mdgrwl

I went out for a pretty spirited drive today for a good 4 hours or so on some hill / mountain roads in northern NJ. Oil never reached over 230 degrees.

Mobil 1 0W40 was never meant to be racing spec oil. If your using it at the track, fail on you. Its a balanced oil for DD and some spirited driving in a high performance engine.

If your tracking your car hard, Mobil 1 0W40 is not the right choice. Otherwise its great oil.

chrisridebike8

temperature is a pretty good measure of friction. if there is less friction, the temperature is lower. by your logic, if the oil isn't cooling the motor as much, the water would have to. that isn't the case. my water temp is 5-10 degrees lower as well. and why would these cases start popping up about people trying different oils and having lower temps. I'm still never using Mobil again.

Not trying to bash, but if you only reached 230, especially with MCT, you aren't driving that hard. If I do 2 WOT pulls through maybe 2 gears I can hit 235 with Mobil 1. I used it at the track once (like many people have). I changed it before and after, as well as the brake fluid. And saying that Mobil 1 is fine for an AMG is like telling me to put all season tires on my car. Sorry, but I don't like compromise (for the most part...extremes are bad too).

when it comes to oil, everyone is an expert, and everyone has an opinion. Mobil doesn't work for the way I drive, and I personally will not use it again. I just started this thread to give some useful info to people that were experiencing high oil temps. use the info as you wish

natman316

so from the previous post....can i run a 5w30 on my car? and should it run cooler?

chrisridebike8

I did not say that. The car was designed for 0w40 or 5w40. 5w30 might be too thin to properly lubricate. So will it run cooler? Idk. That's a pretty expensive gamble if you want to find out.

Ingenieur

are you saying the 30 degree drop is due to better lubricity?
if the ambient temp is say 70 and the oil is 230 vs 260 that is a 15% reduction in friction...not likely

friction is a small percentage of the total thermal load of the engine
most of it is heat of combustion
any oil of a similar weight/type/API/etc will lubricate the same
there is no magic elixer

it's not 'my logic' but basic mechanical engineering

there are parts of the engine not cooled by water, such as the crank bearings, piston underside, cams, etc. (Porsches used to be primarily oil/air cooled, no water)

not sure how water temp can be lower since it is regulated by a theremostat?

in absolute terms you are saying your water temp is lower and the oil temp is lower, but the water pump and oil pump move the same mass flow, correct?

this would imply the efficiency of the engine has gone way up since there is much less heat being rejected, ie, more thermal energy being converted to mechanical

your fuel mileage would go way up (less friction and more heat into motion)

if the oil temp goes down (for a given weight/age/type/etc.) at a constant flow less heat is being removed from the engine and the material will be hotter


think of it in these terms:
MB AMG does not hire morons to do this work, they hire PhD's, etc.
their business guys are pretty sharp too

if an oil can give 15% increase in efficiency when under high load why not make it factory fill?

cost? they only pay for the initial fill so any after sales cost would be passed on the the buyer

the cost delta would be almost nothing, even less when factored into the cost of the car
if bought in bulk the difference is zilch

it would improve corporate gas mileage 2-3 mpg, in these times when a tenth is fought for with electric steering, etc., why not change oils to get an order of magnitude more?

there are standard tests available for the mobil and lubro products and the lubricity is the same, with mobil being a bit better in wear tests, but negligible

I test engines for type approval
a simple test can be done with a IR thermometer
run the engines up to a given load and shoot the same points on both engines (each with a different oil)

engine water temp is the same
oil weight/age/type/API/etc. AND one is running 30 F higher oil temp
I can say with a degree of certainty its surface temperature will be lower
definitely if you could measure internals (bearings, pistons, etc.)

it's a closed system in a chemical to mechanical energy conversion if less waste heat is generated the process is more efficient so for a given specific consumption rate more power MUST be produced, or for the same power consumption must go down

you say less heat is generated due to lower friction, I say the same is generated but less is being removed
the 'better' oil has lower thermal conductivity

CoolBDPhenom03

So would lower thermal conductivity be good or bad, then? If less heat is being removed, that sounds bad to me.

Ingenieur

if the oil is removing less heat from the system that in general is bad

if we look only at friction (ignoring heat of combustion and its removal by conduction): assuming for a given system friction is the same and friction generates heat, if the oil lubricating the system is leaving it is cooler, the system MUST be running hotter...the arguement could be made that one oil lowers friction/lubricates better than another, but for our discussion that difference is negligible, ie, oil, any oil, reduces friction enough that the difference is inconsequential when we have oil jets, pressure lubrication, oil impregnated bearings, oil film cushions, etc.

there is very little metal on metal contact in an engine, most contact surfaces are designed to have a consumable side (bearings, rings, etc.)
the rings float and bearings have a clearance and are pressure fed oil
one main metal-metal is the valve train (cam/lifters), others are
wrist pins
cams/journals

the bottom line, imho: any modern synthetic that is specified by the manufacturer is as good as the other, each may have strengths/weaknesses, but in the whole, no difference
-as long as change intervals are the same
-it is allowed to get hot before being loaded up (hot oil works better, hence the low temp warning indicator, plus getting it hot burns off the fuel and water contaminants)
-proper filtration

