Generally, I get 19-20 mpg combined driving for the SL and a little better for the C350. On highway driving for at least an hour I'll get around 26 mpg in the SL and 27+ in the C350. The C350 with a 3.5 liter engine appears to be more fuel efficient than the SL with a 3.0 liter engine. But the SL (in its current tune) has about 35% more hp than the C350.

Power is a function of fuel, air, combustion, and timing. So, more hp requires at least more fuel and air.

So, if I see a significant change in those averages, I will know that the 5W-40 is more fuel efficient than 5W-50. I am comfortable that the 40 weight of the oil at operating temperature provides more than sufficient protection. I really don't run my car at redline for any extended period. Even running at 3500 rpm in 7th gear would probably earn me a free trip to the police station.

 

@S-Prihadi

Last year we witnessed Master Surya's excellent data research (right up this thread) showing camshaft positioning messed up by stock setup.

Notice how cam position is supposed to remain staticly unchanged accross Rpm.

Now see what really happens to position...


cam gets bumped out by surges = HOT LEAN LAG


Go ahead and read that post to understand both oil pressure surges are caused by....
- solenoid deactivating
- squirters activating

Now think about ways to prevent that......


Let me ask...
-- Who recalls how the 3000psi HPFP pressure regulation works (prop valve + lobes) ?

-- Who enjoys wild high pressure regulation ??

-- What does poor mixture control do to gas mileage, combustion heat, mapped mixtures, lean lag ???

-- Can the ECU learn stable fuel fixtures when rail pressure is all over ?

Das oil pressure causing "heavy poky chassis" stock experience. Good neutral mixtures are the necessary base of pressure sensitive throttle.


The improved engine response of MOD-1 is from having smooth linear pressure straight up from idle. Only one pressure drop from squirters.

Notice how camshaft position is not supposed to move at all this whole time. The ECU regulates VVT PWM solenoid against varing oil pressure to keep position steady.

At no time oil MOD moves camshaft. It's helping better than stock position. Nothing too crazy.



link to HPFP...

 

wow, a lot of words written this week!

I have noticed shifts getting smoother the more I drive, especially in Sport Mode. I dont think i have been over 4K or close to redline because the car gets up to speed so quickly with the ECU tune and there is so much more power in the higher gears that downshifting is almost unnecessary in most cases. I don't think I will drive enough to between oil changes to take the intermediary steps between 5w-40 and 5w-50, so my thought is just switching to 5w-50 the next oil change and driving relatively 'conservatively' between the next oil change and the one after. Is this a logical plan or am I missing something?

 

Cali suggestion is to not jump straight to 5 50 instead try to boost your burned oil with W booster or high W oil you can find this few pages behind it was discussed how much and when

 

I went from Mobile 1 0W-40 to Pennzoil 5W-40 to Castrol Edge 5W-50 and am now back to Pennzoil Platinum Euro 5W-40, mostly because the 5W-40 is not only API SP rated, but also MB 226.5, 229.3, and 229.5 approved. The car seems no worse and actually smoother. Too soon to tell, but my mileage may also be improving. I'm giving it a week to see if mileage is actually better.

 

We just got done concluding oil MOD is not for everyone, only trust your own understanding:

> MOD-0 stock: sceptics enjoy stock conditions

> MOD-1 5w-40: advanturous folks pull the plug

> MOD-4 5w-50: pioneers deal with known issues

Every personal choice come with a distinct set of good attributes and limitations.

I think you got the message about not challenging engine with high output while the ECU is relearning engine timings.

Exactly as you describe... engine has plenty of torque/power under 4k.R' without redlining 3rd gear.
This is the Rpm range that was unavailable before. WOT max fuel has always been an available option.

5W-50 is an excellent choice.

As Kristiyan reminds us: a practical way to transition from 5w-40 to 5w-50 is too add couple 100mL viscosity booster shots into old engine 1000.Mi before replacing oil at 5k.Mi EOL.

Greater oil viscosity creates more pressure that requires the ECU to relearn its VVT mapped positioning.
Camshafts are positioned via lookup tables that are fairly static. Meaning viscosity updates are not casual changes. ECU reads CPS position.


Now both E/S always stops in D1
My tranny used to stop D2... all by itself. Poor gear selection stops as TCU learn to best match predictable throttle.
Spong Throttle ==> Goofy Tranny

Countless transformations take place, the best of which is throttle response to drive engine - tranny Rpm based on pedal pressure.

I am crossing 4k.Mi on excellent Motul 5w-50 ester.

There are very few good oil options are limited. I really want to test a 10w-50 and not much a 15w-50.
The engine excellent driveability at all speed is based on stability affected by heat removal.

