Fantastic claims for some synthetics

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Over the years, I've heard so called "testimonials" claiming by switching to a particular brand of synthetic oil, the user experienced a 15% to 20% increase in mileage. I dont doubt that synthetics may flow easier, but these statements seem unrealistic. There's so many other variables, such as fuel quality, wind, air density, temperature, ect. Anyone know of dyno tests that showed a comparable increase? While were on the subject, I also noticed on the Lucas UCL that it states "This product should more than pay for itself in fuel savings alone". Anyone have proof? Hapuna
 
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Ontario , Canada
Not exactly mileage, but Hot Rod magazine had an issue in summer 2002 where they swapped fluids on a muscle car making 400 hp, they gained 10-12 hp by swapping out the fluids, using Royal Purple in engine, tranny and differential. Thats about the only real world test I've seen w.r.t. claims about synthetics, that is if you trust magazines that are sponsored by oil manufacturers. [Wink]
 
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Monterey Park, CA
You know I have been trying to figure that out. Now I believe it's the film strength giving better cylinder sealing for more power. The synthetics seem to just stick to the dipstick whenever I check it. Something like a gel. Right now I am using 15w40 Royal Purple and that's my observations with this stuff. Leo
 
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USA
Wow that is way over the top. The most I have ever heard of is 2% increase in fuel efficency and tht was with all fluids changed to synthetics not just the oil. The large percentages youare talking about might work ok if we are compareing wear metals and oxidation numbers..... but not HP of fuel millage in my opion!
 

Patman

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Oakville, Ontario
I've never understood why they claim switching to synthetic oil will give you better gas mileage. It's not like it's more slippery. That's another wive's tale I believe. If two oils, one dino and one synthetic, are the same viscosity (both at 60cst at 40c and at 10cst at 100c for instance) then the MPG should be identical (except in winter where the synthetic will flow better in cold)
 
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Indiana
quote:
Originally posted by Patman: I've never understood why they claim switching to synthetic oil will give you better gas mileage. It's not like it's more slippery. That's another wive's tale I believe. If two oils, one dino and one synthetic, are the same viscosity (both at 60cst at 40c and at 10cst at 100c for instance) then the MPG should be identical (except in winter where the synthetic will flow better in cold)
Yep. I routinely take a 500 mile trip from Ohio to NC which is a pretty nice natural experiment for gas mileage fluctuations (based on the trip computer mileage readings). The biggest mileage fluctuations I've noticed are due to outside temperature and oil viscosity rather than synthetic vs dino. However, I did notice improved turbo response with synthetic but it did not seem to improve my mileage. Another interesting thing is that I can tell when my oil is starting to thin near the end of its interval because the trip computer starts reporting about an avg. of a 1 mile increase in gas mileage. This was really severe when I ran castrol GTX dino (5w-30) in it a while back where after about 1000 miles, my mileage jumped up by about 1.5 mpg avg on the 500 miles trip. I switched that oil out pronto! [ May 17, 2003, 11:11 AM: Message edited by: VeeDubb ]
 
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Southern California
quote:
Originally posted by Pablo: I don't think Amsoil claims that much. But if you change ALL the lubes 'n oils to synthetic you will notice a difference.
Yeah, your wallet will be MUCH lighter, resulting in better gas mileage from the fact that your car is carrying less weight... [Big Grin]
 
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'Stralia
quote:
Originally posted by VeeDubb: Another interesting thing is that I can tell when my oil is starting to thin near the end of its interval because the trip computer starts reporting about an avg. of a 1 mile increase in gas mileage. This was really severe when I ran castrol GTX dino (5w-30) in it a while back where after about 1000 miles, my mileage jumped up by about 1.5 mpg avg on the 500 miles trip. I switched that oil out pronto!
Veedub, in my 4Runner, the last 3 oil changes have registered a 1/2 MPG drop (measrured over three tankfuls) at the 12,000km mark.
 
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I am not hyping for any brand or any one, but is has been my personal experience that I DO get better mpg using synthetic oil. Avg mpg. with dino = 26-27mpg; Avg mpg. with Synthetic (Mobil 1) 30-32 mpg. All conditions being equal. Good Day, Steven
 
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Southeastern, PA
I'll be a bit of a devils advocate here. The auto makers struggle with increasing gas mileage. If synthetics provided a reasonable level of increase in MPG numbers, why wouldn't they use them for the factory fill in all autos? The cost probably wouldn't be that great, I'm sure the quantities involved would garner a signifigant discount from the synthetic oil manufacturer. The auto makers could spec "synthetic only" in the user manual, thereby offloading the bulk of the cost (over the life of the vehicle) to the consumer. This would allow the auto manufacturers to up their MPG numbers for CAFE with little investment. I would expect that the auto manufacturers have looked into this, I'd like to know what their findings are on synthetic use yielding better MPG.
 
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Clarksville,TN
Tell you fellas something I found kind of funny. I had some 10w/30 syntec in the garage and I thought welp, since I'm not gonna run it in the car any more I'll run it in my lawn mower just to more or less get rid of it. The next time I mowed the lawn I was like WOW! There's a section of my back yard that always trys to stall out the mower but no more. Now I can just breeze right through it. That makes me feel much better about paying more for Amsoil for the truck and car. [Big Grin] [ May 18, 2003, 06:52 PM: Message edited by: JWRENCH ]
 
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Location
Pascagoula, Ms
quote:
The auto makers struggle with increasing gas mileage. If synthetics provided a reasonable level of increase in MPG numbers, why wouldn't they use them for the factory fill in all autos?
This is exactly what Ford has done with their switch to 5W-20 motor oil. Yes, I know they changed the viscosity mostly but they have blended group III base stocks to achieve the necessary specs. That's why Motorcraft is considered a synthetic blend. This is only the beginning & you will see others follow their lead. It's an easy way to meet ever more stringent environmental regulations. Also, I have definitely seen improved mpg when using synthetics, especially Amsoil.
 
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Duvall WA - Pacific NW USA
Now you guys can laugh your collective a$$e$ at me, but when I change ANY single cylinder "device" to synthetic oil the sucker puts more power out....I don't think it's just pychosimatic....(is that a word?) I'm sure I would feel the same whatever brand I used, so I'm not just saying it's an Amsoil thing.
 
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Duvall WA - Pacific NW USA
It isn't pure BS that synthetic lubes improve mileage in real world applications - just compare the viscosities any of the good 75W-90 full synthetic gear oils across a temperature range vs. a 90W petroleum gear oil. Again anything over 5% sounds like hype though.
 
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California, USA
Where the automakers are using synthetics as factory fill is in the differential. At least Ford and GM both use synthetic gear lube now. I don't know if others do, but I suspect they are. This may be where a measurable gain in CAFE, even if small, can be had, not in the engine crankcase or transmission. I have not seen a difference in mpg since I changed the differential oil to 75W-90 Mobil 1 from 80W-90 Valvoline in the BMW. Very mild winters may be the reason. I think it is Redline that claims gains mainly in short-trip driving, where the unit never gets up to full operating temperature.
 
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179
Location
Forest Hill MD
quote:
Originally posted by Patman: I've never understood why they claim switching to synthetic oil will give you better gas mileage. It's not like it's more slippery.
Natural oils have sticky waxes (impurities) that interfere with lubrication. Synthetic oils do not, so that's where the advantage comes from. mobil.com claims 3-5% based upon diesel highway tractor-trailers switching from Delvac 1300 (natural) to Delvac 1 (synthetic).
 
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