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While I can get very low microns on the HVAC, but the decay before 2 hours is already at 302 microns.
So me will do one more long session ovenight, tonite.
Above reading meaning :
60 microns when the 2nd 3/8 vacuum hose is working along the BigBlue hose,this is not a true honest reading as the vacuum pump power is read thru the 3/8" hose.
96 microns, the 2nd 3/8" vacuum valve is shut, thus this is the true honest end to end reading. Suction at HP port (red), micron gauge at end of the line at LP port (blue).
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This is a new record for me, never I could get as low as 43 microns end to end honest vacuuming. But it took me 2 days or more than 24 hours overall .
New dessicant really matters.
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.................................................. .................................................. ............................................Correction : 15 grams extra for other TEST next week.
Good video if anyone wants to understand vacuum decay test and why I fight hard for under 100 microns vacuuming.
Radiator and aftercooler so far no leak. Thus this means my radiator test kit is not good for 4+ hours test. Well cheapo China made stuff, decent but not great.
The aftercooler air breathing section, for LEFT side , I hate it the most. There is no space to spin torx bolt for the pipe locker blade, even after removal of the turbo bypass valve.
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Turbo bypass valve ( black ) removed. Make room for my hand.
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Needed my 2 hand, both index fingers (2) to spin slowly the torx bolt. Tightening with tool is easy.
Single hand using index and thumb, no space.
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Install exhaust system. Got my driver to help me push in the exhaust system so that I can tighten the 2 clamps.
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If engine and tranny mount sinking ( old ) and 4 rubber exhaust hangers streched, these two pipes can kiss the stiffener bar..
It is only 1 finger space/gap, for healthy engine + tranny mounts of mine and all 4 new (in 2020 ) exhaust rubber hangers.
Imagine a tired engine mount and exhaust hangers.
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Secure properly all extra sensors wires..........
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Arrows is my engine oil pump solenoid dummy load (bulbs) and bypass switch.
Prepare to install radiator fan.....
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Make anti-chaffing protection for HVAC hose of compressor to condenser ( liquid line ), to not rub the extra ground wire which has new routing.
Them two do not kiss, but if engine run hard and bad roads, it may kiss. So better be prepared.
HVAC hose get priority, for protection. 1mm PU sheet.
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As usual, fuel pressure test before starting the engine.
I don't understand how I missed this 1 union nut.
I probably did the 15NM, but surely not yet the 90 degrees !!!! Dugghg....it leaked.
The middle finger is FOR ME , after I am done tightening it.
Purging air from LP fuel lines...... I hate crippled engine start.
Fuel spray splash guard ( the white plastic board), because F32 prefuse is close by.... and I have a battery maintainer powering the car.
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Satisfied no leak at 5BAR, time to start the engine.............
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Yes, I flip the airbox.
I need to see fuel pipes and all the union nuts seal integrity when engine running.
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About 60 days engine been out of action, first start today.
FIlled up tranny oil to maximum.
I can't get my tranny to be at 80C plus. I wanted to, because I have emptied the oil cooler and oil cooler lines.
Hottest I could get was 63C.
I got my lower shoulder* ( *where Popeye has his tatoo ) burnt, trying to remove the tranny oil fill pipe.
I was using 2 hands you see, so me got to turn my body to the right and it touched the hot exhaust.....
Will continue...........
Last edited by S-Prihadi; Sep 2, 2025 at 12:16 PM.
You got a new exhaust tattoo!
A true artist will suffer for their art.
Are you adjusting the filtering for the vacuum to be different from factory settings?
You got a new exhaust tattoo!
A true artist will suffer for their art. Are you adjusting the filtering for the vacuum to be different from factory settings?
I don't understand your question.
But if you meant the level of vacuuming I done , is that factory spec ?
No, it is well beyond and above any car factory spec....which are so lame, because MB ( or any car brands ) does not specify good microns value like commercial HVAC products, example Daikin.
I want my system to be super dry, thus it will last longer.
I ran the engine total 30+ minutes, still I can't get tranny to be 80C, hoping that the tranny oil cooler built-in thermostat will open.
