Higher speeds, heavier oils?

[JHZR2]

Originally Posted By: OVERKILL
Originally Posted By: 440Magnum

The autobahn may not have a speed limit, but in practice you can't sustain speed anywhere near as long there as you can on US interstates.


This is true, but there are spots where you can do well over 150mph (I've seen videos of E39 M5's ranging between 150-190mph for extended jaunts) which drives up oil temperature both dramatically and quickly

In the east you can do >100 MPH for sustained periods. I did about 2000km in a 530D wagon filled with five people. About 500km of that was over 160kM/h. The rest was either stopped in cities or 130-140km/h, so all decently quick.

Still got >26 MPG on the whole trip.

In the west, I had a trip in a 911 which sustained over 160km/h, which peaked routinely >260km/h.

 

[supton]

Originally Posted By: CATERHAM
But remember a heavier oil will increase oil temp's which could trigger the safety systems that roll back engine power sooner than they would otherwise on the spec' oil.


Overtemp, as triggered by coolant sensor? I wasn't aware of ECU's having monitoring of oil pressure and temperature, at least on non-performance vehicles. Or are you talking about yet other systems?

 

[Jetronic]

VVT systems sometimes have oil temp sensors, but other than that they're not used much.

Even coolant temps off the scale don't always result in a significant loss of power or rev range, until the engine seizes.

For diesel engines there's usually a fuel temp limit though... but it's so high it's useless really.

 

[A_Harman]

Originally Posted By: 440Magnum
Originally Posted By: David_Corbett
I am informed that one of the reasons that we tend to user lighter oils in North America than Europe is because our highway speeds are markedly lower.


I gotta laugh every time I see this and then drive past the hundreds of miles of "Speed limit 80" signs on I-10.

The autobahn may not have a speed limit, but in practice you can't sustain speed anywhere near as long there as you can on US interstates. Its possible to run 10-12 hours with nothing but fuel and bladder breaks at 80-85 MPH, just in Texas alone. In triple-digit ambient temps over much of that in summer. And people are out there doing it all day.


Now that sounds like a little piece of heaven for enthusiast drivers!

 

[aquariuscsm]

Originally Posted By: 440Magnum
Originally Posted By: David_Corbett
I am informed that one of the reasons that we tend to user lighter oils in North America than Europe is because our highway speeds are markedly lower.


I gotta laugh every time I see this and then drive past the hundreds of miles of "Speed limit 80" signs on I-10.

The autobahn may not have a speed limit, but in practice you can't sustain speed anywhere near as long there as you can on US interstates. Its possible to run 10-12 hours with nothing but fuel and bladder breaks at 80-85 MPH, just in Texas alone. In triple-digit ambient temps over much of that in summer. And people are out there doing it all day.


Absolutely! Texas has some HUGE areas of wide open spaces with hundreds of miles of highway out in the middle of nowhere where you'll be the only car in sight for hours.

 

[SwampSurvivor]

Originally Posted By: KrisZ
3k RPM at partial throttle is nothing. Sustained 3K RPM at 3/4-full throttle, now that will stress the oil out.


I should have pulled a UOA on the oil I had in the Jeep when I towed my popup on the highway in 2nd gear! It spun at >3500RPM for the majority of 70 miles.

 

[hpb]

Mobil and Castrol recommend 5w30 for the V6 Accord here.

With regard to high speed driving, you all have us beat! The maximum speed limit in Oz is 110km/h, and it's fairly heavily enforced in most states.

The only exception is the Northern Territory, which has some sections of road with no speed limits. But we aren't talking multi lane super smooth freeways here - it's your basic 2 lane road, with 3 trailer road trains passing in the other direction literally centimeters from your door. Oh, and lots of wildlife to keep you on your toes!

 

[HTSS_TR]

Engine speed is the determine of oil temperature, higher engine speed up to redline for 20-25 minutes will raise oil temperature more than 20-30C above when engine speed is less than 1/2 redline.

xW20 at 100C is thicker than xW40 at 130C. That why German vehicles are spec with mostly xW40 oil because they can be driven for hours with engine pegs at redline most of the time. Same vehicle is cruising on America Interstates at a leisure engine speed of around 2200-2800 RPM.

