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The focus of the paper is entirely on improving pump efficiency to save fuel. It does not speak to improving engine longevity or performance.
I know this mileage thing is always in the forefront of these discussions and seems to carry a stigma here.
Honestly, most of the articles touting mileage efficiency are marketing material….
It’s possible you may be interpreting efficiency as emissions, This paper is focused on efficiency as stated in the summary/conclusion below.
Though related, technically It’s not the same: you can see mileage is not the focus of that study but rather efficiency, mileage happens to be a byproduct.
Not a lot of fuel savings in their findings right? But rather power savings is the focus of this research second pic. 40-60% gains depending on pump configurations. Wow!
It’s important to keep in mind these are research papers that won’t always transfer to real world conditions.
These should be considered a guide NOT religion.
Last edited by crconsulting; Mar 25, 2025 at 09:50 PM.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
XENTRY Simulation does not show error P06DA00 in the list of faults for the M157 engine. So, I ran my VIN through. XENTRY on shows how to test for the fault -- nothing about repairing or ignoring the Y130 (solenoid).
Welp , this place is degrading rapidly 😕
Over and out folks….
Good Luck!
@CaliBenzDriver I’ll post some replies to your questions, I’m not ignoring you, just have a lot of stuff going. I want to answer some of your questions with concise and detailed replies. keep an eye on your PM’s. It will be more productive at this point.
This place has a lot of different posters trying to pull discussions in different directions.
I feel you always put out informational and well thought out posts. And that’s appreciated by all.
kudos…
Last edited by crconsulting; Mar 25, 2025 at 08:56 PM.
As far as I can tell, another function of the multi stage oil pump is to actually increase cylinder temperatures
yes, that target is achieved above and beyond.
The valve stems love vaporized oil carbon deposits... helps 'em warm up faster.
Joke aside it help evaporate crankcase oil contaminants from combustion: gasoline + water.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by crconsulting
I know this mileage thing is always in the forefront of these discussions and seems to carry a stigma here.
Honestly, most of the articles touting mileage efficiency are marketing material….
It’s possible you may be interpreting efficiency as emissions, This paper is focused on efficiency as stated in the summary/conclusion below.
Though related, technically It’s not the same: you can see mileage is not the focus of that study but rather efficiency, mileage happens to be a byproduct.
Not a lot of fuel savings in their findings right? But rather power savings is the focus of this research second pic. 40-60% gains depending on pump configurations. Wow!
It’s important to keep in mind these are research papers that won’t always transfer to real world conditions.
These should be considered a guide NOT religion.
If you are referring to this table, it is comparing efficiencies between fixed and variable displacement, not flow. Or, are you correlating displacement to flow? And the comparison is between the Gerotor-type pump and the other types of pumps. I'm not sure we can conclude any savings like that because we are remaining constant in the type of oil pump we are using and just changing to amount of oil it's allow to pump. I certanly did not experience 40%-60% gain (or loss) in performance or fuel usage when I disconnected. The paper is an interesting read, but I don't think it applies to what we are doing.
it’s not load operation, but constant operation at a higher load. Does that make sense? Oil pump will probably be fine what you have to look for is what drives the pump.
How would we know? If the engine is designed for low pressure operation for 40ft lbs of torque 60 percent of the time, if we increase that load to 80ft lbs aren’t we the ones redesigning how this system is designed to operate. Aren’t we the ones ARTIFICIALLY increasing pressure? There are hundreds of post with people well in the 200k mark and no mods right?
How do we know with all the conjecture and no solid measurements.
Sorry maybe you can clarify this, not sure what you mean?
Mercedes cannot control how you drive your car. Therefore, you cannot say whether driving your car harder, or more gentle, or unplugging the solenoid, is driving any component harder, or more gentle, than any of their design assumptions. This is what I was getting at with factor of safety. The oil pump is considered a life of engine component. This does not mean there are never any oil pump failures on this or another engine, of course. But people have been putting thicker oil than designed for, well, probably 100+ years, and that naturally increases torque on the oil pump. I never, ever, heard anyone attempt to even make an argument (let alone present actual evidence) that the oil pump could be damaged by running thicker oil. You CAN damage bearings with too much oil pressure but we are dealing with a stock oil pump with stock relief pressure. And as I keep saying, that part is a wash anyway because the peak loads and pressures are reached on a bone stock configuration.
