpm. I checked all the heat shields today, and they are bolted solid (no rust, California car). I'm leaning more and more towards motor mounts.

I purchased RR Racing inserts, but not I'm hesitant to install them. Maybe just start with the front to avoid unnecessary vibes?

 

J

JiggaBro

Member

:

Mazda Protege5

• Jul 24, 2011

• #6

have you ever done anything to the tranny or shifter?
because come to think of it, ever since i put in my short shifter (had to bend the heat shield) at really low rpms and at load the exhaust rattles sometimes and hits the shield making a noise.
i know that all i have to do is bend it a little more but i've been too lazy xD