Thread: More MPG with synthetic? What do you think?

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now you hear here an there on TV and word of mouth people talking about MPG nowadays with todays gas prices. i watched some TV show on the speed channel about gaining MPG HP&TQ by changing to synthetics. they used a 95-96 chev 4x4 truck and changed all the fluids over to royal purple synthetic (engine,tranny,transfercase, diffs.) and they gained like 3hp and 2lbs of torque and some MPG. i've been thinking about it and trying it on my 97 S15 4dr GMC Jimmy 4X4 with the 4.3 vortec. i average around 15 - 17 MPG the highest i've ever got was 18-20 babying it and driving like grandma but otherwise i have a little of the lead foot syndrom but its income tax season and i'm going to give her a tune up and really go through it change the filters over to K&N change all the fluids over to synthetic and start running premium and see if you really get your bang for your buck and if its not worth it this will be the one time and only time i do this.

have any of you tried this or hear of people doing it ????

Oh yeah I've heard of it but the numbers have not been reliable and what I have seen (like above) are just not significant. What you need to do is change everything over, get some good mileage numbers, and then do a complete cost analysis based on all your results. Then get back with us on all the results.

kitz, (head master of the 'do as I say, not as I do' club for men)

Originally Posted by kitz

Oh yeah I've heard of it but the numbers have not been reliable and what I have seen (like above) are just not significant. What you need to do is change everything over, get some good mileage numbers, and then do a complete cost analysis based on all your results. Then get back with us on all the results.

kitz, (head master of the 'do as I say, not as I do' club for men)

well thats why i'm doing it to test it like i said it'll be this one time and one time only unless you really do save then i will stick with but i'll post the overall cost but i want to see if i can get above 20 mpg with my jimmy
i don't know how big the tank is i think 15 gal. but every 200 miles you have to fill it up

Well I do believe it will lower internal losses due to rubbing friction, especially in the elastohydrodynamic friction arena. So in theory what Denny has actually seen should be true.

Kitz

Originally Posted by DennyW

Synthetic oils will give you a slight increase. What I have found over the years is, Keep the oil changes regular, synthetic or not. (even just a good quality oil, so it is not gas contaminated, and 3,000 or less on the oil). Tune up when ever you see a decrease in mpg, including wires, cap and rotor, if so equipped. Keep all filters clean, and change on a regular bases. Tire pressure, and alignments, are also a factor.Your going to get different ideas about this, but this is basic things to do.

i keep up on the tire pressure the're supose to be at 35psi for the vehicle but the tire says 50psi so i keep them at 40psi and change the fram air filter when needed but was thinking of a less restrictive air filter like a fram airhog or K&N or something. plus i change my oil every 3000 miles and i switched from valvoline to mobil 1

also i noticed on my truck it has a ribbed rubber hose from the filter box to the intake was thinking of making a smooth custom one for less restriction.

Originally Posted by DennyW

Yes, that type air filter will help on the breathing. They are intended to draw more, for performance, rather than mileage. At a certain rpm range, the clean stock type filter will work fine, and allow free breathing. If you are running a carb, tune the mixture settings with the air filter installed. That way, you are tunning it the correct way for mileage.

its a fuel injected 4.3 vortec

other friends of mine have bored holes in the bottom of their air box to increase air flow due to air flow sensors where you can't run a cold air intake. not saying i'm going to but its what i've came across

In a prior lifes endeavor I was involved in all manner of lubrication application. Whenever we did fuel economy measures, for whatever product tested, we found that doing fleet testing, e.g. taxi or police fleets was more meaningful. We also did the test blind, i.e. so that the driver didn't know whether he had the "old" stuff, or the "new" stuff. We did this because we found individual references were generally unreliable because people would often unconsciously change their driving habits/patterns/style that would distort the data. We would control the variables such as Denny mentioned so they wouldn't be a modifier of the data. Usually the more vehicles involved in similar operating circumstances, and the more time (to "even out" seasonal effects), the more reliable our results.

All that being said, synthetic oils offered a very small improvement by themselves. Driving style had as much or more impact.

well when i change it over i'm going to use synthetic dextron 2 or 3 whatever it is in the tranny and transfercase$$$ synthetic 75-140w in the diffs$$$$ and moble 1 10w30 synthetic in the motor and switch to K&N filters$$$$ and still run my tire pressure at 40psi

Originally Posted by DennyW

If you by pass the air flow sensor, you are cheating yourself. What you need to do is get a bigger flow sensor, and change the chip. But now, we are getting into performance, over just good gas mileage performance. The reason I say that, is when you up the performance, you have a tendency to use the extra power there. Therefore, you lose the atemp for good mileage, and have switched to the performance mood. Refining what you have, and tuning what is there, is like blue printing. You get it to the best you can, highly tuned, and that will be your best spot. Dollar wise also.

nononono they customized the stock airbox by boreing holes in the bottom to increase air flow - for example you take the top off the air box pull out the filter and look inside the bottom looks like swiss cheese.

the reason i bring that up is my friend has a 93 ford probe GT with a 2.2 turbo and the inlet for the airbox is 1 1/2" and the hose going from the airbox to the intake was 3" and he had the air flow sensor and wasn't able to install a cold air intake so he customized his airbox by boring holes in the bottom to increase air flow.

now me i never looked at the inlet to my airbox i just changed the filter if needed

usually the inlet for the air box is tucked inside the inner fender an i supose he couldn't if the hole is only that size

Originally Posted by DennyW

Be careful, you don't want to use that unless it says you can. Seals, and parts act differently to some oils.

true but it has no leaks now so it might later but it might not either