Anyone ever gain 3-4mpg from synthetic?

[VadersV6]

Ive been running synthetics since i got this car, but never royal purple, which is what I religiously ran in my cobra. Regularaly went 8-10,000 miles between oil changes...engine was immaculate inside, compression was perfect after 5 years of severe abuse, got good mileage. Anyway, the shop I used to get it from, is no longer close to my work, so I quit buying it. Found out Pep Boys carries it, so I bought some and used it for this last oil change on saturday. Before the change, I used some engine flush. Idled it for 5 minutes, let it cool down, idled again for a few minutes, then shut down and drained. I also replaced my alternator again (third one) and cut off a burned section of positive battery cable and soldered in a new section. Didnt have any issues, it was just buggin me. Also replaced the fuel filter. Well I drive 70 miles a day, and always get about 16mpg. I got 18.6 once, but that was driving at 65mph and accelerating very slowly, and inflating all tires to 40psi...and a little miscalculation because of the crappy gauge Im sure. But out of hundreds of tanks of gas, I usually got 16mpg. Well, I always put in 10 gallons out of habit...makes it easier to calculate mileage. Usually at 160 miles, its time to refill. Well, Im at 170 now and have a third of a tank! This isnt a sticking gauge. I was surprised at how much quieter and smoother my engine ran after throwing the royal purple in. Ive never noticed any difference no matter what oil or treatment I would use, but this time it was totally obvious. And now my mileage has gone through the roof....assuming my car isnt just messing with me. Royal purple cant be this good! Ill keep you posted as to whether or not I hit the magical 20mpg barrier.

 

[JDSfastGN]

without filling up how can you get an accurate mileage readout? The gauges are certainly not accurate enough to judge how much is left in there. Not saying you haven't seen an increase, as you may have. Ive never used synthetic before but have heard 1 mpg gains in the past.

 

[Welby]

If you want a true reading on mpg, reset your odometer, fill the car up and drive it until you're near empty (How close to empty isn't important). Then fill up again and note the gallons you put in. Obviously, divide the number of miles you've gone by the exact number of gallons used to get your mpg. Assuming your speedo isn't way off, this will give you the most accurate measurement.

 

[VadersV6]

Yeah I know how to accurately measure gas consumption. After 50,000 miles Ive come to know my car pretty well, and when you get to empty, and the odometer says 160 miles, and you put 10 gallons in, and you repeat this cycle a thousand times, and the gauge never goes higher or lower, and the numbers are always the same, its safe to say its getting 16mpg. When I used to fill the tank and do the standard procedure to measure gas consumption, I always ended up with the same numbers. I was thinking at lunchtime, I was going to take my car out and the gas needle would plummet because its just a sticky gas gauge, but no, it didnt drop. I still have alot of gas in the tank. Looks like Im going to hit 20mpg finally! No TC lockup either, and a ****ty tiny exhaust, stock everything and a smaller than stock cat. Lockup and a free flowing exhaust would probably net me another 4. This is crazy. The only thing I did was throw in royal purple.

 

[NEWCHAPTER]

what weight are you using on the royal purple, i use it in all my other vehicles but have not converted the grand national over yet....

 

[VadersV6]

They were out of 10w-30 so I got the 10w-40. I ran some castrol dino oil the last time around, and within a few hundred miles, the bearings in my turbo are wiped out..gone. And this is even with adding valvoline SYN treatment..one of the best out there. Ive usually ran 20W-50 cause I have a noisy engine, but this time I went thinner and it actually got way quieter. Funny thing about this added mileage is that I dont even have the chip set to lean cruise.