If no load, hard to get tranny oil to be at 80C.
I swap use between Xentry and Banks Gauge.
The oil pressure test port rubber gasket which I made bigger its sensing hole for oil pressure sensor, gave good result. Now I can see 4 BAR or 60 PSI , instead of 58 psi or 55 PSI when engine oil already hot.
The oil test port in discussion
Original
I made bigger hole
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BELOW : Same as above, but with RPM data removed.
Here we can see clearly the pressure control valve doing its thing to lock at 60PSI as maximum. 3 PSI or 6% hysteresis is decent, thus 63 PSI ish average peak.
I also am trying a new oil. Which supposedly has superior stable viscosity long term.
Ravenol PAO video presentation deals with the viscosity loss of polymer VI modifiers.
Video shows two dudes talking shop.... Ravenoil is blended by a giant German oil Co from the Baltic sea.
Multigrade synthetic oils suffer from variable viscosity where PAO remain mostly stable. PAO are a much better match for our VVT positioning not compensated in temps.
I'm sure you will notice & enjoy greater performance stability not derating with high heat.
> SN/SP FORMULATIONS:
The friction modifiers ester chemistry are an essential component of PAO lubricants.
Is the Ravenol VST* 5W-40 PAO available in API-SP made specifically for GDI engines?
It looks like it is ZDDP based API-SN. It's great for hot racing dry lube applications, right?
As far as I can tell the Ravenol RST 5W-50 is also an API-SN formula.
* : VST is the abbreviation of "VollSynth Turbo"
Last edited by CaliBenzDriver; Sep 2, 2025 at 04:52 PM.
Yes, that was what I was asking. From what I gather, you are recommending a 100 micron filter over the filter the factory installed, to extend the lifetime of the vacuum system.
Yes, that was what I was asking. From what I gather, you are recommending a 100 micron filter over the filter the factory installed, to extend the lifetime of the vacuum system.
Ahhh, I see. The unit of microns I speak of is microns of vacuum. Its the proper unit when dealing with vacuuming/evacuation.
Here is some reading....
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This is what HVAC typical manufacturer wants in terms of vacuum microns ( dryness ) and vacuum decay for their HVAC system.
This is new and dry system and lots of copper pipe, not rubber hose, 500 microns is super easy. Decay in 1 hour max 500 microns is easy too.
I attached the PDF for your reading.
HVAC dudes for cars, 99% of them do not go to proper HVAC school and be certified.
Thus the workmanship quality and the level of know how is very low.
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Last edited by S-Prihadi; Sep 3, 2025 at 12:30 AM.
Reason: typo
Okay. I learned something new. I was totally ignorant of microns being a measure of vacuum, or pressure, like inches of mercury, or hecto paschals.
I definitely try to learn something new every day, and thanks to SPrihadi, today I did!
Since my radiator is a virgin, I best test its heat removal capability.
Today I did not log the radiator fan RPM/Duty Cycle yet, maybe tomorrow. Radiator fan is the most important heat removal device when car is stationary like my test today.
The themocouple emergency rigging............
At radiator OUTPUT
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The radiator hose has steel lip/end, so we can read indirectly the coolant temp with decent accuracy if only to compare INPUT to OUTPUT.
Celcius wise heat intensity, this reading spot is not the best....but for this test, it is good enough.
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At radiator INPUT
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Underhood temp is measuring the hot air blast when and if radiator fan is running ( car staitonary) or when car is moving and natural wind force applied to the radiator core.
This is reading both radiator for engine and condenser + aftercooler + tranny oil cooler exhausted hot air.
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I shall explain how to read the graph above.
Radiator OUTPUT gets hotter first, compared to Radiator INPUT... here is why :
- Before thermostat open up, the radiator OUTPUT is part of the closed/limited circulation to heat up the engine faster. So it is exposed to engine coolant heat first/ahead, than the INPUT.
- Thermostat blocks the hot coolant from reaching radiator INPUT, thus you see at the beginning, the INPUT is cooler than output.
- When thermostat opens up, you wil see at data point 2,776 to 3,900ish ( at 5hz data point ) radiator INPUt from 33C rise up to 86C ish.