These engines do have some known weak spots but generally the lubricating subsystem (aside from the solenoid craziness) is not one of them. The oil pump and bottom end are probably capable of an easy 200k of driving time if not quite a bit more (again, if cylinders didn't score, or if rods didn't bend, the latter of which particularly has nothing to do with oil pressure). Over the span of 200,000 miles, the engine (and thus the oil pump) rotate somewhere between 300 million and 1 billion times, different on every car, and different load for every rotation for every car. Mercedes and every other automaker designs components for this and that's what I mean by factor of safety. I mean, using your rear defroster more frequently probably wears down your alternator brushes a little faster than the next guy: who, except an internet troll, would make a big fuss over this?? It doesn't matter, no one cares, it rounds to zero.
Originally Posted by crconsulting
Well lets see, everyone in this thread raves about low end pickup and improvement in bottom end drivability.
What would you think this is causing this Kev?
This is an old road racer trick to advance cam timing a few degrees. Nothing new here. Except we’re achieving this through oil pressure timing.
Normally downside of this is the loss of top end power. (Not a concern with the VVT here) and the propensity for detonation/pre-ignition…
As I said, I’m not here to convince anyone to do anything, just trying to present some solid engineering here.
You can easily google “advancing cam timing degrees detonation pre-ignition”
Theres a LOT of variables here and is this happening currently and detrimental to these motors?
F—— if I know, as I don’t have an engine Dyno and neither does anybody else here.
But the engineering says when you advance cam timing, the results are an improvement in bottom end performance but a higher probability of detonation/pre ignition….
Ha, I knew it. Buddy, no one's cam is being over advanced!! The cam adjusters are simply being delivered enough oil pressure to fully function in the unlocked state and have full, positive, closed loop control over cam timing. It is not an open loop where more oil pressure = more cam advance. Do you know what closed loop is? The ECU is constantly monitoring each cam timing and targeting a specific cam timing and when there is more oil pressure at the adjuster, it is able to more responsively achieve this target. That's how it works. What you suggest is ludicrous and seems designed to incite rather than debate.
When there is insufficient oil pressure at the cam adjuster, it is designed for the locking pin to insert (like for engine startup). If oil pressure falls below a threshold, the adjuster may sort of try to partially lock, or actually lock and then unlock, and this may be another explanation of why some adjusters experience high wear in this region. If so, unplugging the solenoid is beneficial to their longevity. I already established it is beneficial to their performance.
The data I think we have:
- WIS explanation for what the oil pressure control solenoid does and why it exists (fuel economy). Posted above somewhere.
- Logging of oil pressure before and after unplugging by a few members, with posted data, showing how much it decreases, under what conditions, and what the performance curve of the oil pump actually is when operating as a normal, single stage oil pump. Oil pressure generally tracks RPM, as it does with virtually every other internal combustion engine. Posted above or in Surya's thread(s).
- Significant anecdotal data that engines run smoother and are more responsive post unplugging. I will note some have said that didn't notice anything. But it is probably the vast majority. I don't think it's a placebo. I think some engines are just in a state of tune where decreasing oil pressure (when the solenoid is activated) doesn't impact anything and this is probably what Mercedes originally intended. But as the years and miles rack up, more and more of our engines deviate from this ideal mechanical state and probably really need oil pressure to work normally, not reduced sometimes. I don't know if anyone has logged VVT operation and proven that cam timing is more precise post unplugging. It is possible that someone has and I forgot. It's been a journey. It could be that there are other factors and Cali has spent a lot of time on those other possible factors. Posted above.
- We are extrapolating from the M270/274 that the solenoid (which has the exact same stated function) is not actually critical to safe engine operation. Rather, it is critical to emissions/fuel economy compliance and this is why it throws a CEL on some cars, and why Mercedes may have an updated engine software to trigger the CEL for other cars.
- Am I missing anything?
There is also no evidence, anywhere, that dual stage oil pumps were introduced across the markets for anything other than fuel economy/emissions purposes. Please present the evidence that these systems are designed to increase engine or component life. I'll wait.
I have been SOOOOOO busy....in recent days it feels as if my trans has been slow, I mean super slow to engage. About four weeks ago the car asked for oil (added 1.25 5-40 Liquid Molly). I could 'hear' I need an oil change (I know that makes sense).
Checked out the dash yesterday - the car is "due" in 2500mi (to me, that means I am over 6000 on the oil that is in the car - shame on me).
Ten quarts of Molygen will be here Friday via FCP....see what that changes. To this day, engine oil altering the trans is still an odd one.....
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