440i 'turbo wastegate' noise?

[anonymous-user]

Morning all,

I have for some time been bothered by a bit of a strange, and very noticeable noise when the engine in my 440i convertible is under load. It sounds a bit like pinking (for those of you who can remember that), and only happens under reasonable acceleration. It appears to emanate from the area under the right of the steering column - I'm guessing it's coming through a bulkhead grommet and most definitely originates in the engine bay

I took it to my local dealer, and a technician accompanied me out on a drive - within 1/2 mile he'd agreed there was an unusual noise (although he didn't know what pinking was!), and that it didn't sound right. It was subsequently booked into the same dealer - but on collection they said it was normal. They said that they had compared it to other 40i cars and said they could hear the same noise from those too. They suggested it was the turbo wastegate - which sounds like a load of tosh to me.

I have two questions that I'm hoping you can help me with;

• Turbo wastegate noise occurs typically on the overrun, surely, not when under load?

• Have any other 40i owners experienced similar noise?

Many thanks for any advice in advance.

[trickywoo]

Do you notice its any different on Tesco 99 or V-Power? If you notice it less or only in more extreme circumstances I'd suspect detonation.

I'd be taking it to a 'tuner' with turbo experience to find out 100% if it is detonating and go from there.

Shouldn't cost too much and you can then go back to the dealer as necessary.

Really quite worrying that a tech doesn't know about pre-ignition combustion when new BMWs are running boost and looking to be super lean at the same time due to emissions.

[anonymous-user]

Thanks for that - I'll run the tank low and fill it with high-octane and see what difference that makes. Currently, work/life pressures mean I fill it with whatever is available when I happen to need it.

[trickywoo]

had ham said:

Thanks for that - I'll run the tank low and fill it with high-octane and see what difference that makes. Currently, work/life pressures mean I fill it with whatever is available when I happen to need it.

I'd be really surprised if that engine wasn't running knock sensors anyway but its possible they aren't working properly.

I had a turbo car with knock sensing years ago which would still detonate on 95 ron but was much better on super. A tank of Tesco 99 would be a cheap easy first step in investigating it.

[Equilibrium25]

Not noticed any odd noises on my GC.

I run on Shell 99 RON, but the car only 'needs' 95 RON so you shouldn't really see any problems with that.

Might be worth asking on F30post, there are dozens of x40i owners on there.

[anonymous-user]

As it's a '66 plate, you would hope so!

Anyone else any experience of this with 40i engines?

[Limpet]

Can't say I've ever noticed such a noise on my M140i.

There is no audible turbocharger or wastegate noise from inside the vehicle. When accelerating in an enclosed space such as a tunnel or a multi-storey car park, with the window down, you can hear the turbo whistle over the engine note, but otherwise there is very little audible hint that it's a forced induction engine, and I would say none at all from the drivers seat with the windows closed.

There is a route I can recommend if you are struggling with the dealer. We had a loud, but intermittent hood rattle on SWMBO's (then) 3 month old R57 Cooper S which we were getting the run around on, and were being told it was £40 a day for a courtesy car. It's amazing what a factual, polite, but very hacked off public post on MINI's Facebook page achieved... BMW have one too, and they monitor it very closely.

EDIT: I have never run mine on anything other than bog standard 95 RON fuel, although I do avoid supermarket fuel.

Edited by Limpet on Thursday 4th May 14:26

[Worzey]

Not heard it on my 440i (yet) but have seen reports elsewhere that it is probably noise from the injectors (especially if it's a fast metallic clicking noise).

[aeropilot]

had ham said:

Thanks for that - I'll run the tank low and fill it with high-octane and see what difference that makes. Currently, work/life pressures mean I fill it with whatever is available when I happen to need it.

While you 'can' run these things on 95........the ECU will knock back the timing.
A good few tuners have done back to back dyno runs on stock N55 engines previously using boggo 95RON and then again on 99 V-Power, and the engines were usually 20-30 hp down on power on 95.
I doubt the new B58 will be any different.

I ran my 135i N55 on V-Power for pretty much the whole 6 years I owned it, doubt I put more than half dozen tanks of other makes SUL in it in emergencies in that time, and never 95RON.

[Limpet]

aeropilot said:

While you 'can' run these things on 95........the ECU will knock back the timing.
A good few tuners have done back to back dyno runs on stock N55 engines previously using boggo 95RON and then again on 99 V-Power, and the engines were usually 20-30 hp down on power on 95.
I doubt the new B58 will be any different.

I ran my 135i N55 on V-Power for pretty much the whole 6 years I owned it, doubt I put more than half dozen tanks of other makes SUL in it in emergencies in that time, and never 95RON.