To see where the radiator fan speeds up, is by seeing temperature rise of the Underhood Temp Sensor.
When Underhood temp sensor goes hotter, the radiator INPUT gets cooler a bit, from the heat released by radiator supported by the fan.
This is what I meant : In green circle
When the fan or car velocity is fast, the radiator INPUT vs OUTPUT can be cooled down by 30 Celsius.
ADD, the simplified log attached
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Last edited by S-Prihadi; Sep 3, 2025 at 01:33 AM.
Reason: ADD INFO
I find the variation of oil temps interesting because it's an essential engine research.
I'm glad your Revenol PAO is now available in API-SP formula.
You're going to be amazed with the solid performance of this oil, in particular improvements during the first 1,000.Mi. until it starts shading viscosity.
At 2,000.Mi you'll realize the edge has gone missing: VI. MB-Approval Revenol
I thought QR Code would be the specs... nope, it's the official MB certification, nicely included.
Last edited by CaliBenzDriver; Sep 3, 2025 at 06:00 AM.
Today I installed a pair of repaired Bilstein B4 dampers.
I said repaired is because the piston shaft got damaged by DumbAzz Lemforder top mount, as told here : https://mbworld.org/forums/e-class-w...bage-fake.html
I am back to Bilstein B4 from B6, because I want the extra comfort.
Was
Repaired
The black ring will be replacing the duty of the C-clip which Bilstein uses .
Since I can't find properly made top mount from MB, unless I buy the damper set, I will try again the DumbAzz Lemforder, now that my black ring is full ring and not C-clip like Bilstein's.
I am hoping the black ring can handle whatever poor dimension the Lemforder C-clip cavity has to offer.
This is for RIGHT rear damper only.
The LEFT rear damper will use my original to the car aka 2014 damper's top mount from MB, as comparison.
The black ring will be used too. Both my B4 piston shaft got damaged by the DumbAzz Lemforde, thus both needed the repair and the black ring.
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For some reason unknown, maybe sloppy job on my part for not pushing hard into the cavity the allan tool.... when doing a mere 28Nm torque.
The 5mm allan (female) of the damper piston, one of them got damaged.
I still can tighten but only 20Nm at best.
I done this 28Nm many many times, and never I slipped and wear out the 5mm allan cavity.
Anyway, I will buy new Bilstein B4 when they are back in stock.
Still the problem would be, what good rear damper top mount can I buy, which is equal to the MB one????
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The car engine and front exhaust/CAT still has those new car when hot "smell".
The turbo exterior smoked a bit, from whatever lubricant spray I been using on it when cleaning and probably the new unique gasket is settling its shape.
Since it is covered by the heat shield, I do not know where the smoke origin is from exactly.
I done today 25 and 20 minutes heating up the engine and also leak checking.
So far so good.
Last edited by S-Prihadi; Sep 3, 2025 at 10:14 AM.
Here for you Cali.
This is today and the cooling system already burped out of air bubbles 99% .
So the engine coolant reading is more accurate.
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====================
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Here we get to see what RPM, oil pressure and viscosity differences are induced by HEAT to a top PAO oil.
This is significant because our basic VVT positioning does not account for these vatiables.
A Vs. B A Vs. B
COOL 66°C oil pressure Maxes out 58Psi at 1800.Rpm
95°C oil Maxes out 56Psi at 2200.Rpm
-- Hot 95°C oil pressure Maxes out 56Psi at 2200.Rpm
-- Cool 66°C oil Maxes out 58Psi at 1800.Rpm
Meaning the oil max pressure regulated by the pump relief stays about the same but the Rpm does not.
Max pressure Rpm varies by 400Rpm!!
This is a very significant change in hydraulic pressure that corrupts the VVT position.
The VVT look up maps ignore...
oil pressure
oil temperature
They match Rpm to duty cycle to set position.
VVT Maps are used to compute each phaser solenoid duty cycle to dial VVT angle. When oil pressure varies, it alters the cam timings.
These data examplify how oil temperature detune VVT position.
