MPG GAIN with conventional oil vs synthetic!

[D Bone]

I posted the following on the mazda3forums. I would like some opinions from you guys as well.

( http://www.mazda3forums.com/index.php?topic=73195.0 )



OK guys, check this out. First some history. I have a 2006 GT ATX HB with 17,780 miles, stock suspension, 17"x7"x48mm lite weight wheels wrapped in 205/50/17 Kumho SPT's. I have been using Torco SR-1 5w-20 synthetic oil since the 1,100 mile mark.

I reset my on board trip computer the day I changed to the Torco, and I have still not touched it since. It reads 28.4mpg, and has done so (give or take a tenth) for 16,000 miles. I use the old fashioned (but correct) "fill the gas tank every time, and reset the trip odometer every time and then divide the total miles traveled by the gallons filled" method and here's the kicker. The best I have ever done while using the Torco SR-1 5w-20 was 29.6mpg. I have NEVER in over 17,300 miles of driving hit the 30mpg mark.................NEVER.

I recently switched to Valvoline Premium Conventional 5w-20 oil. I ran a quick 50 mile run with the Valvoline, and then I dumped it (and the filter) out and I refilled with 4.5 quarts of more Valvoline 5w-20. That way I had a quick "flush", so that I knew any improvement or lack there of, would be from 100% Valvoline conventional oil. I then filled up with Chevron 87 octane, reset the trip odometer, checked my tires' psi and off I went.

I have had the Valvoline in the motor for only two fill ups, but get this, I averaged over 30 mpg on both tanks!! #@$%!? In over 17k with high dollar Torco I never hit 30mpg once, and on my first two tanks with good ole inferior dino oil, I hit over 30mpg both times (30.2 & 30.1).

I am almost OC about my cars maintenance. I check my tires psi bi-monthly (every month) and my psi is always 1-1.5 psi from where I set it two weeks before. I change my air filter every 10k whether it needs it or not (high desert). I do a drain and refill of my ATX fluid at every OCI (Valvoline Mercon V).

I drive a very boring, very predictable commute (Hwy 14) and I only have a total of 5 stop lights from my door to my office. 70% freeway, 30% city @ 65-70mph is my normal driving habits. I did NOT drive any different for the last 700 miles, compared to my first 17k miles.

So, I would love to hear any body's opinion on why the improvement with $1 conventional oil vs $8 100% TRUE synthetic (Grp IV base oil) oil. I tried to give as much info as possible so you could come to your own conclusions.



Darryl

 

[B00SS]

Did you add any air to the tires when you checked them?

 

[Mystic]

Well, I think the Torco may be a little thicker. Torco was a noted racing oil like Redline and the Torco may trend to be a little thicker.

There are a lot of other things that can affect fuel mileage like weather conditions and wind and crosswinds.

Personally myself I am very undecided about the value of synthetic oil except in extreme weather conditions, for vehicles like the Corvette that require synthetic oil, for racing, for towing, for long oil change periods, and extreme cold in the wintertime. Right now I am using Pennzoil Platinum and I like it but perhaps Pennzoil conventional would be just as good in the warmer months of the year. But I do like using synthetic oil in the wintertime because where I live (in Colorado) it can get cold in the wintertime.

I never actually used Torco oil but I did use their special oil additive (I can't remember what it was called).

Whenever I go shopping for motor oil (I buy at Wal-Mart) I always check out a few brands and I keep asking myself 'Does it really make any difference using conventional or synthetic oil except in very cold weather?' I see a 5 quart container of Valvoline or a 5 quart container of Motorcraft semi-synthetic (cheaper than the Valvoline conventional!) all for nice, low prices. Now the Pennzoil Platinum was not very greatly more. But again, does it really make a difference?

 

[Bryanccfshr]

I am not surprised. But I will offer that temperatures are getting warmer too and fuel formulations are going through seasonal changes.
I do not doubt that conventional oil can out perform a synthetic in this regard. Reality and perception are distinguishably different.

 

[Bryanccfshr]

I agree with your assessment of when Synthetics are of a benefit. For me in my warm climate at home they are not.
For my climate at work in the arctic where it was -36° this week I know my Ford Superduty work truck would not have started (or probably shouldn't have been started)if it didn't have Delo 0w30 in the crankcase. There is a time and place for synthetics but most the time conventional formulations will perform as well and sometimes better .

 

[dailydriver]

.5 & .6 mpg are hardly statistical differences. Kind of like when people claim to have gotten 1 whp more on a chassis dyno from changing spark plug brands.

Besides, fuel mileage is not the sole/primary reason to use a good grp. 4 (or better) synthetic over cheap (but good) dino.

 

[D Bone]

I did not add any more air to the tires (35psi checked with my trusty Craftsman digital gauge).

I could take the "weather conditions, different fuel formulations, cross winds, temperature" arguments if I had at least once hit the 30mpg mark in over 17k miles worth of driving. I have seen all of the above for over 17k, so I tend to think it's in the oil some how.

