I was under the impression that synthetic oil isn't more "slippery" than mineral oil, but that it has a higher film strength. I thought the problem with clutches was in energy-conserving additives, not in the base stock of the oil. I stand ready to be corrected, if I am mistaken.

Predictions are very difficult, especially about the future.

If you mean an additive: Whatever is still atomized, should burn off-(but then it's not aiding in coating anything anyway!), but it'll soak in around the top ring and thoroughly coat the valves. Neither of these are subject to full combustion pressure and temperature spike, and you'll find plenty of carbon left there. Eventually it'll carbon up the chamber like a bad ring, too.

If you mean the synthetic: Not much. As the piston rises, oil(synth or dino) from the oil ring coats the wall. On the downstroke, the top and second rings scrape it back off-this adds to any spritz from the rings and helps coat the skirts . The synth clings in the oil ring and to the piston skirt better, so the walls/skirts get lube sooner.

Easy test: Got a car that goes knocka-knocka on cold start?(piston slap) Change to synth...nite and day difference. 

If I could walk like that, I wouldn't need a doctor.

IMHO, it's the film strength that makes it slipperier(?) and clingier(??). My understanding is that the dino oil molecules are easier to seperate and squish out from the area under pressure, whereas the synth molecules bond more strongly together. In a clutch, it'll maintain a thicker layer between the clutch plates, leading to more slip.

I once had an engineer at Richmond Gear recommend a synth diff lube for a noisy ring and pinion set. His explanation was that the synth molecules are physically larger, and provide more of a cushion between the gear teeth, cutting down the noise.(rear whine is really the teeth contacting the tooth faces)

Was it the film, the molecular size, or something else? I'm not an oils engineer, I don't know for certain.

But it worked!

If I could walk like that, I wouldn't need a doctor.

When leaving the house (in my RV) for a winter cross country trip to, say, Arizona and back...knowing the bike will sit for at least 4 months...part of my "ritual" is to remove the spark plugs and shoot 5 or 6 squirts of MMO into each cylinder...then spin the motor two or three seconds.

Hoping this will stop any rust or other bad stuff during the cold, damp winter months, I've NEVER noticed any ill effects (like smoking upon first start-up) or anything else. Oil consumption is "normal", like 1/2 qt between the 3,000 miles oil changes.

'92 H-D dresser...42,000 miles and runs perfectly. I've done this MMO thing 5 times.

What can I say?

I've done a ton of dealer turbo work for 2 Mitsu dealers, and I've never heard of a specific turbo-use gas additive. Also, the turbo cars get the same oil as non-turbos(whatever min-spec oil the dealers could get cheapest).

That doesn't mean it's not out there being marketed, but then so is the "intake tornado"!

As far as cleaners go, most of it is just marketing. The only FI cleaner I'll use or recommend is Chevron Techron. Most all current injectors are self-cleaning, rotating-plate style, and will never need cleaning anyway...but it also cleans up the fuel system and everything else. But then, a little water is a great top-engine cleaner too.

If you've got seriously carboned up valves or chamber, GM's Top Engine Cleaner rocks.

Jimmy: As far as the lay-up use of MMO goes, anything's better than nothing in keeping cyl wall rust at bay for long layups in damp conditions. The reason you don't see any smoke, etc. at startup is because by the time it's started, it's long since drained past the rings and into the crankcase-the same reason your application is less harmful than running it through the engine and the combustion process continually. Just keep the amount small...that dry-sump crankcase doesn't take much to fill up enough to pop seals and/or blow it out the breather before the oil pump can scavenge it away.(shovels were awful for this, but evo's still do.)    

If I could walk like that, I wouldn't need a doctor.