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Read the WELCOME ALL BMWFANATICS post.
Does the 335i need to be Idled
- Thread starter Dmonic1
- Start date
M
Mike1
Guest
I understand that is your opinion but on what information or facts are you basing your statement?
Not a challenge or anything. Just curious.
Mike
A
anile8-zn
Guest
if it needed to be idled wouldnt it be in the owners manual?
i dont recall seeing it in there
i dont recall seeing it in there
M
Mike1
Guest
If you look in any car manual where the car in question has turbo's it will mention somewhere that it is recommended that you idle the car for a minute to allow the turbo to cool.
Our 996 Turbo which is a Twin Turbo has 3 pages of the manual dedicated just to the cooling of turbo's.
Mike
Our 996 Turbo which is a Twin Turbo has 3 pages of the manual dedicated just to the cooling of turbo's.
Mike
A
anile8-zn
Guest
well i had the 335i and read the manual and it doesnt state that anywhere
M
Mike1
Guest
Hmmm that would concern me...
The Mk5 GTI has an auxiliary water pump which runs once the engine is off to cool the turbo... The Audi Q7 3.0TDI allows you to not only remove the keys from the ignition, but also walk away from the car after a hard drive and it switches off by itself once the temperature is down on the turbo.
Both these cars even with their auxiliary features clearly state in the manual that cooling must be followed through via idling or gentle driving...
If BMW hasnt included this information then I consider it a serious oversight... I work in the oil industry and know how much harm heatsoak (caused by a lack of cooling) can do to a turbo.
Mike
The Mk5 GTI has an auxiliary water pump which runs once the engine is off to cool the turbo... The Audi Q7 3.0TDI allows you to not only remove the keys from the ignition, but also walk away from the car after a hard drive and it switches off by itself once the temperature is down on the turbo.
Both these cars even with their auxiliary features clearly state in the manual that cooling must be followed through via idling or gentle driving...
If BMW hasnt included this information then I consider it a serious oversight... I work in the oil industry and know how much harm heatsoak (caused by a lack of cooling) can do to a turbo.
Mike
hey mike, wats up.
my opinion is based on my common sense. my 335i is only short
of 1 thing i.e driving itself from a to b. so why the hell
would bmw want you to sit even for 1 minute to idle the car when its so
technologically advanced, dont you think the engineers would have
thought about that inconvenience.
my opinion is based on my common sense. my 335i is only short
of 1 thing i.e driving itself from a to b. so why the hell
would bmw want you to sit even for 1 minute to idle the car when its so
technologically advanced, dont you think the engineers would have
thought about that inconvenience.
Hellas
///Member
Check this: TATA bakkies also have the feature that you can take the key out of the ignition, lock the bakkie and walk away whilst the engine is still idling for it's predetermined one minute. Looks freaky, but it's a safety feature for the diesel. I raised the point that technically you have a better chance at stealing the bakkie at that point, but the PC will swithck off the bakkie or the steering lock will limit you, but then again: who WANTS to steal a TATA bakkie??
zaleonardz
Well-known member
M335,
I am with Mike on this one, go research turbo operating temps, go research turbo protectors, and reasons why turbo's fail.
You are perfectly correct that the turbo's are in fact designed to handle a hard shut down, and your turbo is supposed to cope with this.
However simple dynamics, if a device is 200 to 400 deg 'C, and you cut off the lubrication as well as the cooling systems, which is exactly what you do when you turn the motor off, even though the parts are designed for this, repeated hard shut downs, and its going to fail, its just simple physics.
Ask yourself the question, take two identical cars made on the same day, the one car's turbo can last 20,000 and the other car 200,000.
Why is that, in the same sentence as well, your engine is designed to rev to 6,800+ RPM, yet no sane person will rev a cold engine to 6,800 from cold and keep it there, the same applies to the turbo.
You dont need to idle it for a minute, most of the time if you drive normally do you even need to bother driving slowly before you stop.
Just when you come off the highway and you have been chasing that focus revving the crap out of your car and your turbo(s) is at 400 degrees, the last 2 km from the offramp till you get home, keep it below boost level and let the turbo temp drop... No problem that is perfectly fine.
THat is recommended for your discs as well, exact same principle.
\
I am with Mike on this one, go research turbo operating temps, go research turbo protectors, and reasons why turbo's fail.
You are perfectly correct that the turbo's are in fact designed to handle a hard shut down, and your turbo is supposed to cope with this.
However simple dynamics, if a device is 200 to 400 deg 'C, and you cut off the lubrication as well as the cooling systems, which is exactly what you do when you turn the motor off, even though the parts are designed for this, repeated hard shut downs, and its going to fail, its just simple physics.
Ask yourself the question, take two identical cars made on the same day, the one car's turbo can last 20,000 and the other car 200,000.
Why is that, in the same sentence as well, your engine is designed to rev to 6,800+ RPM, yet no sane person will rev a cold engine to 6,800 from cold and keep it there, the same applies to the turbo.
You dont need to idle it for a minute, most of the time if you drive normally do you even need to bother driving slowly before you stop.
Just when you come off the highway and you have been chasing that focus revving the crap out of your car and your turbo(s) is at 400 degrees, the last 2 km from the offramp till you get home, keep it below boost level and let the turbo temp drop... No problem that is perfectly fine.
THat is recommended for your discs as well, exact same principle.
