Loud knocking during the wet only...

[Alexander0628]

In the last week or so with the bad wet weather, mine has been doing this like crazy, it's horrible.

It never used to do it with the oem b-pipe I had, but since I put the j's 60rs in its done it none stop. To be fair it's been some heavy rain but today was so bad, I gave up on where I was going and drove back home.

Bloody j's crappppp.....lol. Will be changing the mani and upgrading my mounts soon so will see if that fixes the problem.

 

[Chewy]

In the last week or so with the bad wet weather, mine has been doing this like crazy, it's horrible.

It never used to do it with the oem b-pipe I had, but since I put the j's 60rs in its done it none stop. To be fair it's been some heavy rain but today was so bad, I gave up on where I was going and drove back home.

Bloody j's crappppp.....lol. Will be changing the mani and upgrading my mounts soon so will see if that fixes the problem.

Those pictures I posted are of the J's, LOL...I can't believe how poor the fitment was, and it's sounding like the all of them from our batch were like it then?

You'll have to let me know how it is after the Mani/Mounts are swapped, I'd still like another one, Haha.

Hope it sorts it out mate!

 

[p1tse]

Bump to the thread

I've recently put a mugen twinloop on
Albeit the b pipe where it joins the cat has a small dent and flat spot so slightly out of shape

But used the car yesterday in heavy rain and noticed some strange behaviours. Wouldn't say loud as per the title, but felt like something was vibrating and rough at the bottom between driver position to bottom of engine below 3k

When on dual carriage up to national speed limit felt fine again

Before doing it sounded like water being spread from tyre tread hitting mudflap type noise, but of course I have no mud flaps lol

Waiting for dry weather to give it a test

 

[cmhshek]

Well..I've just changed from Spoon B pipe to a custom one recently and it's now happening to me.

And it's really bad! So I'm booked back in next week to get it sorted out.

He did say he's had this before in the past and it's pretty much as people have described on here with the water, expanding etc.

I'll probably be getting a new one made free of charge, but he did say it's only a matter of a few mm's that causes the problem.

 

[wj51fut]

You could get a guard made up. Wouldn't take much work. Plus it would protect the exhaust.

 

[p1tse]

A guard sounds interesting.
Still struggling to picture why this may happen, but maybe makes sense why the b pipe hangs as it does then, I.e lower and away from chassis

 

[adam.]

I had some poly exhaust bushes fitted (that lowered the exhaust a little) and it's better, not perfect, but definitely a marked improvement.

 

[Bewesy]

Mine makes that horrendous loud vibration noise in the wet but only under certain conditions:

- The exhaust has to be warm - it doesn't happen when I first drive the car, and the faster I've been driving the louder the noise is when it happens.
- I hit puddles of standing water - normal road spray doesn't make it happen.

I hit a puddle and I get the vibration after a few seconds but then it gradually fades over the course of 30 seconds. If I hadn't had read thread before it first happened I would have no idea what the noise is - its sounds like the engine is dropping out of the car!

The only explanation I can come up with is the spray is cooling half of the hot exhaust and making it bend slightly forcing it closer to the chassis causing the vibration. It then warms back up and stops touching the chassis. If the bottom of the exhaust is cooled it will contract in comparison to the top with the effect of creating a shallow arch shape which then touches the car. This obviously wont happen when the exhaust is cool as the water is not changing the temperature. I know it sounds like a bizarre explanation but if I hadn't hadn't experienced it first hand I wouldn't believe it myself.

I have had a look underneath and where the b-pipe crosses the chassis rail it is quite close there and it looks like it has been touching there occasionally, so I am going to try some slightly longer exhaust rubbers to see if that cures it.

 

[BenLAST]

Cant see how a guard would work? Surely it'd just vibrate off that instead. And plus I can't see it causing damage when it happens, its a concerning noise but not forceful enough to dent the exhaust or floorpan surely.