|
|
|
|
Post Reply |
|
Thread Tools | Search this Thread |
05-08-2009, 10:07 AM | #23 | |
Lieutenant
20
Rep 402
Posts |
Quote:
|
|
Appreciate
0
|
05-08-2009, 10:07 AM | #24 |
pull my finger to get your kinder® surprise
148
Rep 10,455
Posts |
your attitude is pretty douche-y; if you want to start a constructive debate, I suggest you cool it with your 'guns a' blazing' mentality.
__________________
|
Appreciate
0
|
05-08-2009, 10:09 AM | #25 |
pull my finger to get your kinder® surprise
148
Rep 10,455
Posts |
ok, you're right, we're all wrong. Guys let's all agree with markinva aka Dr. Noel Itall.
__________________
|
Appreciate
0
|
05-08-2009, 10:10 AM | #26 | |
Lieutenant
20
Rep 402
Posts |
Quote:
I'm pretty lost as to what you and carve are saying though... |
|
Appreciate
0
|
05-08-2009, 10:11 AM | #27 | |
Been There, Done That.
692
Rep 4,728
Posts |
Quote:
Now, if you were to say Hell raising flame wars, that would be another story. |
|
Appreciate
0
|
05-08-2009, 10:16 AM | #29 | |
Lieutenant
20
Rep 402
Posts |
Quote:
are you saying that you agree with Delta when he insinuates that engines prior to the n52 and n54 had a 5k oil change interval recommended by bmw? Are you saying that you agree that "In the end it all comes down to simple economics. BMW is paying for your oil change so they want to stretch out the intervals as much as possible." |
|
Appreciate
0
|
05-08-2009, 10:20 AM | #30 |
pull my finger to get your kinder® surprise
148
Rep 10,455
Posts |
What Carve is saying (please correct me if I'm wrong) is that the sensor is not a very comprehensive sensor. It uses a pretty primitive method to guesstimate (educated guess) when one should change their oil. It is a guesstimate because it measures the conductivity of the oil and uses that value to plug into a formula (or algorithm) that BMW derived to determine the oil change interval.
The attached was screencapped from that BMW document you attached
__________________
|
Appreciate
0
|
05-08-2009, 10:29 AM | #31 |
Lieutenant
20
Rep 402
Posts |
^Again, I don't take issue with that at all. But I speculate that the sensor isn't the only criteria that changes the "number of miles" until an oil change display. I think time and other factors like mileage are a factor.
I would think that if the sensor noted that oil was deteriorated (and it would have to be very deteriorated under carve's assumption) and you put brand new oil in, the mileage would STILL say you needed an oil change right now, because of those other factors, and because until you reset the thing It will say that. |
Appreciate
0
|
05-08-2009, 10:33 AM | #33 |
pull my finger to get your kinder® surprise
148
Rep 10,455
Posts |
man, I'm just trying to enjoy myself on E90post while at work, all this thinking is hurting my brain!
dude, I agree w/ Carve on the sensor, and you seem to agree as well. Regarding the BMW moneygrab conspiracy theory, I'm indifferent to it, neither agree nor disagree, I just do my own in-between oil changes for the peace of mind. As someone said earlier, it's a pretty small price to pay for insurance.
__________________
|
Appreciate
0
|
05-08-2009, 10:34 AM | #34 |
pull my finger to get your kinder® surprise
148
Rep 10,455
Posts |
the mods forgot to take their meds
I'm kidding, I don't know why
__________________
|
Appreciate
0
|
05-08-2009, 10:35 AM | #35 | |
Major
64
Rep 1,211
Posts |
Quote:
|
|
Appreciate
0
|
05-08-2009, 10:38 AM | #36 |
Lieutenant
18
Rep 481
Posts |
Most likely the explanation is a combination of many factors already discussed at length. Engine oil has been able to reduce friction for quite some time. Many examples exist that demonstrate an engine can run for some time without any oil remaining in the pan. Don't you remember the commercials for Castol as well as Nissan's VQ engine? Some of us have done this experiment accidentally.
If you're engine is run under normal conditions, the BMW recommendation is probably fine. Changing it early is insurance, nothing wrong with that if you are ok with consuming resources when not needed (don't worry, I change my oil more frequently as well). Economics definitely plays a role here as BMW's shift to longer intervals coinciding with their paying the bill is too coincidental to ignore. The likely reason for their shorter recommendation for their earlier cars was to help out the dealer network, you know, back scratching. Most people will still use a dealer to change the oil, convinced it's "necessary" to maintain their warranty. Go figure.
