MPG, cold starts, short trips, thick oil...

[jigen]

This is a very unscientific question and I am asking for just some general feedback as to what people think.

How much of a hit would a vehicle take with MPG using a thicker oil for short trips (2-5 miles) compared to something thinner? Is it significant enough?

So if the same car, same engine, drives 4 miles each day and its always 30 degrees outside... One uses 0w20, another 0w40. Would you be seeing MPG gains on the 0w20 car? Or would the results be so small that you wouldn't tell. Lol sorry this is just some Sunday night outloud thinking (typing).

 

[RiceCake]

Would you see MPG gains? Absolutely. The issue is certain cars (and drivers) react in different ways. It could easily be within the margin of error the difference with some drivers.

But in terms of absolute science, the 0W-20 should increase MPG. The amount is debatable; some pit 5w30 and 5W-20 together by saying 5W-20 could gain %2 in mileage. Down from a 40 weight would be more, obviously.

They're both 0W oils but even then one will be thicker throughout its range then the other. Would you notice this? Hard to tell, I'd bet you would though if you do consistent testing.

 

[Clevy]

I would venture a guess that both vehicles would consume close to the same amount of fuel until the oil has warmed up. Since the vehicle with thinner oil would warm up slightly faster it would then consume less fuel. Now if it was left idling to warm up there may be a bigger difference in fuel consumption but if the vehicle was started,then driven almost immediately then I don't think there would be much difference in a 3-5 mile trip.
The real difference,in my opinion would be wear. The vehicle with the thinner oil would wear slower due to the oil reaching operating temp faster,being more easily pumpable when cold,which would cause less drag on the engine and the oil getting to the top end faster,lessening wear.
This is just my humble opinion though. I have no real data to back it up,so take it for the 02 cents its worth.

 

[JHZR2]

So let me get this straight...

Youre saying very short trip, on fully ambient-cold oil, and they are both 0wt oils?

So the only delta that could possibly exist, assuming that they are both the starting viscosity, is the slight variance in the ambient to a few degrees above ambient viscosities based upon the differences in the slopes to get to 40 vs 20 at 100C.

As we know that the fuel economy difference over many miles with an oil that has 50% different operating viscosity is at best a few percent, and we know that the difference at these operating points is going to be far smaller percentage-wise, then we can comfortably say that the difference will be so negligible that you would not be able to measure it outside of a tightly controlled lab condition.

Now, I read once that GM and others went to 5w30 from 10w30 oils because of slightly better fuel economy at startup. And this is sensible, and I would imagine seeing similar though diminishing returns for the next step from 5 to 0w. But a 0w- vs a 0w is so in the noise, if the trips are short and the difference in operating viscosity cannot manifest itself that youll never see it.

 

[bubbajoe_2112]

Interesting scenario...

According to Honda, moving from 5W30 to 0W20 gives a 1.5% increase in fuel economy. This is using the LA4 (also known as UDDS)test which is a short duration, low avg speed test (7.45 miles and 19.59 mph avg), which seems fairly similar to your drive. Can you expect more than a 1.5% savings going from 0W40 to 0W20? Probably. Will it be a measurable amount over and above the 1.5%? Dunno.

Page 7

UDDS/LA4 test

So theoretically, on a 30 mpg engine you would see about a 0.5 mpg increase. Again, all test based scenarios. No guarantee they will directly correlate to your scenario, but it's something to reference...

 

[bigjl]

i am certain i read in the Acea specs that the target for A1/B1 and A5/B5 fuel economy oils is an improvement of 0.5% over a 15w40 oil of A3/B3/B4.

In the above example I don't think the improvement would be significant but I think there would be one.

There might even be slight drivability improvements, perhaps in line with the improvements you might get from a slightly lightened flywheel.

Perhaps Caterham can add some details as he is a big fan of using thin oils, I assume that is to assist in MPG improvement.

I think you would see maybe 3/4 mpg improvement on a long steady run but I don't think you would see much in short journeys.

Had a read of the above links and I think the figures would be significantly different in most applications as those figures were obtained in a High Efficiency, Low Friction 1.0 engine.

Surely not the typical engine as even the Insight is a 1.3?