I wish VVT Mgt was smarter to self correct variables (temps, Psi) but it is what it is... I am not gonna just sit there and put up with that Benz. The

GDI timings are easily upset and conversely can easily be easily be setup well. Bosch ECU is very loterant in ways to disfunction gracefully.


+++ VISCOSITY NUMBERS BEWARE +++

We knew a good Mobil1 5w40 viscosity at 2k.Mi age is lower than a good Motul 5w40.

Same thing is true for viscosity of
Motul 5w50 vs. Amsoil 5w50.

Numbers are day and night... it really makes me want test-drive the difference and see how my ECU enjoys Amsoil when hot.
On paper it's a superior PAO oil eith better specs.

Next I will put Amsoil API-SP specs to the test...
every lubricant literature reads like a true champion


Excellent Motul 5w50 Grp-V ester.


Most excellent Amsoil 5w50 Grp-IV PAO.

• Higher flash temp
• higher viscosity
• lower poor point
• free keychain with membership

 

Is it possible to accelerate the adaptation process via Xentry when increasing viscosity? I only put on maybe 3500 miles annually with this car.

 

my question was headed in the same direction; I typically do annual oil changes and drive anywhere from 2500-4500mi a year. So our cases (aside from any xentry process) I guess we would start boosting viscosity 1K miles before change?

 

Yes, excellent solution to reach target quickly!

Using Xentry will be the very best way to expedite relearning timings.

This will get the good without much of goofy timings transition. I endorse that!


-- The first target are the 4x individual PWM maps of VVT Gear positioning.

-- The second target will involve fuel mixture per banks and individual cylinders injection.

You got to know advanced Xentry and specifically what necessary engine learning can be done with it.
meaning tune-up necessary ECU maps to land best matching data with vanilla/stock firmware.


Dig-in and keep it simple.

 

i'm definitely willing to try this on my own however I'll gladly take advice/instruction from someone more Xentry knowledgeable. Since there's no mechanical "breaking in" from switching to a higher viscosity, this seems to be a viable path.

 

Yes, you'll enjoy experimenting that - Viscosity is very touchy... steps of 300ML + 200mL. It improves throttle but confuses tranny until TCU relearns to match ECU: then PERFECT day!

I tested blending multiple 100mL booster shots when thin aged oil was dropping its much needed viscosity near 1500.Mi.
Stock saves gas by quickly derating into W30. Not a problem, we're on different tracks.

I realized that MOTUL 5W40 oil run engine super well at first and then engine lost its improved response... I was not sure why... so I kept testing further.

This is 100% due to viscosity sheared by extreme pistons heat.


This got me really thinking about the whole relationship of...:

• throttle performance
• VVT positioning
• oil viscosity
• heat

By adding shots I was able to impact heat so I kept going.... now I am exploring Amsoil PAO better visvosity.

If I learned something... I realized that as advanced the Bosch ECU are, they still thrive on stability to adapt well.

So I cancelled the voltage-swing game: BINGO more power from reliable GDI ignition timings.

Cancel the unstabilities to be left with a LOT MORE GOODS. Very safe if you don't need to redline.


+++ CANCELLING MISFIRES +++
Misfires can be spark related but once ignition is made reliable then what gives?

I have faced that question for 2 decades!

Combustion misfires are caused by poor timings (ALT-LIN) and lean mixtures (MOD-1) forced by stock ECU feedback.

Lean mixtures yield poor power output.

Neutral mixtures are ready for rich accelerations on stock firmware ready for annual SMOG certification.

SIMPLE TEST: Hold your engine at 1500 or 2000 Rpm.
How does it run...what's happening ?
choppy, smooth or in-between?


Once you resolve engine combustion, tranny shadows it perfectly: all good!

 

Okay...this is NOT normal

 

i've had that happen on my 113K motor with a Mobil 1 filter. I should've known better but the OE was out of stock.

 

Get the equivalent OE supplier one (basically before it was branded with an MB logo) when that happens.

 

correct
This may help:

https://www.mahle-aftermarket.com/me...18_english.pdf

Third possibility is interesting, no?

 

That is a Wix OE filter. Liquid Moly 5 40

 

How many miles? The M276 uses a different OE filter. I've never seen anything like that.

I only use these and for a max of 5000 miles. I have since reduced my change interval to 3000 miles (or slightly less).

 

@JettaRed 6200

 

https://www.mahle-aftermarket.com/me...04_2016_en.pdf

Clearly referring to the relief (mechanical) valve, not the electronic pressure reduction solenoid.

 

This is what the dealership sells for the 157 engine

 

As promised.

Some key sections.

 

Yeah I would pass on the Star parts and just get a Hengst.

 

yep, that's what it is.

 

Star Parts are same as Genuine right?

 

Well it's supplied by Mercedes but is made cheaper than the original OE.