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2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by PeterUbers
So instead of "fuel efficiency" is this a case of engineered obsolescence?
No. Just a case of choosing fleet average mileage to meet government mandates over engine longevity. Same thing with the stupid Start/Stop feature. This is NOT unique to Mercedes. Here's what ChatGPT has to say about 2-stage oil pumps:
Two-stage automotive oil pumps are designed to provide variable oil pressure based on the engine's operating conditions. The purpose of a two-stage oil pump is to optimize engine lubrication and improve efficiency in different driving scenarios. These pumps typically have two sets of gears or stages that can operate independently or in conjunction with each other.
The primary advantages of two-stage oil pumps include:
1. **Efficiency:** Two-stage pumps allow for the delivery of the right amount of oil at different engine speeds and loads. At low speeds or light loads, the pump can operate in a low-pressure mode to reduce power consumption. At higher speeds or heavier loads, the pump can engage the second stage to provide higher oil pressure for better lubrication and cooling.
2. **Fuel Economy:** By adapting the oil pressure to the engine's needs, two-stage pumps can contribute to improved fuel efficiency. The pump can reduce its workload when maximum oil pressure is not required, saving energy and reducing parasitic losses.
3. **Engine Protection:** Different driving conditions, such as idling, cruising, or aggressive acceleration, demand varying levels of oil pressure. Two-stage pumps can ensure that the engine receives adequate lubrication under all conditions, helping to protect critical engine components from wear and overheating.
4. **Cold Start Performance:** During cold starts, engines require higher oil pressure to ensure quick and effective lubrication before the oil reaches its optimal operating temperature. Two-stage pumps can help achieve the necessary oil pressure during cold starts.
It's important to note that the specific implementation of two-stage oil pumps can vary among different vehicle manufacturers and models. Some vehicles may use electronic control systems to modulate the oil pump operation based on input from sensors that monitor engine speed, temperature, and load. As technology continues to advance, more sophisticated engine oiling systems are being developed to enhance overall engine performance and efficiency.
That's the text book justification. 50% of the major reasons given are about improving fuel efficiency with the other 50% providing lip service to delivering "adequate" lubrication. What we have found is that in the implementation, lubrication is inadequate for optimal performance and engine health when operating at reduced oil pressure.
Looking at WIS and the oil pressure test procedures and acceptable test results. I was not aware that between .9 and 1.1 bar oil pressure is acceptable at 600 rpm. No wonder the Camshaft Adjusters fail, I'm surprised they last very long at all.
Seems I remember someone presenting a document from the VVT maker requiring more pressure to operate properly.
13 to 16 psi at idle, and 25 to 36 psi at 2500 rpm... When 3500 rpm is 50 to 70 psi, so idle should be at least 35 psi and 50psi at 2500 rpm unplugged, if not better. I'm basing this off of other engines I've tested oil pressure on in the past, so your mileage will vary.
My old 1981 HD Shovelhead runs 15 psi at idle, but it's air cooled with roller bearings for the crank, rods, and camshaft.
I'm sorry, but this is a no brainer.
Hot idle oil pressure is the same plugged on unplugged.
Hot idle oil pressure is the same plugged on unplugged.
I recall reading that starting cold engine oil pressure was high/full pressure until it warmed up a bit and then settled to low pressure ... at idle....?
But the flow should be higher since the vanes from the pump are running the longer travel. Remember, the solenoid shifts the housing closer to the center.
That's my technical assumption, I could be wrong.
It's not variable vane. When the solenoid opens it dumps some of the pressure from the pump which should still happen at hot idle. But the effect is probably limited in that condition.
All right, pumping wise it is like the engine can run two different pumps. A small or a large one selected by an electric valve. It does that by physically expending or restricting the volume of the pump chamber.
Solenoid is NOT involved with dumping out or regulating pressure. It shifts the pump inner size.
> Dual-Rate Pump:
At idle RPM the output pressure is equally low regardless of pump being set low/normal.
When the pump default chamber volume is selected by resting solenoid, the pump is able to build up more pressure against the engine load.
When the pump volume is shifted in reduced position by active solenoid, the pump is not able to build enough volume to squirt oil at any piston.
As soon as a squirter ball on spring would open between 21 and 25Psi the available pressure falls below opening threshold. Essentially squirters peg max pressure low in this case.
("dual-stage" hydraulic pumps are used in heavy machinery where high working pressures are required such as excavator rams - Here we have a small single stage variable pump).
> Pressure vs. Location:
Oil viscosity and conduit length affects oil pressure. There's less oil available at the top rear of Bank1 for HPFP than Bank2 VVT solenoids at front.
The engine oil pressure is not homogenous. To have a little at top rear you need a lot at bottom front.
With normal oil pressure HPFP run noticeably quieter after initial 1k.Mi. The difference is proper oil lubrication of lobe, roller and shaft.
> Startup Lube!!
At startup time the ECU automatically refills all empty oil passages with useable pressure free of air bubbles.
-- On low oil pressure engines this is accomplished by deactivating the solenoid until the ECU is satisfied the VVT gears are able to position the camshafts.
-- On normal oil pressure engine the ECU only ramps up RPM around 1k RPM for a 5Secs short time then drops back in couple steps to 750 then 600 idle.
> New Trick: Expedited Cold Start!