This is why I use synthetic xW20 in my E430 instead of M1 0W40. The reason I use synthetic is I do 1 year OCI at around 10-12k miles.

The S2000 is seeing higher RPM (4-4.5k or higher) most of the time and WOT to 7-8k RPM several times every time I drive it, so I use thicker oil than the recommendation 10W30. I think xW40 is too thick so I mixed xW40 with xW20 to get higher HTHS at around 3.4-3.5.

Oil thickness is pretty much depends on how you use your vehicle(s), you may like it a little thicker or thinner.

 

[demarpaint]

I don't see a problem using a 0W or 5W30 oil under those conditions either.

 

[AEHaas]

Originally Posted By: aquariuscsm

Does using heavier than spec oil in a rear diff result in higher diff temps?


I removed the heavier, OEM spec'ed differential oil in my Ford Expedition, then replaced it with a lightweight gear oil. I felt comfortable doing this in FLAT Florida and I never tow anything. This was some years ago. I ran a specific course over again in otherwise the same conditions and measured the temperature with both lubricants. The lighter grade ran cooler though I do not remember the temperature difference. I took the temperature off the case.

aehaas

 

[Flying_A]

Originally Posted By: CT8
the reason we have thinner oils is because of the EPAs CAFE standards. Then there doesn't seem to be scores of engine failures from the 20wts. Probably the oil pressure and temps would need to be monitored to get more than opinion.


I'm not so sure about that... While true on the emissions and sustainability point, companies like Toyota are now having to do full engine rebuilds in the the 4 cylinders that use 0w20 due to oil consumption. A class action lawsuit has also been filed against Subaru since the introduction of 0w20's in the their engines due to engine failures and the insane amount of oil consumption that has been going on.

Not saying it's the grade as much as it may be low HTHS viscosties, still an alarming trend either way.

 

[CATERHAM]

Originally Posted By: Flying_A
Originally Posted By: CT8
the reason we have thinner oils is because of the EPAs CAFE standards. Then there doesn't seem to be scores of engine failures from the 20wts. Probably the oil pressure and temps would need to be monitored to get more than opinion.


I'm not so sure about that... While true on the emissions and sustainability point, companies like Toyota are now having to do full engine rebuilds in the the 4 cylinders that use 0w20 due to oil consumption. A class action lawsuit has also been filed against Subaru since the introduction of 0w20's in the their engines due to engine failures and the insane amount of oil consumption that has been going on.

Not saying it's the grade as much as it may be low HTHS viscosties, still an alarming trend either way.

I wouldn't be so quick to draw conclusions.
Porsche is having cylinder wear issues in their boxer engines that are spec's for 0W-40 and 5W-40 grades and it is primarily occurring in winter driven cars in temperate climates.

 

[Flying_A]

Originally Posted By: CATERHAM
Originally Posted By: Flying_A
Originally Posted By: CT8
the reason we have thinner oils is because of the EPAs CAFE standards. Then there doesn't seem to be scores of engine failures from the 20wts. Probably the oil pressure and temps would need to be monitored to get more than opinion.


I'm not so sure about that... While true on the emissions and sustainability point, companies like Toyota are now having to do full engine rebuilds in the the 4 cylinders that use 0w20 due to oil consumption. A class action lawsuit has also been filed against Subaru since the introduction of 0w20's in the their engines due to engine failures and the insane amount of oil consumption that has been going on.

Not saying it's the grade as much as it may be low HTHS viscosties, still an alarming trend either way.

I wouldn't be so quick to draw conclusions.
Porsche is having cylinder wear issues in their boxer engines that are spec's for 0W-40 and 5W-40 grades and it is primarily occurring in winter driven cars in temperate climates.


I don't think it's a coincidence that Subaru ditched 5w30 in the naturally aspirated cars in favor of 0w20 and instantly had major engine issues, same with Toyota.

Porsche has been using xW-40 grades for years without that kind of issue, sounds like a design flaw. Not an oil related one.

As a Porsche guy, what model year or engine is this happening in? I haven't heard of anything besides IMS bearings which again, is a design flaw. The M96 3.4 and 2.7 engines are junk. That's the least of their worries.