Above the Rpm of pressure cap: no change. MOD-n helps VVT become reliable.
This test was conducted with new PAO 5W-40 oil with "stable" viscosity.
Last edited by CaliBenzDriver; Sep 3, 2025 at 10:40 PM.
That is what we call oil viscosity vs temperature. So no suprise on oil pressure values changing with temperature when RPM is say 1,800 RPM.
Wait till you see indling in gear brake hold 550RPM between 100C engine oil vs 30C engine oil
It is the chemistry of all engine oil, even single grade ones.
Typical 5W40 - Liquid Moly HT is the test oil
The ECM & VVT can handle the oil viscosity swing, no worry.
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What I seen is that the oil pressure regulator, the one controlling max 60 PSI is doing a better job when engine oil is hotter, say 60C and more.
I think this is quite normal.
Best to make engine oil warm enough before stressing the engine. More so when one is using 5W50
If oil is warm enough, coolant would be long time proper hot already, which is good.
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Cold start, but oil is still 40C and not 30C.
See 60 PSI is easy to get even at 1,200RPM, because of the viscosity at 40C is still VERY high.
220/5 = 44 seconds of duration for above log
> I agree about oil viscosity changing with heat. This has been known for over 100 years.
In fact this is one of the reason I want to keep heat under control.
> I partially disagree when you say: "The ECM & VVT can handle the oil viscosityswing, no worry"
-- The engine lubrication accomodates well viscosity changes but NOT the hydraulic VVT phasers.
-- VVT control is blind to viscosity changes. That is a big deal because it causes LAGGY THROTTLE.
It hardly handles viscosity changes that corrupt intake camshaft position.
> TURBO vs. ASPIRATED...
I know the whole TT experience is not about driveability... it's about pumping boost pressure.
The expectations at rpm below boost are minimal to the point throttle lag is expected as normal.
I am here to share that boosting a neutral fuel map is faster than boosting a lean-laggy fuel map.
> MOD-0 Vs. MOD-1...
Reduced pressure offers the full stock experience.
Normal pressure lowers RPM of lean lag misfires
Better pressure enables pressure sensitive GDI throttle.
The timings performance is all about stable oil matters as stated above.
Stock lubrication is not bad.
Last edited by CaliBenzDriver; Sep 4, 2025 at 01:31 AM.
The timing advance of retard of VVT is monitored and adjusted more than 10 times a second by the ECM.
So oil pressure swing in itself already exist while RPM changes, not only by oil temperature changes.
If the VVT can be within acceptable deviation ( degress ) when and if during RPM rise, that is acceptable.
No VVT system can be as accurate to 0.5 degrees while rate of rpm rise is high.
You must see the Xentry VVT log often and you will get the idea.
This is RPM rise in 1 second, when I do RPM swing to warm up the engine.
When we do 0-60mph WOT, it will also be this fast. Almost 3 gear change under 6.5 seconds.
Tranny in PARK.
See how fast the RPM rate of rise ( or down ) in seconds.
So, when we worry about VVT capability to adapt to changing oil pressure, do not think of the X Y Z oil brand which probably is only 5 PSI worth of difference.
Think of how dynamic the engine RPM rate of rise is during acceleration, which can be up to 30 PSI oil pressure difference in less than 1 second, depending on at what
RPM the engine was before we floor the accelerator pedal.
As I said : "The ECM & VVT can handle the oil viscosity swing, no worry"
Our duty is to make sure we use good oil, don't use oil too long/far and change oil in less than 1 year.
If we can make VVT vane oil leak rate low and all signals to and from ECM - VVT clean and solid, tensioner and chain all good......
there is no reason to worry of the pressure swing.
The timing advance of retard of VVT is monitored and adjusted more than 10 times a second by the ECM.
So oil pressure swing in itself already exist while RPM changes, not only by oil temperature changes.
If the VVT can be within acceptable deviation ( degress ) when and if during RPM rise, that is acceptable.
No VVT system can be as accurate to 0.5 degrees while rate of rpm rise is high.
You must see the Xentry VVT log often and you will get the idea.
This is RPM rise in 1 second, when I do RPM swing to warm up the engine.
