When reaching redline

H

HanJo Lee

Member
Location
New Jersey
Hello all,
I have 05 FX35 AWD and currently have Stillen Intake w/ Z tube, 5/16 Motordyne Spacer, Invidia Gemini Cat Back Exhaust and stock catalystic convertors.
Whenever I reach redline or near at redline, I hear this rattling noise from under the car. Of course I hear the noise only when windows are down.
Don't know where it's coming from exactly but towards like from catalystic convertors.
The rattling noise is like when you try to start an oven.
Is it the rev-limiter? or somethng is wrong with the catalystic convertors?
Is it normal to sound like that?
Does the sound will go away if High Flow Cats are installed?
Any inputs are much appreciated!
Thank you
 
Can't be the rev limiter. You'll know when you hit that.
You might want to check for a loose or broken weld in the exhaust.
How many RPM's does this happen at? Is it gradual?
 
It's probably something loose that is activated by harmonic frequencies. AKA, at a certain engine speed it vibrates this object. For example, after I put on my Stillen intake, I get a rattle noise right at 4k RPM.
 
wouldnt it be the catalyic converters? after a certain while they start to close up ... especially if the car has high mileage on it ... when it revs to a high rpm, the cats might be having difficulty making way for more exhaust gases ... other wise it might be a leak somwere in your exhaust system ... at least thats what i think ... had the same issue with my stillen ceramic headers :eek.:
 
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