Synthetic oil helps FE? (oh no not this topic)

[AlexK]

I'm sure this subject has been debated here a lot. I was wondering why my mileage today was so high. I got 53.2 mpg on one trip with endless red lights, 56.2 on another which I usually get about 47-50 mpg on. Then I remembered I put Mobil 1 in my car last night for the first time (first oil change). Coincidence? Probably, but interesting nontheless.

[Matt Timion]

I've yet to test this. Perhaps this can be a good test for us to do as a group. We can all use sythetics for three months and see if it makes a difference or not.

[aelfwyne]

The idea behind this basically is that thinner oils offer less resistance inside the engine. Typically non-synthetic oils are only available down to 5w20 viscocity rating, whereas synthetic is available in a 0w?? rating (not sure what the higher number is). This is because supposedly, synthetics will lubricate better with less viscocity, which allows lower viscocity (thickness). Therefore, there will be less resistance in the engine from the oil, and it will run more efficiently.

I can say from experience that an engine I've had that had 20w50 in it when I got it (the owner felt all old engines needed heavy oil regardless of condition), and I swapped it out for 10w30, and I could literally feel the engine be more responsive.

Therefore, in theory, there is something to this synthetic oil bit. However, I'm not going to try it as I've got 207,000 miles on my car's clock, and old cars don't typically take to synthetic well. They tend to leak easier with synthetic (perhaps because of its thin-ness, same basic reason some people use 20w50 in old cars). If you're already using 5w20, I'm not sure how much improvement synthetic would offer.

[onegammyleg]

Ime using fully synthetic oils now , but I cant know if I made a FE improvement because I didnt get a baseline form when it had mineral oil in it.

Where I live synthetic costs almost the same as normal oilz ., so I say , ?dont use normal oil , save the dynosaurs !!!?

[rh77]

Originally Posted by AlexK

I'm sure this subject has been debated here a lot. I was wondering why my mileage today was so high. I got 53.2 mpg on one trip with endless red lights, 56.2 on another which I usually get about 47-50 mpg on. Then I remembered I put Mobil 1 in my car last night for the first time (first oil change). Coincidence? Probably, but interesting nontheless.

I think any oil change will show an increase in FE, synthetic or dino.

I just changed the oil in the 'Teg, otherwise I'd try the test with a full-synthetic. I could do it on the next change.

RH77

[Bunger]

I've experienced the same thing as aelfwyne. I got a crx once that someone was running 20w-50 in and i switched to 5w-30 and I could feel the difference instantly. Also on my volvo, I've switched from 10W-40 to 5W-50 syth and I can notice that the turbo spools faster and I reach full boost at a lower RPM. I'm not sure how much gain there is to be had from running lighter synthetics, but I'm sure there is some.

[JanGeo]

Originally Posted by onegammyleg

Ime using fully synthetic oils now , but I cant know if I made a FE improvement because I didnt get a baseline form when it had mineral oil in it.

Where I live synthetic costs almost the same as normal oilz ., so I say , ?dont use normal oil , save the dynosaurs !!!?

Synthetics are made from petrolium too ya know unless you are talking Synlube.

[zpiloto]

Originally Posted by rh77

I think any oil change will show an increase in FE, synthetic or dino.

I just changed the oil in the 'Teg, otherwise I'd try the test with a full-synthetic. I could do it on the next change.

RH77

I agree. I think that it's just coincidence, that and the fact that your breaking the car in. That's close to a 10% change and I don't think mobil 1 will give that to ya unless you were running 80w gear lube before the change I'm running Amsoil 5w-30 changed from Castrol 10-30 and noticed no significant increase in FE but then again thats really hard to quantify with out a Dyno.

[onegammyleg]

Heres a link that I found , they say 8.2% better FE with synthetics.

http://www.smartsynthetics.com/artic...e_increase.htm

[onegammyleg]

Hi JanGeo - ?Synthetics are made from petrolium too?

Yes , true (I guess that is why they still call it oil and not lubricant) but the base oil is highly modified to get a more uniform size of oil molecules.
Then they add , , , additives that stabilise the oil and some also add friction reducing stuff.
Because the oil is constructed and not simply refined they can remove the parts of oil that cause wax buildups, so generaly this means , less varnish and other gummy oild deposits that normally build up inside the engine over a long period of time.

But yeah ,, ?oils is oils - Sol.?