When we do 0-60mph WOT, it will also be this fast. Almost 3 gear change under 6.5 seconds.
Tranny in PARK.
See how fast the RPM rate of rise ( or down ) in seconds.
So, when we worry about VVT capability to adapt to changing oil pressure, do not think of the X Y Z oil brand which probably is only 5 PSI worth of difference.
Think of how dynamic the engine RPM rate of rise is during acceleration, which can be up to 30 PSI oil pressure difference in less than 1 second, depending on at what
RPM the engine was before we floor the accelerator pedal.
As I said : "The ECM & VVT can handle the oil viscosity swing, no worry"
Our duty is to make sure we use good oil, don't use oil too long/far and change oil in less than 1 year.
If we can make VVT vane oil leak rate low and all signals to and from ECM - VVT clean and solid, tensioner and chain all good......
there is no reason to worry of the pressure swing.
Master Surya, what you're saying makes a lot of sense but our cam positioning does not exactly work the way you have it figured...
I thank you for your mind share on this:
"The timing advance of retard of VVT is monitored and adjusted more than 10 times a second by the ECM"
You're saying the ECU is correcting the VVT position ten times every second.
That sounds right but only to a limited extent.... I used to also asume exactly the same thing.
That was a false assumption because I found the reality is different.
You already know this... besides you have not yet connected the necessary dots.
-- Yes the hardware setup has the ability to control positioning with VVT solenoid + CPS.
-- No the software does not run a tight control loop to accurately correct current position.
WIS does not detail this kludge else we would know better. I am not going to reason how this system is simply based on Rpm.
Instead I am going to give you practical cases to prove this system does not compute real-time control the way you are saying.
-1- The wild VVT jerking when squirters begin to open settle this system has no real-time control.
-2- The VVT corruption when oil viscosity is upgraded indicate this is map based ie. not real-time control.
-3- The poor positioning below 2kRpm in stock witness the inability to position intake VVT.
-4- The difference in viscosity between cold vs. hot oil indeed does make an appreciable difference in VVT response when viscosity is borderline. Hence use of 5W-50 and heat control.
This poor camshaft control is 100% the cause of throttle lag below 2000R. and the multiple ways tranny reacts in response.
> LOW ACCURACY....
The stock camshaft position is clearly not acurate for driveability.
VVT Solenoid duty-cycle may be computed 10 times per second to match Rpm accelerations.
The target position is computed based on historical RPM data regardless of any live correction, oil viscosity and engine temperature.
> NEARLY BLIND CPS...
How accurate do you think the reluctors wheels are ??
Look at their low resolution profile... this is what CPS are sensing.
VVT live position is computed regardless of CPS feedback.
> FLIP SIDE...
If stock VVT positioning was smart enough,
oil pressure + viscosity changes would be seemless
throttle would be nimble
tranny would work great
Last edited by CaliBenzDriver; Sep 4, 2025 at 05:26 PM.
On your graph of engine coolant temperature vs oil temperature, it appears to me the graph lines eventually merge so that they are equal and stay equal at some point.
Is it the case that this is optimal, and engineered to behave as such by design and manufacture?
Cali,
Let's not waste our time discussing your VVT "expertise" and complicated oil-cocktail.
Its old news.
You can preach your VVT ,Tranny and whatever other theory at the oil solenoid thread, more suitable newbie viewers over there.
I know my engine and its supporting system better than you.
On your graph of engine coolant temperature vs oil temperature, it appears to me the graph lines eventually merge so that they are equal and stay equal at some point.
Is it the case that this is optimal, and engineered to behave as such by design and manufacture?
It depends on engine load and engine RPM or oil spray pressure to the piston underside, to see coolant temp and oil temp almost similar.
In theory we want the engine oil to reach a temperature it can boils off water vapor and whatever contamination it held in suspension, including fuel dilution if any.
But per 10C of heat rise to engine oil pass its optimum design temperature, its life will be cut by half.
In operation the oil cooler gets coolest fresh coolant, from radiator output.