 

[NEWCHAPTER]

I was thinking about going with the 10w40 to be on the safe side... thanks

 

[VadersV6]

My work is 35 miles from home. Monday morning, the tank was pretty much on empty and I put 10 gallons in. I just now had to refill the tank, and I actually was halfway to work, and could have actually gotten to work on what gas I had left, but decided to fill up halfway there. So it was 230 miles on the odometer when I refilled, and I wasnt completely at empty. So, so far it seems to be between 21-23mpg. Ill know more by the next tank. Ive been wishing for 2 years that i could get 20mpg someday, but gave up. no matter what I did or how I would drive, I never got more than 16-17, except for that 1 time where I got 18. I cant see how changing the fuel filter could improve mileage. I dont see how royal purple could do this on its own. Maybe my cylinder walls were glazed and I had alot of leakdown, then doing the engine flush de-glazed it, and maybe the friction modifiers in RP got my ring seal back...I dont know...thats the only thing that could explain the huge improvement from just an oil change. I even jumped on it and got into boost a few times with this tank, as well as the 4 mile hill I climb every day both ways at 3psi the whole way up.

 

[xcessiv6]

I use 10-40 racing Royal purple for 10 years every fluid I have is Royal Purple
and I get 22mpg on the highway at 75- 80 with a 3500 non lockup convertor.
I would not use any other product, its proven to be the best product on the market and it will not mix with oil, put mineral water and royal purple in a glass container. watch the oil come to the top, shake it up and it seperates.
It is a unique product to say the least.:biggrin:

 

[VadersV6]

The condition of my cobra motor was so good that maybe I never really saw any difference between oils, but I do recall how clean my emissions test came back after 5 years of running hard. It burned cleaner than a new honda. The smog guys were kind of confused cause they never saw numbers like that out of a V-8 car. It did make really good power for what it had and the engine was super clean inside. Like I mentioned in another post, some of the RP drained on my tie rod joint when putting the new filter on, and when I wiped the tie rod with a rag, the sludge literally melted off with a wipe and it looked like a new part. Cleaned it better than engine degreaser! I tried mobil 1 in that car once, and it draine dout looking like nasty tar after just 4000 miles. Mobil is a huge company so they have massive marketing money, so I think alot of their claims are hype...that and all those "independent" tests are really paid for by them. Over at the oildrop.server101.com, where they do all the virgin and used oil analysis, mobil1 is one of the worst oils out there based on true independent testing by them. My personaly experience seems to confirm. Ive tried just about every synthetic out there, and none of them really impressed me, although oils like Quaker State "Q" oils have a really good additive package. Redline is comparable to RP..ive seen how that oil performs and its really good stuff. Valvoline SYN oils are good too. But no oil ever did anything this dramatic for me. I used to use mobil 1 synthetic grease on my punch and dies at work, and always had scuffing problems with the guide rods. I tried 1 drop of RP synchromax on each guide, and after a week of running, there wasnt 1 single scratch.

 

[Ormand]

The friction in the engine is just not going to change enough to give a big increase in gas mileage. Many, many tests have been run to compare friction with different lubricants, and the numbers just are NOT big enough to give the changes you mention. Mostly, the vendors compare HP, since in past years that has been a bigger seller than economy (well, most past years) and usually they cheat a little by using a lower viscosity. But I've never seen a test that showed the kind of gain you seem to have.

 

[VadersV6]

Theres a guy with a mercedes that supposedly gained 8mpg, but I dont know about all that, which is why I said maybe I had cylinder wall glazing, and the flush maybe helped reseat the rings.

 

[Nasty Wendy]

I've been sneaking up to his car at night and putting gas in it. Hehehe.

 

[Gary Wells]

Brent:
As others have said, regardless of how intimate your knowledge is of your car, it's operating characteristics or anything else, the only way to check mileage is to fill the tank, same pump, same direction to avoid any slope issues, same amount of overflow clicks. Anything else is just a rough approximation of mileage.

 

[VadersV6]

Not when youve been doing it 3 times a week for 2 1/2 years, and always know the mileage. I know the gauge moves with acceleration, deceleration, slopes, hills, etc, but I pretty much know where the gas level really is at all times.

 

[Gary Wells]

It's not the accuracy of your math or eyeballs that I doubt, it's the accuracy of movement and / or discrimination of the guage needle that I doubt.

 

[VadersV6]

Thats totally correct when you're dealing with 1 or 2 tanks to get a measurement, but getting an average behavior of the needle and gas consumption out of multiple hundreds of tanks of gas is what Ive done.