335 Owners - Do You Run Down Your Engine?

[kenntona]

I have read that for turbo cars, we are supposed to keep the engine running at idling for a specified period of time to cool the engine/compressor assembly down. The rationale is the prevention of turbo wear and failure. The engine can cool down from the lower gas temperatures in both the exhaust and intakes, and at the same time the engine oil can circulate properly so the turbine will not burn the oil that would otherwise be trapped within the charger with the turbine rotating at high speed.

Two questions:

(1) Do you "cool" your engine down?
(2) Any need for a turbo timer? Unless we are damn sure we can ensure the car does not produce any 'boost' for several minutes prior to the ignition being shut off........

 

[T6]

Re: 335 Owners - Do You Run Down Your Engine?

We have discussed this in the vag forum as a number of the cars are conti and turbo-charged. We are of the view that it is not necessary as there are built in devices already. Some still KS and let the car cool down for a while before cutting engine but this is not really necessary.

You might wanna check after a very hard drive in your ride and when you cut engine, is there some fan still running? If yes, you are likely to have some factory protection in your engine liao. If you dont hear a fan running, don't rule out the possibility of your car not having ran hard enough.

 

[Ahbengdriver]

Re: 335 Owners - Do You Run Down Your Engine?

We have discussed this in the vag forum as a number of the cars are conti and turbo-charged. We are of the view that it is not necessary as there are built in devices already. Some still KS and let the car cool down for a while before cutting engine but this is not really necessary.

You might wanna check after a very hard drive in your ride and when you cut engine, is there some fan still running? If yes, you are likely to have some factory protection in your engine liao. If you dont hear a fan running, don't rule out the possibility of your car not having ran hard enough.

Even my 320i also have this after driving hard in DS mode for prolong period or using steptronic gears.

335? No need lah Kenntona, ever heard of cold-air-intake?

 

[phil]

Re: 335 Owners - Do You Run Down Your Engine?

Ken, you need to cool it down only if you have driven it hard on boost and intend to swicth it off straight away. If you drive "normally" you will be ok

it will crack the housing on the turbo, but its rare

 

[centurion]

Re: 335 Owners - Do You Run Down Your Engine?

doesn't your 335 oil pump continue working after your car is shut down? IIRC the purpose of a turbo timer is not to only to prevent the turbo from destroying itself, but the main use is rather to prevent the turbos from cooking the oil left at the turbos thus destroying the oil and create sludge at the oil lines. That the oil pump continues to work will keep the oil flowing for some time to prevent this.

your coolant pump is also electric and if the oil pump continues to work the coolant pump will work also once the water reaches a certain temperature post engine shutdown.

 

[totoseow]

Re: 335 Owners - Do You Run Down Your Engine?

phil u r alive! where hv u been?

 

[yendor]

Re: 335 Owners - Do You Run Down Your Engine?

IMO, what centurion said was correct. The main reason to have a warm down period is to allow the oil to keep circulating in the turbo bearing core while it is still hot. But in Singapore, its is very difficult to have a situation where you can go from full boost to engine shut down in a very very short span of time. The carparks, small roads and bumps around sees to that.

But, i do not think that there is an electrical oil pump fitted on the engine for lubrication pruposes. Manufacturers go the electric pump way to reduce engine load and increase efficiencies. A mechanically driven pump is a much more relaible compared to an electrically driven one. A failed water pump will not cause immediate overheating and a cracked head, but a failed oil pump at high rpm will cause immediate damage and engine seizure. For those with dry sumps like porsche, there is an electrical pump to circulate the oil to the cooler and sump. But at the edge of the crankshaft, there is still a mechanical pump.

Back to the topic, i think a turbo timer is a waste of time and a breach of security. Cars with immobilisers and smart keys have to leave a little chip near the key slot. This will enable the car to run. For those with the new BMW key fob, this is even worse.

So bottom line, use a good engine oil and drive sedately just before you park your car. Have boost gauge installed so that you know if you are boosting.

Cheers

 

[Mockngbrd]

Re: 335 Owners - Do You Run Down Your Engine?

think i remember the fan still running when i shut the engine off once.... *i think*

 

[phil]

Re: 335 Owners - Do You Run Down Your Engine?

phil u r alive! where hv u been?

went home

the fan still running is not related to the turbo

 

[Terry]

Re: 335 Owners - Do You Run Down Your Engine?

phil!!! we miss you... when are u coming back to sg?

 

[T6]

Re: 335 Owners - Do You Run Down Your Engine?

went home

the fan still running is not related to the turbo

Phil, for the vag cars, we actually have 2 fans and not one. Not sure if that makes a diff though as I am a tech noob.

 

[PerverTT]

Re: 335 Owners - Do You Run Down Your Engine?

Not familiar with the turbo set up of 335i, but I would be amazed if the car did not come with a built -in turbo timer of some sort.

When I first bought my TT, I remember being mystified by a gurgling noise I could hear for a minute or so after the engine was switched off. I quickly found out that the gurgling noise was coolant being automatically pumped through the hot turbo to prevent it being coked. Yes, coked, not cooked though both would have led to the same outcome. The K04 turbo in the TT runs boost pressures up to 2 bar (much higher than the low boost turbos used in the 335i), so the need for a built-in timer is understandable.

As for cooling down, I don't think there is a compelling case for letting the engine idle after a drive, simply to blow cooling air past the hot turbo. That would have been essential with older turbo cars from the 1980s but not with the current generation of turbo cars. To be safe, I usually avoid driving the TT hard a kilometre or so I pull into my garage. That way the turbo gets a chance to cool down a bit before the turbo timer kicks in at the end of the drive.