ECU is learning our engine to provide self-adaptations without any programming necessary.
Since my last oil change, my cold start RPM now only goes up to 900Rpm then drops to idle in extremely short time, like 10s. total from cold crank to low idle.
I really enjoy how this trick happens only because ECU it sas-sis-fied with its target VVT actuation. At first cold idle was a little lower and a little quicker, now the sequence is extremely fast.
>> This tells me... our ECU requires a good viscosity to positively tune these engines. So my next oil change will be a 10 or 15W-40. ✌️
- Compare this startup with the stock timing needed to build up VVT pressure. That helps understand the role of low pressure in wasting the VVT lock pins!
++++ THE FLIP SIDE...
> Your engine keeping its long high idle is a sign the ECU is not yet satisfied by VVT positioning.
> Who is interested to experiment what it takes to get there: @S-Prihadi , yes??
+++ Variability:
The engine best tricks are not consistently played out by the ECU. There is a moodiness factor involved.
- The "start, no-crank" or "900RPM short cold start" can be inconsistent.
- All the advanced SW tricks are new to me... The overall trend is clearly towards gradual improvements the more things settle.
POWER output is truly amazing! 👏
Last edited by CaliBenzDriver; 02-13-2024 at 04:30 PM.
Post #8 I believe has a couple videos showing warm oil pressure with valve connected and disconnected. It's not an M157 but I'm inclined to believe it has similar operation.
Neither of those videos seems to compare hot idle with the valve functioning and disabled. What I did see was at warm idle (~670 rpm), ECT 58C, oil pressure was about 37 psi with the valve turned off, and then it turned on, dropping oil pressure to about 28.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by kevm14
Neither of those videos seems to compare hot idle with the valve functioning and disabled. What I did see was at warm idle (~670 rpm), ECT 58C, oil pressure was about 37 psi with the valve turned off, and then it turned on, dropping oil pressure to about 28.
That would be consistent with the 2 bar limit by the activated solenoid.
Neither of those videos seems to compare hot idle with the valve functioning and disabled. What I did see was at warm idle (~670 rpm), ECT 58C, oil pressure was about 37 psi with the valve turned off, and then it turned on, dropping oil pressure to about 28.
There are three videos in post #8. The second and third video compare hot idle valve on and valve off. Scroll all the way towards the end of each video where the temp is highest. You will see about 18 psi at idle with the valve activated in the second video and about 14 psi with the valve deactivated in the third video. I believe this slight discrepancy of 4 psi is due to the oil being slightly higher temp in the third video.
There are three videos in post #8. The second and third video compare hot idle valve on and valve off. Scroll all the way towards the end of each video where the temp is highest. You will see about 18 psi at idle with the valve activated in the second video and about 14 psi with the valve deactivated in the third video. I believe this slight discrepancy of 4 psi is due to the oil being slightly higher temp in the third video.
Ok, somehow I didn't realize there was a third video. Is there anything in the same video that switches from activated to deactivated? That's what we really need. Because that 18 activated could become 25 deactivated under the current conditions, and that 14 deactivated could become......10, when activated?? You see what I mean?
Ok, somehow I didn't realize there was a third video. Is there anything in the same video that switches from activated to deactivated? That's what we really need. Because that 18 activated could become 25 deactivated under the current conditions, and that 14 deactivated could become......10, when activated?? You see what I mean?
Maybe I used the wrong wording, the valve is plugged in in the second video and unplugged in the third. In the vide where it is plugged in you can see that the solenoid is not energized because he is measuring the resistance. This shows that the valve being plugged in or not has no effect on the hot oil pressure. Again this is not on m157. It's possible that m157 has tighter clearances and runs higher idle oil pressure but I doubt it's much higher to have the solenoid intervene. I believe Kenneyd hooked up a pressure gauge to his m157 so he can confirm.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by PeterUbers
So instead of "fuel efficiency" is this a case of engineered obsolescence?
Ha! Found this. I don't think the 2-stage oil pump falls into the category since it is used by multiple manufacturers, but it does speak to your comment. “…the rumor is by the 1990s mercedes was making such reliable and well-made cars that their replacement parts business started to lose the money so instead they loosened the quality control a bit…”
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Got my baby back after three eternally long weeks in the shop for a stupid seat repair. Not the dealer's fault, but the extended warranty company that were being real dicks (or maybe fake dicks, a.k.a. ******) about approving repair of my passenger seat. The warranty company even tried to invalidate my contract because I had winter tires on the car. In the end, they paid up. Anyway, here's the dummy solenoid installed.
Jetta... what if the dick or ***** identifies as something it is not? Possibly it was a vagina that looked like a dick or maybe even a ***** but in reality was really nothing more than a ***** who thought he was a vagina... in any situation since I removed my solenoid my brakes are quite hard
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by OldManAndHisCar
Jetta... what if the dick or ***** identifies as something it is not? Possibly it was a vagina that looked like a dick or maybe even a ***** but in reality was really nothing more than a ***** who thought he was a vagina... in any situation since I removed my solenoid my brakes are quite hard
In our woke and ambivalent world, perhaps your brakes are something else identifying as brakes, since they are quite rigid.
(WAIT! Is this a family channel and are there kids in the audience?)
02-12-2024, 12:02 AM
