That savings depends on your car and how much you drive. Someone that drives a Prius and averages 10k a year won't see anywhere near $700 in savings. With current gas prices you'd have to get the mileage my car does over 12k miles to make a $700 savings per year at 7mpg.
$2143 over 12k miles for my current 14mpg lifetime mileage
$1428 over 12k miles if I increased mileage to 21mpg
Savings of $715/yr
Synthetic oils last longer and give slightly better fuel mileage. My father-in-law is an engineer at GM and he says the best mileage is with synthetic oil that has friction modifiers which is an expensive additive. Friction eats power. Royal Purple, Joe Gibbs, and Schaeffer are examples of synthetic oil that has friction modifiers. They all cost more than Mobil 1 except Schaeffer but it is hard to find.
81 VW Rabbit Diesel, no mods; burning biodiesel made from used fry vat oil (Picking up from a mom and pop burger joint). My net cost for all transportation expenses is $1/200 miles.
Perhaps synlube is as good as it claims, but it is falling in the extraordinary realm. If there is proof, their site makes it hard to find. Then things like this make me doubt that it is even there.
From their FAQ:
My "Owner?s Manual" recommends SAE 10W-30 motor oil,
can I use SynLube? which is SAE 5W-50 Oil?
A: Yes, SAE 5W-50 is better than the recommended SAE 10W-30 !
You must realize that vehicle manufacturer?s specifications that are given in the "Owner?s Manual" for your vehicle are based on following three factors:
1. The lowest permissible quality specification for the product recommended, such as Motor Oil.
2. The availability of the recommended product.
3. The likelihood of the use of such product by the vehicle owner.
Now we will discus each of these points in detail:
1. No manufacturer ever objects to the use of a "better than recommended" product, if the "better" is based on industry accepted ratings. In case of the Motor Oil these are:
2. SAE Viscosity Ratings
3. API Performance Categories
4. API Energy Conserving Capacity
ILSAC GF-1 or GF-2 approval
If your "Owner?s Manual" recommends SAE 10W-30 Motor Oil, it is OK to use any Motor Oil whose "W" rating number is either the same or lower and whose "second" rating number in either the same or higher.
That is SAE 5W-30 or 10W40 or 5W-50 is OK.
However SAE 20W-50 or 5W-20 or 15W-40 is NOT OK !
2. Manufacturers do not like to recommend products that are not easily available everywhere, in case of motor oil, only few companies make SAE 5W-50 Motor Oil and it is not easily available everywhere in the World. SAE 5W-30 or SAE 10W-30 by contrast can be bought at every gas station and everywhere where motor oil is sold (car parts stores, supermarkets, convenience stores, etc.)
3. Majority of car owners use commonly available Petroleum Motor Oil, therefore, car companies do not even mention the use of Synthetic Motor Oil in their manuals.
The exception is FORD that devotes one paragraph to Synthetic Motor Oil in their 320 page "Owner Guide" for most 1994 and later vehicles. By contrast FORD devotes two full pages to "Washing Your Vehicle".
GM mentions Synthetic Motor Oil only in Corvette manuals because it is the only GM vehicle that requires the use of Synthetic Motor Oil.
DODGE Viper and PLYMOUTH Prowler are the only CHRYSLER (now Daimler-Chrysler or D/C) vehicles that must use Synthetic Motor Oil exclusively.
Bolded the part that caught my eye. Do they themselves know what the numbers mean? I agree with using a lower W number in the oil isn't a problem. The xW-xx is just a labeling system. The actual measured viscosity of the W number is higher than the operating temp viscosity to begin with, and, outside extreme environments, the oil quickly heats up and thins out anyway.
But to claim a thicker operating temp oil is better shows a lack of understanding, or just being misleading. A higher viscosity doesn't mean a better lubricant. Otherwise, maple syrup would be better than astroglide. It takes more effort to pump thicker fluids, and thus more strain on the oil pump. Then, for engines designed for a lighter weight, the channels the oil flows through will be narrower, which will add to the strain.
So the FAA worked on a number of experiments, they found that a mixture of 45% Synthetic, 45% multiweight 20/50, and 10% 30 weight was the best for longevity. The synthetic has its wonderful lubricity, the 20/50 washed the rings, and the 10% 30 weight left a film of oil on the crank for start up to eliminate the metal on metal of a crank that has cooked off its thin synthetic oil.
I use Havoline or Quaker State Synthetic Blend, largly due to a test Chevrolet ran that found the best longevity of bearing life came from these 2 brands. Who were the losers, everything else including Mobile 1 and Castrol due to they're inability to cover the crank after running.
i've heard that(the first paragraph) before. but i've heard and seen for myself the cleaning power of synthetics. also i can confirm that synthetics are drawn to heat, keeping its lube on warm starts. cold starts, well what about lucas?
i often wonder and doubt studies especially since the API does not rate amsoil. it makes me wonder also how many other independent studies do not include amsoil or ALL motor oil for that matter.
Synthetics do clean out the engine extremely well. On Rusty (my 1986 Chevy C-10) I switched to synthetic somewhere between 140K and 150K miles. At 190,000 dad & I took the engine apart to change the timing chain. With the oil pan off, and looking straight up at the crank, the engine was so clean that you would swear you were looking at a new engine. There was also no sludge in the oil pan.
If you ever get the chance, take a gander at an engine that is being taken apart that ran synthetic and E85 it's whole life. It's unlikely that you'll find one that needs it for anything less than overheating until the headgasket blew but still. You'd swear that engine had no more than 20 miles on it. The plugs come out immaculate looking like they've never been run, the combustion chambers are clean, the inside of the engine looks almost new. It's incredible.