[Joe_L]

Hi All,

Today i've noticed a loud hissing/wooshing sound on deceleration which i've never had before and which i dont think is normal. Usually i will just hear a subtle little turbo whistle through the catless DP's. Stuck my head out the window and it seems to be coming from maybe the bottom hood area of the car on the drivers side. Not too sure on that though.

Thinking it may be a leak of some sorts??

My current set up is JB4 on Map 5, catless DP's and Alpina flash.
Should also note the car is overdue on a brake fluid change by a couple weeks (which i am scheduling in for this week), but surely it cant be that can it??

Here's a clip of the sound:
http://videobam.com/XPtTc

Oh and the car is a 2008 335i E92.

It's really bugging me and i hope its nothing too serious.
Thanks for your help guys!

[fo55il]

sounds like the waste gates.

[Joe_L]

Originally Posted by fo55il

sounds like the waste gates.

Hey Bro. Yeh i might get them to check it out when i take my car in for the brake fluid change.


An update though, i drove for about an hour on D mode, fairly light footed and noticed that the hissing sound was not as noticeable (or even there at all) on deceleration. The times that the hissing has happened, i've had it on M mode with a slightly heavier foot/higher revs, car running quite warm.

[Stuart@BMRAutowerkes]

In neutral rev it a little and as the revs fall, listen to the wastegate rattle.. imo sounds more like a clicking than hissing.

[Joe_L]

Originally Posted by Stuart@BMRAutowerkes

In neutral rev it a little and as the revs fall, listen to the wastegate rattle.. imo sounds more like a clicking than hissing.

Thanks Stu...will give it a go when i get back home tonight.
And yeh you're right it is more like a clicking sound mixed with some psschhing lol.

Anyway i have booked in my brake fluid change for Thursday with the boys at Active...So they'll also take a look to see if anything is out of the ordinary that may be causing the sound. Fingers crossed its nothing too serious. Although i haven't noticed anything different whilst driving...its more of an annoyance factor at the moment than anything.

[Joe_L]

Originally Posted by Stuart@BMRAutowerkes

In neutral rev it a little and as the revs fall, listen to the wastegate rattle.. imo sounds more like a clicking than hissing.

Ok got a big update on this one.

So Stu, revved a little in neutral and wastegate rattled like no tomorrow. But understand this is a common thing.

So i took my car to Active today to get the brake fluid changed and have the boys take a quick look as to what might be causing the sound. They also agreed that the sound is being caused by the wastegate rattle.

On the way home, have noticed that the sound is MUCH worse now and has evolved to very much a rattling/clicking sound now rather than a hissing sound. Even more interesting, i put it in to M mode and gave a little gas to see what would happen. Have noticed that there is definitely a LOSS of power now. This was then confirmed by a Check Engine Message, and the loss of power message on the screen. Flicked it back to D mode and the error went away.

So im wondering if it is something abit more serious now

Will probably look to bring it back to active for them to have a more thorough look at it.

[Joe_L]

Ok an update to my update:

Firstly, looks like this issue is now FIXED

Took the car back to Active. Jin took her for a spin to attempt to replicate the check engine message (as the JB4 had cleared the error code i got earlier). Sure enough he was able to.

This then led him to the wastegate vacuum lines, which had cracked in several places. Another fairly common issue from what Jin was telling me.

He replaced them and i no longer have loss of power OR that annoying rattling/hissing sound on deceleration

Once again, big thanks to Jin and the team at Active Motorwerkes.

[cartaa100]

Originally Posted by Joe_L

Ok an update to my update:

Firstly, looks like this issue is now FIXED

Took the car back to Active. Jin took her for a spin to attempt to replicate the check engine message (as the JB4 had cleared the error code i got earlier). Sure enough he was able to.

This then led him to the wastegate vacuum lines, which had cracked in several places. Another fairly common issue from what Jin was telling me.

He replaced them and i no longer have loss of power OR that annoying rattling/hissing sound on deceleration

Once again, big thanks to Jin and the team at Active Motorwerkes.

Awesome post, ill be giving this ago sometime soon!

[Joe_L]

Originally Posted by cartaa100

Awesome post, ill be giving this ago sometime soon!

Yep i would highly recommend getting them replaced/checked if your car has high-ish mileage. It feels like a completely new car now. Im sure you could probably DIY for alot cheaper.

i should note that i still do have a slight wastegate rattle, but it is definitely not as bad as it was with the broken vacuum lines. But more importantly, the sound on deceleration and loss of power issues are gone.