This debate rages on various forums, but there is nothing documented anywhere in or with my M140i that says you get any sort of restricted power output on 95 RON. I also asked the supplying dealer the same question, and they told me that BMW's official line is no advantage to using higher octane fuel.

I guess back to back dyno runs, allowing a few tankfuls to flush the 95 through and to allow the engine to adapt to the posh stuff would be the only proof, but again I haven't seen this anywhere. I am very happy with both the performance and the fuel economy on 95 though.

I will get around to trying it myself at some point, no doubt.

[anonymous-user]

Worzey said:

Not heard it on my 440i (yet) but have seen reports elsewhere that it is probably noise from the injectors (especially if it's a fast metallic clicking noise).

Thanks for the feedback, that sounds like it could be the same thing - could you point me in the direction of any links/reports easily? Will do some Googling later when I get the chance.....

[anonymous-user]

aeropilot said:

I ran my 135i N55 on V-Power for pretty much the whole 6 years I owned it, doubt I put more than half dozen tanks of other makes SUL in it in emergencies in that time, and never 95RON.

I'm going to start using High Octane exclusively and see what difference that makes.

[anonymous-user]

Quick google took me here - a number of suggested causes..

http://www.babybmw.net/forum/viewtopic.php?f=74&am...

...none of which would seem to be harmful.

[aeropilot]

Limpet said:

I guess back to back dyno runs, allowing a few tankfuls to flush the 95 through and to allow the engine to adapt to the posh stuff would be the only proof, but again I haven't seen this anywhere. I am very happy with both the performance and the fuel economy on 95 though.

Evolve have published numerous back to back dyno tests using various fuels on various BMW's.

[jetbox]

My m140 has a noise similar to that which you describe. Running 95 or 99 octane appears to make no difference. It certainly sounds like pinking but I am told it is injector noise

[bmwmike]

Does the b58 use piezo injectors or the normal type?

[Worzey]

had ham said:

Thanks for the feedback, that sounds like it could be the same thing - could you point me in the direction of any links/reports easily? Will do some Googling later when I get the chance.....

Try this...

http://f30.bimmerpost.com/forums/showthread.php?t=...

[weeboot]

For reference, a wastegate is used to regulate boost pressure, whereas a dump valve is used to vent unwanted pressure in the inlet tract.

On that basis, it's very likely to generate a level of wastegate "noise" under moderate acceleration.
The wastegate is a poppet valve in the exhaust housing of the turbo, held closed by a spring (in basic configuration), when the pressure in the exhaust housing overcomes the spring pressure it diverts exhaust gas into the exhaust tract, bypassing the impeller.

Therefore, if you're running at part throttle and the ECU is attempting to modulate boost pressure, it'll be using the waste gate to do it.

[anonymous-user]

Worzey said:

Try this...

http://f30.bimmerpost.com/forums/showthread.php?t=...

Thanks - very much stacks up with the post on BabyBMW linked above.

weeboot said:

For reference, a wastegate is used to regulate boost pressure, whereas a dump valve is used to vent unwanted pressure in the inlet tract.

On that basis, it's very likely to generate a level of wastegate "noise" under moderate acceleration.
The wastegate is a poppet valve in the exhaust housing of the turbo, held closed by a spring (in basic configuration), when the pressure in the exhaust housing overcomes the spring pressure it diverts exhaust gas into the exhaust tract, bypassing the impeller.

Therefore, if you're running at part throttle and the ECU is attempting to modulate boost pressure, it'll be using the waste gate to do it.

Thanks for that - every day's a school day!!

[12TS]

had ham said:

Morning all,

I have for some time been bothered by a bit of a strange, and very noticeable noise when the engine in my 440i convertible is under load. It sounds a bit like pinking (for those of you who can remember that), and only happens under reasonable acceleration. It appears to emanate from the area under the right of the steering column - I'm guessing it's coming through a bulkhead grommet and most definitely originates in the engine bay

I took it to my local dealer, and a technician accompanied me out on a drive - within 1/2 mile he'd agreed there was an unusual noise (although he didn't know what pinking was!), and that it didn't sound right. It was subsequently booked into the same dealer - but on collection they said it was normal. They said that they had compared it to other 40i cars and said they could hear the same noise from those too. They suggested it was the turbo wastegate - which sounds like a load of tosh to me.

I have two questions that I'm hoping you can help me with;

• Turbo wastegate noise occurs typically on the overrun, surely, not when under load?

• Have any other 40i owners experienced similar noise?

Many thanks for any advice in advance.

I've got a 340 - same engine I think. And I can hear the same thing.

Reading around the concencus seems to be that it's the high pressure fuel lines. I took it in for them to have a drive and listen to and was told it was exactly that, and that they all do it.

Oddly sat in the passenger seat I could hardly hear it.

Bit of a let down IMHO - was expecting a better engine note.