Using heavier viscosity oil to increase fuel economy?

[Sludgy]

If your piston rings are worn enough to lower the compression ratio, thick oil could boost FE. But if the enine has good compression, thick oil has to hurt FE.

[wsm41bn]

I run the delo 400 15w40 and my compression ratio is about 10.5 to 1 in the new rebuild

[Mentalic]

Originally Posted by JanGeo

Mineral oil I think breaks down also. Synlube doesn't break down and produce sludge because it doesn't have the sulfur compounds in it like convential oils and it also relies on the solids Moly and PTFE to lubricate and the liquid part to carry the solids through the engine. It also seals the cylinder to ring area to reduce blowby and has graphite to absorb moisture when the lube and engine is cool and then releases the moisture from the graphite when the engine gets hot enough and vents the steam back through the PCV valve. The better filter they provide has does a much better job of filtering the oil along with Neo Magnets to remove trace metal particles.

Check out the postings by budman on his 50k run with Synlube.. He went from overboard advocate to "what was I thinking"....

http://theoildrop.server101.com/foru...fpart=all&vc=1

[n0rt0npr0]

Extremely interesting. Thank you Mentalic for this link.

Originally Posted by Mentalic

Check out the postings by budman on his 50k run with Synlube.. He went from overboard advocate to "what was I thinking"....

http://theoildrop.server101.com/foru...fpart=all&vc=1

[SL8Brick]

The entire motor oil industry is up to thier elbows in hype...at SynLube, they appear to be up to thier necks.
Sorry JanGeo, but from where I'm standing trying SynLube is akin to joining a cult...you can't really join without becoming a believer.

[mustngr]

Consider the advantages of heavier oil in a motor with hydraulic lifters.

Any chance the upside could outweigh the downside, given reasonable windage control?

[ELF]

One thing to consider is the testing done by Lou. Mostly at a steady speed 50 mph,with a fully warmed up vehicle.
I have no doubt you can get the same results with the same kind of testing, however most of us have to start cold, and there is no question that thinner oils will give you better FE during warmup, esp. in winter.
But I think this is a individual thing, your results will vary depending on the condition of your engine and the number of cold starts per tank.

[VetteOwner]

around here our winters are usualyl around 15*F(avg) and it oh so nicely works out that late october/nov that i need to have an oil change so i usually switch over to 5w-30 in my truck and in the late spring to 10w30. my truck uses NO oil between changes so why mess with that works? it was designed to run on dino oil so its gonna be ran on dino oil...

[VetteOwner]

Originally Posted by Mentalic

Check out the postings by budman on his 50k run with Synlube.. He went from overboard advocate to "what was I thinking"....

http://theoildrop.server101.com/foru...fpart=all&vc=1

haha. very interesting i might add.

[itjstagame]

Originally Posted by Sludgy

If your piston rings are worn enough to lower the compression ratio, thick oil could boost FE. But if the enine has good compression, thick oil has to hurt FE.

This was my thought exactly, this should be very easy to check though. Check compression before and after switching to a thicker oil.

In fact try a couple, something like 5W30 dino, 5W30 syn, 10W40, 20W50 and then back to 5W30. Check compression with each oil after 100-500-1000 miles or something.

I 'seems' to me that thicker oil would help with blowby and restore compression, but no oil pressure can stand up to an ignition event, so I'm not so sure.

It just needs to be tested really.