E90 D3 Biturbo, where's my silencer?

[ali]

Crawling about the E90 D3 Biturbo today and noticed it doesn't have a rear silencer but heat shield there from days when the car was once a BMW. Whats the sketch with that then? I know other Biturbos are the same after I asked a pal earlier when I looked at mine.

[Wellsy]

Mines the same, 2009 D3 BT #114.

The Exhaust is Alpina specific so I guess they didn't see the need for it, no point removing the heat sheild. Doesn't really sound much different though, which is probably a good thing. Diesels with loud exhaust sound a bit weird IMHO.

Mark.

[JohnW]

1F88786F-1263-4091-A469-B2E2F329EFAE.jpeg (178.78 KiB) Viewed 992 times

No rear silencer here

[Yad3100]

I might be wrong here, but if memory serves the first box is the silencer and the back box is a resonator. The resonator is used to modify the sound of the exhaust. Given it’s a turbo diesel with a massive particles filter it’s not as noisy as NA and the scavenging that creates addition pulses.

[Wellsy]

Yh the E90 D3 BT is lacking on the sound front, but its always going to struggle to sound good being a dirty diesel. My local garage fixed a water leak for me a while back and they always do a road test to make sure everything is fine. The garage is at the end of my road and I was outside when they took mine out. Its the owners son that does the road tests and he was clearly being very careful as I was watching him, but when he pulled away it sounded alright, no V8 clearly, but had a little rumble to it. No idea what it sounds like from outside when driving.

I wonder what one would sound like with a gutted DPF and straight through centre box?

[Ninety Right]

I wonder what one would sound like with a gutted DPF and straight through centre box?

When searching my D3 BiT out I drove quite a few from completely standard to egr removed to dpf removed and modified or straight through exhaust. In the latter instances some had a remap whilst some didn't. It became apparent an untouched Alpina OE car was better for piece of mind.

The dpf removal and modified exhaust ones had more turbo whistle and and a deeper note when on boost, not forgetting sootage

[Wellsy]

The dpf removal and modified exhaust ones had more turbo whistle and and a deeper note when on boost, not forgetting sootage
[/quote]

Yh absolutely and the issue is now any sign of smoke during the MOT test and instant fail. I have also heard that the MOT will soon include a test to make sure the emissions devices have not been tampered. I think for me rather than mess around and taking the risk, I will just clean until they can't be cleaned any more then replace. I'm about to order a new Whaler EGR Valve for just over £100 and only two bolts and two water pipes to change it. As for the DPF well it working now and I do longer trips regularly so will deal with it when it needs.