__________________
'13 335is convertible (manual)
'11 X3 xdrive35i '15 Sienna Limited AWD (road tripper) '06 330i MT, sport,premium (retired) |
Appreciate
0
|
05-08-2009, 10:46 AM | #37 |
Major
13
Rep 1,187
Posts |
These problems can take a surprisingly long time to become evident. In the case of the Passat/A4 1.8T sludge issue it was about 7 years (give or take). It is also interesting that the problems were limited to the North American market.
|
Appreciate
0
|
05-08-2009, 11:40 AM | #38 |
Lieutenant
20
Rep 402
Posts |
interesting. here's some internet forum speculation I've read on the audi forums. these engines only had 4.0 qt capacities, only used dino oil, and had no electric oil pump or cooling for the turbos after the engine gets shut off. All in stark contrast to the bmw setup (7 qts, oil cools turbo after shutdown (I think?), and speciific syn oil).
|
Appreciate
0
|
05-08-2009, 11:46 AM | #39 | |
Captain
28
Rep 946
Posts |
Quote:
|
|
Appreciate
0
|
05-08-2009, 12:39 PM | #40 | |
Major
13
Rep 1,187
Posts |
Quote:
The turbos are water cooled, and there is flow with the engine shutdown. That said, the sump is small and some owners/dealers did try to run dino. However it appears that even with the proper synthetic the engines will sludge (actually the problem is not "sludge" in the traditional sense) if the oil is left in too long or if the crankcase ventilation system is not working correctly. The most interesting part of this mess is that it is a North American problem. Subtle differences in operating environment, fuel standards and who knows what else can have big impacts on maintenance requirements, occasionally to the surprise of the engineers. And this example shows how it can take time for these issues to surface. |
|
Appreciate
0
|
05-08-2009, 01:29 PM | #41 | |
Lieutenant
20
Rep 402
Posts |
Quote:
|
|
Appreciate
0
|
05-08-2009, 01:40 PM | #42 | |
STEVIL Empire
223
Rep 6,297
Posts |
Quote:
Unfortunately this misinformation can't be prevented and if it really peeves you, I suggest you stop using the internet as a source of information.
__________________
2007 E92 328i 6MT-Space Gray/Black Dakota/Gray Poplar w/heated seats-PCD 4/27/07 (SOLD)
2009 E90 328i xDrive 6AT-Space Gray/Oyster Dakota/Dark Burl Walnut w/ZPP,ZCW,Xenons-ED 4/17/09 - Redelivery 5/30/09 (SOLD) 2014 E84 xDrive28i 8AT-Alpine White/Black Nevada/Silver Matte w/ZMV,ZLP,494 - DD 3/14/14 (SOLD) |
|
Appreciate
0
|
05-08-2009, 01:43 PM | #43 | |
Major
188
Rep 1,105
Posts |
Quote:
Furthermore, their recommended change intervals are what they predict are needed to allow the engine to last for a particular amount of time. We have NO IDEA what their target is, nor their degree of certainty/safety factor used to hit that target. If someone knows I'd LOVE to hear it. |
|
Appreciate
0
|
05-08-2009, 01:54 PM | #44 | |
Major
188
Rep 1,105
Posts |
Quote:
OK...our oil pumps aren't electric- only the water pumps. 7qt of syn is WAY preferable to 4qt of fossil oil for resisting coking and for making is last longer. Still, hot running, 100hp/l turbo engines are more demanding on the oil, but the interval appears (yes- I'm speculating) unchanged from BMW's normally aspirated engines. That doesn't make sense. We also have no information about longevity goals BMW intended. I imagine the majority of people buying BMWs brand new don't keep them beyond the low 100k range, and already expect big depreciation, so that is a likely factor (yes, I'm speculating) I'd be much less concerned running a (non-M) normally aspirated engine on the recommend change interval than a turbo or M engine. In fact, when Subaru started importing turbocharged cars again (2001?), I think they had like a 5-7.5k mile interval, even on synthetic. By 2005 they changed that to 3,750 for all turbo engines, even if driven under mild conditions. Previously that was the interval for "extreme conditions" drivnig. Now they define merely HAVING a turbo "extreme conditions". The interval was implemented retroactively to ALL turbo subies. Think about it...they reduced their interval from 2x as often as BMW to 3-4X as often! |
|
Appreciate
0
|
Post Reply |
Bookmarks |
|
|