 

[SR5]

My car (Opel) in Australia, they say use a 10W-30 mineral or semi-synthetic with a OCI of 15,000KM & 12 months.

The exact same car as mine in Europe, they say use a full synthetic 0W-40 or 5W-40 with a OCI of 30,000KM & 24 months.

I agree with all the talk about ambient temperature, road speed and % of time at WOT. Just saying the longer OCI requires a higher HTHS reserve (& TBN).

Same car, same conditions, same driving style, I would use a very different oil depending if I was doing 6 month OCI as opposed to 24 month OCI.

OP, your car in Australia is a 5W-30. A full synthetic ILSAC oil like M1 5W-30, is not a thick oil. Seems like a nice balance point to me. Half of Australia would be running a 15W-40 mineral or a 10W-40 semi-synthetic in the same car, without any problem. Just like a 0W-20 in America will also give you no problem. It's a bigger deal to us than to the engine.

 

[Merkava_4]

Oil viscosity consideration should be based on ambient temperatures and the space between surface A and surface B.

 

[JHZR2]

Originally Posted By: HTSS_TR


xW20 at 100C is thicker than xW40 at 130C. That why German vehicles are spec with mostly xW40 oil because they can be driven for hours with engine pegs at redline most of the time. Same vehicle is cruising on America Interstates at a leisure engine speed of around 2200-2800 RPM.
.


What? Certainly not hours, unless it's a trabant or seat or some communist era dinky thing. Most everywhere,,even in the less populated farmlands to the east, there still are 120, 100 and even 80 km/h zones that pop up. I just did 2000km to the east and then another 1000 to the west in two separate cars within the last two weeks.

And the 8 speed autos allow you to cruise near or even under 2k rpm even when doing 160km/h.

 

[boxcartommie22]

I HAVE A 2010 FORD F150 RAPTOR OIL SPEC 5W 20. I CALLED FORD SVT I ASKED WHAT TO USE IF OFF ROADING THEY SAID TO MOVE UP TO A 30 OR 40 WT OIL WOULD BE JUST FINE AND GIVE PROTECTION.

 

[Camprunner]

Boy have things changed I can recall driving from MA to FLA in my 1989 Honda Civic SI with Castrol GTX 20w50 in the crankcase driving non stop except gas going 90+ on the highway. Car loved it drove that Honda for over 250,000 miles with 20w50 summer and 10w40 winter.

 

[HTSS_TR]

Originally Posted By: HTSS_TR
xW20 at 100C is thicker than xW40 at 130C. That why German vehicles are spec with mostly xW40 oil because they can be driven for hours with engine pegs at redline most of the time. Same vehicle is cruising on America Interstates at a leisure engine speed of around 2200-2800 RPM.

Originally Posted By: JHZR2
What? Certainly not hours, unless it's a trabant or seat or some communist era dinky thing. Most everywhere,,even in the less populated farmlands to the east, there still are 120, 100 and even 80 km/h zones that pop up. I just did 2000km to the east and then another 1000 to the west in two separate cars within the last two weeks.

And the 8 speed autos allow you to cruise near or even under 2k rpm even when doing 160km/h.

It may not hours, but in some stretch of Autobahn you can run WOT at redline for considerable distance, this can raise oil temp 20-30C or higher than what we can see in US highway.

My point is oil temperature of an engine that run at 5-6k RPM is much higher than 2-3k RPM. So, it depends on how a driver is using his vehicle(s) he/she may need to select oil accordingly.

And this is exactly what I had been doing for more than 7-8 years for my MB E430. I didn't use straight M1 0W40 as recommended, I used mostly xW20 and sometimes I mixed in few quarts 0W40.

 

[Shannow]

Originally Posted By: HTSS_TR
Engine speed is the determine of oil temperature, higher engine speed up to redline for 20-25 minutes will raise oil temperature more than 20-30C above when engine speed is less than 1/2 redline.


Exactly, and that's the point that keeps getting lost in these threads.

Oil temperature response to load is less than that to RPM.

Where load DOES come in is the minimum oil film thickness, but a lot of OEMs are accepting that they are going to operate in boundary and mixed regimes to improve economy (or carbon emissions if that's the bent of your local legislators).