Syn payback on fuel economy?

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1,502
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Indiana
[Don't want to start a range war here.] We have a 2002 Chevy S10 with 2.2l 4-banger. For the moment, disregard engine life, this will be sold long before it wears out. Does synthetic engine oil improve fuel economy? (cycle: 30% city, 50% suburban, 20% freeway) Enough to justify the added cost?
 
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35
Location
Memphis, TN
Can synthetic oil improve fuel economy? Yes. I DO agree with G-Man II, though. I cannot think of ANY circumstances that a synthetic oil could pay for itself based on fuel economy. IMO, at best, you can expect .5-1mpg (at the same weight/viscosity). However, it probably could pay for itself with extended oil change intervals (OCI, drain). Rather than the typical ~3K mile drain of most "dino" oils, you probably would be safe with ~5K mile drains, even without doing an oil analysis, though I would highly recommend getting at least one on the synthetic oil after the engine break-in period. As for the "sell the car before the engine wears out", you must mean prior to ~50-75+K miles, correct? I'm not familiar enough with the Chevy 4-cyl engines to say for sure, but 4-cyl engines typically do run hotter. Also, IMO, domestic engines, in general, are not manufactured to the tolerances that their foreign competitors typically are. They also tend to have greater variability in the engines. Because of this, they can wear more quickly due to abrasion and oil contamination. Both of these can lead to "sludging" of the oil and lower long-term reliability. Anyway, these are just my thoughts on the matter. If nothing else, having records that you have used synthetics (IMO, Schaeffer's 7000 is a great value and oil) might make selling the S10 easier as the prospective owner might believe (correctly?) that you took good care of it. Won't help on a trade-in, though. YMMV... [Smile] Scott
 
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ME
Your best economy benefit would probably be to change the rear end lube over to synthetic. Do it once and reap the benefits for a long time, or possibly forever. After all it'll probably only take around a quart and a half, probably ~$17 to change it.
 
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Spring HIll
Disagree. My vote is "possibly". I don't think you'll see much if any difference if it's a larger engine, if it's driven hard, or a lot of city driving is part of the equation. However, my 4-banger Saturn gets better MPG with M1 5w-30 than it did with any dino product. My driving is pretty much highway-based and at constant speeds. 34MPG with the air on half the time is excellent for this car! Less friction with M1 is a good thing in this case. Of course, your mileage may vary...
 

ALS

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Pittsburgh
I think it would improve it enough to notice IF you did synthetic in the Engine, Transmission, and rear end. Just the engine maybe 1/2 mile to maybe 1 mpg.
 
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323
Location
Minnesota-South Dakota
My parents were using Mobil-1 5W-30 in their Explorer, with synthetic grease in the differentials and Semi-syn in the trans. It was getting 20-22MPG on a regular basis. I, for some reason, talked my dad into Castrol High Mileage 5W-30, which is an awesome oil (not as good as M1 IMO), and the mileage has been 17-19MPG. It is even getting warm here, too! I may try hard to get him on the Valvoline MaxLife Synthetic, but for now, that has been the data, over several thousand miles.
 
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Montgomery, Alabama
quote:
Originally posted by Jelly: http://www.cummins.com/na/pdf/en/products/truck/Fuel_Econ_for_web.pdf I fully agree with what this paper says about mineral vs. synthetics in regards to M.P.G.
This paper makes a blanket statement and does not back it up with any scientific proof. Ie: We did a scientific study and its results were... and it can be found here.... I have seen studies done which show 2-3% increases over petroleum oils for fleet oils but have not seen one done which showed no increase. Perhaps you can contact Cummins and ask for the study or proof that there is no difference and post it here. Cummins is an engine maker and anything which will lengthen the replacement interval for their engines beyond what they were designed for is a threat to their future production. I have spoken to fleets whose non scientific (controlled) testing appeared to show 2% increase. Even then they still fear converting over the entire fleet. The fleet managers are still afraid to incure increased costs for perceived gains in mpg.
 
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1,011
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Montgomery, Alabama
quote:
Originally posted by nascarnation: [Don't want to start a range war here.] We have a 2002 Chevy S10 with 2.2l 4-banger. For the moment, disregard engine life, this will be sold long before it wears out. Does synthetic engine oil improve fuel economy? (cycle: 30% city, 50% suburban, 20% freeway) Enough to justify the added cost?
Do you also plan on extending out the oil change interval? This will help in calculating the break even point on the cost difference. Does the vehicle leak or use oil. This also needs to be answered. How much oil does the vehicle hold? What is the current mpg? Current mileage? (To determine if auto-Rx would be useful) How many miles per year do you drive the vehicle? ----------- [ May 13, 2004, 07:48 PM: Message edited by: wulimaster ]
 

driven2services

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Yes, gear oil, transfer case (if you have one), and transmission oil will pay for themselves. If gas cost $2/gallon, and you get 16mpg, an increase of only 2mpg will save you 1 cent per mile. For every 100 miles you drive, you just saved $1. That's $30 every 3,000 miles, or a free oil change with Mobile 1 or equivalent. [Smile] If you're not keeping it until it's worn out, I would suggest synthetic changed every 8000 miles or more...you could probably go 15000 miles and easily get 100,000 miles before you started having problems because of it.
 