Possibly the Honda Jazz which has is available with a 1.0.

 

[Norm Olt]

Actually, IMHO it's a lot like picking the peanuts out of the...

"4 miles each day" = 1460 miles PER YEAR and @ just 20mpg and with gas at $4.00 per gallon a 10% difference only equals a "$aving$" of...

1460 miles / 20 mpg = 73 gallons X $4 = $292 X 0.10 = $29.20 , or...

TA DA $0.56 per week!!!!!!!!

WOW! What $aving$!

 

[KrisZ]

Originally Posted By: Norm Olt
Actually, IMHO it's a lot like picking the peanuts out of the...

"4 miles each day" = 1460 miles PER YEAR and @ just 20mpg and with gas at $4.00 per gallon a 10% difference only equals a "$aving$" of...

1460 miles / 20 mpg = 73 gallons X $4 = $292 X 0.10 = $29.20 , or...

TA DA $0.56 per week!!!!!!!!

WOW! What $aving$!



That's what everybody seems to be missing in the drive for the thinnest possible oils. They guys that should see the most savings (short trippers in cold climates) will not see them simply because they don't use much gas to begin with.
And guys that drive a lot, will not see much difference either, as the oil is in its operating temp most of the time.

The only savings here are for the manufacturers and their CAFE credits. I read somewhere that Toyota has something to the tune of $2.5 billion of CAFE provisions. Other manufacturers have millions riding on those credits. These are the true winners in this game.

Consumer, so far ends up with adequate protection, but for how long? We may reach a tipping point where manufacturers simply will not be able to keep up the reliability with increasing emission standards. Eventually something has to give.

 

[tarbasd]

Well, if it's 10% less [censored] in the city smog, I would consider the citizens winners. Of course the funny thing in this game that one car doesn't make a significant difference, so every individual's best interest to pollute more.

Edit: It is funny that c.r.a.p. got censored.

 

[Norm Olt]

"10% less [CENSORED]... HA! HA!" only has any real meaning "in the city smog" if you are talking about a pre-90's vehicle (and not too many of those, BTW).

The EXHAUST from a 2006 CA Emissions Honda CIVIC is cleaner than the ambient air in LA. Think of it as a pollution reduction device

When you are talking modern emissions 10% of almost nothing is...

ALMOST NOTHING! (kinda' like $aving$ of $0.56 per week, huh?)

Cheers!

p.s. Although it is not recognized by many (certainly NOT the C.A.R.B.!) there is actually a "Law of Diminishing Returns" and it does apply to carbon-based life forms as well.

 

[bigjl]

Personally I think the fuel savings will be slightly better at operating temperature.

Fuel economy oils are fairly common in Europe now and they lead to benefits at all times.

If you reduces losses due to specific lower HTHS oils, full synthetic oils or oils that are thinner at operating temperature then you will reduce co2 emissions and fuel consumption.

But the individual savings will be very small. As I mentioned above they were looking for an improvement of 0.5% in Europe.

But if you extrapolate that out to the entire driving population and you can easily see the advantages.

You can use fuel economy oils in the VM engine in my Taxi.

The only issue being that finding a 0w40, 5w40 or 10w40 that meets B5 is not that easy as by their very nature they tend to be lower viscosity and therefore more likely to be 0w30 or 5w30.

I am not brave enough to try a -w30 in the Taxi.

Especially with the mileage on it.

 

[Quattro Pete]

Originally Posted By: jigen
Lol sorry this is just some Sunday night outloud thinking (typing).

Is this just hypothetical or are you thinking of running 0w-20 in your Tiguan? I mean, there are no 0w-20 oils that meet VW 502.00 spec which you need to be running while under warranty...

 

[KrisZ]

Originally Posted By: Norm Olt
p.s. Although it is not recognized by many (certainly NOT the C.A.R.B.!) there is actually a "Law of Diminishing Returns" and it does apply to carbon-based life forms as well.


The law of diminishing results has no bearing when all the cost is passed along to the consumer or paid for by tax payers.

