Good vibrations

[Ezra-RS]

Well maybe not so good but a vibration nonetheless. And it's a very specific one.

In 2nd gear, at around 4k rpm I hear a rattle/vibration. This is just a moment and only occurs when pulling hard. When going slow and passing 4k I don't hear it.
I also never hear it in any other gear. And seems to be coming from the front.

The only that changed recently is that I have a sportscat now.

Anyone an idea as to what it can be?

 

[Clart]

exhaust heatshield?

 

[Ezra-RS]

Is there one prone to get loose ?

 

[Munson]

From memory, I think it's probably the down pipe rattling against the subframe.

 

[Ezra-RS]

I'm curious as to why you say from memory? You've see this before?

 

[jinjur]

nah......4k rpm is the heat shield.

In mine, a phase 2 172, its the wire from the downstream lambda sensor just tickling the heatshield at the cat

2 tie wraps in a figure of 8 keeps it at bay dude

J

 

[Ezra-RS]

Oh man! That's exactly what I didn't do. Just left the wire hanging, seeing as it didn't interfere with anything and I was fed up fitting the cat.
Hope that that will solve it!

 

[jinjur]

You did nothing wrong mate, there is no mount for it that i saw apart from the actual connection

When i look at mine which was brand new, it was......well....fairly pert and sat about 1cm from the heat shield. I can only assume at 4k its flapping like a fool, maybe the resonant frequency.

Also, if you have a noisy pipe, it might just be the noise of the exhaust causing the heat shield to resonate. That would be bad luck tbh

J

 

[Ezra-RS]

Well I saw how it was before, secured with two tie wraps in those little holes in the heat shield. I just didn't put it back that way.

 

[jinjur]

There we go dude