By position and purpose, coolant temp sensor is located at the "spent" region of the engine, top most and rear most of cylinder head, so that ECM can read maximum temperature the coolant is experiencing.
But engine coolant cooled oil cooler is double duty, it is an oil warmer and oil cooler too, but when oil cooler temp hot enough, oil cooler is oil cooler.
Air cooled oil cooler, is single duty, it cools the oil. A good example is my tranny oil cooler which is a stand-alone air cooled cooler, it has a thermostat which opens at 80C , if I am correct.
Image below represent a decent showing of which part of engine gets hotter as per coolant flow input to output.
B is the location of the coolant temp sensor.
The thermostat and radiator fan itself can only manipulate-regulate coolant temperature, it can not regulate engine oil temperature.
Also bear in mind my so called engine oil temperature sensor is reading metal skin temperature of my oil pressure sensor port adapter* ( *metric to imperial ), it is not a true
oil submerged thermal sensor like found in M157.
M157 has oil level + oil quality sensor which has an oil temp sensor too and is located in oil pan wet and wild, thus it reads "spent" oil temperature... this would be a good sensor to have.
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The data below comes from a set of logs , where I drove long distance.
The log below is an engine already running for more than 2 hours and was refueling at a fuel stop.
Here is a set of oil and coolant temperature samples , at different sensing location, but only the MB original coolant sensor is immersed in liquid sensor,
the rest of the 3 , my DIY sensors...... are all metal skin sensors. Engine oil pan metal skin, engine oil temperature at oil press sensor adapter skin and Bank 1 return turbo's coolant pipe skin.
Above, speed and RPM as baseline, to see the engine load and wind velocity as cooling power.
Below : At 16,000 ish data points, see how hot the engine oil pan skin temperature is compared to the oil temp sensor adapter.
Oil pan is "spent" oil location in terms of cooling. Engine oil pressure sensor adapter is engine oil cooled by oil cooler.
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WHERE SENSOR IS LOCATED MATTERS
Closer look. Engine stop to refuel car. Probably 3 minutes. See how a turbo's coolant pipe is hotter than engine block when coolant flow stop and is cooler than MB engine coolant sensor
value, when engine already started and coolant is circulating.
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Do bear in mind about this log above, this is before I knew that my engine oil cooler and radiator has partial clogging .
We shall see how much better temperature control in the next few months, now that my engine oil cooler and radiator are virgin new.
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Let see the engine oil pan skin temperature vs others
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The best cooling my car can get while being "slow" ......via wind veolcity is : 120KM/H or 74 MPH.
This speed is the most relaxed cool operation the engine can get.
At this speed the aftercooler heat exchanger also works very well.
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Air cooled oil cooler of tranny. The sensor is also a skin temp of tranny oil pan.
Cali,
Let's not waste our time discussing your VVT "expertise" and complicated oil-cocktail.
Its old news.
You can preach your VVT ,Tranny and whatever other theory at the oil solenoid thread, more suitable newbie viewers over there.
I know my engine and its supporting system better than you.
Surya: you know I am not here to prove you wrong. I'm only here to help volunteer advanced solutions to problems I am testing.
A lot of your preferences, I can respect. I have learned a lot WIS specifics based on your personal interest.
I can say thank you Master Surya! What you're missing is not a problem yet.
The M276 VVT amazin' design is augmented by the oil pressure surges. I'm pointing to rattling and limited NA driveability.
Honestly tell me ppl who design hydraulics don't care about operating pressure... I know we have members who understand oil hydraulic systems here. I used to work at a SKF ball-bearings factory maintaining hydraulic actuators. Oil was well controlled.
The infamous start-up rattling is an undeniable proofthat VVTpositioning is impacted by oil pressure.
You understand that, right?
WIS reads smart but at one point one has to wake up to reality.
This is your thread about All new cooling A to Z: "heat is all right" - Are you serious?
I do not understand what benefit you measured by disconnecting your pump solenoid MOD-1 ?
5W-40 lube's normal
VVT's runs no fault
Heat looks all right
Redline hauls okay
Last edited by CaliBenzDriver; Sep 5, 2025 at 02:36 AM.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
, after I am done tightening it.
