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hey guys a quick question,

aimed people running mugen stuff
my car came with a mugen 4-1 and twin loop but still has its cat on

ive noticed at part throttle, normal driving and between 2- 3.5k revs right in the normal driving band im gettin what i can only describe as resonation or a rattle, ive looked at al the heat sheats im im pretty sure its not that and i dont think its coming from the exhaust

im pretty sure its coming from the manifold and its a characteristic of the mugen one, its def coming from the front of the car in the engine day but it also cant be heard from outside the car

its only does its as partial revs but its annyoing the hell out of me. does anyone have any ideas besides the heatshield

also anyone with a mugen header experience the same thing??

 

here are all the possible reasons why exhaust parts would rattle:

a) its hitting agains something, like frame/bumper or other car part
b) bolts are loose
c) cracks
d) loose material inside resonators/mufflers cats

reason for why it would sound like ****:

e) you're running a motorcycle muffler on a 4 cylinder
f) you have an exhaust leak


causes and solutions:

a) if its hitting body parts, you may fix it by playing around with hangers, in worst case exhaust itself may need to be cut or hangers rewelded. if exhaust part is near the engine and its hitting a non moving part, it may lead to failure of that part like cracks.. etc

b) loose bolts will certaintly lead to rattle and exhaust leak

c) if your heatshield is cracked right around the bolt area, it will rattle, sometimes its kind of hard to notice

d) often double wall piping will have loose material in between like oem header leaving with constant rattle at random rpm, cats going bad will do the same and anything trapped between heatshields

 

Hello,

I had the same problem with my Mugen 4-1 and my Spoon 4-2-1.

It is an inherent resonance of the exhaust pulses of the B18 that you cannot get rid of.

I even called King Motorsports about it and they said it's normal.

You just have to live with it.

Interestingly - I when I put the stock cast manifold back on - I could still hear the resonance - but it was much much quieter.

I have a Hytech header now - and I don't hear that buzzing as much - I'm not sure but I think the anti-reversion cones inside the header help eliminate it.