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401
Location
Southcentral PA
I think some may need to recalculate based on rising fuel prices! The answer in my book is "probably". As long as: (1) your engine doesn't "use" oil. (2) The particular engine benefits from synthetic use, as in tight tolerance, or good computer control, will use less fuel (esp. at idle) if there is less frictional or pumping forces. (3) You drive a lot of city driving, (4) You drive to a shop to get your oil changed, and you go with extended intervals saving you a trip, plus effectively reduces the cost of the oil per mile down closer to mineral. (5) The car stays "in tune" longer because of running cleaner (less volatile material in the intake and various sensors, car uses fuel more efficiently).
 
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College Dorm...
quote:
Originally posted by wulimaster:
quote:
Originally posted by Jelly: http://www.cummins.com/na/pdf/en/products/truck/Fuel_Econ_for_web.pdf I fully agree with what this paper says about mineral vs. synthetics in regards to M.P.G.
This paper makes a blanket statement and does not back it up with any scientific proof. Ie: We did a scientific study and its results were... and it can be found here.... I have seen studies done which show 2-3% increases over petroleum oils for fleet oils but have not seen one done which showed no increase. Perhaps you can contact Cummins and ask for the study or proof that there is no difference and post it here. Cummins is an engine maker and anything which will lengthen the replacement interval for their engines beyond what they were designed for is a threat to their future production. I have spoken to fleets whose non scientific (controlled) testing appeared to show 2% increase. Even then they still fear converting over the entire fleet. The fleet managers are still afraid to incure increased costs for perceived gains in mpg.

Did you even bother to read pages 24-26 to see what the paper actually has to say? "Synthetic base lubricants exhibit superior high temperature stability and low temperature fluidity" "Test results indicate no SIGNIFICANT differences in engine efficiency between synthetic and mineral base lube oils and NORMAL OPERATING TEMPERATURES and therefore MAY not be cost effective" "High temperature stability and low temperature fluidity of synthetic lubricants make them ideally suited for drivetrain components" "Dyno and on-highway vehicle testing has demonstrated SIGNIFICANT benefits in FUEL ECONOMY". Sorry since the paper was commissioned that it must be flawed and any results they come to are invalid simply because they are an engine company.
 
Messages
1,011
Location
Montgomery, Alabama
quote:
Originally posted by Jelly:
quote:
Originally posted by wulimaster:
quote:
Originally posted by Jelly: http://www.cummins.com/na/pdf/en/products/truck/Fuel_Econ_for_web.pdf I fully agree with what this paper says about mineral vs. synthetics in regards to M.P.G.
This paper makes a blanket statement and does not back it up with any scientific proof. Ie: We did a scientific study and its results were... and it can be found here....

Did you even bother to read pages 24-26 to see what the paper actually has to say? "Test results indicate no SIGNIFICANT differences in engine efficiency between synthetic and mineral base lube oils and NORMAL OPERATING TEMPERATURES and therefore MAY not be cost effective" "Dyno and on-highway vehicle testing has demonstrated SIGNIFICANT benefits in FUEL ECONOMY". Sorry since the paper was commissioned that it must be flawed and any results they come to are invalid simply because they are an engine company.

Yes, I read it twice. Once fairly recently. They are saying that fuel economy gains are only happening at non normal operating temperatures. I saw the graph and thought it was strange that it didn't touch zero for either the 5w30 synthetic HHD or the 15w40 HHD non synthetic. This alone should have been a clue as to the legitamacy of the test. If you are going to test synthetics vs dino then you should at least use the same weight oils. Also, why would one go to all the trouble of showing a test based on operating temperatures since they imply most vehicles operate at a fixed temperature and as such most vehicles wouldn't be operating at these extremes for very long unless their thermostats were modified to do so. Until I see the test info, I'll have to stand by my original judgement. On the quote about dyno and highway vehicles showing significant gains, they were talking about diffs and trannys. I hardly call 1 % for diffs statistically significant as that is the data I have gathered from numerous sources. Going from a 85w140 dino to a 75w90 synthetic does get up to 5 % though but that is with a weight change also. I havn't seen where a synthetic helps with the tranny fuel economy enough to be countable. I would like to know which 5w30 synthetic they used as there are not many 30w's out there let alone a 5w30 rated CH-4. Last I checked Amsoil and Royal Purple were the only two. Kenworth has a similar paper out touting its benefits. They don't even mention synthetic engine oil in the paper. They do mention that as the trucks get older (over 400k miles) that it is cheaper to trade on in on a new one by up to 14k dollars a year at this point. They, like Cummins just what to sell more vehicles and would rather you pay 87k/year in financing than try to stretch an extra year out of your truck. Two extra years would net a savings of almost 180k in payments. Remember the residual retail value on the truck would be down to 30k after 4 years according to them. After driving it just 1 more year you could just give the truck away and be saving 57K. You have to look at it from their motivating standpoint. [ May 13, 2004, 10:25 PM: Message edited by: wulimaster ]
 
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2,149
Location
USA
When I changed the engine, trans(manual)and diff to synthetic, I saw a 3mgp increase. My driving habit is 90 highway 10 city. Given the increase in mpg, I've driven about 75k with synthetic and that comes out to a savings to about 600-750 in a course of 7 years. I think given in the long run if you want a cleaner engine, synthetic is the way to go. Sometimes I want to change over to dino given the UOA, but I know synthetic results in a lot smoother engine and is cost efficient.
 
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