Synthetic Oil - Better MPG ?

Tek74 · October 24, 2015

I'm a long time user of Amsoil full synthetic oil. I run it over regular oil or synthetic blends, as I feel it's a bit better engine protection and has longer drain intervals. I've always read that full synthetic improves MPG, but never really put much thought into it, as I thought the improvement was too miniscule to matter. Nor did I ever have a vehicle with the MPG measurement computer.

Well, I recently changed the oil in my new 2015 Silverado 5.3L at about 2200 miles and put in Amsoil synthetic, as always. Driving the same route to work all week (10mi each way in the city), and the same easy driving style, the computer shows that my MPG (previous 50 miles) has gone from about 16.5 mpg to about 18 mpg. I was expecting maybe a 0.5 mpg increase at best, but not a 1.5 mpg gain. I'm gonna check it again at the end of another work week before I confirm its accurate, as I don't like to jump to conclusions too quickly.

Has anyone else see an MPG improvement upon switching from the factory oil to full synthetic?

I'll be installing an Airaid MIT shortly and hope to see an additional 1 MPG gain, as some have claimed in reviews.

Jimbo290 · October 24, 2015

Dear Members,

I've use Mobil 1 Extended Performance 5W30 in my current 2000 Silverado 5.3 L V-8, and Mobil 1 10W30 in my past 1994 Z28 5.7 V-8 6-speed. In both cases, my gas mileage is 2-4 MPG better than the EPA estimates. My truck gets 20-22 MPG on the highway, with all around mileage in the 18-20 range, and the Z28 came close to 30 MPG on the highway when the EPA rating was 26. I also run my Bridgestone Alenza truck tires at 38 psi (3 psi above the door recommendation) which also helps improve the gas mileage and provides for an improved ride. Synthetic Oil lowers the internal resistance in the engine and thus improves fuel efficiency and also extends the life of your engine. I would also suggest that you use the Mobil 1 Filter with Mobil 1 or with Amsoil. Amsoil is slightly better than Mobil 1 Extended performance, but I've not seen any engine wear at all in either GM engine so I can't justify the added cost of Amsoil. My Z28 at 90,000 miles was as tight as the day that I bought it and didn't burn a drop of oil. At the time, I lived in VA and used 10W30 Mobil 1 Synthetic Oil which provided better hot weather protection than the 5W30. While more expensive, Synthetic Oil more than pays for itself especially if you buy it in 5 gallon containers at Walmart. It's the least expensive oil that anyone can use when you factor in the fuel savings. Conventional Oil and Synthetic Blends (which only have 1/3 synthetic oil in them) are the oils that cost the most to run in your vehicle. Go Synthetic!

Jimbo 290

Tek74 · October 24, 2015

Nice MPG gains. I'm hoping my mpg gets closer to 2-3 mpg gain.

With regard to the cost of Amsoil, I paid a little extra to become a Preferred Customer. That gets me a significant discount on the oil and filters. Since we run it in two cars, a motorcycle, and a quad, the cost savings is significant.

Tony Bianco · October 24, 2015

I've always been a Royal Purple fan. I've used it just about every vehicle I've ever owned dating back to the late 80's.

I have a Porsche Carrera, Dodge Viper and a past BMW that are mainly tracked. I used Mobil 1 for a while just to see if I could document a difference in operating temp (of any of the three) or even mileage with the BMW. The BMW was my daily driver at the time and used for a number of road trips. She consistently ran an average of 15 degrees cooler and picked up an average of 1-1.5 MPG during long distance driving.

I am still watching my AT for any documented difference I might be able to post. The RP does live up to its name. If your vehicle is under factory warranty then I'm guessing Mobil 1 would be the factory recommended brand of oil to be used. Castrol was the recommended oil for the BMW. If your engine were to ever suffer a catastrophic failure; the manufacturer (a tech from the manufacturer will normally perform the inspection and diagnosis of the cause of the failure) could void the warranty after testing the oil. RP does not fall within the specs of an approved grade of oil for factory warrantied vehicles.

I did an analysis a few years ago with a couple of older Mustangs belonging to friends. The test was conducted over the duration of most of the lives of each car. 3-5 oil changes per year for each one. Both cars were daily drivers although they are both being used for 1/4 mile runs now. Each owner swore by the brand of oil they used and never strayed from using it in their cars. One Mustang was always changed with Mobil 1 and the other with the RP. The results speak for them selves ........... the wear is more than noticeable.

crafferty · October 25, 2015

I've always been a Royal Purple fan. I've used it just about every vehicle I've ever owned dating back to the late 80's.

I have a Porsche Carrera, Dodge Viper and a past BMW that are mainly tracked. I used Mobil 1 for a while just to see if I could document a difference in operating temp (of any of the three) or even mileage with the BMW. The BMW was my daily driver at the time and used for a number of road trips. She consistently ran an average of 15 degrees cooler and picked up an average of 1-1.5 MPG during long distance driving.