\
Leon328
New member
Have a look at what the guys at BimmerFest say as well.
http://www.bimmerfest.com/forums/showthread.php?p=3572643
There is no mention on a "You must do it" but everybody who has ever had a turbo and used it the way it should be will tell you to idle it afterwards. I destroyed an entire exhaust wheel and shaft on mine by not listening.
http://www.bimmerfest.com/forums/showthread.php?p=3572643
There is no mention on a "You must do it" but everybody who has ever had a turbo and used it the way it should be will tell you to idle it afterwards. I destroyed an entire exhaust wheel and shaft on mine by not listening.
M
Mike1
Guest
When I have a moment I will explain in detail how heatsoak etc works to you guys and how it causes turbo's to fail :wave:
Prob tomorrow morning...
Mike
Prob tomorrow morning...
Mike
A
anile8-zn
Guest
is there not a system in place to provide lubrication to the turbo's after the ingnition is switched off?
i am yet to hear of turbo failures on the n54
and they have been around for 3 years so i think some people would have put suffficient mileage on the cars to test these scenarios
i am yet to hear of turbo failures on the n54
and they have been around for 3 years so i think some people would have put suffficient mileage on the cars to test these scenarios
zaleonardz said:
I understand what you are saying dude this not my first turbo car, but as isaid earlier
this is no old school turbo car and furthermore i could give a rats ass whether the turbos
last 2kms or not as long as its covered by m/plan i ll drive it like i stole it.:clap:
Hellas
///Member
anile8-zn said:
Since the lube is applied mechanically eg a pump that only works when the engine is running, there is no way as yet (on the BMW) that lube will be supplied after the engine is turned off. Except like the Audi that Mike mentioned earlier.
///M335 said:
I think I see your problem there :mmm:
netercol
New member
having played around with turbo's for a long time, (since slapping a turbo on my ford xr3 back in the late 80's ) destroying quite a few, i have the following few PERSONAL opinions..
imho the only valid reason for letting a turbo cool a bit before switchoff is to prevent the oil feeding the center bearing from coking in the housing, thus gradually restricting oil flow to the bearing.
this used to be much more of a problem in times gone by, modern synthetic oils are MUCH more resistant to coking by comparison. the materials your turbo is made of can withstand the peak temps associated with DESIGNED peak boost indefinitely. (obviously it is possible to melt a turbo by exceding temp limits by running lean..)
sleeve type bearing turbos come to a stop almost immediately, ball bearing types +/- 30s.. feeding oil after shutdown is pointless except maybe to cool the center bearing a bit. water cooled bearings used to be used by a lot of manufacturers to lessen the coked bearings effect, but are used much less nowadays because this is much less of a problem (once again , modern synthetics to the rescue)
common turbo killers : overspeeding (due to running higher than designed for boost) puts strain on the structure of the turbo.. bear in mind some small frame turbo's can reach rotational speeds of 120k rpm!
a bmw egghead told me in confidance that this was the reason for the turbo failures experienced on the 320d at our altitude.. the turbo's had to run at a higher than designed for speed in order to reach the default boost setting, thus a certain percentage of them self-destructed due to the compressor blades de-laminating (grenading) the updated turbo apparently had machined compressor's instead of cast..
slamming the throttle open and closed constantly (known as hard driving ) everytime the turbo spools up rapidly, the compressor slams into the thrust bearing which controls axial movement, obviously wearing it over time.. when the play becomes enough for the compressor or turbine blades to touch the housings, goodbye turbo.. hence the upgrading of competition turbo's with 360' thrust collars.. can withstand more abuse.
then oil starvation, due to whatever reason, including coked up bearings..
my 2c
) destroying quite a few, i have the following few PERSONAL opinions..imho the only valid reason for letting a turbo cool a bit before switchoff is to prevent the oil feeding the center bearing from coking in the housing, thus gradually restricting oil flow to the bearing.
this used to be much more of a problem in times gone by, modern synthetic oils are MUCH more resistant to coking by comparison. the materials your turbo is made of can withstand the peak temps associated with DESIGNED peak boost indefinitely. (obviously it is possible to melt a turbo by exceding temp limits by running lean..)
sleeve type bearing turbos come to a stop almost immediately, ball bearing types +/- 30s.. feeding oil after shutdown is pointless except maybe to cool the center bearing a bit. water cooled bearings used to be used by a lot of manufacturers to lessen the coked bearings effect, but are used much less nowadays because this is much less of a problem (once again , modern synthetics to the rescue)
common turbo killers : overspeeding (due to running higher than designed for boost) puts strain on the structure of the turbo.. bear in mind some small frame turbo's can reach rotational speeds of 120k rpm!
a bmw egghead told me in confidance that this was the reason for the turbo failures experienced on the 320d at our altitude.. the turbo's had to run at a higher than designed for speed in order to reach the default boost setting, thus a certain percentage of them self-destructed due to the compressor blades de-laminating (grenading) the updated turbo apparently had machined compressor's instead of cast..
slamming the throttle open and closed constantly (known as hard driving ) everytime the turbo spools up rapidly, the compressor slams into the thrust bearing which controls axial movement, obviously wearing it over time.. when the play becomes enough for the compressor or turbine blades to touch the housings, goodbye turbo.. hence the upgrading of competition turbo's with 360' thrust collars.. can withstand more abuse.
then oil starvation, due to whatever reason, including coked up bearings..
my 2c