 

[gfh77665]

Originally Posted By: KrisZ

Consumer, so far ends up with adequate protection, but for how long? We may reach a tipping point where manufacturers simply will not be able to keep up the reliability with increasing emission standards. Eventually something has to give.


Thats what I said last month here, and I agree 100%. If we go any further on the thinner bandwagon, something will soon give.

 

[Norm Olt]

Originally Posted By: KrisZ
Originally Posted By: Norm Olt
p.s. Although it is not recognized by many (certainly NOT the C.A.R.B.!) there is actually a "Law of Diminishing Returns" and it does apply to carbon-based life forms as well.


The law of diminishing results has no bearing when all the cost is passed along to the consumer or paid for by tax payers.

I'm completely in the dark as to what this is supposed to mean, but...

Considering the WINK I'm hoping you are referring to that insatiable capacity of regulatory agencies (and unfortunately, our modern Guv'mint in general) to over-regulate, recklessly over-spend, GROW their sacred bureaucracy regardless of whether there is any real benefit to anyone (except themselves, of course).

As I've opined before, if there was a way to identify (& regulate!) the water vapor (greatest "Greenhouse Gas" by far) that comes out the tailpipe of an (EVIL) "infernal combustion engine" from mist, rain, fog or simple evaporation THERE WOULD BE REGULATIONS, TESTS, CERTIFICATIONS, etc.

Cheers!

 

[JOD]

Originally Posted By: jigen
This is a very unscientific question and I am asking for just some general feedback as to what people think.

How much of a hit would a vehicle take with MPG using a thicker oil for short trips (2-5 miles) compared to something thinner? Is it significant enough?

So if the same car, same engine, drives 4 miles each day and its always 30 degrees outside... One uses 0w20, another 0w40. Would you be seeing MPG gains on the 0w20 car? Or would the results be so small that you wouldn't tell. Lol sorry this is just some Sunday night outloud thinking (typing).



The difference in fuel economy will be real, but difficult to measure. Comparing a 0W20 to 0W40 being short tripped, you could probably guesstimate a difference of 5% or so. You can't reliably measure a 5% change in fuel economy--there are just too many other confounding variables. That doesn't mean the difference doesn't exist.

In the above hypothetical though, I think there are other reasons to use a thinner oil though, namely that the oil will be closer to the correct operating viscosity.

 

[jigen]

Originally Posted By: Quattro Pete
Originally Posted By: jigen
Lol sorry this is just some Sunday night outloud thinking (typing).

Is this just hypothetical or are you thinking of running 0w-20 in your Tiguan? I mean, there are no 0w-20 oils that meet VW 502.00 spec which you need to be running while under warranty...


Lol, oh God no. 0w-40 all day, everyday.

 

[Norm Olt]

"The difference in fuel economy will be real but difficult..."

As opposed to being UN-real but...? Still so insequential as to be relevant?

Cheers!

 

[JOD]

Originally Posted By: Norm Olt
"The difference in fuel economy will be real but difficult..."

As opposed to being UN-real but...? Still so insequential as to be relevant?

Cheers!


I'm not really sure what you're trying to say? I'll say again, the difference is real, but difficult to measure in real-world conditions. "Inconsequential" or "irrelevant"? Well, I get it depends on how you look at it, but I certainly don't think so. At the the micro level, it's probably enough to make up the cost difference of a more expensive lubricant; at the macro level, it adds up to a lot of oil. I realize "conservation" has become a dirty word and that some view wasting resources is some sort of birthright. Personally, I don't believe that to be the case.

 

[Norm Olt]

I'll explain: $0.56 per week in gas savings that is predicated upon a 10% mileage increase (WAY, WAY OPTOMISTIC for either oil brand or weight) in a car that gets 20 mpg (KINDA' LOW ON AVERAGE today) and a price of $4.00 per gallon for gas (WAY, WAY PESIMISTIC) is inconsequential, IMHO.

The reduction of the "wasting of the resources" in the OP's example and the anticipated extra pollution reduction in a modern vehicle is irrelevant IMHO as it is so miniscule to make any difference: just walking one way, one day, instead of driving would make a much bigger impact.

The real vs. Un-real was meant to be humor. Not to offend. I would hate to offend anyone unintentionally...