I am still watching my AT for any documented difference I might be able to post. The RP does live up to its name. If your vehicle is under factory warranty then I'm guessing Mobil 1 would be the factory recommended brand of oil to be used. Castrol was the recommended oil for the BMW. If your engine were to ever suffer a catastrophic failure; the manufacturer (a tech from the manufacturer will normally perform the inspection and diagnosis of the cause of the failure) could void the warranty after testing the oil. RP does not fall within the specs of an approved grade of oil for factory warrantied vehicles.

I did an analysis a few years ago with a couple of older Mustangs belonging to friends. The test was conducted over the duration of most of the lives of each car. 3-5 oil changes per year for each one. Both cars were daily drivers although they are both being used for 1/4 mile runs now. Each owner swore by the brand of oil they used and never strayed from using it in their cars. One Mustang was always changed with Mobil 1 and the other with the RP. The results speak for them selves ........... the wear is more than noticeable.

First off I want to say thats awesome you were able to conduct an oil test like that. Sounds like it had a good ratio of normal wear n tear and abuse. However there is one possible issue with the test. I am by no means 100% sure about this but thought it may be something interesting for you to look up. I owned a 2012 GT500 and after several hundred miles I wanted to do an oil. Well just like you I've always really like Mobil 1 and Royal Purple. After doing some I found out that basically my only options for 0W50 were Mobil 1 and the Ford Sythentic. But the problem with the Mobil 1 is that it had too many additives and was not recommended for use. But on the flip side for the TR6060 like the on in your viper (depending your year, also got a pic of it?) the Mobil 1 sythentic ATF was the only other approved fluid for it from Tremec. I'm not sure if this applies to the regular mustangs. Just wanted to share my knowledge and experience with mustangs and there fluids.

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fondupot · October 25, 2015

I used up all of my "free" dealership oil changes over the past two years. My next oil change will be using Amsoil Signature Series 0w20. Interested to see the results.

Tony Bianco · October 25, 2015

First off I want to say thats awesome you were able to conduct an oil test like that. Sounds like it had a good ratio of normal wear n tear and abuse. However there is one possible issue with the test. I am by no means 100% sure about this but thought it may be something interesting for you to look up. I owned a 2012 GT500 and after several hundred miles I wanted to do an oil. Well just like you I've always really like Mobil 1 and Royal Purple. After doing some I found out that basically my only options for 0W50 were Mobil 1 and the Ford Sythentic. But the problem with the Mobil 1 is that it had too many additives and was not recommended for use. But on the flip side for the TR6060 like the on in your viper (depending your year, also got a pic of it?) the Mobil 1 sythentic ATF was the only other approved fluid for it from Tremec. I'm not sure if this applies to the regular mustangs. Just wanted to share my knowledge and experience with mustangs and there fluids.

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Thanks! I love modifying cars and conducting a test like this made it even better.

Pics of the Viper and Carrera ........... and a short lived 2011 GT500 one of my sons owned. A 2009 GT500 my other son owned.

For the most part blended synthetic oil brands are very much the same. Full synthetic oil brands have their own proprietary formula. Just as Mobil 1 has its "recipe" so do all of the others.

The 2012 GT500 calls for 5w-50 synthetic oil. As far as transmissions go ....... that's a whole other ballgame. In all of the GM vehicles I've owned (including my 2014 GMC A/T) I use RP engine oil as well as transmission fluid and filter. My truck is out of warranty anyway.

I know I'm getting a little off track with your comment, but thought it might be interesting to note that the RP trans fluid/filter is absolutely one of the best choices I have made to use within all of our vehicles. It's race performance tested, causes VERY smooth shifting and upon my first inspection of use after 1500 miles ........ not a single regret.

Here's an old forum thread to share with you ........ talks about recommended oil for use with the 2012 GT500. Good stuff.

Approved Oils

crafferty · October 25, 2015

Thanks! I love modifying cars and conducting a test like this made it even better.

Pics of the Viper and Carrera ........... and a short lived 2011 GT500 one of my sons owned. A 2009 GT500 my other son owned.

For the most part blended synthetic oil brands are very much the same. Full synthetic oil brands have their own proprietary formula. Just as Mobil 1 has its "recipe" so do all of the others.

The 2012 GT500 calls for 5w-50 synthetic oil. As far as transmissions go ....... that's a whole other ballgame. In all of the GM vehicles I've owned (including my 2014 GMC A/T) I use RP engine oil as well as transmission fluid and filter. My truck is out of warranty anyway.