I drove my car today up mountains/steep grades under very high load, high rpm, for 30 minutes and got no hotter than 230 range (ambient temp was 70F), water was around 210 or so

my car is running dealer installed 5W40 Mobil 1 around 1500 miles old
I do not consider this anything to worry about, it cooled right down to 210 range when I stopped flogging it

bhamg

Ingenieur - All this is great info but something puzzles me. If modern base stocks consist of either normally refined hydrocarbons, cracked hydrocarbons (Gr III), PAO's (Gr IV) or esters (Gr V), are you suggesting that there is that great a variance in the ability to conduct heat for the various base stocks?

Ingenieur

not a great variance, probably moot, that is my point
if oils operate at different temps for a given mass flow rate, they will convey more/less heat....since all oils have ~ the same thermal conductivity, they will operate in approximately the same delta temp
how they react to elevated temps is a different matter

I'm not buying the supposition that under identical operating conditions
mobil 1 260 F
motul 230 F

I believe any oil synthetic/weight/age/API/etc. will operate in the same range since their thermal conductivity is ~ the same
the thermal conductivity of motor oil is ~0.15 to 0.2 (depending on temp, most reach peak at ~85C and stay flat to 125C then drop off again, depending on weight, purity, etc.), and the deviation is small (water is 0.609 W/m K)

the point being, for a given system an oil with a higher thermal conductivity will run hotter because it extracts more from the source, so the source must be cooler, so if an oil is truely running 30 F cooler, it isn't absorbing as much heat, so it must have a lower conductivity?
I don't believe that there is enough variation for this to happen

bhamg

^ Reread what you said, got it, thx.

natman316

i was kinda refering more to the other post that the 5w-30 had better wear protection.

anyways, yeah i wouldnt want to try a different oil than recommended. but i am wondering if there will be a difference on the track if i switched brands of oil. Please do update if you are going to the track.

I have never got temps over 240 on the street and backroad driving, but i am consistently at 250-260 on the track (and sometimes i short shift just because i dont want it to go into limp mode). I noticed that i hit limp mode less also from either the OE tune, secondary cat delete or removing charcoal filters (not sure which, but those were the difference between the two track days I went in my car).

dr_g

I couldn't help not reply to this post after reading so many misconceptions.

You claim to have used two different oils with very similar viscosity but got very different oil temperatures. This simply can't be. Chances are that either the Motul runs a lot thinner than Mobil 1 (and therefore protects a lot less against wear) or your test conditions were simply different for the two oils.

Yes, thinner oils run usually cooler because of more oil flow as well as less internal friction of the oil film (less viscous drag or less hydrodynamic friction inside the oil film). But they also simply protect less against wear. The only way you could judge wear is indirectly through UOAs or directly through engine teardown, not through oil temperature.

Simply ignore the psi rankings in the 540 RAT blog. They don't correspond to what is going on in the engine. The test method employed measures the oil's boundary-lubrication capabilities (antiwear, extreme-pressure, and friction-modifier) additives. It doesn't measure its oil-film strength or hydrodynamic-lubrication capabilities. Moreover, we don't even know if it is being done under controlled conditions and relevant conditions.

You must understand the Stribeck curve to understand lubrication, where all the answers lie:



There are three regions in lubrication, and elastohydrodynamic lubrication (EHL) overlaps with two of them and covers a large portion of the lubrication curve. Therefore, EHL, where PVC (oil-film strength) plays an important role, is important for all engine components, including journal bearings.

The curve basically says that if you can keep the viscosity (n) high, and/or the speed (V) high, and/or the pressure (P) low, you will be in the hydrodynamic lubrication (HL) region, in which there is a thick oil film seperating the moving parts. HL region is the same terrifying phenomenon of hydroplaning of a car, where the car completely loses tire-to-road contact and starts flying on the water, which is caused by driving too fast on water -- hence the usefulness of the Stribeck curve.

So, keep your viscosity (HTHSV) high, load (pressure) low, and RPM high, and you will be fine. However, this is not always practical. For example, there will be cases where you will experience high loads and/or low RPMs, and your bearings will enter the EHL region. Then, PVC (oil-film strength) becomes important.

Also, in the valvetrain and parts of the cylinders and rings, the pressures will always be high because of the inherent geometry, as you don't have the luxury of a large smooth matching surface as in the journal bearings. Therefore, valvetrain and parts of cylinders and rings always run in the boundary lubrication and mixed lubrication regions because the pressures are always high between sliding components due to their smaller surface area.

In summary:

(1) Keep you HTHSV high enough so that you spend as much time in the HL region (rightmost part in the curve) as possible, where there is no metal-to-metal contact at all (like no tire-to-road contact during hydroplaning). The only downside to this is that as you can see in the curve friction increases slowly as you move further right into the curve. This is not due to metal contact but because of the internal friction of the oil. There is no engine wear caused by that by you lose fuel economy if you make HTHSV too large and you are needlessly too far right into the curve.