Torco SR-1 is actually fairly thin at operating temp (7.4 cst I think) but it has a high HTHS rating (for a 20 weight) of 2.9. I wonder if that has something to do with it?



Darryl

 

[dailydriver]

Quote:

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Well, I think the Torco may be a little thicker. Torco was a noted racing oil like Redline and the Torco may trend to be a little thicker.

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The Torco SR-1 is their "regular use" group 4 street oil, vs. the SR-5, which is their group 4/5/high moly content racing oil. I've never checked the specs on the SR-1, so yes, it might be on the "thick" end of the API viscosity range (in cSt).

 

[Bryanccfshr]

Quote:

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Torco SR-1 is actually fairly thin at operating temp (7.4 cst I think) but it has a high HTHS rating (for a 20 weight) of 2.9. I wonder if that has something to do with it?

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Yes, HTHS numbers appear to correlate with fuel mileage. Rather than the sloppy SAE scale, I think HTHS is a better indicator of how thick or thin an oil is.

 

[oilyriser]

The Torco has a HTHS viscosity of 2.9, vs, ~2.6 for the valvoline, so yes it could give lower fuel economy. To be sure, try switching back and forth between the two oils, and see if your MPG goes up and down in synch with oil changes.

 

[flatlandtacoma]

The accuracy of a single tank using your method is no better than 5 to 10%. 30.2 is statistcally equal to 29.6.

 

[D Bone]

It was 2 tanks, not one.

30mpg with Torco in over 17k...........Never
30mpg with dino in 700 miles...........Twice

 

[nuskool]

Or try a different brand of synthetic next time like M1 or Amsoil. I don't know the operating visc numbers, but I think you get my point.

 

[flatlandtacoma]

Ok.
30.2 is statistcally equal to 29.6. Believe it or not, 30.1 is statistcally equal to 29.6 as well. And yes, two individual tanks.

 

[D Bone]

I'll leave the math to you guys that know it, but I'll relate it this way. (the only way I know)

Let's say my daughter has been going to the same pitching coach (girls fastpitch) for almost all of her softball life. She has never hit the magical 50mph mark with that coach, but has been close at 48mph. Then she switches coaches, and after only a handful of lessons, she suddenly throws 51mph in each of her first two games.

Same ball, same distance, same pitcher......Different coach. I know what I'm going to say put her over 50mph, and it ain't the weather!

What's that have to do with oil? Nothing, but it puts the "statistically equal" theory in a perspective that I can relate to.

 

[OriginHacker21]

D Bone - I think it is the oil.

In my own tests (I drive 220 miles a day and I have a scanguage) - I do experience a 1-2MPG increase between using GC 0w30 and Amsoil 5w30 (big difference in the viscosity). The increase being with Amsoil (it being thinner - especially on startup).

Especially on smaller engines (mine being 2.2L ecotec) - a lighter oil should produce some visible MPG increase. I've also noticed that the smaller engines seem to idle softer with lighter oil and rev a lot more freely.

As for conventional vs synthetic ... I'm starting to wonder what the differences is for the normal passenger vehicle (non-performance/turbo) - if there is any difference.

Glad to see you getting better MPG

- thats always a nice thing.

 

[Mystic]

I am with you on that OriginHacker21. I am wondering myself if it is really worthwhile using a synthetic oil in the warmer months of the year. Especially with a lot of synthetics going to Group III is there really that big of a difference? A quality conventional motor oil such as Chevron, Halvoline, Valvoline, Pennzoil, etc., should be perfectly fine unless a person tries to drive 15,000 miles on one oil change. Of course there are cars that require synthetic like the Corvette and it depends on conditions-extreme cold, extreme heat, towing, racing, turbocharging and other things make a synthetic more necessary. For me personally I could probably use conventional oil throughout the year but in the wintertime I would still prefer synthetic.

 

[unDummy]

The weather here is getting warmer everyday. I got a solid 1 mpg with my last fillup. Get this, I didn't even need to change the oil. Cold starts at 50 degrees are so much better then 10 degrees. Anyone want to guess what 40 degree temperature difference does to tire pressure?

The Torco 5w20 SR1 is one of the thinner 20wts. Look at their spec sheet. Could it be too thin? compression loss?

The Synpower 5w20 is even thicker than the cheaper regular Valvoline. Give it a run, maybe you'll have even better MPG confusing your dino vs synth comparison.

 

[conradcliff]

Not to sound anal but the real way to test your gas milage is to fill up your tank, reset the odometer, run till empty, fill up again and divide how many gallons you pumped the SECOND time into how many miles you drove acording to the odometer. Maybe that's how you do it already and I just misunderstood. If you were to just run it to empty and divide however many miles it took to get there with however many gallons it took for that tank it would never be right.

 

[D Bone]

Quote:

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Not to sound anal but the real way to test your gas milage is to fill up your tank, reset the odometer, run till empty, fill up again and divide how many gallons you pumped the SECOND time into how many miles you drove acording to the odometer. Maybe that's how you do it already and I just misunderstood. If you were to just run it to empty and divide however many miles it took to get there with however many gallons it took for that tank it would never be right.

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That's how I do it.