I know I'm getting a little off track with your comment, but thought it might be interesting to note that the RP trans fluid/filter is absolutely one of the best choices I have made to use within all of our vehicles. It's race performance tested, causes VERY smooth shifting and upon my first inspection of use after 1500 miles ........ not a single regret.

Here's an old forum thread to share with you ........ talks about recommended oil for use with the 2012 GT500. Good stuff.

Approved Oils

You guys have great tastes in cars. My 2012 was basically the reverse color scheme of your sons 2011. It was performance white with the thin red stripes which had a black outlined. Ended up selling my 2012 and buying my Silverado since the previous owner had veat the car to death. Regarding oil your correct about the 5w50 I mispoke. I ended up running the motorcraft since thats what all the big tuners use on their cars from stock to 1,500+. Beautiful viper as well, they are on my bucket list to own one day. At 26 money is short now because of these damn student loans! Currently trying to talk my dad into ordering a new viper just to collect it. Since Dodge is canning them.

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Tony Bianco · October 25, 2015

You guys have great tastes in cars. My 2012 was basically the reverse color scheme of your sons 2011. It was performance white with the thin red stripes which had a black outlined. Ended up selling my 2012 and buying my Silverado since the previous owner had veat the car to death. Regarding oil your correct about the 5w50 I mispoke. I ended up running the motorcraft since thats what all the big tuners use on their cars from stock to 1,500+. Beautiful viper as well, they are on my bucket list to own one day. At 26 money is short now because of these damn student loans! Currently trying to talk my dad into ordering a new viper just to collect it. Since Dodge is canning them.

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Thanks!

I've never been a true Mustang fan, but I smiled with each time I lit up the tires with the GT500s.

The Viper is fun, but has too much power for tracking too much. A few years ago I had a turbo installed. 87 octane still gives the car around 750RWHP. My wife was all giggles the first time I took her for a ride after the install.

The Carrera is strictly used as a track car. The wheels pictures are the original shoes. I have a set of HRE wheels for the track. Lol, I'm constantly having to clean the "skin" from the cones off the sides of the car. Cutting the slots too close ..........

crafferty · October 25, 2015

Thanks!

I've never been a true Mustang fan, but I smiled with each time I lit up the tires with the GT500s.

The Viper is fun, but has too much power for tracking too much. A few years ago I had a turbo installed. 87 octane still gives the car around 750RWHP. My wife was all giggles the first time I took her for a ride after the install.

The Carrera is strictly used as a track car. The wheels pictures are the original shoes. I have a set of HRE wheels for the track. Lol, I'm constantly having to clean the "skin" from the cones off the sides of the car. Cutting the slots too close ..........

I honestly didn't purchase a ZL1 because I couldn't see out of the back window lol. And I absolutely hated the SRT8 Challenger the moment I sat in one. But after owning the GT500 I'll be getting another down the road. Once I have a house I do want to build an Exocite with a V8 and use that to track here and there. That viper with a turbo has to be pure smiles and tons of fun especially on highway rolls.

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Z45 · October 25, 2015

When I changed from the factory fill Mobil 1 5W-30 to AMSOIL Signature Series 0W-30, the mileage on my 2009 AWD Cadillac CTS 3.6L went from 21.7 mpg to 24.1 and has held at 23.9 to 24.1 for the last 5 yrs. and 40,000 miles. I changed all the drive line fluids over to AMSOIL at the same time, front and rear diff' and 6-speed trans.

Have use AMSOIL since 1975 and nothing else.

Btw - RP sold out to a petroleum company (Calumet) and I heard recently so did Red Line. AMSOIL is still independent and not beholding to stock holders.

Paulmart · October 25, 2015

I'm a long time user of Amsoil full synthetic oil. I run it over regular oil or synthetic blends, as I feel it's a bit better engine protection and has longer drain intervals. I've always read that full synthetic improves MPG, but never really put much thought into it, as I thought the improvement was too miniscule to matter. Nor did I ever have a vehicle with the MPG measurement computer.

Well, I recently changed the oil in my new 2015 Silverado 5.3L at about 2200 miles and put in Amsoil synthetic, as always. Driving the same route to work all week (10mi each way in the city), and the same easy driving style, the computer shows that my MPG (previous 50 miles) has gone from about 16.5 mpg to about 18 mpg. I was expecting maybe a 0.5 mpg increase at best, but not a 1.5 mpg gain. I'm gonna check it again at the end of another work week before I confirm its accurate, as I don't like to jump to conclusions too quickly.

Has anyone else see an MPG improvement upon switching from the factory oil to full synthetic?

I'll be installing an Airaid MIT shortly and hope to see an additional 1 MPG gain, as some have claimed in reviews.

The way it was explained to me, is that you should wait until the engine is broken in before using amsoil. Friend of mine runs it in his 08 chevy with 300 kms. He's been running it since it had 80k and has changed his oil 3 times.

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