(2) EHL regime and therefore PVC (oil-film strength) is always crucial in any part of the engine, including journal bearings, while being a lot more crucial in the valvetrain and parts of cylinders and rings, where you are always in the BL and ML regions. (Note that in the BL region, AW/EP/FM additives are crucial.) Therefore, always choose an oil known to exhibit low wear due to its higher-quality base stocks. You don't necessarily need a synthetic oil. Nevertheless, with a synthetic, you have a higher high-temperature (130+ C) PVC (higher oil-film strength, thicker EHL oil film) and are better off in the EHL regime.

For racing and other high-load operations, you want to be as far to the right on the Stribeck curve as possible, therefore, as high viscosity (large ƞ) as possible. If your oil-circuit design can tolerate a high viscosity (sufficient oil flow with thicker oil), use thicker oil so that you don't enter the boundary-lubrication region or leftward portion of mixed lubrication with increasing load (increasing pressure P).

Coming back one more time to the 540 RAT blog, it doesn't take into account where you are on the Stribeck curve but does some testing somewhere in the boundary-lubrication region. However, engines operate at various points on the Stribeck curve in reality. Therefore, 540 RAT blog test psi values are useless.

Jasonoff

Edit: Directed to dr_g

What's your thoughts on the 0-40 Delvac? Formally Esso XD-3 Extra

http://www.mobil.ca/Canada-English-L...-esp-0w40.aspx

looney100

For what?!? Delvac is an oil for large Diesel engines (trucks). Not gasoline passenger cars. It doesn't have the MB approval.

Good oil, wrong application.

Jasonoff

That question was directed toward dl_g.

looney100

What, so no one else is allowed to respond?

This is a simple question with a simple answer - you've asked about using a HDEO in a gasoline application. You might as well ask about using a truck tire for your C63. You might be able to get it to roll, but it is far from your ideal solution.

While viscosity is very important, it's not the only thing. You can't assume that any 0w40 will work.

Jasonoff

Thanks for your input.

dr_g

More detailed answer:

Mobil Delvac 1 ESP 0W-40 is an API CJ-4 HDEO, with extra emphasis toward emission-systems protection (ESP). CJ-4 restricts the ash content to 1.0 % to protect the DPF, which restricts the detergent content and therefore TBN. This particular ESP formula is also weak in ZDDP and it has no moly. NOACK maximum limit for CJ-4 is 13%, whereas MB 229.5 and 229.51 limit is 10%. TBN minimum limit for MB 229.5 is 8.0.

Delvac 1 ESP doesn't meet the MB 229.5 TBN spec. It probably also doesn't meet the NOACK spec. On the other hand, Mobil 1 0W-40 SN with its NOACK around 9% or less and TBN at 11.8 exceeds the MB specs.

HDEOs have soot dispersants that you don't need in gasoline engines. Perhaps Delvac 1 is a little thicker than Mobil 1 0W-40 SN (albeit no HTHSV listed for the former), but this is the only possible advantage. Delvac 1 also simply doesn't meet the MB specs. It doesn't list ACEA A3/B4 under its specs either. Run it at your risk if you want to and avoid extended drains.

If you are looking for thicker oil for racing or severe driving, there is Mobil 1 5W-50 SN. However, only MB 229.1/229.3 is listed for that one and no NOACK is given.

BLKROKT

Interesting. At great risk of starting another oil war... a) Are there any other oils you would suggest for a racing application? And b) what are your thoughts on the M1 0W-40 as an all-around performer? My understanding is that it has about the best additive package and overall properties in a 0W-40 oil. For 229.5/229.51 are there any other oils you might recommend?

dr_g

I don't have a particular racing-oil recommendation, but I would recommend a high-quality synthetic with the thickest viscosity that your oil circuit can produce a sufficient oil flow with. That would give you the thickest oil film with more margin for increased load and the highest oil-film strength when the oil film thins under load. A strong ZDDP (phosphorus) and moly content should also help when and where the oil film breaks down and there is metal-to-metal contact.

As an all-around performer, Mobil 1 0W-40 SN is the best or one of the best. There is also the new Pennzoil Platinum Euro 0W-40 and 5W-40 with PurePlus (GTL base stocks), which are similar in quality to Mobil 1. I personally don't like Castrol.

Mobil 1 is a Group III+/PAO/ester blend of base stocks while Pennzoil with PurePlus seems to be entirely a GTL blend of base stocks. I personally like the additive package of Mobil 1 0W-40 SN and prefer it over Pennzoil with PurePlus. It's also easier and cheaper to get it. You can't go wrong with it and it should outperform most, if not all, oils.

Jasonoff

Thanks for the info dr_g. I tried to source the Pennzoil Platinum Euro 0W-40 here in Canada and I pretty much just got the run around.

Blown4door

i run motul on all my amg cars.

Suvneer

Lubro Moly makes really good oil as well. I used it in my WRX STI and never burnt 1 qrt after a few track days. 1 qty of Molbil 1 disappeared in normal DD.